Grinding technology development trend

Grinding technology development trend

  Grinding machining is important processing technology in mechanical manufacturing.cnc  grinding With precision mechanical products, the requirement of increasing the reliability and service life, high hardness, high strength, high wear resistance, high functional new materials application increased, for grinding processing and put forward many new problems, such as material of grinding machining and surface integrity, super precision grinding and high efficiency grinding and grinding automation, etc. Problems to be solved.At present, the grinding technology is moving toward using super hard abrasives, development of precision and ultra precision grinding, high speed, high efficiency grinding technology and the development of high precision, high stiffness of the grinding machine automation direction.

  One.   In-depth development of grinding theory and technology research

   Grinding theory research is the basis for the development of grinding technology, cnc  grinding  the grinding technology and the development of practice and research provides the opportunity for grinding theory, requirement and new topic, in recent ten years, professionals engaged in the work of grinding, grinding technology and phenomenon many factors for a lot of in-depth research and achieved fruitful results. 

 Two.  Unit grinding machine high speed, high precision components manufacturing technology

   High precision grinding machine spindle unit, feeding unit, bearing unit and auxiliary unit is the key parts and components. Spindle unit including spindle power, shaft, bearing, and frame sections, she affects the precision of the machining system, stability and application scope, its dynamic performance and stability of high performance precision ultra-precision grinding, play a key role. Feed unit including the position detection unit, Demand of feed units, therefore, flexible operation, high resolution, high positioning accuracy, not crawl and large movement range, both to have larger acceleration, and large enough thrust, high stiffness, cnc  grinding quick dynamic response, high positioning accuracy. Machine tools supporting technology mainly refers to the supporting member of design and manufacturing technology. Auxiliary unit technology including fast clamping workpiece, high efficiency grinding fluid filtration system, machine safety devices, chip removal and the workpiece cleaning technology, spindle and grinding wheel dynamic balance technology, etc.

Operational safety and environmental protection

Operational safety and environmental protection

 Along with advance in technology and human culture development, the people are more and more high to the working condition improvement and the environmental protection request.Cnc machining  The electric spark forming processing as a result of its own characteristic, can have the driving fluid splash, the smog, the noise, the electromagnetic radiation, the noxious gas inevitably in the processing process and so on the safety factor and the pollution, is noticeable to the operator personal safety and the environment harm. Therefore, for the guarantee electrical finishing industry sustainable development, must act according to “the green manufacture principle”, the realization resources most effective use and the reject threshold produces with the emissions. Should take following measure specifically:

  ①Seal engine bed work area. This is advantageous to the improvement driving fluid, the smog, Cnc machining the electromagnetic radiation and so on to the human body, the engine bed, the working conditions pollution, is advantageous in the operating process prevented receives an electric shock the danger as well as to the noxious gas centralized processing emissions;

 ②Vicarious technical utilization. For example, the environmental pollution which creates for the reduced use driving fluid, may in the guarantee processing efficiency, the processing precision, the processing cost as well as under the processing process stable premise, selects the pollution small driving fluid as far as possible, simultaneously should study, the development vigorously does not use the driving fluid the formed processing technology;

 ③Reject post-processing. The waste liquid, the waste gas produces which after the processing in must pass through processing to be able to discharge. Needs to point out specially, has pollutant reasonable processing to the processing process, not only is advantageous to the enhancement work security, the reduction environmental pollution, but also is advantageous in improves operator's working conditions, causes when the operator work the mood is happy, this regarding

 enhances the electrical finishing industry the social image and the market competitive power also is extremely beneficial.

    The electric spark forming processing technology holds the important status in the manufacturing industry domain, is realizes difficultly to process the material, the complex components precise processing effective method. The researcher should profit from other processing technological development the success experience, enhances strong points and avoid weaknesses, uses the modern science and technology development fully the related achievement, studies the electric spark in the deep person to discharge the mechanism in the foundation, the instruction electric spark forming processing craft theory and the control theory research, improves the engine bed structure and the design method, establishes based on the PC machine open numerical control system, the realization intelligence control technology and the electric spark forming processing technology organic synthesis, Cnc machining simultaneously takes the operational safety and the environmental protection highly, comprehensively impels an electric spark forming processing technology quicker development.

   

Electric spark forming processing craft trend of development

Electric spark forming processing craft trend of development

  Through processes the mechanism to the electric spark forming the research, further promulgates the electric discharge process the inherent laws, and take this as the instruction, impels the electric spark forming processing craft to the high efficiency, Cnc machining the high accuracy, the low loss direction to develop, meanwhile should pay attention to the micro refinement processing aspect the development.

  (1) processing process highly effective

     Not only the processing process highly effective manifests in through the improvement electric spark machining servosystem, the control system, the driving fluid system, the engine bed structure and so on, reduces the above factor to the electric spark forming processing efficiency influence, enhances, the precision work efficiency thickly in under the guarantee processing precision premise, meanwhile should reduce the non-cutting time as far as possible (for example programming time, electrode and work piece localization time, maintenance time and so on), this needs to strengthen the engine bed the automatic programming function, expands the engine bed online backstage programming ability, the improvement and the development suitable electrode and the work piece positioning device.  In the engine bed maintenance aspect, should strengthen the engine bed the multimedia functions and the online help function, regarding the common breakdown, the operator may act according to the computer prompt realization trouble shooting directly,Cnc machining  simultaneously this is also advantageous in strengthens the engine bed the feasibility and operator's operation skill.

  processing process precision  Through uses a series of advanced processing technology and the technique, at present the electric spark forming processing precision had the comprehensive enhancement, some has been possible to achieve the mirror surface processing level. But looked from the overall that, the vanguard technology insufficiently is also mature in the actual production application and widespread, therefore has the necessity comprehensive impetus to have the vanguard technology further consummation and to develop to the industrial production direction. In the guarantee processing speed, under the processing cost premise, makes the electric spark forming processing the precision level further to enhance, causes the electric spark forming to process into some major parts, the essential components finally processing way. At the same time, to processes the precision the weight not to be able to limit merely to the work piece size precision and the surface roughness, but also should include the profile the GDOP, deterioration level thickness as well as the microscopic crack, the oxidation, the corrosion and so on.

 (3) processing process micro refinement  An electric spark forming processing important application domain is the narrow trough, the deep cavity, the tiny components processing, therefore the processing process micro refinement will be the next important development direction. The electric spark processes the mechanism and the conventional electric spark forming processing tiny is same, but has own craft characteristic: Each pulse electric discharge energy is very small, driving fluid circulation difficulty, stable electric discharge gap scope small and so on. Based on these craft characteristic, the tiny electric spark forming processing processing equipment, the driving fluid circulatory system, the electrode preparation and so on inevitably and the conventional electric spark forming processing has the very big difference. Therefore, needs key to study the non-mechanical action。and the disturbance to the processing process influence and so on, further enhances the processing efficiency, the processing precision and the processing process stability.

  

(4) application scope expansion 

At present, not only the electric spark forming processing may process each kind of electric conduction metal material and the complex die space, but also can realize to the semiconducting material, the non-conducting material processing, and has obtained the good processing effect. At the same time, the electrode material type also unceasingly increases. This aspect main trend of development is: Further studies the semiconducting material, the non-conducting material electric spark machining mechanism, promotes its processing efficiency, the processing precision, the processing process stable enhancement, the expansion to be possible to process the material the scope; Besides the processing complex die space,Cnc machining  further realizes to the three dimensional die space, the complex profile processing; Development performance superior new electrode material.

Electric spark forming processing equipment structure improvement

Electric spark forming processing equipment structure improvement

  The model modern machining engine bed development experience, the electric spark forming processing equipment develops to the numerical control direction is a irreversible tendency. On the one hand should by the high accuracy, the high velocity, change into the pursue goal automatically, seizes the market by the technical superiority;precision parts  On the other hand should consider fully the equipment the performance price compared to, through to the engine bed function reasonable localization, makes the structure improvement and the modular design, uses the open numerical control system, enhances rationality which the engine bed designs, provides by the lowest price and the enough function to the user may satisfy each kind of electric spark forming processing engine bed which the different processing needs.

 Modern machining technological development impact, before suits uses the electric spark machining a part of processing domain to substitute gradually for the machining way. But, the modern science and technology development proposed to the components manufacture precision a higher request, each kind of high performance material application is day by day widespread, simultaneously, some components structure tends to the complication, precision parts the microminiaturization, thinly, this all causes the machining technology to be restricted in certain processing domain application, but these are exactly the electric spark forming processing technical superiority, also is it has the existing space and the development potential reality basis.

  For the comprehensive impetus electric spark forming processing equipment technology advancement, while uses the advanced control system, the engine bed structure design also needs further to consummate, its main development direction displays in following two aspects:

 (1) straight line servosystem application  The electric spark forming processing equipment uses the straight line electrical machinery servosystem to be possible to cause the workability to obtain the distinct improvement, the concrete manifestation is:  May realize the axis direct translation, omits a guide screw nut transmission link, thus guarantee axis high speed movement;  Uses the straight line electrical machinery and the slide integration structure, may eliminate between the slide and the electrical machinery because of has the machinery lag in response phenomenon which the middle link causes, enhances the system the sensitivity, reduces the dynamic response time, the guarantee processing process stability;  The straight line electrical machinery servosystem mode of motion had decided its position examination link must use the straight line position feedback part, the realization not middle link direct position examination, thus constitutes an entire closed-loop system, the guarantee processing process high accuracy and the precision retentivity. At present, the straight line servosystem application in deep narrow, the small die space processing and a mould pressing components mold multi-cavity processing aspect has the obvious technical superiority. But, these technical superiority must realize truly, except must unify the electric spark forming processing electric discharge process characteristic, outside the solution straight line servosystem itself technical difficult problem, but also must solve a series of and the straight line servosystem necessary related technology, like translation system dynamic equilibrium, work table structure improvement and so on.

 (2) engine bed mode of motion improvement

   Breaks through the existing electric spark forming processing engine bed mode of motion the limitation, is displays its technical superiority, impels its industrial development another important way. The model modern machining technology development experience, may direct the human circular motion in the engine bed main processing forming movement foundation, specially uses the multiple spindle rotary system and many kinds of translation coordinating group synthesizes many kinds of compound motion way, adapts the different type work piece processing request, the expanded electric spark forming processing processing scope, enhances it in the precise processing aspect comparison superiority and the technical benefit. At present, many electric spark forming processing engine bed has made some improvements in the mode of motion, if Swiss Arch Company produces AGIF the MONDO STAR20(50) engine bed has the EQUIMODE function, can realize the spatial any direction hemisphere stable motion, this kind of stable motion function has the very high practical value in the actual processing. But the present electric spark forming processing engine bed additionally builds the mode of motion is also unitary, the application scope is limited. The electric spark forming processing must in aspects and so on processing precision, processing efficiency, processing scope obtain the significant breakthrough, an important development direction is to the engine bed forming mode of motion innovation and the diversification. Recently, Japan University of Tokyo -odd component doctor, increased Ze prosperous long Professor and so on to propose loss concepts and so on electrode, namely through to processed the way the reasonable plan, might cause the electrode to lose is at and so on the loss conditions, thus caused the compensation which the electrode lost to become extremely simple.

 This concept statement has provided the essential theory basis for the electric spark forming processing mode of motion improvement. Certainly, produces from this the engine bed structural change and the correlation technology theory research also must further the deep person and the consummation, even has the possibility to develop one kind of brand-new processing theory.

 In addition, precision parts the engine bed overall construction design must consider fully the environmental protection as well as a human machine coordination, with the aid of the advanced design method and the method (for example CAD, the finite element analysis and so on) carry on the comprehensive optimized design to the engine bed structure, enhances the engine bed structure fully the sophistication and the rationality.

Electric spark forming processing technology trend of development

Electric spark forming processing technology trend of development

  The advanced technique of manufacture fast development and the manufacturing industry market competition aggravating proposed to the electric spark forming processing technology a higher request,cnc milling machine  simultaneously also for the electric spark forming processing technology processing theory research and the craft development, the equipment renewed has provided the new power. The next electric spark forming processing processing object will be supposed mainly to face the tradition machining not not easily to realize difficultly to process processings and so on material, complex profile, in which fine processing, the precise processing, the narrow dadoing, the deep cavity processing and so on becomes the development priorities. At the same time, but also should pay attention with other special processing technology or the tradition machining technology compound application, displays each processing method difficultly to process in the material processing fully the superiority, obtains the union increment effect. Is opposite says in the machining technology, the electric spark forming processing technology was still a young technology, therefore in the next development, will be supposed to profit from the experience and the achievement which in the machining technological development process will obtain, will process own technical characteristic according to the electric spark forming, will select the suitable processing theory, the control principle and the technique, and will have in the achievement foundation in oneself to consummate, the innovation unceasingly. The electric spark forming processing engine bed the tendency which develops to the numerical control direction already irreversible, but should pay attention cannot pursue blindly “large and complete”. should take the market as the guidance, cnc milling machine the establishment has the open numerical control system. Overall, the electric spark forming processing technology next trend of development should be the high efficiency, the high accuracy, the low loss, the micro refinement, the automation, the security, the environmental protection and so on

 electric spark forming processing theory trend of development

  In recent years, the electric spark forming processing basic theory research not yet made the substantive progress, although some scholars to the processing process electric discharge trace, the material eclipse eliminated the principle and so on to propose some new views, but obtained the significant breakthrough by no means in the electric spark machining mechanism research aspect. The more active research area mainly concentrates in the processing craft theory and the control theory aspect.

  In the processing craft fundamental research aspect, how does the research   8  hot spot mainly is enhance the electric spark forming processing the surface quality and the processing speed, reduces the loss, the development electric spark machining scope, as well as exploration complex, tiny structure processing method and so on. Will apply through the research results in the production practice, will comprehensively enhance the electric spark forming processing workability. In the control fundamental research aspect, the intelligent control always is the research key. The domestic and foreign production new electric spark forming processing engine bed mostly has used the intelligent control technology, this technical application makes the engine bed operation to be easier, requests to the operator lowly. At the same time, the intelligence control system has from the learning capability, but the online automatic monitor, the adjustment processing process, realizes the processing process optimized control.

 Although the electric spark forming processing fundamental research in aspects and so on basic theory, processing craft theory, control theory all has certain development and the enhancement, but the processing craft theory, the control theory need to obtain the further full scale development, must have the breakthrough in the entire electric discharge process mechanism research. Therefore, the electric spark forming processing fundamental research trend of development will be further is discussing the processing craft theory and the control theory, cnc milling machine enhances the electric spark forming processing workability and the processing scope, obtains the better control effect at the same time, key research electric discharge process mechanism.

 The electric spark forming processing mechanism research has not made the unprecedented progress the primary cause except outside the electric discharge process itself complexity, randomness, but also because the research technique and the method lack the innovation. Therefore, it is necessary to profit from other research area the success experience, directs the human advanced research technique and the experimental technology, the victory tradition research technique limitation, the deep person analysis and the revelation entire electric discharge process intrinsic essence, cnc milling machine the establishment may reflect objectively the electric discharge process rule the theoretical model, instructs the electric spark forming processing craft theory and the control theory research, but the computer simulation technical possibilities realizes this process effective tool.

Electric spark forming processing technology present situation and trend of development

Electric spark forming processing technology present situation and trend of development

 Introduction 

 As an advanced technique of manufacture important branch, the special processing technology, the electric spark machining technology, since the 20th century 40's foundations, has had been through repeatedly in particular for more than half centuries the development, Cnc machining has become the advanced technique of manufacture domain indispensable important constituent. Enters after in particular the human for 1990s, along with high technology and new technology and so on information technology, networking, aviation and astronautics technology, materials science technology development, the electric spark forming processing technology also faces a deeper level, the high level direction is developing. Although some traditional processing technology through own unceasing renewal development as well as with other correlation technology fusion, difficult to process the material processing domain in some (especially in mold processing domain) to display the processing efficiency higher superiority, but these technical application has been impossible to substitute for the electric spark forming processing technology difficultly to process processing domain completely and so on in the material,Cnc machining complex profile, mold statuses. On the contrary, the electric spark forming processing technology through profits from other processing technology the development experience, to the micro refinement, highly effective directions and so on, precision, automation, intellectualization is developing unceasingly.

  Electric spark forming processing technology development present situation

   At present, in electric spark machining basic theory research area, because the electric discharge process itself complexity, randomness as well as the research method lack the innovation, until now not yet made the unprecedented progress. But in processing craft and control fundamental research domain, because the research results may apply directly in the production practice, therefore has become in the present electric spark forming processing engineering research a more active domain, its research hot spot mainly concentrates in the highly effective processing technology, the high precise processing technology (glassy surface processing technology), Cnc machining the low loss processing technology, the tiny processing technology, the non-conducting material processing technology, the electric spark surface treatment technology, the intelligent control technology (for example artificial neural networks technology, fuzzy control technology, expert system and so on) as well as aspects and so on operational safety, environmental protection. In the process unit development aspect, the present new electric spark forming processing engine bed in aspects and so on processing function, processing precision, automaticity, reliability improved comprehensively, many engine beds have had online functions and so on examination, intelligent control, modulation, no longer is in the traditional significance special processing engine bed, but looks like in the machining the numerical control engine bed even to process the center.

Light Cutting

Light Cutting

 Besides carbide and tungsten, light is an appropriate “tool material” for  micro-holemaking. Although most laser drilling is performed in the infrared spectrum, the SuperPulse technology from The Ex One Co., Irwin, Pa., cnc milling machine uses a green laser beam, said Randy Gilmore, the company’s director of laser technologies. Unlike the femtosecond variety, Super- Pulse is a nanosecond laser, and its green light operates at the 532-nanometer wavelength. 

 The technology provides laser pulses of 4 to 5 nanoseconds in duration, and  those pulses are sent in pairs with a delay of 50 to 100 nanoseconds between individual pulses. The benefits of this approach are twofold. “It greatly enhances material removal compared to other nanosecond lasers,” Gilmore said, “and greatly reduces the amount of thermal damage done to the workpiece material” because of the pulses’ short duration. 

    The minimum diameter produced with the SuperPulse laser is 45 microns, but one of the most common applications is for producing 90μm to 110μm holes in diesel injector nozzles made of 1mm-thick H series steel.cnc milling machine  Gilmore noted that those holes will need to be in the 50μm to 70μm range as emission standards tighten because smaller holes in injector nozzles atomize diesel fuel better for more efficient burning.  

 In addition, the technology can produce negatively tapered holes, with a smaller entrance than exit diameter, to promote better fuel flow.

  Another common application is drilling holes in aircraft turbine blades for cooling.  Although the turbine material might only be 1.5mm to 2mm thick, Gilmore explained that the holes are drilled at a 25° entry angle so the air, as it comes out of the holes, hugs the airfoil surface and drags the heat away. That means the hole traverses up to 5mm of material.  “Temperature is everything in a turbine” he said, “because in an aircraft engine, the hotter you can run the turbine, the better the fuel economy and the more thrust you get.”

  To further enhance the technology’s competitiveness, Ex One developed a  patent-pending material that is injected into a hollow-body component to block the laser beam and prevent back-wall strikes after it creates the needed hole. After laser machining, the end user removes the material without leaving remnants.   “One of the bugaboos in getting lasers accepted in the diesel injector community is that light has a nasty habit of continuing to travel until it meets another object,” Gilmore said. “In a diesel injector nozzle, that damages the interior surface of the opposite wall.” 

  Although the $650,000 to $800,000 price for a Super- Pulse laser is higher than a  micro-holemaking EDM, Gilmore noted that laser drilling doesn’t require electrodes. “A laser system is using light to make holes,” he said, “so it doesn’t have a consumable.” 

  Depending on the application, mechanical drilling and plunge milling, EDMing and laser machining all have their place in the expanding micromachining universe. cnc milling machine“People want more packed into smaller spaces,” said Makino’s Kiszonas.

  

Turn to Tungsten

Turn to Tungsten

  EDMing is typically a slow process, and that holds true when it is used for  microdrilling. cnc milling machine “It’s very slow, and the finer the details, the slower it is,” said , president and owner of Optimation Inc. The Midvale, Utah, company builds Profile 24 Piezo EDMs for micromachining and also performs microEDMing on a contract-machining basis. 

 Optimation produces tungsten electrodes using a reverse-polarity process and machines and ring-laps them to as small as 10μm in diameter with 0.000020" roundness.  cnc milling machine  Applying a 10μm-dia. electrode produces a hole about 10.5μm to 11μm in diameter, and blind-holes are possible with the company’s EDM. The workpiece thickness for the smallest holes is up to 0.002", and the thickness can be up to 0.04" for 50μm holes.

  After working with lasers and then with a former EDM builder to find a better way to produce precise microholes, Jorgensen decided the best approach was DIY. “We literally started with a clean sheet of paper and did all the electronics, all the software and the whole machine from scratch,” he said. Including the software, the machine costs in the neighborhood of $180,000 to $200,000. 

  Much of the company’s contract work, which is provided at a shop rate of $100 per hour, involves microEDMing exotic metals, such as gold and platinum for X-ray apertures, stainless steel for optical applications and tantalum and tungsten for the electron-beam industry. cnc milling machine  Jorgensen said the process is also appropriate for EDMing partially electrically conductive materials, such as PCD.  “The customer normally doesn’t care too much about the cost,” he said. “We’ve done parts where there’s $20,000 [in time and material] involved, and you can put the whole job underneath a fingernail. We do everything under a microscope.”

Microvaporization

Microvaporization

 Electrical discharge machining using a sinker EDM is another micro-holemaking option. Unlike ,Cnc machining  which create small holes for threading wire through the workpiece when wire EDMing, EDMs for producing microholes are considerably more sophisticated, accurate and, of course, expensive. 

 For producing deep microholes, a tube is applied as the electrode. For EDMing smaller but shallower holes, a solid electrode wire, or rod, is needed. “We try to use tubes as much as possible,” said Jeff Kiszonas,Cnc machining  EDM product manager for Makino Inc., Auburn Hills, Mich. “But at some point, nobody can make a tube below a certain diameter.” He added that some suppliers offer tubes down to 0.003" in diameter for making holes as small as 0.0038". The tube’s flushing hole enables creating a hole with a high depth-to-diameter ratio and helps to evacuate debris from the bottom of the hole during machining。

 One such sinker EDM for producing holes as small as 0.00044" (11μm) is Makino’s Edge2 sinker EDM with fine-hole option. In Japan, the machine tool builder recently produced eight such holes in 2 minutes and 40 seconds through 0.0010"-thick tungsten carbide at the hole locations. The electrode was a silver-tungsten rod 0.00020" smaller than the hole being produced, to account for spark activity in the gap. 

  When producing holes of that size, the rod, while rotating, is dressed with a charged EDM wire. The fine-hole option includes a W-axis attachment, which holds a die that guides the electrode, as well as a middle guide that prevents the electrode from bending or wobbling as it spins. With the option, the machine is appropriate for drilling hole diameters less than 0.005".

 Another sinker EDM for micro-holemaking is the Mitsubishi VA10 with a fine-hole jig attachment to chuck and guide the fine wire applied to erode the material. “It’s a standard EDM, but with that attachment fixed to the machine, we can do microhole drilling,” said Dennis Powderly, Cnc machiningsinker EDM product manager for MC Machinery Systems Inc., Wood Dale, Ill. He added that the EDM is also able to create holes down to 0.0004" using a wire that rotates at up to 2,000 rpm.

Renoho Precision Machinery Technology Co.,Ltd: Taking a Plunge

Renoho Precision Machinery Technology Co.,Ltd: Taking a Plunge: Taking a Plunge   Although standard microdrills aren’t generally available below 0.002", microendmills that can be used to “plunge” ...

Taking a Plunge

Taking a Plunge 

 Although standard microdrills aren’t generally available below 0.002", microendmills that can be used to “plunge” a hole are. “When people want to drill smaller than that, they use our endmills and are pretty successful,” Burton said. However, the holes can’t be very deep because the tools don’t have long aspect, or depth-to-diameter, ratios. cnc milling machineTherefore, a 0.001"-dia. endmill might be able to only make a hole up to 0.020" deep whereas a drill of the same size can go deeper because it’s designed to place the load on its tip when drilling. This transfers the pressure into the shank, which absorbs it.

  Performance offers endmills as small as 5 microns (0.0002") but isn’t keen on increasing that line’s sales. cnc milling machine “When people try to buy them, I very seriously try to talk them out of it because we don’t like making them,” Burton said. Part of the problem with tools that small is the carbide grains not only need to be submicron in size but the size also needs to be consistent, in part because such a tool is comprised of fewer grains. “The 5-micron endmill probably has 10 grains holding the core together,” Burton noted.

  He added that he has seen carbide powder containing 0.2-micron grains, which is about half the size of what’s commercially available,cnc milling machine but it also contained grains measuring 0.5 and 0.6 microns. “It just doesn’t help to have small grains if they’re not uniform.”

Lubricious Chill

Lubricious Chill

  To further aid chip evacuation, Davis recommends applying an oil-based metalworking fluid instead of a waterbased coolant because oil provides greater lubricity. But if a shop prefers using coolant, Cnc machining the fluid should include EP (extreme pressure) additives to increase lubricity and minimize foaming. “If you’ve got a lot of foam,” Davis noted, “the chips aren’t being pulled out the way they are supposed to be.” 

  He added that another way to enhance a tool’s slipperiness while extending its life is with a coating, such as titanium aluminum nitride. TiAlN has a high hardness and is an effective coating for reducing heat’s impact when drilling difficult-to-machine materials, like stainless steel.

   David Burton, general manager of Performance Micro Tool, Janesville, Wis., disagrees with the idea of coating microtools on the smaller end of the spectrum. “Coatings on tools below 0.020" typically have a negative effect on every machining aspect, from the quality of the initial cut to tool life,” he said. That’s because coatings are not thin enough and negatively alter the rake and relief angles when applied to tiny tools.

  However, work continues on the development of thinner coatings, and Burton indicated that Performance Micro Tool, Cnc machiningwhich produces microendmills and microrouters and resells microdrills, is working on a project with others to create a submicron-thickness coating. “We’re probably 6 months to 1 year from testing it in the market,” Burton said.   The microdrills Performance offers are basically circuit-board drills, which are also effective for cutting metal. All the tools are without through-coolant capability. “I had a customer drill a 0.004"-dia. hole in stainless steel, and he was amazed he could do it with a circuit-board drill,” Burton noted, adding that pecking and running at a high spindle speed increase the drill’s effectiveness. 

 The requirements for how fast microtools should rotate depend on the type of CNC machines a shop uses and the tool diameter, with higher speeds needed as the diameter decreases. (Note: The equation for cutting speed is sfm = tool diameter × 0.26 × spindlespeed.)     Although relatively low, 5,000 rpm has been used successfully by Burton’s customers. “We recommend that our customers find the highest rpm at the lowest possible vibration—the sweet spot,” he said.

 In addition to minimizing vibration, a constant and adequate chip load is required to penetrate the workpiece while exerting low cutting forces and to allow the rake to remove the appropriate amount of material. If the drill takes too light of a chip load, the rake face wears quickly, becoming negative, and tool life suffers. This approach is often tempting when drilling with delicate tools.  

 “If the customer decides he wants to baby the tool, he takes a lighter chip load,” Burton said, “and, typically, the cutting edge wears much quicker and creates a radius where the land of that radius is wider than the chip being cut. He ends up using it as a grinding tool, trying to bump material away.” For tools larger than 0.001", Burton considers a chip load under 0.0001" to be “babying.” If the drill doesn’t snap, premature wear can result in abysmal tool life. 

  He added: “You would think with 0.0003" runout and a chip load a third that, say, 0.0001" to 0.00015", the tool would break immediately because one flute would be taking the entire load and then the back end of the flute would be rubbing. 

  When drilling, he indicated that up to 0.0003" TIR should be acceptable because once the drill is inside the hole, the cutting edges on the end of the drill continue cutting while the noncutting lands on the OD guide the tool in the same direction. Minimizing run out becomes more critical as the depth-to-diameter ratio increases. This is because the flutes are not able to absorb as much deflection as they become more engaged in the workpiece. Cnc machiningUltimately, too much runout causes the tool shank to orbit around the tool’s center while the tool tip is held steady, creating a stress point where the tool will eventually break.

Options for micro-holemaking

Options for micro-holemaking

  As in the macroscale-machining world, holemaking is one of the most— if not the most—frequently performed operations for micromachining. Cnc machining Many options exist for how those holes are created. Each has its advantages and limitations, depending on the required hole diameter and depth, workpiece material and equipment requirements. This article covers holemaking with through-coolant drills and those without coolant holes, plunge milling, microdrilling using sinker EDMs and laser drilling.

  Helpful Holes

  Getting coolant to the drill tip while the tool is cutting helps reduce the amount of heat at the tool/workpiece interface and evacuate chips regardless of hole diameter. Cnc machining But through-coolant capability is especially helpful when deep-hole microdrilling because the tools are delicate and prone to failure when experiencing recutting of chips, chip packing and too much exposure to carbide’s worst enemy—heat.

 When applying flood coolant, the drill itself blocks access to the cutting action. “Somewhere about 3 to 5 diameters deep, the coolant has trouble getting down to the tip,” said Jeff Davis, vice president of engineering for Harvey Tool Co., Rowley, Mass. “It becomes wise to use a coolant-fed drill at that point.” 

 In addition, flood coolant can cause more harm than good when microholemaking. “The pressure from the flood coolant can sometimes snap fragile drills as they enter the part,” Davis said. 

  The toolmaker offers a line of through-coolant drills with diameters from 0.039" to 0.125" that are able to produce holes up to 12 diameters deep, as well as microdrills without coolant holes from 0.002" to 0.020". 

  Having through-coolant capacity isn’t enough, though. Coolant needs to flow at a rate that enables it to clear the chips out of the hole. Davis recommends, at a minimum, 600 to 800 psi of coolant pressure. “It works much better if you have higher pressure than that,” he added. 

 To prevent those tiny coolant holes from becoming clogged with debris, Davis also recommends a 5μm or finer coolant filter. 

 Another recommendation is to machine a pilot, or guide, hole to prevent the tool from wandering on top of the workpiece and aid in producing a straight hole. When applying a pilot drill, it’s important to select one with an included angle on its point that’s equal to or larger than the included angle on the through-coolant drill that follows. The pilot drill’s diameter should also be slightly larger.Cnc machining  For example, if the pilot drill has a 120° included angle and a smaller diameter than a through-coolant drill with a 140° included angle, “then you’re catching the coolant-fed drill’s corners and knocking those corners off,” Davis said, which damages the drill.  

 Although not mandatory, pecking is a good practice when microdrilling deep holes. Davis suggests a pecking cycle that is 30 to 50 percent of the diameter per peck depth, depending on the workpiece material. This clears the chips, preventing them from packing in the flute valleys.

Cylinder processing the choice of cutting parameters

Cylinder processing the choice of cutting parameters 

    Engine block choice of cutting parameters including cutting speed, feed rate and feed rate option. Cnc milling machine As the processing equipment is used in high precision and rigidity of machine tools and high-speed machining centers in order to ensure the efficiency of cutting may be the appropriate choice of cutting a larger amount.

  The main processing engine block surface plane and bearing bore, cylinder bore holes such as the processing, while the plane and bearing bore, cylinder bore of the processing method is mainly milling and boring, Cnc milling machine so the discussion here, the choice of cutting parameters are mainly milling and Boring choice of cutting parameters.

 (1) milling the choice of the amount of usage the choice of milling milling effect is directly related to good or bad. Generally speaking, the choice of dosage milling principles: Face milling cutter should be as much as possible when you first take a larger milling depth and width of milling, and then select the larger milling rate of as much as possible. Milling in a specific amount of choice when many factors involved, but in general, rough milling large margin when the workpiece, processing requirements low, the main consideration of the durability of cutter; Fine Milling margin is small, high precision machining, improvement in the quality processing of primary consideration;   In the engine block of the milling process, the use of machine tools as having a high stiffness, high-speed machine tools, big power, rigidity is good, so has chosen the relatively large amount of cutting

  (2) boring dosage amount of choice options under the rough finishing process varies. Rough, the selection of a larger depth of cut, finish, the selection of a smaller depth of cut. Depth of cut determined later, as cutting a large amount of use. In the cutting depth and feed rate after the selection ?=can be a reasonable tool to ensure durability under the conditions of use calculations or look-up table method to determine the cutting speed. In general, the rough, choose a lower cutting speed, finishing, the selection of a higher cutting speed.  In the engine block boring process, the selection of machine tools as having a high stiffness, high-speed machine tools, big power, good rigidity; tool for foreign advanced tools, high quality, rigidity is good, so has chosen the relatively large amount of cutting.

 Through the engine block of the structure and process characteristics of the analysis, discusses the engine block machining process design principles and basis of the choice of cutting parameters, and U-turn at high speed milling and boring, for example, design, Cnc milling machine analysis of the engine cylinder body of high-speed milling and turnover boring process, and in the processing need to pay attention to.

cylinder surface of the main processing and secondary processes

Cylinder surface of the main processing and secondary processes  

   Cylinder surface and support the main processing operations are:  

(1) plane processing At present, the milling of engine blocks is the primary means of planar processing, Cnc machining domestic milling feed rate is generally 300-400mm/min, and foreign 2000-4000mm/min milling feed rate compared to far cry, to be on increasing, therefore, improve the milling feed rate, reduce overhead time is to improve the productivity of the major means of finishing a number of plane engine block when the milling feed rate to reach 2399 mm / min, greatly improved efficiency; Top surface of the cylinder milling is a key process in the process, the flatness requirements for 0.02/145mm, the surface roughness of Ra1.6um. Processing in the cylinder, the use of side and spindle bearing bore positioning, top, bottom and middle vagay only aperture while processing used in the processing line outside of the knife device can better meet the engine block machining accuracy

 (2) General holes machining holes in general are still using the traditional processing of drilling, expansion, boring, reaming, tapping and other craft approach. Issues in the design process of specific programs, use of coated cutting tools,  Cnc machining cutting tools and other advanced tools within the cooling, and using a large flow of cooling systems, greatly improving the cutting speed, improved productivity; he key process before ining ProceW 

(3) deep hole processing of the traditional processing method is used to grade twist drill feed, low efficiency of their production, processing and quality is poor. The deep hole in the engine block processing, the use of gun drilling process; 

 (4) The three-axis machining holes for the cylinder-axis machining holes holes of high precision, long working hours of the restrictive process. Thus, work arrangements, processing methods, tools and so on should be special attention. All cover pre-processing, that is, semi-circular hole and the cylinder block main bearing cap of the shortage of processing, its main purpose is to remove blank margin, release stress, to prepare for the post-order processing; in crankshaft machining processing center hole, using double-sided Boring, boring the first holes in the crankshaft hole at one end to 1 / 2 length, and then turn 180 degrees workbench, from the other end and then bore another 1 / 2 length. 

 (5) The cylinder bore machining cylinder hole cylinder machining processing is a key process in the one, under normal circumstances, the machining process as a rough boring, semi-fine boring, precision boring and honing. Cylinder bore wall for the early detection of casting defects, eliminate stress, should be thick cylinder boring holes in advance; due to the structural characteristics of the different cylinder bore, must be in honing process to improve the cylinder bore surface quality. In the high-volume production, the cylinder bore honing generally use the multi-axis grinding machine or honing Automatic Line. Here we use honing automatic lines, from the coarse-heng. Fine-heng and testing equipment, composed of three;

   (6) Cleaning Cleaning is divided into wet cleaning and dry cleaning. Machining cylinder automatic production line using a large flow of wet cleaning; 

 (7) Detect points outside the line detection and line detection of two kinds. Quality inspection in the engine block,  Cnc machining according to the actual vity; he key process before  iniXsituation with lines outside the detection, the main use of coordinate measuring machine integrated measurements of the cylinder, each 200 samples 1-5 pieces, each class random one.   

Machining Processing Stages and processes of the arrangements

Machining Processing Stages and processes of the arrangements

  Often a part of many apparent need for processing, of course, the surface machining accuracy are different. Processing of high precision surface, often after repeated processing;Cnc machining  As for the processing of the surface of low precision, only need to go through one or two on the list. Thus, when the development process in order to seize the “processing high precision surface,”this conflict, the reasonable arrangement processes and rational division stage of processing. Arrange the order of the principle of process is: after the first coarse refined, the first surface after the hole, the first benchmark other. In the engine block machining, the same should follow this principle

 (1) roughing stage engine block machining process, the arrangements for roughing process, to fully carry out rough rough, trim most of the margin in order to ensure production efficiency; 

 (2) semi-finishing phase of the engine block machining, in order to ensure the accuracy of some important surface processing, and arrange some semi-finishing operations, will be required accuracy and surface roughness of the surface of the middle of some processing to complete, while demanding the surface of semi-finished, to prepare for future finishing; 

(3) The finishing stage of requiring high accuracy and surface roughness of the surface processing;

 (4) secondary processing, such as small surface screw holes, you can finish of the major surface after the one hand, when the workpiece deformation process little impact at the same time also reduced the rejection rate; In addition, if the main surface of a waste, Cnc machining  these small the surface will not have to be processed, thus avoiding a waste of man-hours. However, if the processing is very easy for a small surface bumps the main surface, it should be placed on a small surface finish prior to the main surface finishing;

 (5) should make proper arrangements for secondary processes such as product inspection process, in part roughing stage, the key process before ining Processing Stages and processTand after processing, spare parts all the processing has been completed, should be appropriate arrangements.   

  Stage of processing division, has the following advantage Cnc machining  to ensure accuracy; second, finishing on the back, and will not damage during transport the surface of the workpiece has been processed; again, first roughing the surface defects can be detected early and promptly deal with rough, do not waste working hours. But most small parts, do not sub very thin.

Process design basis

Process design basis

  Affect the engine block part of the process design factors are manifold. Specifically,  can be understood from the following aspects.  

  (1) product object, product drawings and precision parts  technical documents related to the complexity of the engine block under the precision requirements of the process to take corresponding measures. Production targets for the four-cylinder automobile engine cylinder block;

 (2) the production program, the production of the nature and type of production of the engine block the production program of 400 million;

 (3) The annual effective system of work equipment, working for 320 days, with an average equipment loading rate of 80%, two shifts, 16 hours / day.  

   Engine block complex structure, high precision, large size, is thin-walled parts, there are a number of high precision plane and holes.

 Engine block machining process characteristics: mainly flat and the hole processing,precision parts  processing of flat generally use planing, milling methods such as processing, processing of hole used mainly boring, processing and multi-purpose drilling holes. As the cylinder complex structure, so how to   ensure that the mutual position of the surface processing precision is an important issue

The selection of blank  

   Engine block on the materials used are generally gray cast iron HT150, HT200, HT250, there is also cast aluminum or steel plate, this engine block using high-strength alloy cast iron. precision parts Cylinder in the processing prior to aging treatment in order to eliminate stress and improve the rough casting mechanical properties.  

Improve the rough accuracy, reduction of machining allowance, is to improve the automated production line system productivity and processing quality of the important measures. As the foreign box-type parts of rough quality and high precision, and its production-line system has been implemented directly on the blank line, not only eliminating the need for blank check device also saves the rough quality problems due to waste of machining time, increase overall efficiency. Therefore, the refinement of rough is to improve the productivity of the most promising way out. For the engine block production line, can be rough in parts on-line pre-milling six face, removing most of the margin, to facilitate direct on-line parts.

Process design principles

Process design principles 

  Design Technology program should be to ensure product quality at the same time, give full consideration to the production cycle,Cnc machining  cost and environmental protection; based on the enterprises ability to actively adopt advanced process technology and equipment, and constantly enhance their level of technology Engine block machining process design should follow the following basic principles:

 (1) The selection of processing equipment, processing equipment, the principle of selection adopted the principle of combining rigid-flexible, processing each horizontal machining center is located mainly small operations with vertical machining center, the key process a crank hole, cylinder hole, balancer shaft hole High-speed processing of  high-precision horizontal machining center, Cnc machining an upper and lower non-critical processes before and after the four-dimensional high-efficiency rough milling and have a certain adjustment range of special machine processing; 

 (2) focus on a key process in principle process the body cylinder bore, crankshaft hole, Balance Shaft hole surface finishing and the combination of precision milling cylinder head, using a process focused on a setup program to complete all processing elements in order to ensure product accuracy The key quality processes to meet the cylinder capacity and the relevant technical requirements;

  (3) All fixtures are used hydraulic clamp, clamping components, hydraulic pumps and hydraulic control components used in Germany or the United States producing high quality and reliable components;

 (4) The whole line used in all wet processing, using standalone BTA, high-precision machining processes critical horizontal machining center with constant cooling and to install high-precision high-voltage double-circuit band-pass fine filtration system, all with high-pressure processing center in the cold.  According to the technological characteristics of automobile engine cylinder block and the production mandate, the engine block machining automatic production line is composed of horizontal machining center CWK500 and CWK500D machining centers, special milling / boring machine, vertical machining centers matec-30L and other appliances. 

 (1) top and bottom, and tile covered only the combination of aperture rough milling machine dedicated to this machine to double-sided horizontal milling machine, using moving table driven parts, machine tools imported Siemens S7-200PLC system control, control cabinet set up an independent, cutting automate the process is completed and two kinds of automatic and adjust the state;

  (2) high-speed horizontal machining center machining center can be realized CWK500 the maximum flow of wet processing, but because of equipment, automatic BTA treatment system through the built-in tray under the wide-type chip conveyor and the completion of the machining center can be dry processing; machine tool spindle speed 6000r/min, rapid feeding speed 38m/min; 

(3)The combination of front and rear face rough milling machine tool using hydraulic transmission; control system imported Siemens S7-200PLC system control, machine tools have a certain flexibility;

 (4) The special machine TXK1500 this machine vertical machining center by the modification of shape, Cnc machining with vertical machining center features and performance, this machine has high strength, high wear-resistant, high stability, high accuracy, high-profile etc.;    

  (5) high-speed vertical machining center matec-30L of the machining center spindle high speed 9000r/min. Control system uses Siemens SINUMERIK840D control system;  

  (6) high-speed horizontal machining center spindle CWK500D highest speed 15000r/min

Engine parts

Engine parts

   Engine parts in the engine block is a more complex structure of spare parts box, Cnc machining its high precision, processing, complex process, and the processing quality will affect the overall performance engine, so it has become the engine manufacturer's focus parts one.   

   Engine block is the basic engine parts and skeleton, when the general assembly of the base components.Cylinder's role is supporting and ensuring the piston, connecting rod, Cnc machining crankshaft and other moving parts work, the exact location; to ensure the engine ventilation, cooling and lubrication; to provide a variety of auxiliary systems, components and engine installation. 

  Technical Characteristics

   Cylinder cast for a whole structure, and its upper part 4 cylinder mounting hole; cylinder standard cylinder is divided into upper and lower divisions into two parts; cylinder to the rear of the front-side arrangement of the previous three coaxial mounting hole of the camshaft and the idler axle hole.

  Cylinder process features are: the structure of complex shape; processing plane, more than holes; uneven wall thickness and stiffness is low; processing of high precision typical of box-type processing part.

 The main processing of the surface of cylinder block top surface, the main bearing side, cylinder bore, the main and camshaft bearing bore holes and so on, they will directly affect the machining ccuracy of the engine assembly precision and performance, mainly rely on precision equipment, industrial fixtures reliability and processing technology to ensure the reasonableness.

   Technology program is the preparation of the master process is to process planning and key process equipment design guidance documents. Cnc machining The correct process of program design, facilitate the systematic application of new scientific and technological achievements and advanced production experience, to ensure product quality, improve working conditions, and improve process technology and process management level.

Signal Cable Connections

Signal Cable Connections  

   The chain must be completed and have high integrity to provide the communication path for control signals to pass over. Depending on the specific design of the programmable control system, loss of communication to the I/O system will cause a critical failure, stopping the CPU scan .cnc machining parts In other systems, configurations can be accomplished that allow the unaffected portions of the programmable controller system to continue to operate.  

   As we saw earlier, communication between chassis can either be parallel or serial. Parallel communication uses multiple conductors to pass all bits of a byte or word of data simultaneously. Serial communication provides a method for single bits of a byte or word of data simultaneously. Serial communication provides a method for signal bit of a byte or word to be transmitted sequentially. The difference this has on cable design and selection is significant. Parallel cables are made of as many as 16 or more pairs of twisted individual conductors, protected by a shielded external jacket. cnc machining parts Multiple pin connectors are connected to one or both ends of the cable. The "D" type is popular, providing 25 or 39 pins in a standard configuration. Earlier design used a round type positive contact threaded design and certain manufactures still use this type of connector, although most have found the "D" type satisfactory.

 This cable is normally made available by the programmable controller manufacturer, and while it may seem expensive, the assurance of having a well-designed and thoroughly tested cable is worth almost any price compared to tracking down an intermittent problem later during a critical production period. The programmable controller manufacturer will provide parallel cables designed to operate with its equipment in various lengths, from 2 ft (feet) up to as much as 500 ft. Serial cables on the other hand are generally easier to use and less expensive to purchase or build. Manufacturers may or may not provide these as an item to purchase, and may just refer the purchaser to a third party source. Serial signal cable is normally a single or dual twisted pair of conductors, and is often just connected directly to the I/O driver or receiver with screw terminals. The only major reason to use parallel over serial is the great communication speed available with parallel, which can be a factor of 10 to 1, or more.

   Troubleshooting and Repair   

  Even the best of today’s well-designed and manufactured programmable controllers require occasional preventative maintenance and repair. This section looks at some of the tools provided by the manufacturer and techniques for general maintenance.  

   Most of the medium- and large-sized programmable controller systems available today are designed to be maintained by individuals with a wide variety of skills, without the benefit of in-depth formal training of this piece of equipment. This is accomplished in the design by providing individual modules of functionality installed in a chassis serviced from the front (all module types including power supplies). Front access is critical to proper maintenance. This allows easy inspection and replacement of the suspected bad module. Module health is determined by inspecting the LED indicators normally provided on the front of each module. Typical indicators will be on or off depending on the design and individual condition of the module in question. Various CPU and I/O modules will have indicators showing I/O control communications status, memory integrity, power supply tolerance check, scan integrity, and others. On future controller designs, and even today on a few systems, it is likely that English language messages will be displayed on the controller advising the user or maintenance personnel that a particular failure has occurred and recommended actions to take.

 The modular design and diagnostic indicators are, of course, important, but would be quite useless without well designed documentation provided by the manufacturer for the programmable controller system in question. Proper documentation will have sections dedicated to each major subsystem including CPU, I/O, and programming device. Each should explain in depth the stop-by-stop inspection of the system. All possible combinations of failure mode should be listed, along with suggested actions for repair. This will most often involve only the substitution of a re- placement board for the suspected failed unit. The user is urged to purchase a set of spare modules for the system in question as recommended by the manufacturer. This is normally, at a minimum, a single replacement module for each CPU and programming device serviceable module, and spare I/O modules equal to 10% of the number in the system.   

  While the design of system and documentation provide an easy vehicle for system maintenance once trouble is detected, it is always better to perform preventative maintenances where possible. Some systems available today provide levels of predicted failure detection that allow excellent preventive maintenance.

 This can range from automatic singling of low battery conditions on the memory modules to predicting an output circuit failure before the circuit is energized. This particular phenomenon can be extremely valuable in performing predictive maintenance on critical systems. Examples of this would include emergency circuits for rapid shutdown of a machine sequence or plant process. Outputs that fail prior to their need may not be detected in time to provide this critical service.

 The documented ladder logic diagram is a very useful tool for troubleshooting, especially on a complex system. It allows maintenance personnel or "walk through" the I/O segment in question, forcing transitions in specific inputs and outputs, while watching the system's reaction. cnc machining parts Many times this can ferret out a tough system problem, and may help isolate problems external to the controller such as an open sensor wire.  The major manufactures of programmable controller systems maintain 24 h telephone service numbers for users requiring emergency, service. Their highly trained personnel can normally walk the user through his problem and determine what action he should take for repair.

  

Installation and Maintenance of PLC

Installation and Maintenance of PLC

  Today’s programmable controller, properly installed, will provide a maximum of productivity with a minimum of maintenance. Cnc machining This section will cover the strength forward but critical areas of installation and maintenance of the programmable controller. It is intended to serve only as an overview on the subject, with the best guide for use being the documentation provided by the programmable controller manufacturer. This section will include rack installation for the CPU and I/O racks involved, line power, grounding, and signal cable consideration. Troubleshooting techniques as well as repair situation will be examined, and finally, training options will be presented.

   Rack Installation

   Depending on the size of the programmable controller being considered, the installation of the racks or chassis can be a simple or very complex task. Since most controllers are of open or particular application area. Many times this is a NEMA 12 type enclosure. Cnc machining It provides an environment in which the controller can operate without exposure to the grime outside the enclosure. Most racks can be mounted in either a panel type mounting arrangement, or a 19 in rack mounting. This is not true of controllers of the very small variety, as they are normally a panel mount only design. Rack mounting is generally used where the equipment is otherwise controlled. This type of installation is common where many instruments are mounted and used along with the programmable controller equipment. In either case, wire conductors must be routed in the rack; this is done with commercially available conduit that provides a means to bring in and out as many as 100 to 200 individual conductors from input and output points to real-world sensors and actuators. It is important that this phase of the design and installation be handled with care as it will dramatically affect the ability to maintain the systems. In addition to allowing any required system maintenance, this early care will make any system additions or modifications much easier.

  Line Power and Grounding     

    Proper power to the programmable controller is critical. Today’s systems are available in a wide variety of electrical configurations. Virtually all are designed for use in single-phase power systems, and most are now beginning to be offered with the optional ability to operate in a DC supply environment. AC designs are offered in either single voltage supplies, Cnc machining such as 115 or 230V AC; while some can be configured as either through a selection made on the power supply. Proper grounding of the power supply connection is required for a safe installation. Some programmable controller designs have individual grounding connections from rack to face- plates and other system components, so care must be taken to follow well electrical practice in system grounding during electrical installation. In certain applications, a 24 or 120 V DC power supply is required. This is common for installations that axe made where no AC power is available, such as remote electrical generation stations. It is also found where AC power is unreliable and where loss of control is considered an unacceptable situation