2017年9月10日星期日

Precision parts processing Surface Hardening of Nitriding

Precision parts processing Surface Hardening of Nitriding
    Precision CNC machining parts Nitriding is somewhat similar to ordinary case hardening, but it uses a different material and treatment to create the hard surface constituents.
In this process the metal is heated to a temperature of around 950(510) and held there for a period of time in contact with ammonia gas. Nitrogen from the gas  is introduced into the steel, forming very  hard nitrides that are finely dispersed through the surface metal.
   Nitrogen has greater hardening ability with certain elements than with others, hence, special nitriding alloy steels have been developed.
  Precision CNC machining parts Aluminum in the range of 1% to 1.5% has proved to be especially suitable in steel, in that it combines with the gas to form a very stable and hard constituent. The temperature of heating ranges from 925 to 1,050(495~565).
   Liquid nitriding utilizes molten cyanide salts  and, as in gas nitriding, the temperature is held below the transformation range. Liquid nitriding adds more nitrogen and less carbon than either cyaniding or carburizing in cyanide baths.
Case thickness of 0.001 to 0.012in.(0.03~0.30mm) is obtained, whereas for gas nitriding the case may be  as thick as 0.025 in.(0.64mm). In general the uses of the two-nitriding processes are similar.
   Nitriding develops extreme hardness in the surface of steel. This hardness ranges from 900 to 1,100 Brinell, which is considerably higher than that obtained by ordinary case hardening.
Nitriding steels, by virtue of their alloying content, are stronger than ordinary steels and respond readily to heat treatment. It is  recommended that these steels be machined and heat-treated before nitriding, because there is no scale or further work necessary after this process.
 Precision CNC machining parts Fortunately, the interior structure and properties are not affected appreciably by the nitriding treatment and, because no quenching is necessary, there is little tendency to  warp, develop cracks, or change condition in any way. The surface effectively resists corrosive action of water, saltwater spray, alkalies, crude oil, and natural gas.

 Precision CNC machining parts



2017年9月3日星期日

Types of Casting And manufacturing process

Types of  Casting  And manufacturing process

    Precision CNC machining parts Casting is a manufacturing process in which molten metal is poured or injected and allowed to solidify in a suitably  shaped mold cavity. During or after  cooling, the cast part is removed from the mold and then processed for delivery.
    Casting processes and cast-material technologies vary from simple to highly complex. Material and process selection  depends on the part’s complexity and function, the product’s quality specifications, and the projected cost  level.
     Castings are parts that are made close to their final dimensions by a casting process. With a history dating back 6,000  years, the various casting processes are  in a state of continuous refinement and evolution as technological advances are being made.
A:Sand Casting  
    Sand casting is used to make large parts (typically iron, but also bronze, brass, aluminum). Molten metal is poured into a mold cavity formed out of sand (natural or synthetic).
    The processes of sand casting are discussed in this section, including patterns, sprues and runners, design considerations, and casting allowance.
    The cavity in the sand is formed by using a pattern (an approximate duplicate of the real part), which are typically made out of wood, sometimes metal. The cavity is contained in an aggregate housed in a box called the flask.
    Core is a sand shape inserted into the mold to produce the internal features of the part such as holes or internal passages. Cores are placed in the cavity to form holes of the desired shapes. Core print is the region added to the pattern, core, or mold that is used to locate and support the core within the mold.
  Precision CNC machining parts  A riser is an extra void created in the mold to contain excessive molten material. The purpose of this is to feed the molten metal to the mold cavity as the molten metal solidifies and shrinks, and thereby  prevents voids in the main casting.
    In a two-part mold, which is typical of sand  castings, the upper half, including the top half of the pattern, flask, and core is called cope and  the lower half is called drag,  The parting line or the parting surface is line or surface that separates the cope and drag.
    The drag is first filled partially with sand, and the core  print, the cores, and the gating system are  placed near the parting line. The cope is then assembled to the drag, and the sand is poured on the cope half, covering the pattern, core and the gating system.
    The sand is compacted by vibration and mechanical means. Next, the cope is removed from the drag, and the pattern is carefully removed. The object is to remove the pattern without breaking the mold cavity.
    This is facilitated by designing a draft, a slight angular offset from the vertical to the vertical surfaces of the pattern. This is usually a minimum of 1.5mm(0.060in.), whichever is greater. The rougher the surface of the pattern, the more the draft to be provided.
    The molten material is poured into the pouring cup, which is part of the gating system that supplies the molten material to the mold cavity.
    Precision CNC machining partsThe vertical part of the gating system connected to the pouring cup is the sprue, and the horizontal portion is called the runners and finally to the multiple points where it is introduced to the mold cavity called the gates. 
    
    
    

2017年7月23日星期日

cutting speed

cutting speed, precision metal parts feed rate is an important parameter in the CNC machine tool cutting parameters, mainly based on the machining accuracy and surface roughness and the tool, workpiece material properties, select the maximum feed rate, machine tool stiffness and feeding system performance limitations., near the corner of contouring feed rate should be appropriately reduced in order to overcome the inertia or process systems is caused by deformation in the contour around the corner "overtravel" or "under process" phenomenon. to determine the principles of the feed rate : When the workpiece quality requirements can be guaranteed, in order to improve production efficiency, can choose a higher feed rate generally selected in the range of 100 ~ 200mm/min. processing in high-speed steel cutting tools, cutting, machining deep hole or should choose a lower feed rate, generally 20 ~ 50mm/min select range of .3 when machining accuracy, surface roughness, the feed rate should be selected smaller, generally in the 20 ~ 50mm/min range within selected .4 tool air travel, especially long-distance back to zero, you can select the CNC system given the maximum feed rate.
  precision metal parts back to eat the knife amount (or side knife to eat the amount determined under the premise of ensuring the quality of the machined surface, the back of cut (ap) should be determined according to the stiffness of the machine tool, workpiece and tool under the conditions allowed by stiffness, should as much as possible so that the back of cut allowance equal to the workpiece, thus reducing the number of tool path, and increase productivity.
   precision metal partss machining centers with axial and neck power head, to achieve the linkage of the three coordinates. Polar coordinate interpolation instruction and cylindrical interpolation instruction program optimization and development, and the machining station repeated positioning error of the effective compensation, the initial fast and reliable precision milling on the side of the rotary to improve the machining accuracy and surface finish quality.

    precision metal parts

2017年7月17日星期一

Types Of Commonly Used Tool Of The CNC Milling and Tool Type Selection

Types Of Commonly Used Tool Of The CNC Milling and Tool Type Selection

Precision CNC machining parts NC milling tool types, in order to adapt to high-speed, high efficiency and high degree of automation features of CNC machine tools, the tool is moving in the direction of standardization, universal and modular development, including the milling cutter and hole machining tool. meet the requirements of efficient and specific milling, developed for a variety of special purpose tool. There are many ways to the classification of the CNC milling tool tool structure can be divided into: (1) the overall style, mosaic, welding or machine clip connection, the clamp can be divided into translocation and indexable two special type, such as composite tool, damping tool manufacturing tool materials can be divided into: (1) high-speed steel cutting tools, carbide cutting tools, (3) diamond tool, other materials, cutting tools, such as cubic boron nitride cutting tools, ceramic cutting tools. from the cutting process can be divided into: flat end milling cutter, rounded end mills, ball end cutter and taper milling knives.

Machining Centers, Tool Type Selection

Precision CNC machining partsTool selection in CNC programming state of human-computer interaction should be based on the processing capacity of the machine tool, workpiece material properties, processing procedures, cutting parameters and other relevant factors, the correct selection of the tool and tool holder, tool selection The general principle is : easy to install, good rigidity, durability and high precision to meet the processing requirements under the premise, as we choose a shorter shank in order to improve the rigidity of tooling production, processing parts of the geometry is to select the tool type the main basis.

Precision CNC machining parts A milling cutter selection of machining curved parts, in order to ensure that cutting edge and contour is tangent to the cutting point, to avoid the blade and the workpiece contour interference, generally use the ball head knife, rough two-edged cutter, semi- finishing and finishing with four-blade cutter, milling the larger plane, generally use the blade inlaid disc cutter, milling flat or stepped surface in order to increase productivity and improve the surface roughness, generally universal cutter milling keyway, in order to ensure the dimensional accuracy of the slot, usually two-edged keyway cutter, posted on Free paper Download Center http://eng.hi138.com
2. hole machining tool selection. hole machining of CNC machine tools in general no drill mode, due to poor rigidity of the drill and cutting conditions, the selection of the drill diameter D should satisfy L / D 5 (L conditions for the drilling depth, the drill center drill before positioning to ensure the accuracy of the positioning of the hole processing, fine twist the choice of floating reamer reaming orifice want to chamfer, boring should try to use a symmetrical edge boring head, cutting, cut vibration to balance the boring; try to choose a thicker and shorter shank in order to reduce cutting vibration. economic type CNC machining, tool sharpening, measurement and replacement of more than manually, taking up the auxiliary long time, therefore, must be reasonable to arrange the order of the tool in general should follow the following principles: (1) to minimize tool quantity, a tool clamping to complete all processing site rough finishing tool should be used separately, even if it is the same dimensions of the tool, The first milling drill, the first surface finished, two-dimensional contour finishing, (6) possible, as far as possible use of CNC machine tools, automatic tool changer, in order to improve production efficiency In addition, the durability and accuracy of the tool and the tool price relationships requires attention, in most cases, choose a good tool, although the increase in the cost of the tool, processing quality and the resulting efficiency can greatly reduce the overall processing costs. In short, according to heat treatment condition of the workpiece material, cutting performance, and allowance to choose good rigidity, high durability cutter is to give full play to the CNC milling machine production efficiency and access to the premise of a satisfactory quality of processing. 
 Precision CNC machining parts


   

2017年7月9日星期日

On the application of precision milling technology in the processing center

On the application of precision milling technology in the processing center

Precision CNC machining parts  machinery manufacturing industry plays a very important position in the national economy as a whole, including metal cutting, basic and reliable precision machining means during the process of NC programming, tool selection and cutting the amount of very important, it is not only a huge effect on the quality of the parts to be processed, and can even determine the machine the efficacy of play and production safety is carried out smoothly in the preparation of the processing procedures, tool and cutting, the preparation of high-quality processing program premise.

Precision CNC machining parts  Machinery manufacturing industry plays a very important position in the national economy as a whole, precision metal cutting, basic and reliable means of processing, mechanical, electrical, electronic and other modern industrial sector plays an important role. Tools design, manufacture and use since ancient times is highly valued, here we are talking about tools, not only refers to the machine tool for machining, we are more concerned with the cutting tool. tool to promote the development of metal cutting technology. an extremely active and very critical factor, it can be said machining technology development, innovation, history is the history of tool development.


Precision CNC machining parts  introduced in 2008, the Little Giant company produced two milling machining center, but has not been able to truly part and universal CNC turning and milling machining center milling functions. Tool selection, machining path planning, cutting the amount of set programmers just set the parameters, you can automatically generate the NC program and transferred to the CNC machine tools to complete the processing, CNC machining, tool selection and cutting to determine the state of human-computer interaction, which is common machining stark contrast, it also requires the programmer must master the basic principles of tool selection and cutting to fully consider the characteristics of CNC machining, programming, study and master the CNC milling machining center, milling functions for complex shape, and accuracy require high precision machining of rotary part, to upgrade my unit of CNC precision machining capabilities, with a very important practical significance.
      
 Precision CNC machining parts

2017年7月2日星期日

Dry processing


Precision CNC machining parts The machining quality mainly is refers to the work piece the processing precision and the surface quality (including surface roughness, residual stress and superficial hardening).Along with the technical progress, the machining quality enhances unceasingly.The 18th century later periods, the machining precision counts by the millimeter; At the beginning of 20th century, machining precision Gao Yida 0.01 millimeter; To the 50's, the machining precision has reached a micron level; The 70's, the machining precision enhances to 0.1 micron.

The influence machining quality primary factor has aspects and so on engine bed, cutting tool, jig, work piece semifinished materials, technique and processing environment.Must improve the machining quality, must take the suitable measure to the above various aspects, like reduces the engine bed work error, selects the cutting tool correctly, improves the semifinished materials quality, the reasonable arrangement craft, the improvement environmental condition and so on.

Precision CNC machining parts Enhances the cutting specifications to enhance the material excision rate, is enhances the machining efficiency the essential way.The commonly used highly effective machining method has the high-speed cutting, the force cutting, the plasma arc heating cuts and vibrates the cutting and so on.

The grinding speed is called the high-speed grinding in 45 meters/second above es the high-speed cutting (or grinding) both may enhance the efficiency, and may reduce the surface roughness.The high-speed cutting (or grinding) requests the engine bed to have the high speed, the high rigidity, the high efficiency and the vibration-proof good craft system; Requests the cutting tool to have the reasonable geometry parameter and the convenience tight way, but also must consider the safe reliable chip breaking method.

Precision CNC machining parts The force cutting refers to the roughing feed or cuts the deep machining greatly, uses in the turning and the grinding generally.The force turning main characteristic is the lathe tool besides the main cutting edge, but also some is parallel in the work piece has processed superficial the vice-cutting edge simultaneously to participate in the cutting, therefore may enhance to feed quantity compared to the general turning several times of even several http://www.wendangku.net/doc/90cc2c195ef7ba0d4b733b53.html pares with the high-speed cutting, the force cutting cutting temperature is low, the cutting tool life is long, the cutting efficiency is high; The shortcoming is processes the surface to be rough.When force cutting, the radial direction cutting force death of a parent is not suitable for to process the tall and slender work piece very much.

The vibration cutting is along the cutting tool direction of feed, the attachment low frequency or the high frequency vibration machining, may enhance the cutting efficiency.The low frequency vibration cutting has the very good chip breaking effect, but does not use the chip breaking equipment, makes the knife edge intensity to increase, time the cutting total power dissipation compared to has the chip breaking installment ordinary cutting to reduce about 40%.The high frequency vibration cutting also called the ultrasonic wave vibration cutting, is helpful in reduces between the cutting tool and the work piece friction, reduces the cutting temperature, reduces the cutting tool the coherence attrition, thus the enhancement cutting efficiency and the processing surface quality, the cutting tool life may enhance 40% approximately.

To lumber, plastic, rubber, glass, marble, granite and so on nonmetallic material machining, although is similar with the metal material cutting, but uses the cutting tool, the equipment and the cutting specifications and so on has the characteristic respectively.

The lumber product machining mainly carries in each kind of joiner's bench, its method mainly has: The saw cuts, digs cuts, the turning, the milling, drills truncates with the polishing and so on.

The plastic rigidity is worse than the metal, the easy bending strain, the thermoplastic thermal conductivity to be in particular bad, easy to elevate temperature the conditioning.When cutting plastic, suitably with the high-speed steel or the hard alloy tools, selects the small to feed quantity and the high cutting speed, and uses compressed air cooling.If the cutting tool is sharp, the angle is appropriate, may produce the belt-shaped scrap, easy to carry off the quantity of heat.

Glass (including semiconducting material and so on germanium, silicon) but degree of hardness high brittleness is big.To methods and so on glass machining commonly used cutting, drill hole, attrition and polishing.To thickness in three millimeters following glass plates, the simple cutting method is with the diamond or other hard materials, in glass surface manual scoring, the use scratch place stress concentration, then uses the hand to break off.

To the marble, the granite and the concrete and so on the hard material processing, mainly uses methods and so on cutting, turning, drill hole, shaping, attrition and polishing.When cutting the available circular saw blade adds the grinding compound and the water; The outer annulus and the end surface may use the negative rake the hard alloy lathe tool, by 10~30 meter/minute cutting speed turning; Drills a hole the available hard alloy drill bit; The big stone material plane available hard alloy planing tool or rolls cuts planing tool shaping; The precise smooth surface, available three mutually for the datum to the method which grinds, or the grinding and the polishing method obtains.

Cutting tool in hot strong alloy application

The aviation processing also changes rapidly. For example, nickel base heat-resisting alloy like several years ago the most people had not heard Rene88 now occupies to the aircraft engine manufacture uses the total metal quantity 10~25%. Has very good showing and the commercial reason regarding this. For example, these heat strong alloy will be able to increase the engine endurance moreover to permit the small engine work on the big airplane, that will enhance the combustion efficiency and reduces the operation cost. These tough good materials also present the expense on the cutting tool. Their thermal stability causes on the knife point the temperature to be higher, thus reduced the cutting tool life. Similarly, in these alloy carbide pellet remarkably increased the friction, thus reduces the cutting tool life.

As a result of changes in these conditions, can be very pleased to have processed many titanium alloys and nickel-based alloy materials C-2 hard metal alloys, in the application to today's cutting edge of blade to the crushing and cutting depth of the trench lines badly worn. But using the latest high-temperature processing of small particles hard metal alloys to be effective, cutlery life improved, but more importantly to enhance the reliability of applications in high-temperature alloys. Small particles hard metal than traditional hard metal materials higher compression strength and hardness, only a small increase in the resilience of the cost. And resulted in high temperature alloy processing than traditional hard metal resistance common failure mode more effective.

PVD (physical gas phase deposition) coating also by certificate effective processing heat-resisting alloy. TiN (titanium nitrides) the PVD coating was uses and still was most early most receives welcome. Recently, TiAlN (nitrogen calorization titanium) and TiCN (carbon titanium nitrides) the coating also could very good use. In the past the TiAlN coating application scope and TiN compared the limit to be more. But after the cutting speed enhances them is a very good choice, enhances the productivity in these applications to reach 40%. On the other hand, is decided under the low cutting speed in coating superficial operating mode TiAlN can cause to accumulate the filings lump afterwards, micro collapses with the trench attrition.

Recently, used in the heat-resisting alloy application material quality already developing, these coating but became by several combinations. The massive laboratories and the scene test has already proven this kind of combination and other any kind of sole coating compares in time the very wide scope application is very effective. Therefore aims at the heat-resisting alloy application the PVD compound coating possibly to become the focal point which the hard alloy new material quality research and development continues. With the MTCVD coating, the coating ceramics gather in the same place, they hopefully become a more effective processing to research and develop newly are more difficult to process the work piece material the main impact strength.

Dry processing

Including the refrigerant question is technical and the commercial expansion industrial production tendency another domain which the cutting tool makes. North America and the European strict refrigerant management request and the biggest three automobile manufacturer forces them the core supplier to obtain the ISO14000 authentication (the ISO9000 environment management edition), this causes the refrigerant processing cost rise. To the car company and their core supplier said obviously one of responses which welcome is in the specific processing application avoids completely the refrigerant the use. This kind did the processing the new world to propose a series of challenges for the cutting tool supplier.

Recently, already appeared some to concern this topic to promulgate the speed, to enter for, the coating chemical composition and other parameters very substantial comprehensive nature very strong useful technical papers. Wants to concentrate the elaboration in here me "does the processing viewpoint" in the operation and commercial meaning automobile manufacturer new.

The metal working jobholders can the very good understanding related refrigerant use question, but majority cannot understand concerns except the technical challenge (for example row of filings) beside does the processing question in the cutting tool - work piece contact face between. Usually may observe to the refrigerant disperser scrap which flows out, but the pressure surpasses 3,000 pounds/An inch 2 high speed refrigerant also can help to break the filings, specially soft also the continual scrap can cause in the cutting tool - work piece contact face trouble.

Uses does the cutting craft the components result is the engine bed uses the wet type processing components to be hotter than. Whether before you do allow them to survey in the open-air natural cooling? If processes newly the hot components put frequently to the turnover box, elevates the environment temperature, whether components full cooling and just right enough permission precision examination? Also has the handling side several dozens on hundred components to be able to operate the worker to increase the extra burden.

With many cutting tools/The work piece technical question same place, these latent questions need to state whether dryly adds the ability line. Luckily, has very many ways to elaborate these questions. For example, the compressed air was proven row of filings becomes the question in very many applications the situation to have the successful echo.

Another plan is called MQL (minimum lubrication) a technology, it replaces the traditional refrigerant by the application the quite few oil mists constitution. This is a recognition compromise plan, this kind of minimum technology can large scale reduce the refrigerant the headache matter, moreover the smooth finish which processes in many applications very is also good. This domain still had very many research to do, moreover the cutting tool company positively participated in such research was absolutely essential. If they will not do fall behind the competitor, will be at the disadvantageous position.

In the factory the special details design other perhaps better plan according to the world in. The manufacturing industry jobholders possibly still could ask why they do have to use recent development the technology to replace the refrigerant method diligently which the tradition already an experience number generation of person improved enhances, because implemented especially does the experiment and the defeat which the processing or the subarid processing produced possibly causes the higher short-term cutting tool cost. The concise answer is when the bit probably accounts for the model processing components cost 3%, the refrigerant cost (from purchases to maintenance, storage, processing) can account for the components cost 15%.

Perhaps does the dry processing is not all suits to each application, but above discusses likely other processing questions are same, needs from a wider operation, the environment and the commercial angle appraises. Will be able to help the cutting tool company which the customer will do this to have the competitive advantage, but these will not be able to provide unceasingly is in the passive position.

Cutting tool and nanotechnology

Can fiercely change the cutting tool industry the enchanting new domain is the miniature manufacture, or the processing small granule forms the product which needs. Must refer to is its here does not have about the cutting tool miniature manufacture first matter; Second must say the matter is it is not remote.

Why the miniature manufacture and are the cutting tool related. Because most main is the particle size smaller, the hard alloy toughness of material better also is more wear-resisting. (Some experts define with the nanometer level pellet for are smaller than 0.2 mu m, but other people persisted a nanometer pellet had to be smaller than the hard alloy tools prototype which 0.1 mu m) made already to complete and the test,It is said that wear resistant theatrically increase. The question is the nanometer level hard alloy pellet cannot depend on the smashing big material formation, they are certain through the smaller material constitution, but processes the molecular level granule is not easy and the economical matter.
  
Precision CNC machining parts



2017年6月25日星期日

The formed cutting tool

The formed cutting tool
Precision CNC machining parts When machining, the work piece has processed the surface is depends upon the cutting tool and the work piece makes the relative motion to obtain.According to the surface method of formation, the machining may divide into the knife point path law, the formed cutting tool law, the generating process three kinds.

The knife point path law is depends upon the knife point to be opposite in the work piece surface path, obtains the superficial geometry shape which the work piece requests, like the turning outer annulus, the shaping plane, the grinding outer annulus, with the profile turning forming surface and so on, the knife point path are decided the cutting tool and the work piece relative motion which provides in the engine bed;

Precision CNCmachining parts The formed cutting tool law abbreviation forming, is with the formed cutting tool which matches with the work piece final superficial outline, or the formed grinding wheel and so on processes the formed surface, like formed turning, formed milling and form grinding and so on, because forms the cutting tool the manufacture quite to be difficult, therefore only uses in processing the short formed surface generally;


Precision CNCmachining parts The generating process name rolls cuts method, is when the processing the cutting tool and the work piece do unfold the movement relatively, the cutting tool and the work piece centrode make the pure trundle mutually, between both maintains the definite transmission ratio relations, obtains the processing surface is the knife edge in this kind of movement envelope, in the gear processing rolls the tooth, the gear shaping, the shaving, the top horizontal jade piece tooth and rubs the tooth and so on to be the generating process processing.Some machining has at the same time the knife point path law and the formed cutting tool method characteristic, like thread turning.
  
Precision CNC machining parts