Electric spark forming processing technology present situation and trend of development

Electric spark forming processing technology present situation and trend of  development

 I、Introduction

Precision metal parts 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, 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, 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. 

II、Electric spark forming processing technology development present situation

 Precision metal parts 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), 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.

 III、Electric spark forming processing technology trend of development

Precision metal parts 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, 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 traditionElectric spark forming processing technology present situation and trend of  development

 I、Introduction

Precision metal parts 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, 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, 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. 

II、Electric spark forming processing technology development present situation

 Precision metal parts 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), 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.

 III、Electric spark forming processing technology trend of development

Precision metal parts 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, 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, 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. 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, 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.

Hydraulic System

Hydraulic System

  CNC machining parts The history of hydraulic power is a long one，dating from man’s prehistoric efforts to harness the energy in the world around him．The only sources readily available were the water and the wind—two free and moving streams.

  The watermill，the first hydraulic motor，was an early invention·  One is pictured on a mosaic at the Great Palace in Byzantium，dating from the early fifth century·The mill had been built by the Romans．  But the first record of a watermill goes back even further,  to around 100 BC，and the origins may indeed have been much earlier·The domestication of grain began some 5000 years before and some enterprising farmer is bound to have become tired of pounding or grinding the grain by hand．Perhaps，  in fact，the inventor was some

farmer’s wife，since she often drew the heavy jobs·

 CNC machining parts Manv mills staved in use until the end of the 19th century，but they had been in the  process of being replaced by the Steam engine as a source of power for the previous 150  years．The transmission of the power generated by the waterwheels was by shafting and  crude gears or pulleys．The steam engine for the first time employed an enclosed moving

 stream of fluid(steam) under pressure—the principle to be later employed in hydraulic  power transmission—for transmitting power continuously from the point of generation to  the place where it was used·

  The transmission of hydrostatic power to a distant point began long before that,however ．Hero of A1exandria，in the first century AD，built a device in which a fire on the temple  altar expanded air in a closed container．The air pressure forced water to travel along a tube

 to the temple doors where，spilling into a container，it provided the force through ropes and  pulleys to magically open the doors

  Hero also produced a steam engine of sorts．

 Its motion depended on the reaction forces   from jets of steam，as in the present steam turbine，but it was little understood and it was no   more than an interesting curiosity·

  The invention of early forms of the hydraulic pump has a similarly early origin·The first pumps were not used to develop hydraulic power，however' but only to transfer water for  irrigation or to remove it from mines

 Archimedes applied the principle of the screw to hydraulic machines in the third century BC． 

 His screw pumps were used to raise water for irrigation or to the level of aqueducts·The piston   pump，the first mechanical device capable of generating pressure in a column of liquid，is believed to have come from Egypt at a similarly early date．Like the screw pump，it was used only as a means for moving water and not as a means for generating hydraulic power·

  In more recent years， the role of leadership in hydraulic power application has been taken over largely by some of the larger earthmoving and construction equipment manufacturers the total Power involved is often greater than that required in even the largest aircraft systems．the concentration of this power in a few very large loads，as compared to the multitude of smaller loads in an airplane，has spurred the system designer to find new，creative ways to distribute and control the power．This he has succeeded in doing to obtain maximum precision of control and productivity while minimizing power consumption．

  in modern mobile and industrial applications，the system designer has made full use of the wonderful flexibiIity and adaptability of hydraulics．  It can readily be directed around corners and past involving joints that virtually defy mechanical power transmission．  It can be divided easily to serve individual loads or recombined to power a high，single一load demand． Electrical and pneumatic power distribution have similar flexibility，but lack the compactness

 and certain of the other important characteristics of hydraulics

   CNC machining parts A very significant feature of hydraulic power is its extreme power density． Fig．1 0．1 shows a comparison of a 400 hP(1hp=0·7457kW)hydraulic pumping source with a diesel engine and an electrical motor of the same power capacity．The contrast is obvious and is one that otters both an opportunity to the user of hydraulic power and a challenge to the designer

 of hydraulic components.

  The high—power density in a hydraulic pump or motor creates design challenges beyond those found in many other products·High loads on rapidly sliding surfaces，extreme fluid   velocities and rapidly recurring pressure applications on pumping elements(vanes，pistons。   gears) demand careful design attention to assure long life，complete reliability and efficient operation·The user,on the other hand，reaps the benefit of a family of apparatus that is highly responsive，finely controllable and simple to apply．When the designer understands the user’s needs and the user understands the equipment’s full capabilities，the maximum  potential of hydraulic power can be achieved．

Shaper, Planer, Milling and Grinding Machines

Shaper, Planer, Milling and Grinding Machines

 Shapers 

Precision metal parts Shapers are machine tools used primarily in the production of flat and angular surfaces. In addition, the shaper is used to machine irregular shapes and contours which are difficult to produce on other machine tools. Internal as well as external surfaces and shapes can be produced on the shaper. Common shapes produced on the shaper are flat, angular, grooves, dovetails, T-slots, keyways, slots, serrations, and contours. Single-point cutting tools similar to the type used on the lathe are used in machining most surfaces on the shaper. Contour surfaces can be produced with either a single-point tool or a formed cutting tool. When using a single-point cutting tool for contour surfaces, the depth of cut must be constantly regulated by the machine operator to achieve the proper contour . Profilingattachments can be used on some shapers to regulate the feed motion and provide duplication of other parts. Numerical control units also enable the production of irregular surfaces with constant regulation of the depth of cut.

   Shapers are classified by the plane in which the cutting action occurs, either horizontal or vertical. In addition the horizontal-type shapers are further classified as push or pull cut. A push-cut shaper cuts while the ram is pushing the tool across the work, and a pull cut machine removes material while the tool is pulled toward the machine. Vertical shapers use a pushing-type cutting action and are sometimes referred to as slotters or keyseaters.

 Planers 

Precision metal parts Planers are similar to shapers because both machines are primarily used to produce flat and angular surfaces. However, planers are capable of accommodating much larger work- pieces than the shaper. In planer operations the workpiece is mounted on the table which reciprocates in a horizontal plane providing a straight-line cutting and feed action. Single-point cutting tools are mounted on an overhead cross rail and along the vertically supported columns. The cutting tools are fed into or away from the workpiece on either the horizontal or vertical plane, thus being capable of four straight-line feed motions.  Cutting speeds are slow on the planer because of the workpiece size and type of cutting tool being used. In order to increase the production of the planer, multiple tooling stations are employed. Two tooling stations are located on the overhead cross rails, with usually one tooling station on the vertical supports. Another method of increasing production on the planer is to mount a number of workpieces on the table at the same time. This method is only feasible when the workpieces require the same cut and are relatively small in size. The planer size is designated by the maximum workpiece capacity of the machine. The height, width, and length of the workpiece that can be accommodated on the planer's worktable varies with the type of planer.

 Milling Machines

  Precision metal parts Milling machines are probably the most versatile machine tools used in modern manufacturing with the exception of the lathe. Primarily designed to produce flat and angular surfaces, the milling machine is also used to machine irregular shapes, surfaces, grooves, and slots. The milling machine can also be used for drilling, boring, reaming, and gear-cutting operations.   A number of different types of milling machines are manufactured in order to serve the multitude of needs and the diverse applications. Milling machines are classified according to their structure and include column-knee, fixed bed, planer, and special machines.

 Grinding Machines

  Grinding machines utilize abrasive grains, bonded into various shapes and sizes of wheels and belts to be used as the cutting agent. Grinding operations are used to impart a high-quality surface finish on the workpiece. In addition, the dimensional accuracy of the workpiece is improved since tolerances of 0.00001 in. [0. 00025mm] are possible in grinding operations. Both internal and external surfaces can be ground by using the variety of grinding machines available. Related operations—which use abrasivesin various forms such as paste, powder, and grains—include lapping, honing, and drum finishing.   

  Grinding machines are classified according to the type of surface produced. Common surfaces and classifications of grinding machines are surface, cylindrical, and special machines.

Design of machine elements of 2

Design of machine elements of 2

 Precisionparts Machine design is a vast field of engineering technology. As such, it begins with the conception of an idea and follows through the various phases of design analysis, manufacturing, marketing and consumerism. The following is a list of the major areas of consideration in the general field of machine design:

  ① Initial design conception;  ② Strength analysis; ③ Materials selection;   ④ Appearance; ⑤ Manufacturing;  ⑥ Safety;  ⑦ Environment effects;  ⑧Reliability and life;                               
   Strength is a measure of the ability to resist, without fails, forces which cause stresses and strains. The forces may be;

 ① Gradually applied;  ② Suddenly applied;  ③ Applied under impact;   ④ Applied with continuous direction reversals;  ⑤ Applied at low or elevated temperatures.       

 Precisionparts If a critical part of a machine fails, the whole machine must be shut down until a repair is made. Thus, when designing a new machine, it is extremely important that critical parts be made strong enough to prevent failure. The designer should determine as precisely as possible the nature, magnitude, direction and point of application of all forces. Machine design is mot, however, an exact science and it is, therefore, rarely possible to determine exactly all the applied forces. In addition, different samples of a specified material will exhibit somewhat different abilities to resist loads, temperatures and other environment conditions. In spite of this, design calculations based on appropriate assumptions are invaluable in the proper design of machine.

  Precisionparts Moreover, it is absolutely essential that a design engineer knows how and why parts fail so that reliable machines which require minimum maintenance can be designed. Sometimes, a failure can be serious, such as when a tire blows out on an automobile traveling at high speeds. On the other hand, a failure may be no more than a nuisance. An example is the loosening of the radiator hose in the automobile cooling system. The consequence of this latter failure is usually the loss of some radiator coolant, a condition which is readily detected and corrected.

 The type of load a part absorbs is just as significant as the magnitude. Generally speaking, dynamic loads with direction reversals cause greater difficulties than static loads and, therefore, fatigue strength must be considered. Another concern is whether the material is ductile or brittle. For example, brittle materials are considered to be unacceptable where fatigue is involved.     
  In general, the design engineer must consider all possible modes of failure, which include the following:

①Stress; ② Deformation;    ③ Wear;  ④ Corrosion;  ⑤ Vibration;    ⑥ Environmental damage;     ⑦ Loosening of fastening devices.                           

   The part sizes and shapes selected must also take into account many dimensional factors which produce external load effects such as geometric discontinuities, residual stresses due to forming of desired contours, and the application of interference fit joints.

  

Design of machine elements

Design of machine elements

    Precision metal parts  The principles of design are, of course, universal. The same theory or equations may be applied to a very small part, as in an instrument, or, to a larger but similar part used in a piece of heavy equipment. In no ease, however, should mathematical calculations be looked upon as absolute and final. They are all subject to the accuracy of the various assumptions, which must necessarily be made in engineering work. Sometimes only a portion of the total number of parts in a machine are designed on the basis of analytic calculations. The form and size of the remaining parts are designed on the basis of analytic calculations. On the other hand, if the machine is very expensive, or if weight is a factor, as in airplanes, design computations may then be made for almost all the parts.

    Precision metal parts   The purpose of the design calculations is, of course, to attempt to predict the stress or deformation in the part in order that it may sagely carry the loads, which will be imposed on it, and that it may last for the expected life of the machine. All calculations are, of course, dependent on the physical properties of the construction materials as determined by laboratory tests. A rational method of design attempts to take the results of relatively simple and fundamental tests such as tension, compression, torsion, and fatigue and apply them to all the complicated and involved situations encountered in present-day machinery

   Precision metal parts  In addition, it has been amply proved that such details as surface condition, fillets, notches, manufacturing tolerances, and heat treatment have a market effect on the strength and useful life of a machine part. The design and drafting departments must specify completely all such particulars, must specify completely all such particulars, and thus exercise the necessary close control over the finished product.