1. Control and improvement to the man-made factor which influences the work piece surface quality by wire cutting.

The control and improvement to the man-made factor mainly includes the determination of processing craft and the choice of processing method, this may realize through the followings:

1.1 The reasonable arrangement of cutting route. The guiding ideology of this measure is to avoid destroying the work piece material’s original internal stress balance as far as possible, and prevent the remarkable distortion of the work piece material in the cutting process, because the cutting route is not reasonably arranged under the function of champing and so on, that causes the drop of cutting surface quality. The separation of work piece and its supporting part should be arranged finally, to make the rigidity better in the processing.

1.2 The correct choice of cutting parameter.

1.3 Use the near distance processing. In order to enable the work piece to achieve the high precision and the high surface quality, adjust the wire support altitude promptly according to the thickness of work piece, and make the distance of top nozzle and work piece approaches as near as possible, this may avoid that the oscillation amplitude of line electrode is oversized and influences the surface quality of the processing work piece because of the far distance between top nozzle and work piece.

1.4 Pay attention to the fixation of processing work piece. When the work piece soon finished cutting, its joint strength to the parent material will inevitably drop, at this time, because of the impact of processing fluid, the deflexion of processing work piece must be prevented, because once deflexion occurs, the cutting gap can be changed, the light situation may influence the surface quality of work piece, the heavy situation may cause the badly cutting and discarding of work piece, therefore, must try to find solutions to fix up the processed work piece firmly.

2. Control and improvement to the machine tool factor which influences the work piece surface quality by wire cutting.

The single cut wire cutting machine belongs to the high accuracy machine tool, the maintenance of machine tool is very important, because the processing work piece’s high precision and high quality is directly based on the machine tool’s high accuracy, therefore each time before processing, the machine tool’s active status must be inspected, that can provide the high condition in processing work piece. The precautions should be pay attention to and the measures adopted are as follows:

2.1 Before the processing, the electrode wire must be inspected, the tension of electrode wire also have the very tremendous influence to the surface quality of work piece, for the work piece which requests high processing surface, should enhance the tension of electrode wire as far as possible under the premise of wire non-breakage.

2.2 The single cut wire cutting machine generally uses the working fluid which is made of emulsified oil and water. The spark discharge must be carried on in the liquid medium which have the certain insulating ability, the insulating property of working fluid can compress the electric discharge channel penetrated, thus the spark discharge is limited in the smaller channel radius, forms the instant and partial high temperature to melts and gasified the metal, after the electric discharge finished, rapidly restores the electric discharge gap and become the state of insulation. If the insulating ability is too low, the working fluid becomes conductor, and cannot form the spark discharge; if the insulating ability is too high, the electric discharge gap is small, the scraps discharge is difficult, and the cutting speed is reduced. Before processing, different types of emulsion must be chosen according to different technology conditions. Furthermore the condition related to the coolant must be inspected, and inspect the liquid volume and the dirty dirt degree, guarantee that the insulating ability, washing performance and cooling performance of the working fluid meets the requirements. 

2.3 The wear situation of the electric conducting block must be inspected. The single cut wire cutting machine has to consider changing the block’s cutting position or replacing it generally after 50 ~ 80 hours’ processing, when there’s dirt, use the cleaning solution to clean it. What must be pay attention to is: When change the position of the block or replace it, the electrode wire verticality must be readjusted, in order to guarantee the precision and processing surface quality.

2.4 Inspect the rotation situation of control wheel, replace it if rotates not well, carefully inspect also the damage and dirt degree of the upper and lower spray nozzle, eliminate dirty with the cleaning liquid, when there is damage, the prompt replacement is needed. Also the situation of wire that stores in the wire cylinder should frequently be inspected, if the wire has lost oversized, it can affect the processing precision and surface quality, needs prompt replacement. In addition, the bad condition of electric conduction block, guide wheel and upper and lower spray nozzle also can cause the vibration of line electrode, by now even if the processing surface can carry on good electric discharge, because the line electrode vibration, wave ridge or stripe is also very easy occurs in the processing surface, finally causes the bad roughness of work piece surface.

2.5 Maintain the stable supply voltage. The unsteadiness of supply voltage can cause the unsteadiness of the beginning and end portion of electrode and work piece, thus causes the unsteadiness of disruptive discharge process and affects the surface quality of work piece.

3. Control and improvement to the material factor which influences the work piece surface quality by wire cutting.

In order to process the wire cutting product which has high size precision and good surface quality, careful consideration must be carried on about the use of the work piece material:

3.1 Because the different materials of work piece, the melting point, pneumatolytic point, thermal conductivity and so on are all dissimilar, thus even if according to the similar way of processing, the surface quality of work piece that obtained is not the same, therefore must make the corresponding choice of work piece material according to the actual surface quality needed. For example if to achieve the high accuracy, hard alloy materials must be chosen, and should not choose the stainless steel or unhardened high-carbon steel and so on, otherwise it’s very inaccessible to achieve the request.

3.2 Because the remaining interior stress of work piece material has big influence on processing, when processing the heat-treating material, because removing big area of metal and cut-off processing will destroy the relative equilibrium of the remaining stress of material interior, thus may affect the processing precision and surface quality of products. In order to avoid these situations, should choose the material which has good forging property and high hardenability, and deforms a little in the heat treatment.

3.3 During processing each parameter should be set to the optimum condition, in order to reduce the wire breakage phenomenon. If wire breakage occurs, it will return to the initial point inevitably, put on the wire again and go on processing, that will drop the surface quality and processing precision. Also when processing should attentively listen to the sound which the machine tool makes, the normal processing sound should be very smooth "rip - rip". At the same time; under normal processing, the oscillation amplitude of the ampere meter and voltmeter’s indexes of the machine tool should be very small, at the steady state, now the feeding speed is uniform and steady.

There are many factors which influence the surface quality, but so long as carrying on the systemic analysis and scientific classification to it, this kind of complex and in disorder factors may be controlled, thus improve and enhance the surface quality of work piece.