Summary of Application Technology of EDM in Mold Making

Key words: mold manufacturing; EDM; process flow;Mold making,Aluminum alloy mold,application technology

Application of EMD in modern mold processing

2 Process flow for mold manufacturing EDM

Mold manufacturing EDM includes multiple process steps, each of which directly affects the quality of mold processing. Here, the process flow is introduced in accordance with the operation sequence of EDM, and the main process points are analyzed.

2.1 Process determination of mold EDM

2.2 Tool electrode design and manufacturing

2.3 Fixing and correction of workpiece and tool electrode

2.4 Processing positioning

2.5 Electrical parameter configuration

2.6 Monitoring of the process

3 Discussion on the important application technology of EDM in mold manufacturing

Mold manufacturing EDM includes some important application technologies, such as: mirror EDM, precision EDM, multi-axis CNC EDM, deep hole EDM, etc. The main points of these technologies are discussed below.

3.1 Mirror EDM

Mirror EDM generally refers to EDM machining with a surface roughness value below Ra0.2um, and the machined surface has a specular reflection effect. Mirror EDM is mainly applied to the complex mold cavity, especially the precision machining of complex surfaces that are not easy to be polished. It can save the manual polishing process and improve the performance of the parts. It is very important to shorten the mold manufacturing cycle. significance.

Mirror EDM mainly has the following technologies:

(1) The most critical factor for successful mirror processing is that the EDM machine should have a mirror finishing circuit.

(2) Use advanced mixing methods to improve the surface roughness of EDM and achieve faster processing speed. For large-area EDM, the improvement is significant.

(3) A process using multi-electrode replacement. It is required that the consistency of the plurality of electrodes is good, the manufacturing precision is high, and the repeated clamping of the replacement electrodes and the positioning accuracy are high. Advanced processes such as high-speed milling of electrodes, positioning methods using reference balls, and fast-clamp positioning systems can be used to meet the requirements.

(4) Choosing a reasonable inter-sequence material balance is the key to ensure processing quality and processing efficiency.

(5) The general principle of the electrical configuration is: the main parameters use a small peak current, a small pulse width, a large pulse gap, the use of negative polarity processing. There are some differences between the selection of some non-main electrical parameters and conventional machining. For example, the discharge time should be longer, the lift height should be shorter, and the lift speed should not be too fast.

(6) Use the shaking processing method to ensure the smooth processing of the mirror surface.

(7) The electrode must be polished. The discharge properties of the electrode material are excellent. Reasonably choose the electrode scaling size. The material that is easy to process the mirror surface is selected as the workpiece material. The commonly used mirror surface processing materials are: SKD61, NAK80, STAVAX and other imported steel materials.

(8) Some operation skills in mirror processing: using the timing processing function of the CNC EDM machine; if the mirror-machined cavity is a regular rotation shape, if the machine tool is equipped with a C-axis, then the tool electrode and the C-axis are concentric. The C axis is rotated at a reasonable speed during processing; the working fluid is generally treated with an appropriate pressure side flush on the basis of oil immersion processing, so that the working fluid at the processing part is in a slight circulation state; Minimize downtime, especially if the ink layer left on the machined surface is not removed.

Application of EMD in modern mold processing

3.2 Precision EDM

Precision molds such as micro connectors, IC plastic molds, mobile phones, CD cases, etc., have become very popular mold varieties on the market. Although the technology of high-speed milling for micromachining of molds is progressing, the fine parts of precision mold parts by EDM have always occupied a major position in processing.

Each processing step in the precision mold EDM process is closely related to the machining accuracy. The main points of precision mold EDM technology:

(1) Choosing a good discharge machine is a prerequisite for precision EDM.

(2) A process using multi-electrode processing. According to the characteristics of different processing gaps in the rough, semi-finishing and finishing of the processing part, several corresponding size scaling electrodes are used to complete the rough, semi-finishing and finishing of a cavity.

(3) In order to ensure extremely high repeat positioning accuracy and not reduce the processing efficiency, a quick-clamping positioning system is adopted. Such as Sweden's 3R and Switzerland's EROWA device.

(4) Precision processing methods are used to ensure the quality of the electrodes, and high requirements are placed on the manufacturing level of the electrodes. The electrode should be fully tested for size and shape before being used in EDM. When choosing an electrode material, consider using a more expensive copper-tungsten alloy material.

(5) The control method of the high-grade machine tool used in precision machining is generally intelligent, and people should try not to modify the main parameters of the electric gauge to avoid affecting the spark gap of the machine's optional conditions.

(6) In the finishing process, the liquid processing method without flushing or oil immersion processing is usually adopted, and the high-speed lifting operation is used to remove the chips. The quality of the working fluid is very important.

(7) Before the end of precision machining, it is generally necessary to repeatedly measure and process to ensure the final dimensional accuracy, which is called patching.

(8) The entire processing process is required to be standardized and has a mature process technology level. There should be clear process arrangements and requirements for each part of the part. Each process is processed in strict accordance with the process and requirements to ensure the success rate of high-precision parts manufacturing.

(9) Pay attention to the influence of the machining environment and the machining accuracy of the tools used.

(10) The working attitude and processing technology level of processing technicians are very important for the completion of precision machining tasks.

Application of EMD in modern mold processing

3.3 multi-axis linkage CNC electric discharge machining

The numerical control system of the numerical control EDM machine has multi-axis digital control, and the relative motion between the electrode and the workpiece can be complicated and diverse. It is possible to machine complex parts with simple electrodes. If you can use UG and other software data files to automatically generate machining instructions to control the workbench and spindle multi-coordinate CNC servo motion, with high efficiency

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