Slow evolution machine tools are high-precision machining machines which can reach a machining precision of several µm, and surface roughness can reach <0.2 µm. However, some mold factories do not pay attention to details when using slow evolution machines, thinking that good machine tools can achieve effective and high precision machining at will. In fact, precision machining must establish the concept of precision machining!
01
Process the prerequisite
Slow evolution machine tools are all delivered with a library of process parameters, and their process parameters are generally obtained under specific conditions (such as room material, electrode wire, temperature of 20 ± 3 ℃, humidity 40-80%, etc.). If the following conditions change or do not comply with standards, this may cause differences in treatment results.
1) Rinse specification: During treatment as a function of standard parameters, the difference must be less than 0.5Bar after comparing the indicated value of the water pressure pressure gauge with the theoretical value;
2) The space between the room and the nozzle: 0.05 ~ 0.10 mm;
3) When surface roughness is required, the cutting-oriented cutting wires can be selected when RA ≧ 0.35 µm (it is recommended to use the same type of wire as machine tools). Get a good treatment surface, focus on surfaces.
4) During the finish, please make sure that water µS <10, especially during finish, please follow the requirements of process parameters. If necessary, replace the resin or pure water.
02
Temperature effect on treatment accuracy
In order to carry out a high -precision and high quality slow travel wire cutting, the stable environment must comply with the prescribed requirements, and there should not be direct sunlight or air flow , and temperature changes should be monitored. The temperature range of the machine tool guarantees that the accuracy of work is 20 ± 3º.
Ambient temperature changes have a great impact on the precision of the treatment, and their impact is reflected in three aspects: size, position and shape. As the figure below shows, the larger the temperature change and the larger the size of the part, the more it is affected by the temperature. For example, a part with a length of 200 mm will have a dimensional error of 0.01 mm when the temperature difference is 5 degrees. It is best to finish a larger part in a boot.
Effect of the change in room temperature on the precision of the treatment
The thermal characteristics of CNC machine tools have a significant impact on the precision of machining, which represents almost half of the machining precision. The precision of treatment of the tool-machine when stopped for a long time and the thermal equilibrium state is very different. By operating for a period of time. After starting the machine, you must invest in high precision treatment and production. However, the process of preparing machine tools is ignored or unknown to many factories.
If the tool-tool is interrupted for more than a few days, it is recommended to preheat for more than 30 minutes before high precision treatment; – Forecast process. The preheating process is to allow the tool to participate in the repeated movement of the machining axis. of the coordinate system and repeatedly moving the diagonal line. During the execution, you can write a macro program on the tooltip to allow the tool to carry out preheating actions on several occasions.
03
Factors affecting the effectiveness of treatment
There are many factors that affect the effectiveness of the cutting of slow travel wire. If there is ineffectiveness in the treatment, you can consider the two factors introduced below.
(1) High pressure water cannot actually be washed due to the limits of the parts structure and tightening.
Currently, it depends if the cut parts can be improved in tightening. Certain parts are affected by the support necklace and the lower surface is increased, certain parts are affected by the position of the pressure plate and the tightening screws, so they must lift the upper nozzle. the lowest point. When the low surface is raised, it depends on the question of whether the luminaire with the lighting surface of the luminaire and the counter can be used, or that the part can be tight directly on the counter.
Due to the influence of the screw pressure plate and parts, if the jaw pliers can be used to tighten operators who fear that the upper nozzle has not fallen to the lowest point, a gauge of flagship of 0.1 mm can be prepared if necessary. For parts which are indeed limited by the structure and cannot be washed effectively with high pressure water, the cutting energy cannot be reduced to this time, you must have a correct understanding of the ‘Cup efficiency.
(2) linked to the wire transport system (linked to maintenance)
1) Check if the coolant of the conductor block is normal. Especially if there is cooling water for the lower conductive block, as copper powder will drop during the cutting process. must be blocked.
2) The lower guide wheel on the lower arm turns flexible. Check and clean;
3) Is the wire collection wheel normal?
4) Check the voltage and speed of the wire and readjust if necessary;
5) Check and clean the wire guide nozzle and the driver’s block.
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