Issues to pay attention to in mirror spark machine forming processing

Today I will discuss several issues to pay attention to when processing with a mirror spark machine.

1. Issues related to improving processing accuracy:

This mainly includes dimensional accuracy and profiling accuracy. There are many factors affecting profiling accuracy, the first being electrode wear. Therefore, for sharp corners, thin sheets, and the main cavity, it is necessary to process them separately. This part of the cavity, like a pattern mold, requires a significant increase in pulse width. Use large pulse width and small current processing, primarily to meet the low wear requirement. Secondly, prevent re-adhesion, especially with graphite. During high-energy processing, pay attention to observation to prevent damage to the geometric shape of the cavity. Additionally, it is important to choose an appropriate linear (oscillating) trajectory.

2. Issues related to improving surface finish:

In addition to the previously mentioned alignment, clamping, and mechanical precision factors that need to be eliminated, it is also important to wait until the previous standard pit completely disappears before moving on to the next standard. During processing, especially with precision standards, do not stop for long periods to prevent electrode deformation, which would hinder the ability to polish according to the predetermined standard. Mirror power processing can be utilized. Without mirror power, the surface quality requirements are very high, and the electrode may not be reused. Using small pulse width, briefly switching polarity, or adding a bit of uniform, fine graphite powder can have special polishing effects.

3. Issues related to improving processing stability:

Ensuring stable processing is an important condition for improving productivity and the quality of cavity molds. Unstable processing not only directly affects the erosion speed but often causes arc pulling, burning, and damage to the processing profile, leading to interruptions in processing, and in severe cases, even scrapping the mold. 1. Start by addressing the processing area, determining an appropriate current density, estimating suitable peak current, and selecting appropriate pulse duration and interval time. 2. Ensure timely and smooth removal of processed products; prevent local 'bridging' that can cause short circuits and arc pulling. 3. Pay attention to the cleanliness of the working fluid, changing oil or replacing the paper core as needed (especially in machines using both graphite and copper electrodes). 4. For graphite electrodes, avoid using positive pressure to prevent loose debris. 5. Ensure servo sensitivity.

4. Issues related to arc initiation:

Before initiating an arc, there are a series of abnormal phenomena, such as smoke, sound, and whether the spark color is normal; observe whether the screen display indicating spindle feed is stable. If instability or reverse retraction is detected, it indicates carbon buildup; if cleaned in time, it will not cause serious burning of the electrode and workpiece. However, if not addressed promptly and the time is prolonged, once a short circuit occurs, the processing may appear stable on the surface, but at this point, there will be overcurrent, the discharge spark will be dark red, the sound will be muffled, and white smoke will emerge, with graphite electrodes shedding debris. Stop to check and clean thoroughly; otherwise, the arc initiation may repeat.