another #My-Engines #DIY #EDM #machining #video. Finally he got his pulse EDM working. He had blown the protection diodes and the pulse transistors in the #electronics. His numerous 25Ω power resistors were inadequately heatsinked. He found that long on-times were the key to low electrode wear, backwards from what I would have expected. Sadly he doesn’t say anything about his parameters (voltage, current, frequency, duty cycle) or circuit design. Looks like he’s at about 5kHz. He’s using a diesel fuel pump to circulate his lamp-oil electrolyte (kerosene) through water filters.
on 02025-03-12another #machining #video, by #My-Engines, on die-sink #EDM based on Ben Fleming’s book, using varying sizes of capacitors in an RC setup (16μF, 32μF, 192μF) with the lower capacitances giving a finer finish. He has some detergent (“wetting agent”) in his water electrolyte, presumably an nonionic surfactant (he says his tap water works better than deionized or distilled). However, though big electrodes worked fine, his thin copper and brass sheet electrodes eroded too rapidly, and he wasn’t able to get a stable “burn” out of either them or graphite. Lamp oil worked better than vegetable oil or water for him. #electronics #bootstrapping
on 02025-03-12