Wire EDM machine

[Neale]

hi; i also making my own wire edm, can you please tell me if the schematics of this machine are available?
Also what control hardware/software are you using?
regards
Mariano

Mariano,

This was a group project and I do not have current circuit diagrams, but I have asked the guy who designed this part if he can let me have copies and I shall be happy to make them available here. However, this comes with a warning! The actual electronic design is not particularly difficult or exotic, and it uses fairly standard switching techniques. A lot of the cleverness is actually in the firmware that runs on the embedded PIC microcontrollers. Again, I'm happy to describe our algorithms but I'm not sure that there is much point in actually publishing the code. It might take me a week or two to get hold of a copy of the circuit diagrams, so please do not expect them immediately.

There are a couple of main reasons why we have not published this kind of information before. One is that the whole project is experimental and things keep changing. In particular, we recognise that the current electronics design is lacking a few significant features/capabilities, so if we built another machine, we would base it on the current design but definitely not copy it as it is today. Secondly, as I said, the design is not particularly difficult if you have a good background in modern electronics. If you do not have a good understanding of this, and the very significant problems of getting high-power switching, digital electronics, and a massive spark/electrical noise transmitter in close proximity, you are not going to get it to work. Understanding the circuit diagrams is not the problem here; it is to do with board layouts, cable runs, isolation between different parts of the circuitry, good earthing practice, etc. It is not an easy system to build and to make work. In fact, I would even go so far as to say that if you do not have the skills and experience to design the electronics, you probably do not have the capability to recreate our design and make it work. And we do not have all the diagrams, etc, to show how our machine was put together at this level of detail. It was a one-off and a lot of this was developed and modified during building. Our electronics guru has a large cardboard box full of discarded PC boards, gathered over a couple of years of development.

As for control hardware - we have avoided use of any of the usual motion control systems (Mach3, LCNC, grbl, etc) and written our own. Gcode-to-step translation is done offline by separate software rather than using real-time translation as these other systems do, and we download a "step file" which is a step-by-step instruction list to the PIC memory. The PIC drives conventional stepper drivers and stepper motors moving the axes via ballscrews and profile Hiwin-style rails. All the firmware running in the PIC microcontrollers, which includes a very simple user interface, was written by members of the team. This does mean that our spark generator and motion control PICs communicate in a way that is probably a little bit different to most of the published techniques, which often need modification to standard software to allow pausing and reversing to take place. Again, this is an area which we know needs to be improved, another reason why we have not published our design. Why publish something which we know is deficient and which we would never do again if we built a Mark 2? We would build on the existing system, but not copy it.

I'm sorry if I sound rather unhelpful, but suggesting that you could take our design, copy it, and have a working system is so far from true that I can only say that you could use it get help your own design, but I would almost guarantee that even if you copied our design to the last detail, I would be surprised if it worked. And I can't even give you those details because many of the subtle changes to wiring, board layout, etc, have never been documented.

However, I do wish you luck with your project - getting a machine like this to work at all is a major achievement, and not many people (outside the commercial space) have managed it.