Wire EDM Machine Retrofit?

Hi guys we have an old wire edm machine at work that does not currently work. I have looked but have found nothing on anyone converting a wire edm to Linuxcnc. Can someone point me in the right direction to find some information on this please, that is if it has even been done.

Thanks Mike

Hi Mike
I have a Sodick wire edm machine that is still a work in progress in terms of retrofitting it to linuxcnc. I abandoned it for a while now but here is my opinion on retrofitting a wire edm machine using Linuxcnc.

Retrofitting the motion, wire tension, wire feed, flushing pumps and valves etc - no problem, it mainly depends on the drives installed and how they are controlled, but that is the case with any CNC retrofit. In my case they were step/dir so i used a Mesa 7i76E card.

The problem came in with the spark generator. There is a lot of unknowns there. Im my case, i could not find any information on how to control it, so i tried building my own...

I managed to get the machine to cut, but dead slow..... Basically too slow to be of any use, even for hobby use.... There is still a lot of development work that i want to do on the spark generator and feedback when time permits. 

It is possible, though, look at the BAXEDM product and videos on youtube. 

Henk

I don't know if it's been done in LCNC, but the strange EDM requirement is the ability to run the toolpath in reverse to manage arc gap.

I believe LCNC has this ability using the 'adaptive-feed' feature.  i.e. negative feed results in the tool (wire, electrode) backing up along the cut path.

Tommy's right - LCNC can move just about anything... but I'd suggest having a look in the manual on adaptive feed and see if that looks like it'll manage the arc gap appropriately.

I wonder if the plasma-centric THCAD output could be mapped to adaptive feed so if arc voltage drops the toolpath is run in reverse until the gap is sorted out?  Or if the arc generator onyour machine has a low-voltage analog output you could feed in to LCNC?

There's a good YT vid from Applied Science on a hole-popper EDM using Kflop and it's ability to run in reverse.  If LCNC's adaptive feed sounds promising to you the concepts in the vid might help.

As Tommylight say, LinuxCNC can run a wire EDM machine, although will require more work than a regular mill, since there is more interconected systems.

First of all you need to understand how your machine is build. New machines control the pulse generator in the main NC control, but really old ones had a separate generator that the operator had to select the spark parameters manually. If it's one of the newer ones and the NC control is dead, you are going to have to make your own, although maybe some of the power stages can be used. Pretty sure you can control the pulse generation in LinuxCNC, but I would avoid it at first.

You need to connect your servo voltage to the adaptative feed pin, with a selectable bias to set the gap and moove backward when the gap is lower than the threshold. On modern wire machines, pulses are AC to avoid electrolysis so if you want to measure the voltage directly might be a a bit extra trickier than simple DC. With some electronics you can output the servo voltage averged, and measure it with an analog input or a ADC like the THCAD.

If your machine is a 5 axis one, you have to create a kinematics module. You might use the hot wire kinematics module and add the Z one. Anyways at first U and V can be left for the future.

Flushing is a simple as controlling a VFD. Wire breaking detection just a input pin. Wire speed can be controlled a motor in velocity mode, and wire tension with a servo in torque mode and close the tension loop in LinuxCNC.
 

I am looking at a sodick a320 right now, and I am willing to work out hal component to control the spark generator. As the machine is fully functional, this should allow for a significant amount of reverse engineering. It might take more than me to sort it out however..

Hello Henk, I am from Argentina, owner of a SODICK A320 EDM machine. The NEC9801UF pc stopped working and has no further fix. Can you help me in something?
Thank you so much

BAXEDM on youtube is now using LinuxCnc (Ethercat) for wire EDM. I don't know how much he is willing to share but here is his latest video:

yeah, I am not terribly interested in such a expensive EDM DIY build, only because cheap EDM machines are available. that said, the info is helpful to some degree. I passed on my Sodick purchase I need to finish getting 2 of my Hurco mills operational and sell off a 2 machines to make room.