looking to Wire EDM any current users

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17 Sep 2011 13:48 #13232 by cncbasher
i'm looking at implementing and building a wire edm , anyone currently using EMC and have , any workable solutions
i'd be interested in some pointers

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19 Sep 2011 09:05 #13284 by andypugh
cncbasher wrote:

i'm looking at implementing and building a wire edm , anyone currently using EMC and have , any workable solutions
i'd be interested in some pointers

I think that wire EDM is difficult with the current trajectory planner, as I don't think that it really supports backing-out of the current move. I believe that wire EDM needs this ability to be able to maintain the spark-gap (especially if the material moves/warps)

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01 Oct 2011 02:48 #13569 by wanispissd
I have lately been thinking about trying to setup a wire edm with emc2 control, but the details of the edm functionality really are sparse. One guy on cnczone has reported doing in on emc .. search for user 'mdynac'. Implementing it as proof of concept and implementing it functionally are two different things...

I think Andy is right, that the current limitation of emc is that it cannot go in reverse. I was thinking last night (a bit abstractly) that if you could output all the axis positions at a given interval (based on feedrate) and have the most recent ..say .. three positions retained, you could use those as destinations for a program that could reverse motion. Basically when the wire short is detected, the existing program pauses, and the "two steps backward, one step forward" could run, before resuming the original program. For purposes of a wire edm, the requirement to go in reverse is often only for very very small distances (of a very recently traveled path). I think the challenge would be to output positions fast enough, as while as record delete the oldest and reorder the newest into a small program. I hear computers are good at that sort of thing, so it may not be too bad. Toward a functional implementation, I would not know where to begin..... maybe it could even be done with variables for recent positions and a canned cycle.

If anyone has suggestions, I would be glad to hear them. I just happen to have a dead wire machine that I have been thinking about trying a retrofit on, and it would make a great test platform. It currently is complete with motors and a deionized water setup, so motor drives and of course the power supply are the challenges. For the power supply, I have stumbled upon the "Garden of EDM" design (easy to google) that seems really well thought out but sadly has no reports of success. Perhaps the whole edm subject is a hobbyist white whale, when attempted beyond simply 'proof of concept' levels ?

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03 Oct 2011 08:49 #13621 by andypugh
wanispissd wrote:

I think Andy is right, that the current limitation of emc is that it cannot go in reverse. I was thinking last night (a bit abstractly) that if you could output all the axis positions at a given interval (based on feedrate) and have the most recent ..say .. three positions retained, you could use those as destinations for a program that could reverse motion.


Can you read C?
I think that the code here
git.linuxcnc.org/gitweb?p=emc2.git;a=blo...4944b795c1747d56be4c
Is what calculates the actual positions, and it would be interesting to know how easy it would be to make it back-up.
The main question would be whether the previous path elements persist in the queue, or whether they are deleted after being completed.

This is also the code which would have to change to support pause/jog/touch-off/resume I think.

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30 Nov 2011 17:47 #15230 by PKM
I was asked for Wire EDM conversion recently.
The point is that it should also have adaptive feed rate. Is it possible with EMC2?

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30 Nov 2011 19:02 #15233 by andypugh
PKM wrote:

I was asked for Wire EDM conversion recently.
The point is that it should also have adaptive feed rate. Is it possible with EMC2?


Adaptive feed-rate exists, but it can't back-up the cut to break contact if the part moves.

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30 Nov 2011 19:18 #15235 by PKM
Thanks, Andy, I understand that.
But in case the the part does not move, is it absolutely necessary?
Where can I read about adaptive feed rate?

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30 Nov 2011 19:37 #15236 by andypugh
PKM wrote:

Thanks, Andy, I understand that.
But in case the the part does not move, is it absolutely necessary?

I don't know, I have only very peripherally used a wire-EDM.

Where can I read about adaptive feed rate?

linuxcnc.org/docs/html/gcode_main.html#s...daptive-Feed-Control

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01 Jun 2014 11:02 #47586 by clkeck1
I just wanted to bump this topic and see if there has been anymore thought put into the reverse step?

I just bought 2 Mitsubishi wire edms from a foreclosure that "need boards". They are a DWC-90HA and a DWC-110SA.

I'm not familiar with the machines or controls and they weren't under power when i looked at them. If I can make one out of 2 I will probably run it as is. But if not I want to explore the possibility of retrofitting the control. I have a Mori MV35/40 mill and SL-4 Lathe that i have already converted and run everyday.

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01 Jun 2014 17:50 - 01 Jun 2014 17:51 #47596 by andypugh

I just wanted to bump this topic and see if there has been anymore thought put into the reverse step?


I don't think the people who know enough about the motion planner are found on the forum.

You ought to get more information and help if you ask on the developers mailing list. (look at the "community" link at the top)
Last edit: 01 Jun 2014 17:51 by andypugh.

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