Eltee Pulsitron Sink EDM...Need Help!

[Beezer]

I thought I would take a chance and post this question here in hopes that there just might be someone on this forum that is familiar with this ancient beast of a machine.

A couple years ago my bosses acquired a "Eltee Pulsitron" sink EDM machine at an auction in the hopes that we could find a good use for it. The control unit is MDL: EP-30/RD and the EDM unit is MDL: TR20.
I had never used a EDM machine before so it was going to be a challenge.

I had the machine working for a couple weeks but onetime while I was playing around with it doing a test run it suddenly quit cutting and the ram returned to it's home position. There is still current at the electrode but it seems that whatever circuit that controls the ram is not working.

Just wondering if anyone is familair with this EDM unit and have any ideas of what circuits I should check? We got a basic wiring schematic with the machine but nothing that gives detailed trouble shooting info or voltages.

Any help anyone could give would be appreciated.

Thanks,
Carl

[MetLHead]

Beezer,

Can you post a picture of the machine and control boards? Believe it or not, I used to work for a company that made the control boards for Eltee. It's been a while, but I may still remember a thing or two.

Regards,
Scott

[Beezer]

Thanks Scott. I will bring my digital camera to work tomorrow and snap a bunch of pictures.

One thing I forgot to mention is the machine was in the process of doing a cut operation, not sure if that is the correct term to describe what an EDM machine does, but anyways it was working when I started to make some adjustments to the main controller when it quit cutting and the ram returned to it's home position. I believe I was adjusting the "ON Time" and "OFF Time" when it quit. I was using settings that I had found in the manuals that came with the unit which had been hand written, most likely by the operator of the machine at the company that owned the machine. These settings worked fine for me in the beginning but no longer work. No matter what settings I use the RAM always returns to the Home position after I switch off the edge finding feature of the machine.
I had someone I know from another machine shop who knows how to operate a sink EDM machine to come in and have a look and he could not get it to work either. We confirmed that there is voltage between the electrode and ground. He figured there was something wrong with the Gap control circuit but we have no way to confirm that.

I will get those photos asap Scott.

Carl

[Beezer]

Well believe it or not I got the machine working again today. I pulled out all the boards again and cleaned the contacts with contact cleaner, wiggled all the relays in their slots, check to make sure all IC's were pushed in properly and double checked all the fuses. Not sure if any of that did the job or I just was not using the right controller settings before but it's alive again. Now if I could just learn how to set it up properly for different jobs. HEHE

Carl

[MetLHead]

Beezer,

Glad you got it going again! I'd still love to see pictures of it if you dont' mind. I just want to see if it has the controls that I'm thinking of.

Regards,
Scott

[Beezer]

Here is a photo for you Scott.

[Beezer]

Another showing the inside of the main control unit.

[MetLHead]

Beezer,

Thanks for the pictures. The machine looks familiar, but I'm afraid the controls were made before my time. I remember working on the TR21 which had the EP300 control boards in it. The company was called Andtron, but I don't remember if the name was on the boards or not. I also worked on the VMC-900 which was an add-on control for an orbiting head. Ah, the memories ...

Thanks,
Scott

[Beezer]

Ah ok. We got a System 3R rotating head with the machine but I still have not figured out how that is suppose to work.

The only bad thing is when I told my boss I got the machine working again he said he already had some work he wanted me to do with it.
Not sure what I have gotten myself into now. LOL

Carl

[TAB]

Beezer,

I am not familiar with the machine you have but it looks similar to the older charmille mnaula units.

The contorl panel looks to be solid state and the ram looks tobe hydraulic. The toggle switches on the unit appear to be a capacitor bank. The LED readouts are for Z position and or the Z axis cut depth as well and or control settings. It looks like there is a mic on the ram which would be used to set the Z depth of cut if the LEDs don't. The machine contorls are likely used for control the ram.

The 3-R unit is desinged to allow the electrode to index. It looks like the it may also orbit as well. There will be threaded rod with a nut which when it reaches the nut the orbit begins.

I hope this helps. If you have any specific qeustions please post detailed (with text pointes) pics and I will try to assess the situation for you further.

[Beezer]

Here is a better photo of the control panel but some of the printing on the panel is hard to see so I have added some pointers with text to clear it up abit.

The main (large) control unit has more adjustments on it but there is a smaller control unit on the machine itself which seems to be more for finer finishing work.

There is no digital readout for Z position or depth but instead a dial indicator on the ram head is used along with a micrometer head for setting the depth of cut. I microswitch is used to trigger when the set depth of cut has been reached and stops the cut cycle.

There is a DRO system used for the X and Y axises.

Carl

[TAB]

OK dude here is the skinny.

The elspesed time is a non issue, ignore it for now.

The voltage and amparage will corespond to teh electrical conditions in the manual. They should have a table of seetings based on electorde surface area, and the work piece material. The tables should also tell you how to set the switches on teh power setting for amps. The pulse timer has on time and off time. The on time is the time the power is actually applied through the electrode and the off time is the time it is not. This is important as the process is like blasting rocks with lightning. The oil is used to clear out the dubris generated, but you need the off time to allow the chunks to solidify and flush away. This will play into the manual cycle timer which contorl sthe amount of time the electrode is in the cut and how long it is rasied to clear out the cut. The retract works like a plunger (depending on the electrode geometry)to move fluid and metal out of the cut area. This is important to prevent over cut. Over cut is when the finish size is larger than anticipated becasue the loose debris is conducting the power to the workpiece. It behaves as if the electrode were larger.

The Servo is used to control the speed and senesitivity of the ram more servo quicker response.

Polarity works like a welder and reverse polaity will cut faster but with much higer wear. I think you want electrode negative to cut normally (don't quote me on that it has been a while).

As for the ram it sounds like you understand how that works.

There should be a settign to allow you to bring the electrode to the top of the work piece to set the depth, but I don't see that. It may have to do with the gap sensitivity.

You really need the manual or else you are cooked. these guys could hepl you if you don't have them. I have never used tehse guys but they claim to have manuals.

http://www.machinerybrochures.com/shop/page693.html

I hope this helps.