Mitsubishi DWC-110H "110 WIRE BREAKAGE" alarm

Hello!
Trying to do some very first cuts with this old machine (year 1988.), unfortunately there occurs this "110 WIRE BREAKAGE" alarm almost right after I push START button. Wire is still intact- no breaks at all. Wire sensor switch (the one with whisker)also works wihout any flaws. Electrodes (carbide contacts)are new. Where to search for a solution?

I know you say that the wire sensor switch (the one with the whisker) is working fine, but it has been my experience that it is always those sensors or something directly related to them.
I would go through them again checking them with an ammeter and following them back to boards from there.

GL

Jay Crumb

JayCrumb said:

I know you say that the wire sensor switch (the one with the whisker) is working fine, but it has been my experience that it is always those sensors or something directly related to them.
I would go through them again checking them with an ammeter and following them back to boards from there.

GL

Jay Crumb

Click to expand...

Thanks Jay, I will recheck both switch and wiring. However Im for 99% sure these should be ok. This kind of CNC and machinery is new for me, so there can be somewhat stupid newbie questions from me. What is the function of that isolated contact (on my machine wire from that point is number 237 if this can help) coming from lower block? What I see is that wire slides over that contact. Maybe it is for some condition signal (like if there isn't current flow between two points machine thinks of broken wire)? I have suspicion it has relation to contact plate in wire basket. Correct me if Im wrong.
Guntis

It was the sensor (it became "sticky", most of the time it would show closed contacts, sometimes return to normal state). Ok- now machine allows to press Machining button. However right after that on CRT label CONTACT is illuminated in red- no machining! There is no short circuit between table and wire, liquid resistivity is normal. I even removed power wires from generators H1 and H2- result is the same: CONTACT after pressing MACHINING button. Which board/part of EDM controls existence of contact? What look next?

Just a thought but did you look very closely along the path of the wire to make sure there are not even a little piece of wire stuck some where? The metal guide tube on upper head, the area that cuts wire, check and remove power feeders, piece in flush cup area, in the tube leading to rollers and aspirator before wire cutter? My machine has a break pad just before it goes to the upper head section and one time it some how got hooked on the top of the pad to cause the contact light as well.

Tvalen1432

The CONTACT problem occured due to relays (small 24V Matsushita's) on RIFA board and FS unit. On FS board there is optorelay that switches on contactor RA11 (located near FS board), and by this make connections in main units (1H and 2H). If the contactor contacts are open and if we try to start machining then CONTACT become illuminated in red. Now it is possible to switch Machining ON without errors, voltmeter show voltage, and it is possible to change machining parameters in Interrupt screen. It seems that very soon there will be first sparks. Now only a minor repair/refurbishing of power cables is needed.
Yes- this machine is somewhat different and more complicated than other CNCs (machining centres/lathes) and sometimes require more deeper investigation of problem. Machine is not so new however. I have already successfully disabled unneeded autothreading and I/H options through changing parameters in CNC.

Thank You for giving an update. I think it's important that we post the resolution or answer to the problem for others.

Thanks,
TValen1432

So- there is already approximately 3kg of wire used trough my first experiments. Im impressed with machine perfomance- parts are so nice, so precise. As my main interest is cutting 2D parts(only contours, without any taper or similar fancy things)I generate parts in easy to use CamBAM software. I have made some sort of postprocessor there to use it with EDM. It works, and gives pretty good result.