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Mysterious wire break on Agie EDM main cut


Mar 29, 2023
Hi everyone

I am experiencing this mysterious wire break alarm for the last few months on the Agie Wire EDM. It cuts no problem when cutting an open profile (like parting something off), but when it is cutting in a closed profile (starter hole within a block), it would break again and again. It even happened on a program that I had been running for the last 5 years with I perimeter (peak current) set at 18 with no issues at all in the past.

For example: I'm wiring a 1 inch thick stainless 304 block with a starter hole, I set the Z value at 2 inches due to strap clamps, and the wire would break multiple times with the I perimeter set at 18. The wire would break about 1 inch below the work piece inside the lower guide head. At first I lowered the I perimeter to 17, and it worked for a while, then started breaking again. I thought maybe I set the Z height a bit high and lost flushing, so I lowered Z value to 1.3 inches, it worked a while. then started breaking again. Finally I lowered the I perimeter to 16 and the wire break completely stopped, but then the cycle time is also a lot longer due to lost efficiency.

I already tried the following:

1. Cleaned and rotated the upper and lower power feed to a new spot.
2. Put in brand new bearings for the bottom roller guide (to prevent any jerky motions).
3. Double-checked the technology and perimeters.
4. Replaced pressure roller (pizza cutter) on the upper guide head
5. Replaced M14 Motor (done by the service guy) to get rid of another alarm "Wire cutter motor speed differs from the present speed”
6. Checked wire tension with tension gauge.
7. Made sure the water conductivity is not too high.
8. Made sure it's using high quality Japanese Hitachi wire.

Also I noticed the lower toroid guide has a groove on the center hole, see image belowUntitled.png

But the service guy said it's caused by cutting a taper at more than 2 degrees from a while ago and not related to the wire break. I wanted to replaced this toroid guide but found out it's over $3000...

Anybody experienced something like this before? Thanks in advance for your input!
I believe the first thing I'd try is to use flushing from the top nozzle and suction on the bottom nozzle.

Have you thoroughly cleaned the lower head, inside and out, including all the power cables at both terminations? How are the pinch rollers on the back, any noticeable defects/wear?

Have you checked your flushing pump, ours gave up the ghost a few years back and caused poor flushing with no alarms. Also what is the state of the filters?

Are you using the calibration functions when you swap out the wire spool? (assuming it's the same as the Progress V4 I'm familiar with) They were 'TRolle' and 'wire jockey' if I recall correctly, these can give issues if not used.

Assuming everything above is OK I would start by cranking the flushing and instead of lowering the "I" parameter that low I'd lower the "ISH" parameter by one. If I remember right it works better than messing with "I" in these cases.

Also I see you had wire issues in the past and you switched to Hitachi wire.

I used Hitachi wire in the past and had some issues as we were being sold old spools and as these are not vacuum bagged like the Italian or German stuff they can oxidize and cause issues if they are old stock.

Best brand of wire I ever ran on that AGIE was BEDRA.