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Dirty water in cutting tank..

U

Utry2win

Aluminum
Joined
Aug 17, 2011
Location
Lakeland, FL
Ok, so I will start by saying, I am so green to EDM its not even funny. We recently purchased our first WEDM and I am tasked with learning it. Question I have is, how dirty does the water in your tank get while cutting a part? I am currently running a job out of A572 GR50 material, basically mild steel. 2" thick, about 16 linear inches worth of cut. The water gets so cloudy in just a few minutes that I cannot even see the part anymore. Something I am doing wrong, or normal? The machine fills the tank, and throughout the cutting process it uses the flushing from the heads as the only water source for the entire cut. It overflows back to the tank to be filtered and reused. I see videos on youtube of people cutting parts, even long cuts, and the water stays fairly clear. Is it the material? The wire? Cut parameters? Something else I'm missing?

Machine = Excetek V350G
Wire = .012" hard brass
 
I would say your water condition is normal. On our Sodick, the water will get so dirty you can't see the part.
 
Well that is good to hear. Another question about this particular job. I am cutting a slug out of a longish slot in this part. There are cross holes perpendicular to the wire. On the start side of the slot, it cuts right past the hole and around, but once it gets to the hole on the opposite side, I am getting wire break problems. It seems slowing my feed rate down to .08ipm from the machine's suggested FR of .1181ipm keeps the wire from breaking. What I cannot understand is why it flies right by the hole in the first side, but has break after break on the second hole. Wisdom?
 
Utry2win said:
Well that is good to hear. Another question about this particular job. I am cutting a slug out of a longish slot in this part. There are cross holes perpendicular to the wire. On the start side of the slot, it cuts right past the hole and around, but once it gets to the hole on the opposite side, I am getting wire break problems. It seems slowing my feed rate down to .08ipm from the machine's suggested FR of .1181ipm keeps the wire from breaking. What I cannot understand is why it flies right by the hole in the first side, but has break after break on the second hole. Wisdom?
Click to expand...

Check the holes for chips from drilling them. Chips can cause wire breaks and/or lead to short circut while cutting.
 
when I have to cut thru something with holes intersecting the cut, I plug the holes with aluminum or something like that. You can then take it out when you're done
 
Clean and clear. It may be worth mentioning, this part has two identical slots side by side. The cross hole runs completely through the part. The problem side is always on the right hand side of the slots. My thoughts were an issue with flushing possibly, but still cannot get it to make any sense. In attached picture I show which holes are the issue, for reference.hole issue.jpg
 
Any interruption in the part may cause you to break the wire. Experience will teach you when you need to use different parameters. Starting from the edge of the part, lower your power settings until you are 1/8 inch into the part. If the part doesn't come completely up to the top or bottom flush cup, adjust settings. If your machine detects conditions as they change, it will adjust settings, otherwise you will have to do it.
 
Utry2win said:
Clean and clear. It may be worth mentioning, this part has two identical slots side by side. The cross hole runs completely through the part. The problem side is always on the right hand side of the slots. My thoughts were an issue with flushing possibly, but still cannot get it to make any sense. In attached picture I show which holes are the issue, for reference.View attachment 277522
Click to expand...

I see, that is kind of odd. I noticed you said "cutting a slug out"...Is that a solid plate when you start? Or are they somewhat roughed in before you get it? Could be once you get to those point in the part, with the hole being there, it's possible you may have some movement on the slug itself, causing it to pinch on the wire. You really shouldn't have any problems cutting something like that.
 
I run a Pair of Sodick machines, depending on the material the tank water can get very cloudy. Rough cutting steel will usually be the worst with a dark brown cloud forming around the part, and sometimes filling the whole tank.

Sounds like your machine is doing the same thing.
 
jz814 said:
I see, that is kind of odd. I noticed you said "cutting a slug out"...Is that a solid plate when you start? Or are they somewhat roughed in before you get it? Could be once you get to those point in the part, with the hole being there, it's possible you may have some movement on the slug itself, causing it to pinch on the wire. You really shouldn't have any problems cutting something like that.
Click to expand...

Yes, the slot areas are solid, with the exception of the .377" hole through, and a single 1/4-20 blind hole on each side. The part does spring open .003" total per slot at the open end from stress relief, but I cannot imagine it did that quick enough to pinch anything. I have the wire starting on the left side, and cutting the profile, it stops .1" from breaking out, drains the tank, and I add magnets to retain the slug from falling. After cycle start again, it finishes the cut, and waits for me to remove it before starting the next slot. The parts came out great, and well within tolerance, just trying to learn the secrets of a new skill is all.

Here is a copy of my program. I have a ton on notes in there, reminding me of what each mcode does, until I learn them confidently.

%
O8996
G90 (ABSOLUTE)
G95 (INCH MODE)
G59 G0 X-1.1871 Y0.03
G92 X-1.1871 Y0.03 (CUT START POSITION SETTING)
M20 (THREAD WITH AIR)
M78 (FILL TANK)
S1761 D.00827 (CUTTING PARAMETERS AND WIRE OFFSET)
(INSERT TOOLPATH HERE)
G1 G41 X-1.193 Y0.03
G1 Y0.
G1 Y-2.93
G3 X-0.693 Y-3.43 I0.5 J0.
G1 X-0.625
G3 X-0.125 Y-2.93 I0. J0.5
G1 Y-0.1
M41(DISCHARGE POWER OFF)
M42(WIRE FEED OFF)
M58(DRAIN TANK)
M00 (ADD SLUG RETENTION)
M78(FILL TANK)
S1761 D.00827 (CUTTING PARAMETERS AND WIRE OFFSET)
(INSERT REMAINING TOOLPATH HERE)
G1 Y.03
G40 Y.05
G0 X0.1309 Y0.03
G92X0.1309 Y0.03
M00
S1761 D.00827
G1 G41 X0.125 Y0.03
G1 Y0.
G1 Y-2.93
G3 X0.625 Y-3.43 I0.5 J0.
G1 X0.693
G3 X1.193 Y-2.93 I0. J0.5
G1 Y-0.1
M41(DISCHARGE POWER OFF)
M42(WIRE FEED OFF)
M58(DRAIN TANK)
M00 (ADD SLUG RETENTION)
M78(FILL TANK)
S1761 D.00827 (CUTTING PARAMETERS AND WIRE OFFSET)
(INSERT REMAINING TOOLPATH HERE)
G1 Y.03
G40 Y.05
M58(DRAIN TANK)
M30
%

20200203_141946.jpg
 
Utry2win said:
Yes, the slot areas are solid, with the exception of the .377" hole through, and a single 1/4-20 blind hole on each side. The part does spring open .003" total per slot at the open end from stress relief, but I cannot imagine it did that quick enough to pinch anything. I have the wire starting on the left side, and cutting the profile, it stops .1" from breaking out, drains the tank, and I add magnets to retain the slug from falling. After cycle start again, it finishes the cut, and waits for me to remove it before starting the next slot. The parts came out great, and well within tolerance, just trying to learn the secrets of a new skill is all.

Here is a copy of my program. I have a ton on notes in there, reminding me of what each mcode does, until I learn them confidently.

%
O8996
G90 (ABSOLUTE)
G95 (INCH MODE)
G59 G0 X-1.1871 Y0.03
G92 X-1.1871 Y0.03 (CUT START POSITION SETTING)
M20 (THREAD WITH AIR)
M78 (FILL TANK)
S1761 D.00827 (CUTTING PARAMETERS AND WIRE OFFSET)
(INSERT TOOLPATH HERE)
G1 G41 X-1.193 Y0.03
G1 Y0.
G1 Y-2.93
G3 X-0.693 Y-3.43 I0.5 J0.
G1 X-0.625
G3 X-0.125 Y-2.93 I0. J0.5
G1 Y-0.1
M41(DISCHARGE POWER OFF)
M42(WIRE FEED OFF)
M58(DRAIN TANK)
M00 (ADD SLUG RETENTION)
M78(FILL TANK)
S1761 D.00827 (CUTTING PARAMETERS AND WIRE OFFSET)
(INSERT REMAINING TOOLPATH HERE)
G1 Y.03
G40 Y.05
G0 X0.1309 Y0.03
G92X0.1309 Y0.03
M00
S1761 D.00827
G1 G41 X0.125 Y0.03
G1 Y0.
G1 Y-2.93
G3 X0.625 Y-3.43 I0.5 J0.
G1 X0.693
G3 X1.193 Y-2.93 I0. J0.5
G1 Y-0.1
M41(DISCHARGE POWER OFF)
M42(WIRE FEED OFF)
M58(DRAIN TANK)
M00 (ADD SLUG RETENTION)
M78(FILL TANK)
S1761 D.00827 (CUTTING PARAMETERS AND WIRE OFFSET)
(INSERT REMAINING TOOLPATH HERE)
G1 Y.03
G40 Y.05
M58(DRAIN TANK)
M30
%

View attachment 277532
Click to expand...

Seems like you are doing the right stuff, and dont have a slug bouncing around in there. RJT is right about any interruption in the cut can have affects on the wire itself. You'll just have to tinker with the cutting conditions and let it do its thing. I cut a lot of interrupted cuts and parts with various heights, sometimes you just have to find the average thickness and make small adjustments and just let it cut. Glad to hear parts are coming out good. Sorry not much help.
 
jz814 said:
Seems like you are doing the right stuff, and dont have a slug bouncing around in there. RJT is right about any interruption in the cut can have affects on the wire itself. You'll just have to tinker with the cutting conditions and let it do its thing. I cut a lot of interrupted cuts and parts with various heights, sometimes you just have to find the average thickness and make small adjustments and just let it cut. Glad to hear parts are coming out good. Sorry not much help.
Click to expand...

More help than you are taking credit for. Sometimes knowing you're on the right track is just as important. I appreciate everyone taking the time to answer my questions.
 
I've never seen that before, I cut stuff with all kinds of holes and chambers. Never had k e cause a breakage issue. Maybe theres slight hardening on the rim of the slot and it causes it to break.
 
I run a Mitsubishi FX and I too would have a lot of problems when I had cross holes. I believe it has to do with flushing as well. In some areas the debris would go into the hole and then come back at the wire thus breaking it. I lower or higher the flush at those areas and seem to have less problems. Of course the settings, like the others mentioned, go hand in hand with flushing.

And I too agree that just knowing your on the right track at times is the greatest help of all and motivates you to keep pushing on learning. There is always something to learn. Good luck!

Tvalen1432
 
Lowering the flush and backing off the power a bit near the big holes should help. I never ran a Mits but on a agie I can make a point .100 before and .100 after and call up a low power & flush setting in the problem areas then return back to full power once its past. Also make sure your not squeezing it in a setup vise.
 
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