Makino Duo 43 CNC Wire EDM

Our machine is only 5-6 years old. It will be cutting fine when suddenly the parts have a .012 inch taper (top to bottom). We realign the machine and everything cuts fine for awhile then, wham! Its cutting a taper again. The pieces being cut are less than an inch in diameter. We have been cutting the same parts (and material) since the machine was brand new. They (the parts) are set up in a multi-piece fixture so, it moves (almost) the entire length of travel. The fixture is not moving / is not the problem. It gets greased regularly and the factory has been no help. Any ideas or help would be greatly appreciated.

Thank You,
Crazy

Hi Crazy:
When the machine does this odd behaviour, does the control tell you the U and V axes are moving?
Is the control telling the truth?

Is the defective part conical or is it just leaning over sideways like the leaning tower of Pisa?

Does the taper happen everywhere around the periphery of the part or just in random places at random times?
Is it consistently 0.012" or does it vary?

Did you notice if it happens only right after you home the machine or does the machine run for days and weeks without being turned off and just randomly do weird shit every once in a while?

Is there anything you can do to provoke the bad behaviour?
Anything you can do to make it stop?

Once you know the answers to all these questions, contact Brian Pfluger at Makino and ask him to poke his technical guys for you.

It might be something as simple as a software issue that just needs a reload, it might be something mechanical like a dragging tank seal, or it might be something more ominous; nobody can tell until you can describe the behaviour pretty accurately.

Cheers

Marcus
Implant Mechanix • Design & Innovation > HOME
www.vancouverwireedm.com

Thank You, Marcus

Marcus,

My guys tell me that it is only every once in a while that it does this (weird shit) after running for weeks on end (with no shut down). It's not a consistent .012" inches (last time it was .007"). It is a straight taper (like Pisa) all the way across the parts (slots, grooves, radii). They run (2) twelve piece fixtures; lights out; on (mostly) solid Nickel. So, it gets really expensive when it happens. The guys say they have no idea about the 'U' & 'V' as that would require constant recording of the values (for comparison) in our production environment. We have a couple of hundred part numbers but, they all mount the same on the Makino, on the fixtures. The only thing they can do to stop it is to re-align the heads, they say. We have a large (mechanical) maintenance department here in our plant. And, they are 'clueless' to this problem, too.

My friend 'Kiwi' from New Zealand (also a Machinist) always says "Cheers." Are you from that part of the world?

Thanks again. Cheers to you also,
Mr. CDC

Sounds expensive ...

So, what has/is being done to remedy this situation?

I am not familiar with Makino machines but for starters:

Have checked your error codes?

Have you examined your guides, nozzles and contacts?

Have you checked your program(s)?

Have you checked the one(s) in the machine(s)?

Have you dry run through your program(s)?

Did you watch for U/V movement?

If your not using U/V have you (can you) disabled them?

Have you double-checked your fixtures and procedures?

Have you ensured that you are not dropping slugs and hanging the wire/nozzles?

Hi again Crazy:
The only ways the upper and lower heads can move out of alignment relative to one another is if one gets bumped, or the U or V axis (or both) is commanded to move.
A command doesn't have to be a deliberate statement in the code; a software glitch or unclean power could theoretically have the effect of creating a "pseudo" command, but you'd think it would show up in other ways than always commanding the same axis to always move about the same amount.

I thought maybe a sticky homing sensor could be the problem but it does not appear to be related to homing the machine.

Is there any chance at all a slug is getting trapped in the lower flush cup and pulling something out of alignment? (I know you've said "No Way" but are you absolutely positive?

It would sure be nice to find out if the U or V axis actually move when it does weird shit; could you rig a camera to watch the screen or rig touch sensors on the U and V slides and record what happens over time?

I certainly wouldn't give up on the problem; but it's so hard to diagnose intermittent random problems like this when they happen infrequently enough that you can't just watch a cycle and see the problem occurring.

Another option: could you perhaps re-write the code so it does a touch on a registration block after each feature is cut and stops the machine if the touch shows a change in apparent position of the block? I know that'll really screw up your cycle time but at this point you may not have much choice.
At least that way you could see if the upper head has actually been commanded to be out of position with respect to the lower and if the U or V axis actually shows a shift from Zero on the display and where in the code the problem occurred.

Ideally you'd be able to log all instances of motion related power to the U and V servomotors but I have no idea if a Makino can do that or how you'd go about it if the machine can't. (Obviously there should be no instances without an explicit command)

Last; no, I'm not a Kiwi, I just picked up the "cheers" expression some time in my past and it's stuck with me for decades. (I probably got it from a Kiwi )


Cheers

Marcus
Implant Mechanix • Design & Innovation > HOME
www.vancouverwireedm.com

I would imagine your machine is using the split guide system. If this is happening after a wire break break I know what your problem is. On the Makinos it is set up to center the wire through the guides with an upper die. What happened in our shop someone moved the upper block where the water jet and die mount to make the stream better not realizing that they have moved the wire out of center of the split guides . Remove the flushing nozzles and boxes . With the guides open and tension on the wire the wire should be in the center of the guides when you close the guides if the wire moves in the Y direction you have a problem . What happened to us was the wire guide was closing on the wire of center.Causing taper .713-305-5012 if you need help Good luck sir.

gabedrummin said:

I would imagine your machine is using the split guide system. If this is happening after a wire break break I know what your problem is. On the Makinos it is set up to center the wire through the guides with an upper die. What happened in our shop someone moved the upper block where the water jet and die mount to make the stream better not realizing that they have moved the wire out of center of the split guides . Remove the flushing nozzles and boxes . With the guides open and tension on the wire the wire should be in the center of the guides when you close the guides if the wire moves in the Y direction you have a problem . What happened to us was the wire guide was closing on the wire of center.Causing taper .713-305-5012 if you need help Good luck sir.

Click to expand...

Interesting ...

Assuming this is the case ... how could his operators/machinists consistently and persistently not notice this?

If this is what is happening, somebody is changing it back to the correct position at some point and then somebody, perhaps the same somebody, is getting it wrong ... again.

Rinse and repeat ...

Hi gabedrummin:
If this turns out to be the problem whatever tech at Makino the OP has been working with should get a major dope slap.
You'd think this would be common knowledge among the techs, and one of the very first things for the tech to investigate.
It would also be one of the obvious things for Makino to fix so it cannot happen again, as KilrB points out.
The mind just boggles.
Cheers

Marcus
Implant Mechanix • Design & Innovation > HOME
www.vancouverwireedm.com

Crazy,

I am sorry to learn of your difficulties. In reading the above descriptions, I am thinking that your issue might be Operator induced. The Split Guide wire system on your DUO43 is excellent in its simplistic maintenance and long component life, but there are some operational procedures that your operators have to consider with the split guide system. I believe what is happening is that the operators might be manually threading the wire after a wire break, and they are not performing this recovery method correctly. I have seen this be an issue before in the past a few times, as this stems from operators not fully understanding the Split Guide system and not breaking or realizing bad habits from operating other Wire EDM machines.

My preference is to let the machine run unattended and rethread itself in the event of a wire break, as the machine will rapid back through the cut geometry up to the break point at relatively high speed (about 2" per minute). The reality of performing manual threading is not really saving any time if this is the case that is leading to your part error. I believe the operators might be performing a manual rethread after a wire break, and they are not unspooling enough wire to where the wire reaches the rear pinch rollers and is put under tension. Operators that are used to running round guide machines simply unspool enough wire until the wire is in the lower head. This method works that same on Makino's round guide system, but when performing manual threading on the Split Guide system that open and close, the wire must be unspooled enough until the wire reaches the pinch rollers...once this happens, the wire is put under tension and is then automatically centered in the guides, and then the guides close and continue operation. Makino does have a Step-By-Step procedure for performing manual threading on the Split Guide system, and we can provide this to you for your reference.

I don't want to wrongly accuse your operators of this error, but from what you have described, I believe improper manual threading of the wire is the most likely cause of your issue. Please continue to work with Makino Technical Support, and be sure to request and discuss this with someone from the Applications Group. Our Applications Engineers will be much better suited to dealing with "process" related challenges rather than focusing on addressing individual symptoms. Please let me know if I can be of any further assistance!

Best Regards,

-Brian

Brian,

Whether this is the cause of the OP's problems or not, is there not some way for the machine to perform a check to ensure the wire is in the guides before it resumes cutting?

... and while I'm at it ...

Thanks for what you do here Brian.

Whether it's part of you job or you're doing this on your own time it's good to see an honest to goodness factory "rep" here on PM putting in time to help.

I only wish some of the other mfg's would do the same ... and I've told them so on more than several occasions.

If you take the flush cups off you can see the wire alignment . Open the guides while the wire is running and note whether or not the wire jumps away from the guides .We have 4 duo 43s . Never had any problems until we hired several operators . When it was just me no problems. Good luck sir.We do as much trouble shooting on our own before bringing in Makio. Ask to speak with Mike Dillion at Makino.

KilrB,

The main important factor with threading the wire on the Makino Split Guide system is to get the wire back to the rear pinch rollers before the guides are closed. Tension is applied to the wire once the wire reaches the pinch rollers, and this tension ensures that the wire is centered in the guides. Makino has offered a few different sensors over the years to "check" wire location within the guides, but these sensors increase maintenance intervals, and were pretty much more trouble than what they were worth.

The Split Guide system has been around since the hey-day of Hair Bands (that's the 1980's), so it’s a very mature and reliably proven system. The mechanics of the Split Guide system for automatic threading are pretty simple, and are probably best appreciated with a video and explanation. The only time we see issues with “wire out of the guide” conditions on the Split Guide system is when the wire is manually threaded…and the operator treats the machine like a typical Round Guide machine. As explained earlier, the wire MUST reach the rear pinch rollers during wire threading process so that the wire is pulled to the center before the guides are closed. Makino does have a procedure for manual threading of the Split Guide system, but the reality is that manual threading should be rarely (if ever) required.

…and “Thank You” for the recognition on contributing to the PM community. This is something that I do on my own, and I’m happy to give back and help out our fellow EDM’ers whenever possible!

-Brian

KilrB said:

Brian,

Whether this is the cause of the OP's problems or not, is there not some way for the machine to perform a check to ensure the wire is in the guides before it resumes cutting?

... and while I'm at it ...

Thanks for what you do here Brian.

Whether it's part of you job or you're doing this on your own time it's good to see an honest to goodness factory "rep" here on PM putting in time to help.

I only wish some of the other mfg's would do the same ... and I've told them so on more than several occasions.

Click to expand...

Has your problem been fixed ? What did you do to correct it ?

Makino Duo 43 CNC Wire EDM--Crazy

gabedrummin said:

Has your problem been fixed ? What did you do to correct it ?

Click to expand...

Sorry for taking so long to reply. But, the maintenance man form our Makino Dealer just left. A few things have happened to report. First, and most importantly, you were all correct, spot on and we thank you. Once I gave your replies & suggestions to the operators and lead men, well I got nothing! Nobody was doing anything wrong! Once I gave it to the Senior Manager, he (finally) got to the bottom of it. We did have operators whom were hand threading the wire, after it broke, and were not getting it right (they honestly admitted that they had not read the replies that I got from you, that I handed out, that I questioned them about, days later). You can lead a horse to water but...). Secondly, we also had a broken nozzle and needle(?) according to the dealers maintenance guy (today). Thirdly, we have a leaking pump seal (totally separate issue). Makino wants (about) $3,300.00 for a new pump (and will not sell us a seal, I am told). Our Senior refuses(!) and is trying to buy / adapt a cheap aftermarket pump (From Grainger's?). [I don't think they are very happy with Makino, right now, in upper management].

Thank You again, all of you!

Sincerely,
Mr. C. D. C.
Journeyman Machinist (43 years)
CNC Lathe & Mill Operator
Makino EDM button pusher (when they are really desperate...been a couple of years...don't do set-ups, etc..)

Crazy@VMS said:

Sorry for taking so long to reply. But, the maintenance man form our Makino Dealer just left. A few things have happened to report. First, and most importantly, you were all correct, spot on and we thank you. Once I gave your replies & suggestions to the operators and lead men, well I got nothing! Nobody was doing anything wrong! Once I gave it to the Senior Manager, he (finally) got to the bottom of it. We did have operators whom were hand threading the wire, after it broke, and were not getting it right (they honestly admitted that they had not read the replies that I got from you, that I handed out, that I questioned them about, days later). You can lead a horse to water but...). Secondly, we also had a broken nozzle and needle(?) according to the dealers maintenance guy (today). Thirdly, we have a leaking pump seal (totally separate issue). Makino wants (about) $3,300.00 for a new pump (and will not sell us a seal, I am told). Our Senior refuses(!) and is trying to buy / adapt a cheap aftermarket pump (From Grainger's?). [I don't think they are very happy with Makino, right now, in upper management].

Thank You again, all of you!

Sincerely,
Mr. C. D. C.
Journeyman Machinist (43 years)
CNC Lathe & Mill Operator
Makino EDM button pusher (when they are really desperate...been a couple of years...don't do set-ups, etc..)

Click to expand...

And what's their problem with Makino?

They shouldn't need someone to explain that none of their problems were Makino's fault ...

Crazy,

I am glad to hear that your machine is back up and running properly, and that you have verified and corrected the source of your process issue!

As for your pump seal issue, I understand the sticker shock. The pumps are a purchased component from Grundfos, and Makino does not offer any wear parts or replacement components for this unit. I would strongly recommend against installing a "cheaper" aftermarket pump, as the digital inverter and control of this multi-stage pump are integrated into the machine control. I suggest that you try and contact the pump manufacturer (Grundfos) to see what services or repair parts they might be able to offer, and it would be helpful to have the pump information for them (there is a metal tag on the pump near the base of the unit).

-Brian

Brian Pfluger said:

Crazy,

I am glad to hear that your machine is back up and running properly, and that you have verified and corrected the source of your process issue!

As for your pump seal issue, I understand the sticker shock. The pumps are a purchased component from Grundfos, and Makino does not offer any wear parts or replacement components for this unit. I would strongly recommend against installing a "cheaper" aftermarket pump, as the digital inverter and control of this multi-stage pump are integrated into the machine control. I suggest that you try and contact the pump manufacturer (Grundfos) to see what services or repair parts they might be able to offer, and it would be helpful to have the pump information for them (there is a metal tag on the pump near the base of the unit).

-Brian

Click to expand...

FWIW you can't get Grundfos "wear parts" from Agie-Charmilles either ...