reducing cycle times

Hi Everybody!!

I'm running a couple of Agie-Charmilles cut 300 machines and we are looking at reducing cycle times on our production parts.

Just wondering if anyone has some advice/tips/tricks to improve cycle times. Is there a wire that cuts super fast? Are there any technology settings that can be overridden to make it go faster? Do you have some tricks that you've learned over the years to increase feed rate? We are only roughing so accuracy isn't as important as speed. Currently we are doing tapers that are around 27 degrees so I do need a wire that can handle that but I am working on reducing the taper to broaden my wire options.

Does anyone have experience with angling the work pieces to get rid of the extreme tapers?

Thanks!

mike

Hi TurboGuy:
The maximum feedrate you can hit ultimately comes down to how well you can keep the cut debris out of the slot and how much power you can get into the wire without breaking it.
So the quality of your flushing is paramount and the strength of the wire is probably second in importance.
In regard to flushing, one of the big problems with taper cutting is the increasing difficulty the machine has forcing water into the slot as the taper angle increases, and the nozzles increasingly do not point in the same direction as the developing slot.
Tilting the job helps re-align the slots but the nozzles no longer seal on the upper and lower part faces so you gain a bit and you lose a bit, unless you can build a flushing box to present flat faces to the nozzles and have a good fit between the part and the flushing box.
For some shapes this works terrifically well, but only some shapes can be conveniently buried in the box.
A great example is a cylindrical bar that you want to make an angled cut across.
If you bury it in a rectangular block that has a close fitting round hole through it, you can cut through the bar in much less time because the flushing is way better.

The second place to look is your wire choice.
Some of the coated wires are designed to pit aggressively as they are used, and that entrains a bit more water into the kerf right where it's needed.
A few of these are other metals than brass, so they can tolerate the deeper pits without breaking.
Zinc coated wires apparently work that way, but I'm told the performance of these wires is greatly affected by the kind of machine they're run on.
My understanding is that some of the Charmilles machines are optimized for coated wire whereas on my Chmer, I can't tell the difference in performance between coated wires and plain brass.

Third of course, is monkeying with the settings; trying to crank up wire current, on time, servo pressure etc etc.
The best controls have the most sophisticated and responsive sensing circuits and will keep the wire charging ahead for the greatest amount of time possible whereas lesser machines are lazier and take a bit of time to respond to what they sense in the spark gap.
However, when you jigger the settings, every change from factory settings carries a penalty somewhere else; accuracy and predictability are the main victims, but so are wire breaks.

Fourth is machine condition; better maintenance correlates directly with better speed, and the effect can be substantial.
The condition of everything from the DI resin to the flush cups, discharge cables and on and on may have dramatic effects.

Last on my brief list is machine choice; some are optimized for speed, some for accuracy, and you can't have both at the same time (although some of the maker's claims would have you believe otherwise).

Cheers

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

I'd agree across the board with Marcus' suggestions. A couple things I might add or comment on are...

- On my older Agie 170HSS I had, I was able to get tremendous increase in cutting speed in aluminum (and a to a lesser extent in ti) by using CobraCut B wire. It's a copper wire with zinc oxide coating of some sort. It would literally double the feed rate in aluminum in something like 1" thick material, and the difference was even more noticeable on very tall parts. It didn't seem to give the same results in steel, and I typically ran CobraCut A on that. (btw: CCB was extremely expensive, but the math penciled out -- it was definitely worth using in aluminum). I never tried it on the Cut2000 I ran for a few years, as that was someone else's machine and the work I was cutting was typically not production. Straight brass worked great on that machine, and coated wires seemed to have little benefit.

- Regarding settings: I have never found any "magic" there. If the settings are cutting reliably and it "sounds" good (and you probably already know the sound you're listening for when cutting well), then the potential gains are probably negligible.

- Since "flushing is everything", I would at least try to tilt the part, though I think Marcus perfectly described that you will gain in one aspect and lose in another. On a high-volume job though, it's probably at least worth the time to test.

- One more thing I'd add: if your job is high volume, sometimes it can pay to look everywhere else instead of messing with the cutting. Fixturing, part prep, part cleaning, inspection, running unattended, cleaning the machine... anywhere else you can look to pick up efficiency may be a better use of your time.

PM

Thanks! All good advice. Is there any advantage to using thinker wire? I'm using .010" wire right now. Do you think that I would make any significant gains switching to .012" wire? Just a thought.....

TurboGuy said:

Thanks! All good advice. Is there any advantage to using thinker wire? I'm using .010" wire right now. Do you think that I would make any significant gains switching to .012" wire? Just a thought.....

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The only advantage I saw was to the seller, as each spool has less (length of) wire on it so you need to buy more ...

Otherwise I saw no gains on our Robofil and CUT machines.

Don't forget that you will have to buy .012" guides too.

If you are roughing only and aren't too concerned about finish and size try lowering your wire tension and dropping Aj 4-6 points and see what you get.

I have one job similar to what you describe that runs faster with the addition of a fast skim pass ...

It's only @ 23.2 degrees but doing this allowed me to drop the tension and Aj on the rough, hold my tolerances, and lower the cycle times.

Thanks! by about how much would you lower the tension? I'm running at 1.0 right now. Would dropping it down to .8 be too much??

TurboGuy said:

Thanks! by about how much would you lower the tension? I'm running at 1.0 right now. Would dropping it down to .8 be too much??

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That's going to depend on your size and finish requirements.

I'm running the above job @ 0.9, but I'm coming back with a fast skim @ default settings.

Personally I would never go below 0.9 but if your requirements are wide-open ...

Old thread,(no pun intended) but remember that a single pass cut is trying its darndest to cut your path accurately in that single cut while at the same time trying to optimize speed. On my Robofils, sometimes I'll load 3 cut technology (501, 502, 503) but only program and run the 501 rough cut. The machine won't worry so much about the finish or final accuracy but will cut faster because it "thinks" it has finishing passes. To adjust the size I just change the CLE value. This isn't great for precision or taller parts, as you may get some bellying, but overall, it helps especially when a part gets ground afterward anyway. Hope this helps!