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Mitsubishi FX20K Skimming issues

Artefx

Plastic
Joined
Oct 9, 2019
Morning all,

We have some major issues during the 3rd and 4th skims on our FX20K.

These skims are always dead slow, way less than the FA value. Sometimes even dropping to 0, then speeding up for a second before dropping again no mater what plate thickness we cut.

I realise the machine is getting on in years but this issue has only really started to appear over the last year or so. And the type of jobs we do havent changed.

The epacks were (when it ran well) and are still the standard ones from the manual so i dont see why i should have to change them.

Any suggestions?

Lee
 
Pm should be off as well as adaptive control. How much are you leaving for a skim, what material, and how tall?

I agree with plastikdreams... when skimming (for Mit's users), try turning off your Power Master and Adaptive Control options and I offer the same advice for any-and-all wire machines that have similar adaptive features.

While these options are advantageous in roughing and bad-flush conditions, skimming is usually much less problematic and IMHO, these "thinking" options can interfere with the simplicity of skim-cuts and instead, allow the machine the opportunity to "outsmart" or even "argue" with itself ("Uh oh... slow down. Oh no... a sharp corner. Oh no... too much material left in a fillet, what'a we do now? Hey, we've got 2" of straight cutting, let's speed up.") Umm... no thanks.

IMO, most skim cuts are quite straight-forward and simplistic and don't need a "conversation" among multiple, algorithmic "gremlins", all cranking handles within the control.

Since I've been wrong before, I ask any OEM apps-guys who frequent this venue; if you have a better explanation or strategy for skim cutting, straighten me out on this as I don't wanna short-change your product's abilities or speak in error.

BG
 
Thanks for all the replies guys.

Looks like i'll try without adaptive and pm, though, honestly, they have always been turned on on all the cuts ive done over previous years. It seems odd i have to change things like that now.

FYI material is either hard 01 or hard D2 toolsteels ranging from 20 to 90mm thick. The problems occur on every thickness unless we use e-packs for thicker material (eg 30mm steel needs 40 thick e-packs). The only problem in doing this is that we are having sizing issues. Everything cuts too tight / small.
 
I just had a similar issue on a MV2400 except mine would slow to a stop on the 2nd skim. Turned out to be a cable to the lower head was bad. Might want to check for continuity.
 
Hi Lee,

Just small question, rough cut goes ok?

If that so check the water pressure for skim it should be around 1 on the flowmeter, another point very important is the water quality, please check it is on 24 and if you could measure with device for microSiemens it should go around 15 microSiemens measuring directly on the clean water tank. Clean the resistivity sensor before measuring.Give new position on power feeders upper and lower and if DD guides has a lot of hours please change them.

If the problem persist please check the offset values, for the 3rd and 4rth skims maybe the wire find so much material to do the skim cut. in order to solve this depending on what you're doing punch or die, in punch reduce the offset and remember it is radial, for die do the reverse higher the offset, but only in rough cut and 1st and 2nd skim and leave the 3rd and the 4rth to the original values. The point is to make the increment a litle bit soft, also ckeck the water flow in the rough that should be strong, around 10 put your finger while fluid on trying to cut the flow if you're able to do it the water pump is not OK andyour problem comes from the first cut on the water flow part.

Best regards.
 
I agree with plastikdreams... when skimming (for Mit's users), try turning off your Power Master and Adaptive Control options and I offer the same advice for any-and-all wire machines that have similar adaptive features.

While these options are advantageous in roughing and bad-flush conditions, skimming is usually much less problematic and IMHO, these "thinking" options can interfere with the simplicity of skim-cuts and instead, allow the machine the opportunity to "outsmart" or even "argue" with itself ("Uh oh... slow down. Oh no... a sharp corner. Oh no... too much material left in a fillet, what'a we do now? Hey, we've got 2" of straight cutting, let's speed up.") Umm... no thanks.

IMO, most skim cuts are quite straight-forward and simplistic and don't need a "conversation" among multiple, algorithmic "gremlins", all cranking handles within the control.

Since I've been wrong before, I ask any OEM apps-guys who frequent this venue; if you have a better explanation or strategy for skim cutting, straighten me out on this as I don't wanna short-change your product's abilities or speak in error.

BG

I need a little more understanding of the function of adaptive control and PM. Adaptive regulates the speed of the cut based on condition and ability to prevent wire breaking. PM controls the spark/cut regulating to maintain a set amount consistently. Is that correct as a general description? If so then how do you set your skim cut offsets to get the desired end result? By turning them off it seems you would have to judge by trial and error and depending on if your skim was outside of the part or inside of it. Sorry I'm a bit confused and am still not getting the whole PM and adaptive thing. Hopefully some one can explain to where it will just click. I would like to learn a better way because there are parts that I have problems like this such as when there are holes in the die and I'm cutting the contour across those holes and debri or what ever causes wire break on even a skim be it flush or PM adaptive setting IDK. Thanks All.

Tvalen1432
 
"Since I've been wrong before, I ask any OEM apps-guys who frequent this venue; if you have a better explanation or strategy for skim cutting, straighten me out on this as I don't wanna short-change your product's abilities or speak in error.

BG"

tvalenzuela1432,

Sorry Tvalen, but what I posted is the limit of my specific knowledge on this. As stated in my last paragraph (above), I was hoping an active AE with the latest information could jump in and help you (I'm retired and it's been several years since I "played the piano").

Call Mit's applications for help... they're a lot smarter than I am. :scratchchin:

BG
 
I need a little more understanding of the function of adaptive control and PM. Adaptive regulates the speed of the cut based on condition and ability to prevent wire breaking. PM controls the spark/cut regulating to maintain a set amount consistently. Is that correct as a general description? If so then how do you set your skim cut offsets to get the desired end result? By turning them off it seems you would have to judge by trial and error and depending on if your skim was outside of the part or inside of it. Sorry I'm a bit confused and am still not getting the whole PM and adaptive thing. Hopefully some one can explain to where it will just click. I would like to learn a better way because there are parts that I have problems like this such as when there are holes in the die and I'm cutting the contour across those holes and debri or what ever causes wire break on even a skim be it flush or PM adaptive setting IDK. Thanks All.

Tvalen1432

From what I have experienced PM helps to minimize wire breakage when you do not have optimum cutting conditions (like cutting through holes, steps, have bad flushing or even if your nozzles are more that .012" away from the part.

I attached a picture straight out of Mits manual regarding Adaptive Control, hope it helps.
Untitled.jpg
 








 
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