Mitsubishi cx20 4 axis issue.

[klrskies]

Our cx 20 isn't interpolating 4 axis correctly. It's as though the upper level geometry level is programmed at a greater "z" height than the actual part is. Any advice appreciated.

Ken"

[klrskies]

I'd like some help in regard to calibrating the upper and lower pivot point distances with the mitsubishi pick-up block and discuss the related values the machine puts it to its registers.

[Royster]

Hi, You need to perform a Taper-Z as per the machine manual.

If you've done this let me know and I will try to elaborate

[klrskies]

In regard to the values we get when running taper z, they always come up around .280 ~.300 for both upper and lower heads. Were going to cut a test piece on an 1" tall block where a 20 degree angle should go tanent to the perpeindicular end of the block at exactly half way, .500" if not, something is wrong. but yes weve run the taper z function and it appears to be good, installing the values into the appropriate registers.

[klrskies]

After our test cut, we see the point where the 20 degree angle should have gone tangent to the vertical wall (midpoint of a 1" thick workpiece)was not in the correct location.

We recorded the "V" value during the angled portion of the cut with our Z height @ 3" ( .570)

We changed the z height to 4" and ran it again, and although the "V" value should have been greater, it wasnt.

Almost like were programing off fixed z location instead of the machine compensating for the actual z heigt of the upper head...

[klrskies]

In our code, it appears that we cannot have any value in the same line that indicates to use the machines table to pivot points of the upper and lower guide.

We want the machine to cut the correct geometry regardless of Z height of the head...but were not figuring that out...

[Royster]

How about this:
Make sure your 4 axis program has offset and a G41/2 on the first line of G01 code

[klrskies]

Yes, G41 is there.

[Royster]

Ok, for a standard 4ax program our Z values might be as follows

Z1=0 (workpiece bottom)
Z2=20.000 (Adaptive control measure height)
Z3=50.000 (Combination of guide height and actual Z height)
Z4=7.500 (Guide height)
Z5=40.000 (Workpiece top)

metric values of course for us brits

Hope this helps

[klrskies]

Thanks royster,

In the program code, our software (peps) writes 2 lines of code indicting the machine is to use the calculated guide distance compensation values stored in the machines registers... they are around .300"

When writing a program, the programmer can let the upper heads z position default to the workpiece height and the generated code will have the correct 4 axis geometry if the upper head is in light contact with the top of the workpiece. If the programmer/ operator wishes to operate the program with the upper head higher than the workpiece height for additional clearance, he needs to indicate that additional value in peps when beginning the program in a dialog box that shows where the head will be located or edit into the code by writing the additional numerical value+ machines guide pivot registry code prior to loading the program into the edms memory.

It had been my understanding that if no guide pivot point compensation values were put in the program and no additional clearance values were put in the program software, and the machine only read it's own registry values for guide height compensation, the machine would automatically compensate for what ever Z position the head was in, but apparently we have to add any additional value that we raise the upper head above the workpiece either when we generate a program in peps, or edit it in manually. We gave the program to Mitsubishi to review. Automatic geometry compensation
For whatever position the operator put the head in would be good if possible.

Ken

[Royster]

Righto, I'm not familiar with peps (we use Esprit) In your G code all you require at the top of your NC is (amongst other things of course) the following:

%
L1/my-programme
H1=0.205
Z1=0
Z2=20.000
Z5=40.000
G62 X0 Y0
G92 X0 Y0 etc etc

no other Z is needed as Z1 is the bottom of job (or where size held) Z5 is the top of the job (or where size held) regardless of where your Z column is DeltaZ3 takes care of that for you. and Z2 is simply a measure where Adaptive Control does it's thing...

Hope this helps