Need Help!- Allen Bradley 8400 programming tips

[DGA]

I bought a Bridgeport type Lagun mill with an Allen Bradley 8400 CNC control. It all works fine, but I have no manuals with it. I know G code well and Fanuc machines no problem. My problem is I can't figure out how you set the workpiece coordinate, 0,0,0 off the part. It shows nothing for work offsets, but has "fixture" offsets, which I think might be the work offsets, strange I know. Any ideas, or a manual even?

[DGA]

OK, nobody responding, it sucks when you do Google searches for info and all that comes up are your own posts in these forums! Can anyone recommend a CNC programming book, like something from Peter Smid, that has specific control sections for Allen Bradley?

[jmelson]

Originally Posted by DGA I bought a Bridgeport type Lagun mill with an Allen Bradley 8400 CNC control. It all works fine, but I have no manuals with it. I know G code well and Fanuc machines no problem. My problem is I can't figure out how you set the workpiece coordinate, 0,0,0 off the part. It shows nothing for work offsets, but has "fixture" offsets, which I think might be the work offsets, strange I know. Any ideas, or a manual even?

I used an A-B 7320 some time ago, on that, say, you had an edge finder on the minus side of the X of the part. You'd enter G92 L2 P1 X-0.1 and it would set the G54 coordinate system to -0.1"
(I think I've got this all right, it was a decade ago.)

The 7320 didn't have specific buttons for work offsets, you had to do it by G92 offsets.

Jon

[advt001]

I have a mill with an AB8400 on it that is waiting on a retrofit. I'll look on monday to see if I can find anything useful.

[DGA]

Originally Posted by jmelson I used an A-B 7320 some time ago, on that, say, you had an edge finder on the minus side of the X of the part. You'd enter G92 L2 P1 X-0.1 and it would set the G54 coordinate system to -0.1" (I think I've got this all right, it was a decade ago.) The 7320 didn't have specific buttons for work offsets, you had to do it by G92 offsets. Jon

Thanks Jon, it does have G92, will see what might work there.

[DGA]

Originally Posted by advt001 I have a mill with an AB8400 on it that is waiting on a retrofit. I'll look on monday to see if I can find anything useful.

Thank you, if you actually have the manual and want to sell it I would def. be interested. Or, if you could even copy a page, I have a fax or something, anything would be a big help. This mill is all good to go and I have parts I need to machine but no good if I can't set a coordinate zero and be confident it is where it is supposed to be.

Maybe if you have a working program stored there and post it here, I could see what the start up codes need to be.

[advt001]

What do you need first? G&M codes? I will take the manual home with me tonight in case you dont get online till then.

[DGA]

Thanks for that. I got the work offset thing figured out, it has a Fixtures offset page, has 12 offsets. It has a setting for "Last offset" for some reason, like you can block out the last 10 or something, it had a zero in that setting, which meant it had ALL the offsets blocked. Why you would block offsets I have no idea, or be able to enable some. So I unblocked them all. My issues now are trying to get it to use a G42 tool offset, it uses the length offset but I can't get it to run the tool off the side of the part, always uses centerline for some reason.

[DGA]

Originally Posted by advt001 What do you need first? G&M codes? I will take the manual home with me tonight in case you dont get online till then.

Did you find the Allen Bradley manual? I still have a lot of questions on this control, like how to DNC a program, mid program restart, etc etc. Will buy your manual off you if you are willing to sell.

[imserv]

Here is some sample code that will run our machine with an AB8400 w/ 24 tool ATC:

Fred Smith - IMService
IMService web site



%
;Rectangle G-code for AB-8400
;Created with Vector-Cad-Cam 12
;Fred Smith - IMService
N010 G90
N020 G70
N030 G17
N040 G40
N050 G99
N060 ;2x 2 contour with .25 R corners
N070 ;FlatEndMill .25_1/4_internal-climb
N080 G45O01
N090 T04O04
N100 M03S2700
N110 M08
N120 G00X0.0Y0.0Z3.0F2.0
N130 G92X0.0Y0.0Z3.0
N140 ;
N150 ;
N160 G00X0.25Y0.125Z0.8
N170 G00X0.25Y0.125Z0.1
N180 G01X0.25Y0.125Z0.0787
N190 G01X0.25Y0.125Z-0.125
N200 G01X1.75Y0.125
N210 G03X1.875Y0.25I1.75J0.25
N220 G01X1.875Y1.75
N230 G03X1.75Y1.875I1.75J1.75
N240 G01X0.25Y1.875
N250 G03X0.125Y1.75I0.25J1.75
N260 G01X0.125Y0.25
N270 G03X0.25Y0.125I0.25J0.25
N280 G00X0.25Y0.125Z1.6
N290 G00Z3.0M09
N300 G99
N310 O0M05
N320 G45O01
N330 G00X0.0Y4.0
N340 G45O0
N350 G00Z0.0
N360 ;T01
N370 M30
%


The AB8400 is a very powerful controller, even given it's 20+ year age.
It has programmable sequencing, subroutines, etc. The DNC is not as
good as I would like for extremely large programs, but it does an excellent
job of look ahead on internal programs so that 3D surfaces and 2D
contours are very smooth.

[imserv]

P.S. Shift-Down Arrow keys pressed simultaneously for additional tool offset pages.

Fred Smith - IMService

[DGA]

So it DOES have DNC, I didn't know, the control says nothing like that on any screens. Can you tell me what to look for, something to go on? It has only 15KB of memory and if you use Surfcam or the like you can easily blow past that limit, DNC is a must have I think.