Centerline or Work Surface Programming?


To All:
Just curious which method most other shops use on their CNC mills,
Centerline Programming (where the geometry outline dimensions are used
for toolpathing and the tool's diameters are manually offset in the
machine control), or Work Surface Programming where the tool is offset
from the geometry in the CAM system and no dia. offsets are manually
entered in the control (other than minor adjustments for wear and such).
[ ] Centerline Programming.
[ ] Work Surface Programming.
[ ] Other.
Comments?
Reply to
BottleBob
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Later,
Charlie
Reply to
Charlie Gary
Reply to
Polymer Man
Occasionally, we'll mdi edit in cutter comp out on the shop floor where we hadn't had the foresight to do this upon the initial part programming...in this case, the offset value will tytpicvally be very small, as opposed to it's usually being entered into the table as an actual tool dia. ( common being such as a corner rounding / deburring tool, where the original cutter was crashed or is currently being used on a different maching center )
Reply to
PrecisionMachinisT
Bob, I think you got it confused. Centerline is just that - the gcode is the centerline of the toolpath with a zero offset (not the part profile). To confuse things a bit, the English programmers at my work use the terms On-line (centerline) and Offline (dia comp).
I find that shops that do quite a bit of at machine programming and edits tend to use Dia comp (or offline). Very popular for folks manualy entering data from prints. Aerospace shops with lots of kellering and multi-axis work use Centerline (or CL files).
-- Bill
Reply to
Bill
Bill:
Well that's certainly possible. They are not terms I normally use, that's one reason I gave a detailed definition of what I meant by each term. For anyone else that might respond to this thread; please choose your answer according to my definitions.
Reply to
BottleBob
Bob, it was quite clear what you meant. I'm sure you will never hear the end of it.
Best Daveb
Reply to
Anonymous
BottleBob wrote in news: snipped-for-privacy@earthlink.net:
I use this method primarily for reasons of being able to come back and check a program against a print 2 or more years later.
Reply to
Anthony
BottleBob wrote in news: snipped-for-privacy@earthlink.net:
Reply to
The Deburr Guru
Back in the day, we used to program from the center line and use cutter comp to finish the part. We nearly always used HSS tooling, and half of them were reground. Now that cam software is quick and easy, and carbide is nearly as cheap as HSS, we rarely use Cutter comp.
Reply to
Dave Lyon
BB, the way I understand it "Centerline Programming" has the code offset from the prints dims by 1/2 the dia of the endmill & you don't put any tool dia in the control leave it 0 & use the wear for minor adjustments. The code on centerline programming will not look like the print.
Work Surface programming the code will read just like the print dims & you have to enter the cutter dia in the control..
But what the hell do I know I'm a lathe man ask my mill .
Reply to
Why
For milling programs we use a CAM system to program the path of the center of the cutter, and use zero tool diameter offsets, or small amounts just for adjustment.
Though, on our turning machines we use WSP (hi Cliff ), and we are not currently using a CAM program.
Reply to
Bryce
Bob, I only brought it up as my current employer does it both ways. We had a heated debate about how to put a note in the top of the program for the setup guys to see. We came up with:
(Toolpath is Centerline - set intitial comp values to zero.) -or- (Toolpath is part profile - set intitial comp values to tool dia.) -- Bill
Reply to
Bill
(DATE=00/00/06) (TIME=10:50:52) (POST PROCESSOR=VR11B-5X.CFG) (WORKFILE NAME=-8_TOOLPATHS.CATPRT) (OPERATION NOTES) ( X Zero Datum -A- ) ( Y Zero Center Line of Hinge Pin) ( Z Zero Center Line of Hinge Pin ) (TOOL LIST) (T6.. 0.250 DIA END 4 Flute / Single End / End Mill .75 MCL 2.0 MPL DIA. COMP. D06/ZERO TOOL LENGTH COMP. H06 / G143) (PIVOT DISTANCE = 13.452)
Bill, You can substitute RAD, DIA, WEAR or ZERO andit's then clear what the operator needs to do for each tool. The entire list is in the header and on the set up sheet with the appropriate notes.
Reply to
John R. Carroll
Bill,
Why would you have two setup/programming methods? Not having an in-house standard is a recipe for disaster.
Tom
Bill wrote:
Reply to
brewertr
To All:
After some posts by helpful people and further research, I'd like to correct my original erroneous definitions of Centerline Programming and Work Surface Programming.
Here are the definitions as I now understand them:
Centering Programming: Programming where the tool is offset from the geometry (either manually or in a CAM system) and where usually no tool diameter offsets are necessary in the control.
Work Surface Programming: Programming where the geometry outline is used for toolpathing and where the tool diameters have to be offset in the control.
Wear offsets, or cutter comp. offsets, can be entered in the control for either programming method.
Sorry for any confusion my error may have caused.
Reply to
BottleBob
I use "centering" programming. Work Surface Programming is for sissies.
Dale
Reply to
DrFrye
Looks like I misspelled "Centerline" to boot. This thread has not been an auspicious start for the week.
Reply to
BottleBob
BB,
So your saying by your example Cliff is NOT Centerline Programming in the example he posted for the SL-1 lathe?
I must admit though Cliff was right and I was wrong, he said I wasn't reading his example code right. When I said he made two mistakes in the two lines he posted I was wrong he made five mistakes, proving that his convoluted method is more prone to error.
Post # 231 subject: Mori Seki SL1 NC lathe programming Example was to place a .01" Radius at Z.0 X1.0 with a tool nose radius of .031
Cliff's example programming from the TNRC,
End of Cliff's example
How many mistakes did Cliff make? Here's the list
Line # 1 G01 X 1.063 (X start should be X.980) Line # 2 G02 (radius is counter clockwise G03 is Counter Clockwise) # 2 X1.187 (X end is wrong should be X1.062)
# 2 Z-.031 (Z end is wrong, Z start is .031 so Z end is Z -.01) # 2 R.072 (R value is wrong R value is R.041)
Now using my G50 method and my programming technique to place that same radius on the part Example was to place a .01" Radius at Z.0 X1.0 with a tool nose radius of .031 For this example start is Z.0 and X can be just abut anything.
G01 X.918 F.002 G03 X1.0 Z-0.041 R0.041
No wonder Cliff wont post a sample profile or corresponding G-Code for Peer Review, he is worse than worthless his mistakes are costly and dangerous.
Tom
Reply to
brewertr

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