[tpsimer]

Is there a way to write a parametric program like a g71 roughing cycle that will feed forward rapid back a few thousandths, rapid to cutting position and feed, repeat.
We cut a lot of plastic and it is hard to deal with the stringers. I have tried a g74 and it works ok but is slow.

thanks
tony

[SirDenisNayland]

There is a way to write pretty much anything and everything you can think of.

Cheers

[txcncman]

Is there a way to write a parametric program like a g71 roughing cycle that will feed forward rapid back a few thousandths, rapid to cutting position and feed, repeat.
We cut a lot of plastic and it is hard to deal with the stringers. I have tried a g74 and it works ok but is slow.

thanks
tony

What seems to be the slowness you are having associated with using G74? There might be ways to speed it up.

[tpsimer]

What is the best way to go about learning how to write programs using parametric programming. I have done a little reading since I posted and Lynch has written a book covering this. Is it any good? What other sources are available?
tony

[tpsimer]

What seems to be the slowness you are having associated with using G74? There might be ways to speed it up.

Using the short feeds it seems to feed back and forth rather than using rapid moves to back off and move forward. It works well to break chips but slows the cutting path down by more than double the original path.
tony:violin:

[txcncman]

Using the short feeds it seems to feed back and forth rather than using rapid moves to back off and move forward. It works well to break chips but slows the cutting path down by more than double the original path.
tony:violin:

There are 2 factors that effect the G74 tool movement. First is the infeed amount (I) and second is the machine parameter that controls the retract amount. In other words, the tool infeeds the I amount and backs away from the cut the retract amount to break the chip. Reset the retract amount parameter to something smaller, say in the 0.005" range. I bet that will speed things up significantly.

If you really want to try parametric, upload a copy of a print and your current program.

[tpsimer]

There are 2 factors that effect the G74 tool movement. First is the infeed amount (I) and second is the machine parameter that controls the retract amount. In other words, the tool infeeds the I amount and backs away from the cut the retract amount to break the chip. Reset the retract amount parameter to something smaller, say in the 0.005" range. I bet that will speed things up significantly.

If you really want to try parametric, upload a copy of a print and your current program.

With the fanuc 21t it uses 2 line program for cycles. In the first line is:
g74 R????. I think this is the amount to retract after it retracts the full programmed infeed. I have put this to 0 but the control retracts the full amount of the Q infeed perameter. Is there a perameter to change ththe amount preset in the control? I would prefer to have that at 0 and control the full retract with the R in the first line. On the Haas control it is setting 22. However, I have not had a chance to run plastic on this machine yet. I have only worked here for a couple weeks and have not much experience with the haas yet.
tony

A typical usage would be:

G0 X3.25 Z.05 T0101 M8
G71 P.... Q... U... W... D... F...
N... G0 X2.
G1F.018 Z-1.9375
X2.875
X3. Z-2.
Z-3.
N... X3.25
G28 U0. W0. M9
M1

i have been programming g-code since the early 80's and never thought that parametric programming would help. I would like to learn it now as with what little reading I have done I see it could be useful. If not, It doesn't hurt to learn more!
thanks

[txcncman]

With the fanuc 21t it uses 2 line program for cycles. In the first line is:
g74 R????. I think this is the amount to retract after it retracts the full programmed infeed. I have put this to 0 but the control retracts the full amount of the Q infeed perameter. Is there a perameter to change ththe amount preset in the control? I would prefer to have that at 0 and control the full retract with the R in the first line. On the Haas control it is setting 22. However, I have not had a chance to run plastic on this machine yet. I have only worked here for a couple weeks and have not much experience with the haas yet.
tony

A typical usage would be:

G0 X3.25 Z.05 T0101 M8
G71 P.... Q... U... W... D... F...
N... G0 X2.
G1F.018 Z-1.9375
X2.875
X3. Z-2.
Z-3.
N... X3.25
G28 U0. W0. M9
M1

i have been programming g-code since the early 80's and never thought that parametric programming would help. I would like to learn it now as with what little reading I have done I see it could be useful. If not, It doesn't hurt to learn more!
thanks

Machine parameter. Not program parameter. I do not have ready access to a manual for your control and have no idea which machine parameter controls the retract amount.

I do not have time to get into detail with the parametric programming for this and do not remember the exact syntax, but you could write your own cycle similar to the G74 with something like:

#100 = (Z to cut to)
WHILE [#100 GT #(parameter for Z position)] DO 1
1
G01 W-(amount of cut in)
G00 W0.005(amount of retract)
END

[tpsimer]

Machine parameter. Not program parameter. I do not have ready access to a manual for your control and have no idea which machine parameter controls the retract amount.

I do not have time to get into detail with the parametric programming for this and do not remember the exact syntax, but you could write your own cycle similar to the G74 with something like:

#100 = (Z to cut to)
WHILE [#100 GT #(parameter for Z position)] DO 1
1
G01 W-(amount of cut in)
G00 W0.005(amount of retract)
END

Thank you for the time you have taken to answer my questions. This is exactly what I needed, just an example of what this would look like. Much shorter than writing it out longhand (which I did once before) It is not hard to write out longhand but takes alot of room in a program and makes it difficult to edit later on. Copy past functions on a computer makes it easy. I think I will search my library for help. Again, thanks
tony

[sinha_nsit]

What is the best way to go about learning how to write programs using parametric programming. I have done a little reading since I posted and Lynch has written a book covering this. Is it any good? What other sources are available?
tony

As on today, Lynch is $95.00, and Smid is $43.74.
The cheapest is this ($9.52, including shipping, for a used copy):
[ame=http://www.amazon.com/Programming-using-Fanuc-Custom-Macro/dp/0071713328/ref=sr_1_2?ie=UTF8&qid=1341719441&sr=8-2&keywords=fanuc]CNC Programming using Fanuc Custom Macro B: S.K Sinha: 9780071713320: Amazon.com: Books[/ame]

[tpsimer]

As on today, Lynch is $95.00, and Smid is $43.74.
The cheapest is this ($9.52, including shipping, for a used copy):
CNC Programming using Fanuc Custom Macro B: S.K Sinha: 9780071713320: Amazon.com: Books

thanks for the link. If the library doesn't have it I will by both authors.
tony