Machsupport Forum
G-Code, CAD, and CAM => G-Code, CAD, and CAM discussions => Topic started by: Mountainman on October 01, 2013, 08:24:45 PM
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Ok, I am trying to peck with a 3/16 end mill
I wanna rapid peck. I tried this with G73 R-.49 ( end mill is about .5" above face of workpiece) Z-.57 Q.007
What I ended up getting was the drill doing a peck like the canned cycle where it completely withdraws from hole. I just need it to go up and down by the Q value.
Anyone have any suggestions? How do I get it to rpid down to .01 above the workpiece and then peck down by .007 retract by .007 and go down by .014 up by .007 and down by .014 till the desired Z is reached.
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Mountain Man:
The drill cycle G83 is for deep holes, with full retract each peck. G73 cycle is for a short retract to break the chip, but not a full retract. Perhaps you have given the parameters the wrong values. Check the use of the R,L,Q parameters in the G-code description list. The "Q" parameter is a "delta" increment along the Z axis, according to my G-code list.
Personally, the descriptions in the listing could have been done better, such as showing a list of the R,L,Q parameters for drilling type, with an example. There are better descriptions than what is in the Mach3 listing.
John
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There is a CNC G-code Wizard that enables you to write custom G-codes of any kind. The Wizard is not free, but they offer a 30 day trial.
www.cnccookbook.com
My first CNC mill many years ago had (3) canned cycles for drilling;
G80, straight hole drill, no peck.
G81, Peck drill with full retract.
G82, Peck drill, partial retract.
The G-codes had all the parameters after the G-code, in ( ) parentheses that were set-up so you could enter your own variable values for the specific drilling action: hole depth, chip break distance, number of pecks to bottom of hole, full retract or partial retract, dwell at bottom of hole, and feedrate of drilling. The company is no longer in business. I thought all the G-codes worked that way until I had to retrofit my older machine to Mach3.
Regards,
John
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I put down G73 R-.49 Z-.57 Q.007 and every retract it was going to -.490. That is not a short retract like I was expecting. Now the ability to determine dwell at end of drilling would be a biog plus for mach. But no, I have to use a different canned cycle so I get a dwell time. More time wasted.
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SO what do you have the G73 pullback value set at ??
Just a thought, (;-) TP
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Just tested the G73 here and it works like it is suppose to.
Please explain what you think it should be doing based on your example code.
(;-) TP
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I expected it to go down to z-.49 in one rapid and start taking .007 pecks all the way down to z-.57. Not full retracts to z-.49
G73 pullback value? I was on settings screen and can't find that entry box.
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I believe that the reason you see what you see is that you have the pullback setting larger than your total depth to drill so it only retracts to the R level instead of the peck value.
To set the pullback value fro G73
General config, pins and ports, Mill options.
AND you may have to learn the secret handshake to make the setting change.
(;-) TP
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Thanks for that. I learned something new today.
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I believe that the reason you see what you see is that you have the pullback setting larger than your total depth to drill so it only retracts to the R level instead of the peck value.
To set the pullback value fro G73
General config, pins and ports, Mill options.
AND you may have to learn the secret handshake to make the setting change.
(;-) TP
All right, so how should I command teh machine to go down to z-.49 and then start small pecks all teh way to z-.57 w/ .007 pecks?
Handshake? I'm only at the 3rd degree.
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Here is how I would do it.
The G98 sets the end of function retract level, G98 sets it to go back to the initial level (Z0)
Z-0.570 sets the depth to drill
R-0.490 sets the start point of the function and the retract level
Q0.007 sets the peck depth
The G73 pull back value must be set manually via the config section BEFORE you start the cycle.
From the X0Y0Z0 point it will rapid down to the R level and start the peck and retract cycle. It will peck .007" and retract .014" , then rapid back down to just shy of the peck depth and then peck down to the next peck level then retract. It continues this all the way down to final depth. The final peck if less than the peck depth will adhere to the final depth and stop short if needed. At eh end of function then it retracts back to the initial level Z0.000. IF you do not want it to retract back to the intial leval and just stay at teh R level then use G99 .
Sample code:
G0 X0 Y0 Z0
G98
G73 Z-.57 R-.490 Q.007 F1 (set G73 pullback to .014")
G80
M30
(;-) TP
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I'll play with that for future reference. Thanks, BTW, have you got a screen shot of what the G73 config looks like? I guess there is no way to change teh pullback value from within the program?
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Well Actually you can control the Pullback from the Gcode side. You will HaVE to create an Mcode. I use M120
THen apply the Pullback as a P (parameter). The Mcode looks like this:
PullBack = Param1
'MsgBox"" & Pullback
SetOemDro(91,Pullback)
End
You would use it BEFORE the G73 call and the Gcode call would be like this:
M99
M120 P.014 ( THis sets the G73 pullback level)
G73 Z-.570 R.490 Q.007 F1
G80
(;-) TP
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Woah (http://rpgmaker.net/media/content/users/27827/locker/BOWING_SMILEY.gif)