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G73 hiccups
« on: October 01, 2013, 08:24:45 PM »
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.

Re: G73 hiccups
« Reply #1 on: October 02, 2013, 01:46:48 AM »
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
 
Re: G73 hiccups
« Reply #2 on: October 02, 2013, 05:32:52 PM »
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


Re: G73 hiccups
« Reply #3 on: October 02, 2013, 06:17:33 PM »
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.     

Offline BR549

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Re: G73 hiccups
« Reply #4 on: October 02, 2013, 07:06:32 PM »
SO what do you have the G73 pullback value set at ??

Just a thought, (;-) TP

Offline BR549

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Re: G73 hiccups
« Reply #5 on: October 02, 2013, 07:19:27 PM »
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
Re: G73 hiccups
« Reply #6 on: October 02, 2013, 07:34:20 PM »
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.   

Offline BR549

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Re: G73 hiccups
« Reply #7 on: October 03, 2013, 01:57:28 AM »
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

Re: G73 hiccups
« Reply #8 on: October 03, 2013, 04:39:01 AM »
Thanks for that. I learned something new today.
Re: G73 hiccups
« Reply #9 on: October 04, 2013, 04:22:22 PM »
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.