Disperate feed rates

More
07 Jun 2011 20:17 #10362 by Scout
Disperate feed rates was created by Scout
I have a rotating axis (A) and an linear axis (X). The A has a max feed rate of 3600 degrees/min and the X 18 inches/min but when I'm machining I only want the x feed no more than 10 ipm. If I use F10 the A slows to a crawl but F1800 permits X to attain the max 18 ipm. The only solution I see is to limit X to 10 ipm in stepconf but I wonder if I'm missing something. Doing this, of course, slows down my G0 moves.

Thanks for any suggestions

Please Log in or Create an account to join the conversation.

More
07 Jun 2011 20:56 - 07 Jun 2011 20:56 #10364 by BigJohnT
Replied by BigJohnT on topic Re:Disperate feed rates
When I posted your question on the IRC I got this response.

[15:52] archivist_emc JT-Shop, he has to learn the inverse time mode or guess his feed rate, currently the trajectory planner has no clue of the radius the tool is at www.linuxcnc.org/docview/html/gcode_main.html#sub:G93,-G94:-Set
[15:53] JT-Shop thanks
[15:54] cradek if both X and A are moving and he programs F10 in the normal G94 mode, doesn't he get what he want?
[15:54] JT-Shop I would assume so
[15:55] cradek but yes in general the solution is G93 as recommended here www.linuxcnc.org/docs/devel/html/gcode/o..._code_best_practices


John
Last edit: 07 Jun 2011 20:56 by BigJohnT.

Please Log in or Create an account to join the conversation.

More
08 Jun 2011 10:31 #10369 by Rick G

Please Log in or Create an account to join the conversation.

More
09 Jun 2011 18:29 #10395 by Scout
Replied by Scout on topic Re:Disperate feed rates
Mea culpa

radek is right. My error was in programming an A only move after the combined move so F10 was still in effect and limited the A axis to 10 degrees/min. I just couldn;t see for looking.



Thanks or the help.

Please Log in or Create an account to join the conversation.

More
24 Jun 2011 16:49 #10845 by Scout
Replied by Scout on topic Re:Disperate feed rates
There is still a problem but a simple if not elegant solution. I'm driving my position by some transcendental functions and sometimes there is a series of lines where the x axis doesn't change. This causes the A axis to feed at the slower rate as specified in the manual. I wish the specs said that if there is a x position specified then feed would be based on the x axis but they say instead that if x doesn't change feed is based on the A axis. My solution is to put a 0.0001 inch wobble in the x axis that is not noticeable in the product but causes the interpreter to think x has changed.

Please Log in or Create an account to join the conversation.

More
24 Jun 2011 20:16 #10847 by BigJohnT
Replied by BigJohnT on topic Re:Disperate feed rates
When I linked this thread to the IRC the response from the IRC was:

he should use G93 he should use G93 he should use G93 he should use G93


John

Please Log in or Create an account to join the conversation.

More
25 Jun 2011 08:59 #10858 by Rick G
Replied by Rick G on topic Re:Disperate feed rates
From one of John's post...

www.linuxcnc.org/docview/html/common_mac...r.html#sub:Feed-Rate

1. If any of XYZ are moving, F is in units per minute in the XYZ cartesian system, and all other axes (UVWABC) move so as to start and stop in coordinated fashion
2. Otherwise, if any of UVW are moving, F is in units per minute in the UVW cartesian system, and all other axes (ABC) move so as to start and stop in coordinated fashion
3. Otherwise, the move is pure rotary motion and the F word is in rotary units in the ABC “pseudo-cartesian” system.


So could you set the proper rotary feed rate for the rotary only moves and revert to the proper linear feed rate for combined moves?

Rick G

Please Log in or Create an account to join the conversation.

Time to create page: 0.112 seconds
Powered by Kunena Forum