G71

More
09 Sep 2017 23:48 #98751 by Patrik T
Patrik T created the topic: G71
I am very glad there is a G71 cycle in LinuxCNC. Thanks to Andy I believe (thumbs up icon).
Cool that it also does pockets.

May I ask a couple of questions about the G71 cycle.

1) I implemented this
github.com/LinuxCNC/linuxcnc/blob/andypu.../g71/python/remap.py
as REMAP=G71 modalgroup=1 argspec=PDrjlikfst python=g71.
Is a remap the intended way to use this?

2) How much of it is supposed to work at this stage? Because arguments R, L, I and K does not seem to do anything. It leaves nothing axially for finishing.
I attach a screenshot of the program I tested with. It is visible in the tool path that it sometimes leaves 2 mm for finishing and sometimes 3 mm. It also does the roughing cuts at S400 F400, but the finishing cut seems good at S200 F400.

3) What the intended difference between the J, L and the I, K values?

Best regards
Patrik
Attachments:
More
14 Sep 2017 07:09 #98933 by andypugh
andypugh replied the topic: G71
Currently the remap version is a proof of concept, intended as an improvement on the ben potter G71 branch that you can also find in the git repository,

Currently G71 with pockets is indeed remap-only and suffers from that in that it lacks some important info that a fully integrated cycle would have. You should find that the other patch works better, but does not do pockets.

Because of a limitation in the current interpreter one of the roughing offsets is an integer, so has to be given in terms of thousandths of the current program units. (I have forgotten which, but might remember to look tomorrow. (I am grabbing a few minutes late at night on a work trip to the US to look at the forums))

So, yes, remap only, and not ready for release, but can make parts. Calling the profile as a sub should give an exact profile, despite any slight flaws in the code of either version, but cut depth may be erratic on that cut.
More
22 Sep 2017 20:44 #99288 by Patrik T
Patrik T replied the topic: G71
OK
I am using this now instead.

More
27 Sep 2017 17:43 - 27 Sep 2017 19:06 #99523 by Patrik T
Patrik T replied the topic: G71
Last Edit: 27 Sep 2017 19:06 by Patrik T.
More
28 Sep 2017 10:06 #99543 by andypugh
andypugh replied the topic: G71
Which version (and how) is that?
More
28 Sep 2017 11:54 #99546 by Patrik T
Patrik T replied the topic: G71
No version, I made it from scratch (except for stealing your regex).

G71 P71 D4 R1 I2 K.5 J.5 L4

P = Sub number
D = Stock removal cut depth
R = Stock removal retract height
I = X-allowance
K = Z-allowance
J = Constant surface feed factor
L = Number of decimals

The Q-word in the G-code tells the lathe to connect to the next programmed surface with a fillet radius of that size.
More
28 Sep 2017 13:48 #99549 by skunkworks
skunkworks replied the topic: G71
Could you share?
More
29 Sep 2017 12:13 - 29 Sep 2017 21:15 #99608 by Patrik T
Patrik T replied the topic: G71
I tried to convince myself that I could use CAM or ngcgui, but in the end I just did the work. I did the G71 I had wished for, with pockets and fully compensated all the time. I also threw in fillet radii between all types of moves. At first I thought getting the most efficient retract between pockets would be arduous, but I found a brilliant way to do pockets easily, inside, outside or backwards. I'd share, at a fee.

The Python remap feature is great, thanks Michael.
Last Edit: 29 Sep 2017 21:15 by Patrik T. Reason: A bad mood was showing through.
More
03 Oct 2017 21:31 #99857 by andypugh
andypugh replied the topic: G71
I do hope that we will get G71 as an actual G-code at some point. I was hoping Ben was going to do it, but he seems to have found other things to do.
It's on my list. Along with multiple spindles, but I have a bunch of bugfixes that are higher priority, and only just got a working dev machine back.
Time to create page: 0.072 seconds
Powered by Kunena Forum