09 Sep 2017 23:48 #98751 by Patrik T
G71 was created by Patrik T
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
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
14 Sep 2017 07:09 #98933 by andypugh
Replied by andypugh on 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.
22 Sep 2017 20:44 #99288 by Patrik T
Replied by Patrik T on topic G71
I am using this now instead.

27 Sep 2017 17:43 - 27 Sep 2017 19:06 #99523 by Patrik T
Replied by Patrik T on topic G71
Last edit: 27 Sep 2017 19:06 by Patrik T.
28 Sep 2017 10:06 #99543 by andypugh
Replied by andypugh on topic G71
Which version (and how) is that?
28 Sep 2017 11:54 #99546 by Patrik T
Replied by Patrik T on 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.
28 Sep 2017 13:48 #99549 by skunkworks
Replied by skunkworks on topic G71
Could you share?
29 Sep 2017 12:13 - 29 Sep 2017 21:15 #99608 by Patrik T
Replied by Patrik T on 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.
03 Oct 2017 21:31 #99857 by andypugh
Replied by andypugh on 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.
02 Apr 2018 16:15 #108263 by Patrik T
Replied by Patrik T on topic G71
Tapered propeller axle. Some vibrations, maybe should have used the tailstock. There will be another finishing cut and threads after cool down.

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