Cant get threading going in Linuxcnc

[John11668]

Hi Guys
Not been here for a while . Do please excuse me

So I have been progressively converting My Boxford TCL125, initially to Mach 3, then further to linuxcnc to try and get me a screwcutting capability.
I do have it working , But it just will not execute a G76 instruction for a threading canned cycle
I am using Gmocappy on linux mint. Hal and Post hal gui files have been edited to make the speed indicator and tool change functions work.
All the traverses function in slow and fast jog and the machine is happy to execute a turning routine in both G94 and G95 with feeds of up to 2mm/rev as an exercise (have not tried higher ) Cant imagine I would need bigger pitches on this machie .

Initially I did have problems with the pulses from the sensors but these were upgraded and I am now happy they are reliable . They give clear indications in “Hal show configuration” and steady speed reading on the gmocappy screen. I had wondered if the Boxford index disc with 100 x 2mm holes was too fine so tried with a disc I made myself with 48x 4mm holes but this is no different.

I can run with this disc in mach3 and using pin 12 (single notch) , I see a speed of about 1150 revs .
Changing index in Mach3 to pin 13 it reads a speed of 55k which seems as near to 48/1 as I can reasonably expect. And the readings are pretty steady so I am not suspecting noise as the problem.
Linux was initially sluggish on the machine I was using, slow to boot , slow internet, etc so moved the HDD to another machine . It is now quick and responsive but still won’t execute G76.

Code here!

Goes through to line 11 quite happily executing tool change on the way but then refuses at G76.
No error message just sits there.
%
(Thread M10 x 1.5)
(CHANGE TO T6 ON Front TOOL POST)
M6 T06 G43
G54 G90 G94 G18
G21 G80 G95
G90 G7
M08
F1.5 S350
M3
G4 P5
G0 X10 Z10
G76 P1.5 Z-12.5 I-0.001 J0.1 R1.0 K1.5 Q0 H3 L0
G00 X45
G00 Z30
M09
M5
M30
%

Have tried different spindle speeds from 100 to 600 but no change.

I am not quite ready to jump out of my tenth floor window yet but it is rapidly coming to that stage
Can anyone shed any light on what we might be missing or where the fault may lie
TIA John 

[Clive S]

I think this is the code I used on the Boxford that I converted to Linuxcnc
G0 G40 G18 G80 G21 G49 G95
G90 G7

F1.5 S470
M3
G4 P1
M7
(Change the fist X to the Dia P = the Pitch K = Thread depth)
G0 X10 Z10
G76 P1.5 Z-12 I-0.1 J0.1 R1 K1.5 Q29.5 L0 H1
g0 X30
g0 Z50
M9
M5
M2
%

Is it waiting for spindle at speed ? is the encoder counting the correct way?


Boxford-18-12-2020.tar.txt remove the txt


Edit: If I am not mistaken K3 should be 1.5

[Doddy]

I'm with Clive on this one (standing on the shoulders of the LInuxCNC giant :). - check that gmocappy needs or doesn't need a spindle-at-speed signal, then use the monitor to check the state of the signals that lead into this.

Apologies - I've not looked into this myself but from distant memory the Axis GUi for LinuxCNC (the name of which confused the hell out of me at first) has similar.

[John11668]

I am not sure what gmocappy needs in the way of "at speed " signal . I know I do not have the ratio correct in that a call for S300 would give me a true speed reading of say 420 and I have not yet found the parameter to correct this . What I do know is that in the stepconfig wizard there is a requirement for 98% spindle speed set and I am guessing that this is well exceeded.
And WRT the direction of counting is it actually possible to determine direction without a third set of sensors ?

Other than that the the above is pretty much unfathomable to me.
My problem is that I am trying to make a machine work in order to give myself a threading function. and until weeks ago I had never even seem Linux cnc.
I will never ever become fluent in it so I really need someone to lead me by the hand here

I have looked at the text file provided by that link but have to admit it has lost me

[Clive S]

I am not sure what gmocappy needs in the way of "at speed " signal . I know I do not have the ratio correct in that a call for S300 would give me a true speed reading of say 420 and I have not yet found the parameter to correct this . What I do know is that in the stepconfig wizard there is a requirement for 98% spindle speed set and I am guessing that this is well exceeded.
And WRT the direction of counting is it actually possible to determine direction without a third set of sensors ?

Other than that the the above is pretty much unfathomable to me.
My problem is that I am trying to make a machine work in order to give myself a threading function. and until weeks ago I had never even seem Linux cnc.
I will never ever become fluent in it so I really need someone to lead me by the hand here

I have looked at the text file provided by that link but have to admit it has lost me

I see that you have also posted on the linuxcnc forum.

Once you have used stepconf then you have to hand edit the files as stepconf will overwrite them

The zipped up file I posted is my working config (I think you have a different tool changer) to view the file you have have to rename it by removing the "txt" from the end and then unzip it.

As have been asked on the other forum it would help to post your hal and ini files

[Doddy]

Easy answer to the sensor question:

1 sensor gives speed.
2 sensors gives speed and direction
3 sensors gives that and an index pulse (absolute position)

Re the Linux side of things... that’s best answers on a one on one rather than a forum free-for-all, I’ll leave that and my amateur exploration of Linux Cnc for now unless there’s no other takers.

[John11668]

I see that you have also posted on the linuxcnc forum.

Once you have used stepconf then you have to hand edit the files as stepconf will overwrite them

The zipped up file I posted is my working config (I think you have a different tool changer) to view the file you have have to rename it by removing the "txt" from the end and then unzip it.

As have been asked on the other forum it would help to post your hal and ini files

Hi Clive and thanks for your input.
When I first asked the question on both forums , I was unaware that the same faces would respond on both. Sorry if this causes a problem . maybe we just need to establish which is the best platform to carry on..

My toolchanger at this stage is a pair of hands , which are prompted to act by an onscreen message.

I will try to insert your configuration into axis but have to say that I am not familiar with axis . So Please excuse me if I have to come back with another query.
I will try to send a zipped up set of all my current config files , but it may take me a while as I am quite committed over the next couple of days .
Shall I do it here or "over there "

I am not expecting miracles from this machine . It is really just a learning platform for me , but if I could get to the stage where I can make a few small shoulder bolts in both metric and imperial, it would then go into the corner of the workshop , while I hopefully move on.

[Clive S]

John. There are more people that use Linuxcnc on the other forum Andy Pugh on there is very knowledgeable.

You have to remember that none of us have crystal balls (get ready for the pun)

In other words how can anybody help without pictures and the config files.

I see that you have put some of them on the other forum but they are not complete ie the INI file is missing.

https://www.youtube.com/watch?v=UaHC0L7MXGo

https://www.youtube.com/watch?v=TibpSsLeoEY

https://www.youtube.com/watch?v=lNNHD98pX2o

[John11668]

So will continue the thread over there Clive .Will zip and post everything I can.