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configuring lathe problem stepconfig

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20 Mar 2015 01:26 - 20 Mar 2015 01:29 #57021 by Clive S
Hi
Would somebody care to look at my configs attached.

Problem is the Z axis is not working (DRO goes round but the motor does not).

I have had my lathe working ok under axis and I have been trying to set an encoder up to have a go at screw cutting.

I set the encoder index ,A and B up in stepconfig and its added lines in the hal ini.

I have noticed that in the ini file it show 3 axis but I have only set it to X and Z.
In the hal ini it seem to show U step and U dir (should this not be Z step etc)

The encoder appears to work as it is giving me the rpm on the axis screen.

I don't see the wood for the trees. Thanks. Clive



File Attachment:

File Name: Myford_Lathe.hal
File Size:3 KB


File Attachment:

File Name: Myford_Lathe.ini
File Size:2 KB
Attachments:
Last edit: 20 Mar 2015 01:29 by Clive S. Reason: trying to attach file

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20 Mar 2015 14:36 - 20 Mar 2015 15:51 #57030 by ArcEye
Hi

It shows 3 axes because it counts X Y Z etc, that is normal, does not mean you have to use all of them and you have the correct coordinates set as X Z

It looks like you just need to change udir and ustep to zdir, zstep.

Do it in gedit not stepconf or you risk messing up an otherwise OK config

No idea how the names got that way to start with

regards

EDIT

Attached is an altered copy, try that, can't immediately see anything else wrong with it
Attachments:
Last edit: 20 Mar 2015 15:51 by ArcEye.

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20 Mar 2015 23:05 #57034 by Clive S

Hi

It shows 3 axes because it counts X Y Z etc, that is normal, does not mean you have to use all of them and you have the correct coordinates set as X Z

It looks like you just need to change udir and ustep to zdir, zstep.

Do it in gedit not stepconf or you risk messing up an otherwise OK config

No idea how the names got that way to start with

regards

EDIT

Attached is an altered copy, try that, can't immediately see anything else wrong with it


Ok update It was the ustep and udir that I had to change (I had done it before but I use caps Z) it seems to like only lower case.

What I did notice was that I ran a new stepconfig with lathe and again it put in ustep and udir for the pins in the HAL strange!!

I have now tried a G76 line and as expected it runs the thread cycle if you stop the spindle you can turn it by hand and the thread Z moves
if you reverse the spindle say 10 revs the go forward again the thread does not start again until the 10revs have been done.

if you turn the spindle backwards the Z does not move is that correct?

Would you mind giving me a sample G76 line of code for say a M10 x 50mm so I can do further tests then I can learn how to program it. I use mm for the lathe.

I still need to calibrate the z move it seem to move about half what is required.

Many thanks for the help. Clive

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21 Mar 2015 12:42 #57061 by cmorley
What version of linuxcnc are you using? master?
U and V axes were added recently and there may be a bug.

Chris M

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21 Mar 2015 15:32 - 21 Mar 2015 16:07 #57062 by Clive S

What version of linuxcnc are you using? master?
U and V axes were added recently and there may be a bug.

Chris M


I installed the 2.6 hybrid iso then ran the update which brought it up to 2.7 (so a complete new install)

my ini files are attached in #57021

edit I don't remember having the same problem on the mill just had it on the lathe profile

I have been playing with gmocappy (only saying this for completeness)

Clive
Last edit: 21 Mar 2015 16:07 by Clive S. Reason: Added text

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21 Mar 2015 16:55 - 21 Mar 2015 16:56 #57063 by ArcEye

Would you mind giving me a sample G76 line of code for say a M10 x 50mm so I can do further tests then I can learn how to program it. I use mm for the lathe.


This is a template so will cover whatever thread size
(ignore the M code, that is just a local one to set the pulley number for correcting the speed)
;; Threading with G76 

;; Speed of 300 is stable and only requires F450 to cut 1.5mm thread
;; P[itch]
;; Z[FinalExtent] - Ensure there is an overrun element so that deceleration happens beyond end of thread, 3 mm sufficient in this example
;; I[ThreadPeakOffset - cant be 0, neg for external pos for internal, if diameter is critical you can add PeakOffset to Diameter to negate this value]
;; J[FirstCutDepth - positive offset]
;; R[DepthDegression 1.0 is constant depth 2.0 is constant area 1-2 depth decreases & area increases 2> area decreases]
;; K[FullThreadDepth positive offset beyond I for root of thread]- Q[CompoundSlideAngle eg 29.5] 
;; H[SpringPasses at full thread depth] E[TaperAmount in units - normally 0] L[Taper- L0 None L1 entry L2 Exit L3 Both] 

#<_Diameter>=40
#<_Z_LeadIn>=15
#<_Pitch>=1.5
#<_Z_Finish>=-15      
#<_PeakOffset>=-0.001
#<_First_Cut_Depth>=0.01
#<_Depth_Regression>=1.0
#<_ThreadDepth>=1.5
#<_CompoundSlideAngle>=0
#<_Spring_Passes>=2
#<_TaperAmount>=0
#<_TaperType>=0

#<_Feed>=1.5
#<_Speed>=300

G18 G21 G40 G49 G54 G80 G95
G90 G7
M101 P3 (SET PULLEY SETTING 3 FOR GOOD TORQUE)
F#<_Feed> S#<_Speed>
M3
G4 P10
M7
        (GO TO OS DIA AND Z LEAD IN 
G0 X#<_Diameter> Z#<_Z_LeadIn>
G76 P#<_Pitch> Z#<_Z_Finish> I#<_PeakOffset> J#<_First_Cut_Depth> R#<_Depth_Regression> K#<_ThreadDepth> Q#<_CompoundSlideAngle> H#<_Spring_Passes> L#<_TaperType>
G00 X45

M9
M5

G28

M2

The Z lead in figure is quite important, because that is what enables everything to be aligned and at the right speed before cutting commences
I normally allow 10x the thread pitch roughly, so 15mm for a 1.5mm pitch

if you reverse the spindle say 10 revs the go forward again the thread does not start again until the 10revs have been done.


I am not sure why anyone would ever do that, but I suspect it is because you have both A and B channels on your encoder,
so it knows you have moved away from position in reverse and is bringing you back to where you were, before starting.

regards
Last edit: 21 Mar 2015 16:56 by ArcEye.

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21 Mar 2015 18:01 #57064 by Clive S
Many thanks you have been more than helpful

I will have a play with the code and see what happens.

Regarding the 10 revs back I was seeing if reversing the chuck (by hand) would reverse the Z, but I did not know if it should do that (I do have B set up)

So I don't know if B pulse is working yet as it should.

I will try a tapping cycle as that should reverse it.

Would I be better off with a 100 slot disc (mine is 64 slot)?

Clive

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21 Mar 2015 21:16 #57067 by ArcEye

Would I be better off with a 100 slot disc (mine is 64 slot)?


You might well be.

I have a 120 hole disc on mine, which was the limit of the number of 3mm holes with 3mm spacing I could get on the disc.
I prevoiusly had a 60 hole version and this is much smoother.

I just have an A and a Z, no B. I don't want to do rigid tapping and as all threading is done in the same direction, B was no advantage.

regards

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21 Mar 2015 22:28 #57070 by Clive S

Would I be better off with a 100 slot disc (mine is 64 slot)?


You might well be.

I have a 120 hole disc on mine, which was the limit of the number of 3mm holes with 3mm spacing I could get on the disc.
I prevoiusly had a 60 hole version and this is much smoother.

I just have an A and a Z, no B. I don't want to do rigid tapping and as all threading is done in the same direction, B was no advantage.

regards


Ok I will cut a 100 slot and test it out.

I have read some ware "The advantages of using both A and B are increased noise immunity and increased resolution"

thanks Clive

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21 Mar 2015 22:54 #57071 by ArcEye

I have read some ware "The advantages of using both A and B are increased noise immunity and increased resolution"


That is true, but the disadvantage to me was having to fit another reading head and wire it in B)

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