Can't get lathe to Feed
26 Apr 2021 09:37 #207091
by andypugh
Replied by andypugh on topic Can't get lathe to Feed
If you can find even one pin for a single pulse per rev (drive A and Z from one pin), then you can get threading working without much effort.
2 pins would be better (separate A and Z) though.
2 pins would be better (separate A and Z) though.
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26 Apr 2021 15:02 #207125
by PCW
Replied by PCW on topic Can't get lathe to Feed
Theoretically you could get 2 PPR with 1 A+Z pin (and a 1/2 disk encoder wheel)
if the encoder component could be taught to count rising and falling edges of A
if the encoder component could be taught to count rising and falling edges of A
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26 Apr 2021 15:11 #207126
by andypugh
To stray off the subject of this thread, we could also look at doing what the car industry do, and using a missing-pulse for index.
There are even systems that give position, index and direction on a single line, by changing the duty cycle of the square wave to indicate direction.
Replied by andypugh on topic Can't get lathe to Feed
Theoretically you could get 2 PPR with 1 A+Z pin (and a 1/2 disk encoder wheel)
if the encoder component could be taught to count rising and falling edges of A
To stray off the subject of this thread, we could also look at doing what the car industry do, and using a missing-pulse for index.
There are even systems that give position, index and direction on a single line, by changing the duty cycle of the square wave to indicate direction.
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26 Apr 2021 15:28 #207129
by PCW
Replied by PCW on topic Can't get lathe to Feed
There are also some of the magnetic encoders that use PWM for absolute 1 turn data
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01 May 2021 17:54 #207560
by rider-83
Replied by rider-83 on topic Can't get lathe to Feed
You are correct Andy. A CNC lathe with no screw cutting partly defeats the point. So I'm going to pull my finger out and sort it out. There for I'll start a new thread on this subject.
I see that recently there is a thread 'Threading on a Boxford TCL lathe' which will be useful, but starts a little bit further on that were I'm currently at.
Nick..
I see that recently there is a thread 'Threading on a Boxford TCL lathe' which will be useful, but starts a little bit further on that were I'm currently at.
Nick..
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01 May 2021 19:23 #207566
by andypugh
Replied by andypugh on topic Can't get lathe to Feed
Do you have the tool changer working?
(Where is this lathe, I am guessing somewhere in the UK. being a Boxford?)
(Where is this lathe, I am guessing somewhere in the UK. being a Boxford?)
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02 May 2021 07:02 #207603
by rider-83
Replied by rider-83 on topic Can't get lathe to Feed
I haven't dealt with the Tool Changer yet. That will be my last task.
I'm not looking forward to that particular problem
Yes I'm in the UK
Nick
I'm not looking forward to that particular problem
Yes I'm in the UK
Nick
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03 May 2021 22:21 #207755
by andypugh
Replied by andypugh on topic Can't get lathe to Feed
I am also in the UK (Essex). Not that that is any particular help with the current restrictions.
I would hope that the toolchanger would be fairly straightforward with the "carousel" HAL component. Do you know what the position feedback is from the changer?
I would hope that the toolchanger would be fairly straightforward with the "carousel" HAL component. Do you know what the position feedback is from the changer?
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04 May 2021 05:43 #207792
by rider-83
Replied by rider-83 on topic Can't get lathe to Feed
There is no feed back from the ATC.
It's a simple stepper/worm wheel arrangement.
The indexing is locked via eight 45degree notches and a ratchet pawl.
Stepper indexes 45 + say 5 extra forward, then back 5 to hold against the ratchet.
You have to teach the initial 'Position 1' as a 'home' postion.
I have considered making an encoder wheel with three proxy sensors, but space is VERY restricted, as the tool turet is tiny.
The ATC will have to be dealt with later after I've sorted out the spindle & G76 encoding. At least if I add an extra parallel port for my spindle I will have the available inputs to handle the ATC encoder if I go down that route.
It's a simple stepper/worm wheel arrangement.
The indexing is locked via eight 45degree notches and a ratchet pawl.
Stepper indexes 45 + say 5 extra forward, then back 5 to hold against the ratchet.
You have to teach the initial 'Position 1' as a 'home' postion.
I have considered making an encoder wheel with three proxy sensors, but space is VERY restricted, as the tool turet is tiny.
The ATC will have to be dealt with later after I've sorted out the spindle & G76 encoding. At least if I add an extra parallel port for my spindle I will have the available inputs to handle the ATC encoder if I go down that route.
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04 May 2021 06:46 #207794
by rider-83
Replied by rider-83 on topic Can't get lathe to Feed
Hey Andy,
I'm teaching you to suck eggs here!.
I've just looked at the HAL carousel componet (Which I never knew existed)
and its been written by a guy called Andy Pugh. Thats a coincidence, because thats your name as well !
I'm teaching you to suck eggs here!.
I've just looked at the HAL carousel componet (Which I never knew existed)
and its been written by a guy called Andy Pugh. Thats a coincidence, because thats your name as well !
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