Machsupport Forum
Third party software and hardware support forums. => LazyTurn => Topic started by: cornbinder23 on April 26, 2012, 11:10:04 PM
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I have a C3 index pulse card set up on a G540, I get the index pulse LED to light when I rotate the
spindle by hand, but if I turn it on the LED flashes very sporadically and when I try to read the spindle rpm I get nothing
Also tried a threading routine and when posting the gcode I get an error saying no spindle feedback when returning to the
program screen. I can try and take some screen shots and post pics when I get home. I am trying to turn a 24tpi internal
thread in 6061. I am just starting out trying to really understand mach turn now, I have used Mach3 mill for a
couple of years so I feel pretty confident with that.
I converted this lathe last year and am just now finding the time learn mach turn haha
Any tips or help would greatly be appreciated
Jayson
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Jason,
To do threading you need to have the index working properly.
In Configuration >Ports & Pins check the following:
- Index is enabled - also port and pins are correct
- Timing is not enabled
- Use Spindle Feed Back in Sync Mode is checked also Spindle Speed Averaging
You may want to play with the Index Debounce & Debounce Interval values.
I will assume that you are using registered copy of Mach.
RICH
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I did not have the spindle feedback in sync mode checked.
I am still manually operating the spindle on my lathe, no vfd and still changing belts
But I still can not read true spindle speed. When in cycle mode
I have the belts setup for 150 rpm (I have not verified actual with a photo or contact rpm meter)
When I manually start the spindle I press the spindle button on mach turn and it reads 177 rpm, when I stop the spindle Manually)
the dro reads between 50-100rpm with the spindle off but jumps back up to 177 rpm (steady, no fluctuation?)
once I manually start the spindle.
This is on a licensed copy, I have two licensed copies for my mill and lathe.
Jayson
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Not sure what you are meaning by
"But I still can not read true spindle speed. When in cycle mode"
Do you think the 177RPM is wrong?
If you attach your xml I will have a look through your settings to see if there is a problem with them.
Hood
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I will post that up today Hood, thank you.
Jayson
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Here is the xml
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xml looks to be fine so a few questions.
When you are getting the steady 177RPM showing do you think that is wrong?
You said you stop the spindle manually but it still reads 50 to 100, by manually are you meaning you just shut off the spindle and not tell Mach its off?
If so then that is likely why you are still getting the readings, likely two things, first Mach is still searching for a pulse as you have Not told it not to and also averaging may make the readings more persistent.
You say you dont get a spindle speed reading in cycle mode, can you explain that? What I should say is you have to tell Mach the spindle is on or it wont look for the spindle speed, whether that is via the button in Mach for spindle or whether it is via M3/M4 it doesnt matter but you must use one.
Hood
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Exactly Hood,
Mach dosen't know that a manual switch is turned on or off in this case.......
1- User clicks the Spindle button to inform Mach that the spindle is on
( even though the spindle is already rotating there will be no rpm reading until Mach is informed)
2- then, if you turn your spindle off then the DRO will indicate some value for the rpm which is not true
( may not even be repeatable to the same value...rpm value just drops to some value)
3- then when you manualy turn the spindle on the DRO will not update until you again click the spindle button to
inform Mach
As far as not showing the correct rpm that is a different matter......
RICH
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Thanks for the help guys, I just assumed that if the spindle was manually turned off Mach would read 0 rpm
As far as the true rpm comment, was more a general statement to explain that the led for the index pulse does not flash every time
the C3 flashes, is that normal?
Jayson
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The index pulse on screen can not keep up with the true index pulse due to the refresh rate of the screen. It is being seen correctly by the driver however so no worries there, it is purely a visual thing.
Hood
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OK, so now I tried to use the threading wizard for a 24 tpi thread and it says Over max feedrate, The axis velocity on X is 100ipm and the rpm setting in the wizard is set to 177 rpm, what gives?
Jayson
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X is not the axis in question it is Z that does the traveling for lathe threading.
Hood
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I meant the Z sorry, about the threading wizard, on the pitch, I thought I read somewhere that you input
the tpi for standard threads, is this correct? Or should I enter the pitch for a 24 tpi thread, which I think is 0.04167
I think?
Jayson
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Jayson,
As it says on the screen... pitch...... which is 1/24 in your case.
If it say's over max feedrate then you are trying to cut a thread with the motor rpm to high for the velocity you defined in motor tuning.
ou may want to take a look at Threading on The Lathe write up in Members Docs.
RICH
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I only ever do metric threads so always pitch, well when I say I only do metric threads I mean I only work in mm. If for example I am doing a BSP or UN or Whitworth thread I will divide 25.4 by the TPI to get the pitch in metric. Easiest way to do at the machine is use the DRO itself. In your case enter 1 into the DRO and click the enter on your keyboard then highlight the DRO again and press / on your keyboard then 24 (or whatever TPI) and when you press enter again on keyboard you will have the pitch :)
Hood
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Hood,
Never new that ....... ??? just tried and works like a charm :)
How do you know these neat little lilttle things?
RICH
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Just a tinkerer and try things no one else thinks of. For example MDI D1X10 or L1X10 or whatever letter you wish ;)
Hood
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Hood,
Glad it wasn't D1x1000 as i would fall asleep waiting to get there, never the less, interesting :D
got any others?
RICH
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Thanks everyone! , I just finally successfully turned a 1.37x24tpi thread for my friends Mtn bike, now I have to figure out
how to turn the left hand thread on the the other part haha!
Jayson
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Rich
That one was found when I made a typo here at home, suppose its a bug in a way but really cant see how it would be harmful as the intention would be to do a G0 or G1 move anyway. The worst that would happen is if you had previously done a G1 move then commanded D0 rather than G0 the axis would move at the previous feedrate rather than a rapid.
Jayson
Few ways to do a left hand thread.
1. Tool placed upside down and spindle reversed and feed normal direction.
2. Tool placed at opposite side of work, spindle reversed and feed in normal direction
3 Tool correct way up on normal side, spindle normal direction but feeding from chuck to tailstock.
With 3, you would have to provide an undercut at the start so that your tool doesnt rub whilst waiting for the index and also if your accel is relatively slow you would have to have that wide enough so the axis has a chance to accelerate to full speed before it starts cutting.
Hood
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Ok, so I set my zero's (z end of part, x center of rotation)
Then I go to the threading wizard, and input my data
1" depth internal thread LH (Z start 0, Z end -1)
1.37X24tpi (X start -.65, X end -.685)
Cutting on the backside, spindle reversed, normal feed direction.
Problem is it wont let me enter a negative value in the X start box, if that makes sense?
Or am I going about this wrong?
Jayson
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Looks like the standard wizard DRO is not formatted to allow you to enter a negative for the start X. You can easily change that by opening it in screen4 or Machscreen and changing the format string of that DRO.
To do that open the screen designer then File, Open then browse to Mach3 folder. Then Turn Addons then Simple Threading and you should see threading (lathe).set, double click it and choose the resolution to view. Then double click the DRO you want to change and you should see the properties box, in the format string it will have %.3f, change that to %+.3f then close that box, save the screenset then thats it. Restart Mach if you have it open and then when you go into the wizard you should be able to enter a -
Hood
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I have a very firm grasp on machining and electronics, but software makes me twitch
Its kind of a joke in the shop I work in "All you gotta do is..." In my line of work, if you hear
that from mgmt. you are in for some loooong weeks.
That said I will give it a go Hood, I really appreciate everyone's help here.
Jayson
P.S. why does the tool path window show an image of an external thread, when I am cutting internal?
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P.S. why does the tool path window show an image of an external thread, when I am cutting internal?
It shouldnt, post a pic of it if you can
Hood
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Everything went great! til I turned on my computer haha
But seriously folks I did not see a screen designer in my mach folder?
Jayson
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Get it on the downloads page.
Hood
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Thanks Hood, that was painless!
Will try to post a pic of the finished part as soon as its done
trying to button up my 3d printer rhis weekend as well.
Jayson
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look forward to it.
Hood