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Author Topic: Lathe Threading Wizard Rev 1.17  (Read 21445 times)

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Offline AVRnj

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Lathe Threading Wizard Rev 1.17
« on: January 29, 2014, 05:31:31 PM »
Hey everyone,

I just converted my lathe for CNC.

I have been playing around with the lathe turning wizards and the first few I tried worked fine.

I than tried the Lathe threading wizard.

I entered in some standard values, and posted the code. Just like any other wizard, the paths appeared in the window.

When I went to run it, my z axis went positive for a while, than returned to it's prior position, and just sat there and did nothing, it looked like it stopped at the G76 line in the code.

The only thing I can think of is my actual spindle speed is not connected to Mach3, and perhaps Mach3 is waiting for my spindle to get up to the speed I set in the wizard?

I at a loss and tried many different values and kept getting the same result.

Any help would be greatly appreciated.

Thanks.

Offline Hood

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Re: Lathe Threading Wizard Rev 1.17
« Reply #1 on: January 29, 2014, 05:35:37 PM »
You need the Index pulse hooked up as Mach has no way of knowing the spindle speed and also no way to know where the index is so it can sync the threading.
You could uncheck the options on General Config (use spindle feedback in sync mode) for simulating if you wanted but it would not give you an accurate thread, so best not try and cut anything.
Hood

Offline AVRnj

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Re: Lathe Threading Wizard Rev 1.17
« Reply #2 on: January 29, 2014, 05:53:01 PM »
Ok, that makes sense.

I guess I need to get an encoder or tachometer and hook it up toy lathe and mach3?

Are there any resources that explain how to do this in a painless way?

Thank you!

Offline Hood

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Re: Lathe Threading Wizard Rev 1.17
« Reply #3 on: January 29, 2014, 05:57:25 PM »
If you are using the parallel port then the index pulse from an encoder will be too short to use.
Most people use a slotted disc with an optical sensor.
Optek OPB917B is one I have used in the past, all that is required in addition to the disc and the sensor is a current limiting diode so you dont fry the LED, I used 220ohm when hooking to 5v.
If you do a serch for OPB916B or OPB917B on this site you should find posts that I have made telling how to connect.
Hood

Offline AVRnj

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Re: Lathe Threading Wizard Rev 1.17
« Reply #4 on: January 29, 2014, 07:22:08 PM »
Ok, thank you very much for your help.

Offline AVRnj

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Re: Lathe Threading Wizard Rev 1.17
« Reply #5 on: January 30, 2014, 08:16:26 AM »
Hood, I have been looking into this a bit more and wanted to see if I could ask you a quick question.

When you say that the index pulse from an encoder would be too short, would that also include the output of a Hall effect sensor?

I have a few extra Hall effect switch sensors laying around, and some magnets, and I was thinking of putting a neodymium magnet on the back of my chuck and mounting the hall sensor to read the magnet every time it turns. I would think that would allow for 1 pulse per rotation and was wondering if that would work in your opinion?

Just trying to use what I have rather than buying more stuff.

Thanks!

Offline Hood

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Re: Lathe Threading Wizard Rev 1.17
« Reply #6 on: January 30, 2014, 08:31:11 AM »
Yes a hall could well work, will all depend on the hall I suppose but people do use them.
Hood

Offline AVRnj

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Re: Lathe Threading Wizard Rev 1.17
« Reply #7 on: January 30, 2014, 08:34:09 AM »
OK, thanks, I will give it a shot.

Can I ask one more question, from reading other posts about this topic, I assume all I should really have to do is connect the output of my hall to an input on my G540, enable the index and pick the pin I connected it to? Is it that simple or am I missing something?

Thanks for your help.

Offline Hood

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Re: Lathe Threading Wizard Rev 1.17
« Reply #8 on: January 30, 2014, 08:57:19 AM »
If your spindle speed  is controlled via Mach you also need to make sure the Max RPM in Spindle Pulleys (from Config menu) matches the Velocity you have in Motor tuning. Also make sure the ratio is set to 1 in spindle pulleys.
Hood

Offline AVRnj

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Re: Lathe Threading Wizard Rev 1.17
« Reply #9 on: January 30, 2014, 09:26:52 AM »
Hood, thanks.

My lathe has belt controlled speed for now, so I am not controlling the speed through Mach.

I hope to try this out tomorrow, thanks much for your help!