Machsupport Forum

Mach Discussion => General Mach Discussion => Topic started by: kencor1 on April 25, 2009, 07:06:10 PM

Title: Help with spindle speed control for Mini Lathe
Post by: kencor1 on April 25, 2009, 07:06:10 PM
I am looking for advice on what hardware and wiring needed  to begin to use spindle speed control on my converted  CNC Mini Lathe.  What boards can anyone suggest, and if you could point me in the direction to find out how to wire the lathe, it does have a variable speed control knob on it.

Thanks for any help you can give.

Tom
Title: Re: Help with spindle speed control for Mini Lathe
Post by: jtheath on April 25, 2009, 11:36:34 PM
Hi Tom,

I just got my Taig microlathe fully converted.  For motor control I am using a C6 Step/Dir conversion as a potentiometer replacement.  The DC output and ground from the C6 provides input in place of two legs of the pot.  I also used a C3 board with optical sensor to close the loop.  Both boards acquired from cnc4pc.com.

The C6 requires a 12V power supply and the C3 a 5V supply.  Grounds should be case isolated.

Hope this helps,   Joe
Title: Re: Help with spindle speed control for Mini Lathe
Post by: Peter Homann on April 26, 2009, 12:38:37 AM
I am looking for advice on what hardware and wiring needed  to begin to use spindle speed control on my converted  CNC Mini Lathe.  What boards can anyone suggest, and if you could point me in the direction to find out how to wire the lathe, it does have a variable speed control knob on it.

Thanks for any help you can give.

Tom

Hi Tom,

HAve a look at the DigiSpeed range of Speed controllers I make and sell.  The DC-06 uses step and dir control sognals. The DC-03 and DC-02 use PWM. They all have an option for an on-board DC/DC converter so that an additional isolated 12V supply is not needed.

http://homanndesigns.com/store/index.php?main_page=index&cPath=1

I use a DC-02 on my Taig mill and 7x14 lathe as it has an option for an onboard  potentiometer so it can be used in a manual mode when required as well.


Cheers,


Peter.
Title: Re: Help with spindle speed control for Mini Lathe
Post by: simpson36 on April 26, 2009, 03:11:21 AM
I've had trouble with a couple different boards and recently tried out Homann Design's new stuff.

The new PWM version puts out a rock steady control votage from Mach3, something I was unable to get with the other boards. I finally have a nice steady Mach3 controlled spindle speed on my X2. HIGHLY recommended.

CAUTION CAUTION CAUTION!!!   Make absolutely sure to use an ISOLATED speed controller. If you connect non-isolated speed controllers to the variable speed controls in these import machine tools, you get a pop and expensive smoke.

That goes for replacement variable speed drives also like those from Minarik and KB. I fried two Minarik controllers connecting them to CNC4PC boards. And that takes out a lot of other stuff with it when if goes. That is the expensive way to learn about 'isolation'.

Suggestion: leave yourself a way to switch back to manual control while a program is runing. Sometimes you may need to vary the speed during a cut to clear up chattering, etc.



Title: Re: Help with spindle speed control for Mini Lathe
Post by: Hood on April 26, 2009, 03:33:03 AM
Suggestion: leave yourself a way to switch back to manual control while a program is runing. Sometimes you may need to vary the speed during a cut to clear up chattering, etc.
Not just use SRO or FRO in these situations?
Hood
Title: Re: Help with spindle speed control for Mini Lathe
Post by: simpson36 on April 26, 2009, 04:04:50 AM
Hood,

I have not had success changing speed in Mach once a program is running. I have not tried in a while as I gave up getting my spindle to work with Mach until recently when Homann came out with a new board that works beautifully. So this is goint to be a priority again.


What is the correct proceedure to change spindle speed while a program is running?
Title: Re: Help with spindle speed control for Mini Lathe
Post by: Hood on April 26, 2009, 04:08:51 AM
Does the slider not change that for you?
Hood
Title: Re: Help with spindle speed control for Mini Lathe
Post by: simpson36 on April 26, 2009, 08:51:15 AM
If you are referring to the up and down buttons in the Spindle Speed panel on the program run page, then no they did not have any effect for me but then that was several versions ago and I was having trouble with the whole speed control issue anyway. The spindle speed wavered all over the place, and it was anyone's guess what programmed changes were going to do.

I'll give it a try again now that I have the speed comtrol working. It sure would be handy to manually tweak the speed (and/or feedrate) of a running program..

Right now I'm down waiting for a new power supply, so I'll post back when I'm running again.

Thanks for the help!
Title: Re: Help with spindle speed control for Mini Lathe
Post by: kencor1 on April 26, 2009, 10:42:58 AM
Thanks for the input. I think I will try the Homann board, and see if I can figure out how to make that work.

Tom
Title: Re: Help with spindle speed control for Mini Lathe
Post by: kencor1 on April 26, 2009, 11:59:52 AM
Peter,
 I was just looking at your website. I think that the DC-02 is the way that I want to go.  Can you tell me what options would be best for me, the lathe that I have is a Clarke 7x12 Mini lathe. I used the the Ron Steele CNC conversion Instructions and ordered the recommended proximity sensor from Euro Spec #is12-y4-n-oc. I just want to be sure that I will not run into any problems with the wiring. Also I plan on using the Smooth Stepper, will that be any problem?

I also think that I want to use the existing manual speed contron knob, and the dc-dc converter, also the led not on the board.  What do you think would be best, you know allot more than me.

Thanks,
Tom
Title: Re: Help with spindle speed control for Mini Lathe
Post by: Hood on April 26, 2009, 02:05:07 PM
If you are referring to the up and down buttons in the Spindle Speed panel on the program run page, then no they did not have any effect for me but then that was several versions ago and I was having trouble with the whole speed control issue anyway.

What revision of Mach was that? As far as I am aware the SRO and FRO have been sliders for a long time rather than buttons. You may be using a custom screen rather than the standard and in that case then that may be why it did not work as the buttons may not be asigned properly. I myself use my own screens and have buttons for overrides but also use analogue inputs and pots for FRO/SRO

Hood
Title: Re: Help with spindle speed control for Mini Lathe
Post by: Peter Homann on April 26, 2009, 09:58:28 PM
Peter,
 I was just looking at your website. I think that the DC-02 is the way that I want to go.  Can you tell me what options would be best for me, the lathe that I have is a Clarke 7x12 Mini lathe. I used the the Ron Steele CNC conversion Instructions and ordered the recommended proximity sensor from Euro Spec #is12-y4-n-oc. I just want to be sure that I will not run into any problems with the wiring. Also I plan on using the Smooth Stepper, will that be any problem?


I also think that I want to use the existing manual speed contron knob, and the dc-dc converter, also the led not on the board.  What do you think would be best, you know allot more than me.

Thanks,
Tom



Hi Tom,

The DC-02 is a good way to go. You need to decide wow you want to mount it. If you have the optional switch, indicator leds and pot mounted on the DC-02 board, then it needs to be mounted so that these components protrude through a front panel. If the DC-02 is to be mounted inside a CNC controller, then the switch, Leds and manual pot are connected to the DC-02 via flying leads.

If you let me know how and where you want to mount it, I can advise on the best configuration.

As to the Smoother Stepper, it works fine with the DC-02.

The proximity sensor, requires 12V as it's supply and provides a 12V output. You can still use it by not feeding it through the DC-02. (note, the DC-02 does not need the index sensor to be connected to it. It is just to conveniently feed the index signal to your breakout board via the DC-02 mini-din cable). The DC-02 is designed for a 5V index sensor such as the Omron EE-SY672. Have a look at the engineering note. http://www.homanndesigns.com/EN001.pdf

If you want to use the proximity sensor through the DC-02, you will need to provide a voltage divider to reduce the 12V output of the sensor to 5V.

Cheers,

Peter.


Title: Re: Help with spindle speed control for Mini Lathe
Post by: kencor1 on April 27, 2009, 08:36:51 AM
Thanks, Peter.  I think I will mount it in the controller, not on the lathe itself, I think it will be easier that way. Please advise on what setup would be best.  Also are there "novice' Wiring Diagrams for the hookup that I can look at?
Thanks,
Tom