Messages

11

General Mach Discussion / Re: Spindle/ C Axis using CSMIO/IP-A

« on: October 16, 2018, 11:41:13 AM »

Looking at the electromagnetic clutches and this type of thing is available off ebay.

 https://www.ebay.co.uk/itm/Genuine-John-Deere-Electromagnetic-PTO-Clutch-AM119536/183059126213?epid=1516104299&hash=item2a9f2c97c5:g:9M0AAOSwyphaedn8:rk:7:pf:0

Can't get any holding torque data but spoke to a few suppliers and they are fitted to lawnmowers with an engine size of 12hp plus. Would have to make a reducing coupler from 46mm down to 1" and change the pulley to HTD type. Any thoughts whether something like this would suitable?

Also thinking would this have to be fitted on the spindle side due to possible magnetic interference to the servo motor encoder?

Mick

12

General Mach Discussion / Re: Spindle/ C Axis using CSMIO/IP-A

« on: October 16, 2018, 04:49:59 AM »

Hi Hood

You would still need to disengage the  Servo as any motion on it would be detected by the CSMIO and it would try to correct and would throw a fault although probably not when disabled but not sure how easy that would be to do, if at all, from within Mach/CSMIO. Even if a way can be found then I don't think driving a servo motor would be the best idea for a drive even with it disabled

Totally agree some kind of clutch is needed to disengage the servo.

My main concern at the moment is the accuracy of the C axis. The manual for the Lexium 28 drives states an accuracy of 0.044 of a degree. The resolution of the encoder is factory set at 2048. So I think this is 2048 x 4 =8192PPR. So 360 degrees/8192= 0.044 degrees. If I take a 150mm max turning diameter this would give me an accuracy of 150 x 3.142 = 471mm. So 471/360= 1.31mm per degree. 1.31x0.044=0.057mm. (Think that's right)
Ideally, I would like to have an accuracy of around  0.01mm.

I would need to either gear the servo motor 5/1 or change the encoder resolution to achieve this. I do need to gear the servo motor at least 2/1 for torque purposes and hoping I can adjust the encoder resolution to do the rest?

This encoder resolution can be adjusted via P1-46 up to a value of 40,000. I have tried adjusting this on the X and Z axes but got some strange results.

I'm trying to figure out why Schneider would state an accuracy of 0.044 when the parameter allows you to set a lot finer resolution possibly which would give you more accuracy. 
Have you adjusted the encoder resolution on any of your drives?

Attached a couple of manual screenshots.

Mick

13

General Mach Discussion / Re: Spindle/ C Axis using CSMIO/IP-A

« on: October 15, 2018, 07:58:53 AM »

Hi Hood

I think I may be missing something here but if I use the existing VFD and Spindle motor why would we need to use separate profiles? The spindle is using the 0 to 10v analog output from pin 7 or 8 on the I/O connector and the encoder will be connected to the csmio/enc. The C axis will be treated as its own axis not a spindle the same as X and Z and use one of the encoder channels on the I/O. The analog voltage to the C axis will come from pins 1-6.   
Does this sound right? Are we talking about the same thing? 

These clutches look great. Not going to be a standard fitment though and I think expensive. Do you have any supplier contacts?

14

General Mach Discussion / Re: Spindle/ C Axis using CSMIO/IP-A

« on: October 14, 2018, 09:08:31 AM »

Hood

The plan is to use it as a rotary axis at some point. 

Craig

 Induction motors and VFDs are a poor choice for indexing


The Jaguar 550 VFD works fine with the original motor and it was never my intention to use it for any kind of indexing or rotary axis. Only for turning and threading. Hence why we are talking about fitting a 1.5kw servo motor alongside the original spindle motor. 

Given that 99% of my milling requires just a free running spindle the question must
be asked 'does all the complication of an indexable and/or C axis make sense?'. Probably not...

This is something I would like to do and I don't believe it would be that difficult setting this up as a separate axis. 

Mick

 

15

General Mach Discussion / Re: Spindle/ C Axis using CSMIO/IP-A

« on: October 13, 2018, 05:10:43 PM »

Hood

I have read the reply from CS Labs a few times and I am wondering if the second line is hinting at it being possible to do something like SwapAxis() feature in Mach except via VB scripts. It might be worth asking them to clarify.

I will ask for further clarification on Monday. Can you please clarify exactly what is meant by indexing? I thought this referred to set index points EG (1 degree, 10 degrees, 20 degrees etc) which is not a fully functioning rotary axis. With an accuracy of 0.1 degrees as stated by CS Labs, would this not be useless for any kind of semi-precision work?

 If you were machining a part with a 150mm diameter that would give you an accuracy of 0.13mm (150x3.142/360x0.1)  

I like the magnetic clutch idea will do some research on those. Don't think Mazak will steal my idea in a rush. lol

Bill

Thanks for your comment.

Looking at the moment to keep the original spindle and VFD and using a small Servo motor geared down for C axis machining.  

16

General Mach Discussion / Re: Spindle/ C Axis using CSMIO/IP-A

« on: October 13, 2018, 11:56:33 AM »

I think something like this may work and be easy and cheap enough to make. Not sure how much tension would be needed on the auxiliary wheels once the C axis was engaged.
Try not to laugh too much. Lol

 

17

General Mach Discussion / Re: Spindle/ C Axis using CSMIO/IP-A

« on: October 13, 2018, 07:15:59 AM »

Hood

Thanks for the reply. Yes, we did touch on this in my other topic. Using two Mach profiles was not really what I wanted but for the small amount of inconvenience of shutting one profile down and opening another sounds like it outweighs the headache of trying to get this set up as a combined Spindle/C axis.

What are your thoughts on keeping the original Spindle motor for turning, threading etc and having a smaller C axis motor that is engaged when the C axis profile is enabled?

I had this motor in mind. https://uk.rs-online.com/web/p/servo-motors/1110826/?sra=pmpn

The stall torque is only 7nm but as I would only be using it as a rotary C axis, I could mechanically gear it down to achieve a lot higher torque.


This is a response I had from CS LABS regarding Spindle/ C axis       


Hello,

 
In Mach3 you can't use a servo drive as a spindle and a fully functional rotary axis at the same time.

However, you can use a servo drive as a spindle and an indexed rotary axis (spindle positioning from VB macros with an accuracy of 0.1 degrees).

Using a servo drive as a spindle and a rotary axis at the same time was supposed to be provided by Mach4. It surely will be possible with simCNC.

As for a servo drive connection, you have to connect it the same way as the other servo drivers and then run "Spindle Axis" function in plugin.

 

18

General Mach Discussion / Spindle/ C Axis using CSMIO/IP-A

« on: October 12, 2018, 06:26:50 AM »

Hi All

Recently started a conversion using the CSMIO/IP-A on a Denford Senior lathe. With the help of people on this forum made huge progress and now have the X an Z-axis working perfectly using Lexium 28 servos and drives.

The original spindle motor is connected to the CSMIO and also works well as it should.

I would like to have a combined spindle/ C axis in order to facilitate some live tooling in the future. My plan is to fit a new Lexium servo motor and drive to power the spindle. (Appropriate size not yet decided)

I have successfully wired the X and Z axis using the analog +/- 10v and also have the VFD working using the 0 to 10v speed command on the spindle.     

Can anyone advise on how this would be configured and connected to the CSMIO so I can switch between Spindle and C axis? 

Mick
 

19

General Mach Discussion / Re: CS Labs CSMIO/P-A

« on: October 04, 2018, 03:14:15 PM »

Hi All

Had to take the wife away for a week so sorry for no update.

All good set the X-Axis up now and no issues what so ever. Done several tests with my 0.01mm gauge and see no error at all on both Z and X. Would be interesting to get a 0.001 gauge to test.

As previously discussed with acceleration. I can set the acceleration way above what is set in the drive and it does not fault out. So I think Hood was right in his previous comment.

Need to get the spindle sorted now and torn between exploring further the two motor options or 3 phase Lexium 32. This is totally off-topic so will start a new topic over the weekend.

Thanks again to Hood, Craig and everyone else who commented. 

Cheers
Mick     

20

General Mach Discussion / Re: CS Labs CSMIO/P-A

« on: September 23, 2018, 03:43:49 AM »

That makes total sense now.

I have the max rpm set in the drive at 1000rpm. I have the velocity set in Mach at 5000mm min which gives me 1000rpm max speed of the motor using 5mm ball screws.

So like you have worked out the 5000/60/1000=0.083. Which is slower than the drive setting of 0.030.

The manual is saying parameter 1-34 sets the acceleration if in velocity or PT mode. Screenshot attached.

I'll try setting 1-34 to something a lot higher to see if it does affect the acceleration.

Am I right in thinking if it does then settings in Mach would not be accurate outside the drive limits.  

Mick