Hello Guest it is July 21, 2019, 03:41:17 AM

Author Topic: Spindle Index problem.  (Read 25738 times)

0 Members and 1 Guest are viewing this topic.

Re: Spindle Index problem.
« Reply #10 on: May 04, 2008, 03:20:35 PM »
Simon,

The slot width on Art's Boxford was more like 20mm in the manual. Also, when I was doing a tachometer on my big manual lathe, it needed a Schmitt trigger IC to clean up the  output of the opto switch to get a clean signal to feed to a frequency counter.

Ian

Offline SimonD

*
  •  143 143
    • View Profile
Re: Spindle Index problem.
« Reply #11 on: May 04, 2008, 03:36:01 PM »
Ian,

Thanks for the reply, it is driving me nuts!

I was going by what the manual stated... The manual I've got states "3 slots at 4mm and one at 8mm" So I assumed one at 6mm would work OK. I figured it should at least work OK at low revs.

The CNC4PC C3 card I am using already has a Schmitt trigger IC on it.

Do I really need to set "pulley ratios" I have been just using pulley set 1 set to the maximum speed rating 0-3200 rpm Is this wrong?

What have you got the step/direction settings set for on the motor tuning? I set them up the same as the C11G manual suggests. e.g. 1000 steps per and 1500 velocity and something really small for accel (I can't remember off the top of my head)

Thanks
Simon
Re: Spindle Index problem.
« Reply #12 on: May 04, 2008, 04:23:49 PM »
Simon,

Can't help with pulley ratios, I am still on manual spindle control.
Settings, Steps per mm at 1000.
Kernal speed is now 100kHz.
Acceleration at 286 mm/sec/sec. I have seen faster recommended but this is about 0.1 sec from 0 to maximum, which is fast enough for me!
Step pulse at 4.
Dir pulse at 4.

Experimenting with the Geckos, I got the X up to 4000 mm/min,scary stuff!

Ian
 

Offline SimonD

*
  •  143 143
    • View Profile
Re: Spindle Index problem.
« Reply #13 on: May 04, 2008, 05:31:44 PM »
Ian,

I might end up on manual speed control at this rate! seems a shame as it is all wired up!

kernel at 100kHz sounds scarey! my poor little PC can't cope with that. I will experiment with the kernal once it is all running.
4000mm/min is very scarey on a machine with only a 200mm or so of total travel!

I am just connecting up the front panel, it used to work off 12v but luckily it also works on 5v so all the buttons are trivial to wire up to a 2nd parallel port. (if the postman ever brings the card!)

I really wanted to get the spindle working while I was waiting for the smoothstepper and 2nd BOB to arrive.
It seems to run fine and I can change the speed using Mach3 it just doesn't go to the speed I request which is really annoying, I am so close yet so far away! I have a funny feeling it is something to do with pulley ratios but I don't know.

The "calibrate spindle" routine just seems to mess everything up completely. I start off with a fairly linear spindle range albeit producing the wrong values and after running the calibrate spindle I get complete rubbish! to the point this afternoon where I have had it running nothing but 0 and full speed for any commanded speed and then some wierd "calibration" where the spindle would respond to everything except s200-s300 where it was stationary!

Tomorrows job might be to make the slot wider, I can see it making a difference at the top end of the speed range but I don't see how it can help at the lower end of the speed range.

Simon



Re: Spindle Index problem.
« Reply #14 on: May 04, 2008, 07:46:17 PM »
Hi Simon

I too am waiting for a SS and a second BOB i hope this info may be helpful.

I am running a milling machine it has 12 spindle speeds via belt change.

My new motor and VFD allows the motor to run at double speed

I am not  using an index pulse on the mill so at the moment this does not confuse the issue.

With the motor being able to run at double speed i decided to set the minimum speed at 50% at/on any given pulley

So i set up 12 pulleys and according to the speed chart i set the minimum to 50% and max to 200% of each pulley speed giving me 12 pulley speeds

On pulley 10 i now have a speed range of 500 rpm to 2000 rpm "NO VFD it would have been 1000 rpm"

Now this is where some trial and error comes in, varying the steps &/or velocity so that on max speed i get 10 volts on the BOB and at 50% speed i get 5 volts on the BOB i could get this accurate as my VFD has frequency output

The settings of the motor setup are a starting point 1000 x 1500 mine are a lot lower

Set the trim pot to the centre

Run at max speed monitor voltage "To high lower step value" "To low raise step value"

Keep this up until you get close to 10 volts then use trim pot to set to 10 volts exactly

Then try 50% speed this should read 5 volts

I think if you get this bit working correctly then move onto setting up the pulse card

I to am using Arturos products, excellent but the instructions can be vague at times  ;D ;D ;D

HTH
Phil_H
The Good Thing About Mach3, Is It's very Configurable

The Bad Thing About Mach3, Is It's Too Configurable

Offline SimonD

*
  •  143 143
    • View Profile
Re: Spindle Index problem.
« Reply #15 on: May 05, 2008, 07:35:48 AM »
Phil,

Thanks for the reply...

I have 1 pulley set up set to min 0 max 3200 rpm.
If I go to the motor tuning page and press the up arrow key then I get a solid 10v out of the BOB. I think this tells me the max speed is set ok.

If I then command a S3200 I get 9.15v out of the BOB. I also get this when I set the speed to S2000, in fact I get the same anywhere between S2000 and S3200 at S1600 I get 7.6v

I think I need to reset the spindle calibration but I can't seem to find out how to do it. Any ideas anybody?

As for the RPM reading, Thanks to Hood and Overloaded for pointing out the debounce value and that is was set too high. I am now getting a constant reading but I think it is reading twice as fast as it should be.


Thanks
Simon

Offline SimonD

*
  •  143 143
    • View Profile
Re: Spindle Index problem.
« Reply #16 on: May 05, 2008, 09:28:36 AM »
I take it back, The reading on the rpm is about right, certainly at slower speeds. I manually counted revolutions and am getting about the same although I can't count any faster than about 250 rpm!

Now how do I get the spindle range to be linear? I have tried the "calibrate spindle" dialog but it seems to be making it worse, not better. the lower end of the range seems to be fairly linear at present but only upto s2000

Thanks
Simon

Offline Graham Waterworth

*
  • *
  •  1,863 1,863
  • Yorkshire Dales, England
    • View Profile
Re: Spindle Index problem.
« Reply #17 on: May 05, 2008, 10:35:55 AM »
Hi Simon,

if you go to diags is the current pulley set to 1?

I have a disc with 7 10mm slots and one 20mm slot, Mach reads this with the timed signal through a CNC4PC C3 board, I have very good control from 200-4500 rpm with no spindle calibration.

I also found that if the slotted disk was painted black it was better, ? :o , answers on a post card  ;D

You will find if you do threading you will need a multi slot disk,  more slots makes for better pitch control.

Graham.
« Last Edit: May 05, 2008, 10:39:48 AM by Graham Waterworth »
Never give up, time will pass, the cloud will clear, the sun will shine once more.

Offline SimonD

*
  •  143 143
    • View Profile
Re: Spindle Index problem.
« Reply #18 on: May 05, 2008, 11:04:06 AM »
Hi Graham,

Yes the current pulley is set to 1. I thought if I get the first pulley set up then I should be able to work the others out but...
I did try putting black tape around the disc but it made no difference as my disk has a myriad of holes around it on a different pitch from the original timing and I though maybe they were masking the signal.

I didn't realise I would need more slots to do threading. I will have to cut more.

Thanks
Simon

Offline Hood

*
  •  25,849 25,849
  • Carnoustie, Scotland
    • View Profile
Re: Spindle Index problem.
« Reply #19 on: May 05, 2008, 11:24:55 AM »
Simon
 I will disagree with Graham regarding the multi slots being needed for threading. I do a lot of threading, in fact I have just finished making 30 or so pullstuds for my mill and the threads are perfect, also a month or so back I made a load of pullstuds up for Brett (Chaoticone) and these too were perfect, same with the toolpost bolts I made, the prop shafts I have made and so on. The largest thread I have done so far was 2.5 inch BSP and the  smallest thread I have done was M4  so maybe if you go ultra small it will be a different story but I dont think so.
 My spindle isnt controlled by the Index pulse however as the spindle speeds on my Lathe are controlled with Electromagnetic clutches, possibly if you have the speed set and controlled from a VFD a multi slot disc might be better.

Hood