The illusive Boxford 260vmc

Im fast leaning in that direction, i may just wait and buy the tachulator, its off the shelf, programmable, it comes with the sensor, and it has good reviews, I did'nt want to go down the build your own route as ive done all this PCB DIY before it drives me nuts but at least i had a go. the thing is i dont enough hours in the day as it is. Having built the circuit got the display and the sensor now comes all the tinering about, it really would have been quicker and less hastle to just buy one lol. but i really do believe in buying within the UK if possible..

On a side note i2i i think you may have converted one of these machines before, Do you know where i start to calibrate (if that is the term) the machine with mach EG so 10mm in mach is 10mm on the axis..

It may be different for you as you've got different stepper drivers in your machine. But the jist of it is, set it to mm, set the step and direction pins for each axis and enable the axis, got to motor tuning and set the steps to 200, the velocity to 1500, and the acceleration to 50, for x y and z, making sure you save tha axis settings each time. You'll need to set the step pulse length to 5ms, and you'll only need to do that once.

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Originally Posted by i2i

It may be different for you as you've got different stepper drivers in your machine. But the jist of it is, set it to mm, set the step and direction pins for each axis and enable the axis, got to motor tuning and set the steps to 200, the velocity to 1500, and the acceleration to 50, for x y and z, making sure you save tha axis settings each time. You'll need to set the step pulse length to 5ms, and you'll only need to do that once.

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I did all that at the begining, Sorry I made a hash of that question... What i was trying to say is, what do i need to do to make the amount of travel in say the x axis 10mm on the bed and 10mm in mach, so if i tell mach to move the x axis 10mm it moves 10mm as opposed to say 12mm for example? .... there, clear as mud lol

ok what are the steps set at in motor tuning, and what exactly do you get if you move it 10mm by mach

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Originally Posted by i2i

ok what are the steps set at in motor tuning, and what exactly do you get if you move it 10mm by mach

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LOL im not getting this am i lol Ok I thought i had to set the screw spec so mach knew how far 1 rev of the stepper would cause the bed to travel, I wanted to know how i find this information to put into mach lol, sorry im between shifts at the moment so ive had a night shift and no sleep till tonight so I can reset my body clock while im off work.


Rick

there is a way to do it automatically in mach, you enter the pitch and steps and gearing and it works it out for you, but it should be 200 steps. Try it on 200 steps, it's easy to change when you know how much it's out.

go to the settings page, and it's in the lower left corner

"set steps per unit

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Originally Posted by i2i

there is a way to do it automatically in mach, you enter the pitch and steps and gearing and it works it out for you, but it should be 200 steps. Try it on 200 steps, it's easy to change when you know how much it's out.

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Ah ok, well I will get out in the yard and uncover it as soon as I get 5 mins

i'm sure i set the last one at 200 steps in motor tuning.

basically the motor has 200 steps per revolution, if the pitch of the ballscrew was 1mm and the screw was directly driven by the stepper, then one revoultion of the stepper would give you 1mm set at 200 steps. But if the pitch was 2mm then it would have to be set at 100 steps to give you 1mm movement. It gets a bit more complicated when the stepper drives the ballscrew through a toothed belt and two different sized pulleys, as in the boxford. So to get back to the 1mm movement for one revolution on a 2mm ballscrew you would have to gear the motor down by 2:1 at 200 steps.

Blimey sorry about that i dropped off to sleep there :) Ok so if i find out the pitch of the screws and the gearing of the steppers i will be ready to set this information in mach... I will get on that first thing tomorrow morning, That should be fun lol..

Rick

Morning.
Mine is set up like this:
Motor Tuning and setup
X steps per = 1000
Velocity = 1200
Accelleration = 500
Step pulse = 5
Dir pulse = 0

For the Y: the same

For the Z:
Steps per = 1000
Velocity = 1200
Accelleration = 500
Step pulse = 5
Dir pulse = 0

For the spindle:
Steps = 200
Velocity = 600
Accelleration = 1000
Step pulse = 5
Dir pulse = 0

And in the Pulley Selection:
Pulley 1
Min speed = 0
Max speed = 2000
Ratio = 1

Hope this helps,
Regards,
John.

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Originally Posted by MHJ

Morning.
Mine is set up like this:
Motor Tuning and setup
X steps per = 1000
Velocity = 1200
Accelleration = 500
Step pulse = 5
Dir pulse = 0

For the Y: the same

For the Z:
Steps per = 1000
Velocity = 1200
Accelleration = 500
Step pulse = 5
Dir pulse = 0

For the spindle:
Steps = 200
Velocity = 600
Accelleration = 1000
Step pulse = 5
Dir pulse = 0

And in the Pulley Selection:
Pulley 1
Min speed = 0
Max speed = 2000
Ratio = 1

Hope this helps,
Regards,
John.

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Thanks John, I suppose the first question for you is do you have a 260vmc? and are your ball screws and steppers standard? and if so what is the pitch of your ball screws? and what is the stepper to lead screw gearing?, Inquisition out of the way :smile: its nice to have the details you posted as i would like as much information in this thread about these machines as possible, the reason I started the thread is because so little information is available on the net About it.

Every little helps as the woman said when she ........... in the sea!!


Rick

Those are the settings for my Boxford 260 VMC. They should get you up and running.
Ball screws and stepper motors are standard. As to your other questions, I'll dig through my archives for the information....I have of course no memory left after the Denford Easiturn3 conversion, which I finished yesterday. (Don't mention that though, because I've spotted a job list drawn up by the Domestic Engineer.) If you want the other Mach3 settings I use, just shout.
Regards,
John.

Hi John, what drives are you using for the steppers and spindle (analogue voltage), and what mode for the steppers.

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Originally Posted by MHJ

Those are the settings for my Boxford 260 VMC. They should get you up and running.
Ball screws and stepper motors are standard. As to your other questions, I'll dig through my archives for the information....I have of course no memory left after the Denford Easiturn3 conversion, which I finished yesterday. (Don't mention that though, because I've spotted a job list drawn up by the Domestic Engineer.) If you want the other Mach3 settings I use, just shout.
Regards,
John.

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Have you got a saved mill profile?

Thanks John.. :)

Rick, have you got the drives running?

Oh yes all axis duely played with!!!!

ok, so what are the steps set at in motor tuning and if you move an axis 1mm what does it actually move.

I will try that now.

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Originally Posted by i2i

ok, so what are the steps set at in motor tuning and if you move an axis 1mm what does it actually move.

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All axis set to
Steps per=1000
Volocity=250.02
Accelleration=50
Step pulse=5
Dir pulse=0


Ah yes and my axis are going minus from home i think there is a way to reverse that isnt there, will do axis travel measurements in a moment...

yes we can make the axis go the right way, but the movement is the important one for now

Ok if i move the Z axis from 0.0000 to 1.0000 i get a movement of 5mm.

ok change the steps to 200, and try again

Ok with 200 steps if i jog the Z axis from 0.0000 to 1.0000 i get a movement of 1mm. but slow.

it will be slower as it's a fifth the amount of steps, but it's the RIGHT AMOUNT OF STEPS PER UNIT.
This must stay at this setting.

Next step is to set the jog rate at 100%

Press "tab" to get the mpg screen and set the jog rate to 100% (just below the "slow jog rate")

Ok it was already at 100% :)

to speed up the axis you raise the velocity, but the faster you go the more chance you have of stallling the motor and loosing steps.

Ok thats cool what would you suggest for volocity and accell

the only time you alter the steps is if you change the mode the stepper driver drives the motor, eg., half step 1/8 step ect.
But for now we'll use the settings the drives are on, which gives you 200 steps per unit.


PS. see post 243.:smile:

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Originally Posted by i2i

PS. see post 243.:smile:

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:redface: Done :smile:

i normally use 1500 for velocity and 50 for acceleration

You can of course increase these settings, velocity gives you speed and acceleration defines how quickly you get to that speed. Too much acceleration and it'll stall so be gentle with the acceleration.

I've had the boxford running at 3000 on the velocity, which is 3m a minute, but you risk stalling the motor that way, that's why i stay at 1500.

you may want to lower the velocity a bit on the "z" as it's always a bit heavier on the stepper, 1000 or 1200 should be good.

Have a play around, don't worry about stalling a drive, at this stage you're not machining so best to find out the limits of the drives now.

The motors Sound good (they sound right) at 1500 and im not in any hurry for more speed.

don't feel too confident, you've got the spindle to come.:eek:

i've not used the stepper drivers you have, so i don't know their limits. The settings i've used are for Parker sd2/3 drivers.

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Originally Posted by i2i

don't feel too confident, you've got the spindle to come.:eek:

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Well the spindle works from mach at the moment ive set the low speed to 320 and the high speed to 2000 rpm.. great fun lol

buy yourself a cheap tacho (ebay £7 approx), or use the pulse to set the speed range to match mach correctly.

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Originally Posted by Ricardoco

Well the spindle works from mach at the moment ive set the low speed to 320 and the high speed to 2000 rpm.. great fun lol

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you should get at least 3200 rpm from that machine.