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D-man
17-03-2017, 01:30 PM
Hey guys,

Ive just bought another machine and have had to strip the board out of it in order for it to work. Ive now stuck my spare EDINGCNC CP5 board in, however, doing this as you know i have to set the steppers etc up again.

The machine come with the following:

90 tooth pulley on the pinion
18 tooth on on the motor side
HTD500 5M Belts

Stepping leadshine drivers are set to 1600 steps per revolution @ 8 microsteps via dipswitches

Maybe its just a brain fart, but im struggling to work this out more so the ratio of the belt and pulley so if someone can give me the easy way that would be great

Greeny
17-03-2017, 04:21 PM
To get pinion to rotate 1 revolution the motor needs to turn 5 revolutions (90/18)
1600 pulses rotates motor 1 revolution.
So need 1600 x 5 = 8000 pulses for pinion to turn 1 rev.

Can't work out distance (D) travelled for 1 rev of pinion without more info.(Num teeth on pinion & rack mod if it's r&p)

Once you know distance travelled for 1 rev of pinion= D, then distance per pulse = D/8000

**Edit, seems you need pulses per mm so its 8000/D

Cheers

D-man
17-03-2017, 04:27 PM
Nice one Greeny! Its helical rack and pinion pal, I can get the pinion teeth count but not what mod it is [emoji30]

Any ideas it's not wrote on or anything.

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Greeny
17-03-2017, 04:45 PM
Sorry don't know much about helical r&p.( or any r&p if truth be known :redface:)
I suppose you could move axis by hand & measure how far you need to move it to rotate pinion 1 revolution.
This would give you a very rough but sensible number which you could then refine by trial & error.

Hopefully someone else will have a much better answer!

JAZZCNC
17-03-2017, 04:45 PM
Mark it and rotate one ful revolution and measure distance moved.. . . Simplizzzzz

D-man
17-03-2017, 04:46 PM
I will give that a go cheers lads

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JAZZCNC
17-03-2017, 04:51 PM
how many teeth on pinion and whats it's diameter

D-man
17-03-2017, 07:38 PM
how many teeth on pinion and whats it's diameter

23 teeth and 32mm dia mate

D-man
17-03-2017, 08:08 PM
OK so im getting round about 96.16mm for one revolution of the pinion.

96.16 divided by 8000 = 0.01202 steps per revolution ???

m_c
17-03-2017, 08:22 PM
23 teeth and 32mm dia mate

1.25MOD is 32.69mm OD.
24DP is 1.09" (27.68mm), and 20DP is 1.308" (33.22mm), and 22DP does not appear to be a common size.

So assuming 1.25MOD and me reading the correct number from the chart, gives a pitch of 3.926mm per tooth, or 90.289mm for one rotation of the gear.

Or to assume 20DP, it would be 91.7194mm per rotation.

Are you sure it's a 23 tooth gear?
As even working backwards from 96.16mm, it doesn't fall on any common tooth size.
That's assuming I'm not making a complete hash of the calculations.

Off course, easier option would be just to measure the distance over as many teeth as possible and calculate the tooth pitch that way.

m_c
17-03-2017, 08:26 PM
OK so im getting round about 96.16mm for one revolution of the pinion.

96.16 divided by 8000 = 0.01202 steps per revolution ???

Wrong way to think about it.
You need steps per mm.
So if it takes 8000steps to move one pinion rotation of 96.16mm, then you divide the 8000 by 96.12, which gives 83.19467554 steps per mm.

D-man
17-03-2017, 08:31 PM
1.25MOD is 32.69mm OD.
24DP is 1.09" (27.68mm), and 20DP is 1.308" (33.22mm), and 22DP does not appear to be a common size.

So assuming 1.25MOD and me reading the correct number from the chart, gives a pitch of 3.926mm per tooth, or 90.289mm for one rotation of the gear.

Or to assume 20DP, it would be 91.7194mm per rotation.

Are you sure it's a 23 tooth gear?
As even working backwards from 96.16mm, it doesn't fall on any common tooth size.
That's assuming I'm not making a complete hash of the calculations.

Off course, easier option would be just to measure the distance over as many teeth as possible and calculate the tooth pitch that way.

I'm fairly certain they are the right numbers, I will check again in the morning mate and come back to you.

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D-man
17-03-2017, 08:35 PM
Wrong way to think about it.
You need steps per mm.
So if it takes 8000steps to move one pinion rotation of 96.16mm, then you divide the 8000 by 96.12, which gives 83.19467554 steps per mm.

I did try it that way but didn't want to mention in fear of looking daft, as I calculated it as it was written [emoji23]

Cheers for the help lads much appreciated.

Attached a few pics just in case I've missed or got something wrong [emoji15]

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JAZZCNC
17-03-2017, 08:37 PM
OK so im getting round about 96.16mm for one revolution of the pinion.

96.16 divided by 8000 = 0.01202 steps per revolution ???

Nah wrong got it wrong.

You now have distance pinion travels for one rev which is 96.16 but you have 5:1 ratio so this drops to 19.232 for one rev of the motor which is the affective pitch. So now simply divide 1600 by pitch to get the steps per mm ie: 1600/19.232 = 83.194 steps per mm

Doh didn't see MC done it.!

D-man
18-03-2017, 08:19 AM
Defiantly a 23 tooth pinion

32.82 Dia Pinion (digital Gauges so may change each time lol i will also try a normal set in case these are off.)
93mm Travel now lol (Hard to get to the pinion to mark it, but i would rather go with this measurement)

D-man
18-03-2017, 08:54 AM
OK so now im confused. i punched these numbers into software, however, when I want to move 50mm (In MDI) im getting something like 267mm when marking the gantry and measuring

m_c
18-03-2017, 09:59 AM
OK, go back to basics.

Set the steps/mm to 100, mark the big pulley/pinion, and command a move of 80mm (8000 steps).
Does the pulley/pinion move one complete revolution?

D-man
18-03-2017, 10:13 AM
OK, go back to basics.

Set the steps/mm to 100, mark the big pulley/pinion, and command a move of 80mm (8000 steps).
Does the pulley/pinion move one complete revolution?

Ok that was just over quarter of a turnhttps://uploads.tapatalk-cdn.com/20170318/2c8f0a5522a01eb5a2d29a7bbfb64290.jpg

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m_c
18-03-2017, 10:46 AM
With the same 100 step/mm setting, try a move of 16mm and see how far the motor itself turns.

Greeny
18-03-2017, 10:55 AM
Just thinking of possibilities:

Are you sure it only rotated 1/4 turn? Not 1 1/4 or 2 1/4 etc,
as you previous test seems to indicate too much rotation not too little i.e moves 267mm instead of 50mm.

Also are you sure the leadshine driver pictured (1600 steps/rev) is the one driving that motor?
Could one of the others be driving it and have different microstepping settings?

D-man
18-03-2017, 10:56 AM
With the same 100 step/mm setting, try a move of 16mm and see how far the motor itself turns.

I'm getting multiple turns from 16mm! Lol it still hasn't stopped yet

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D-man
18-03-2017, 10:57 AM
Just thinking of possibilities:

Are you sure it only rotated 1/4 turn? Not 1 1/4 or 2 1/4 etc,
as you previous test seems to indicate too much rotation not too little i.e moves 267mm instead of 50mm.

Also are you sure the leadshine driver pictured (1600 steps/rev) is the one driving that motor?
Could one of the others be driving it and have different microstepping settings?

All motor switches are the same apart from Z

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D-man
18-03-2017, 11:01 AM
With the same 100 step/mm setting, try a move of 16mm and see how far the motor itself turns.

Ok I'm getting 1 revolution on the small pinion attached to motor. @ 16mm movement with 100spr

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m_c
18-03-2017, 11:04 AM
Ok I'm getting 1 revolution on the small pinion attached to motor. @ 16mm movement with 100spr

So that tells us the microsteps are correct, as with those settings and distance, the controller is sending 1600 steps.

Are you sure the 18:90 gearing is correct for the pulleys?
And everything is moving smoothly and not stalling?

D-man
18-03-2017, 11:07 AM
So that tells us the microsteps are correct, as with those settings and distance, the controller is sending 1600 steps.

Are you sure the 18:90 gearing is correct for the pulleys?
And everything is moving smoothly and not stalling?

Yeah everything runs lovely, i will count them again to make sure 2 mins

D-man
18-03-2017, 11:20 AM
So that tells us the microsteps are correct, as with those settings and distance, the controller is sending 1600 steps.

Are you sure the 18:90 gearing is correct for the pulleys?
And everything is moving smoothly and not stalling?

Yep, defiantly 18 teeth on motor side and 90 teeth on large pulley to pinion

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m_c
18-03-2017, 11:30 AM
Yep, defiantly 18 teeth on motor side and 90 teeth on large pulley to pinion

In that case it is definitely a 5:1 ratio, so with the 100 step setting, the big pulley should turn once with a move of 80mm (16x5).

Once that's confirmed, work out the tooth pitch. Measure over as many teeth as you can, then divide your measurement by the number of teeth you've measured over, then multiply by the number of teeth on the pinion (23).
Then that will give the distance one revolution of the pinion should give.

Then divide 8000 (number of steps for one revolution), by that distance, which should give you the correct steps per mm.

D-man
18-03-2017, 11:31 AM
I've just done a movement with your settings 86.0215 and it moves 55 mm when asking it to move 50. So I'm nearly there.

Last time I think I mucked up

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Greeny
18-03-2017, 11:32 AM
Deleted as no longer relevant

D-man
18-03-2017, 01:48 PM
Thanks for all your help guys, ive managed to dia it in. Completely my fault i think. managed to get it within 1mm and fine tuned it with mach3 settings

D-man
18-03-2017, 03:24 PM
Guys whats the best way to find out the pitch of the Z screw?

mekanik
18-03-2017, 03:36 PM
Mark it and rotate one ful revolution and measure distance moved.. . . Simplizzzzz

D-man
18-03-2017, 03:37 PM
Ah ok

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m_c
18-03-2017, 03:41 PM
Measure it would be the obvious answer, but I'm going to guess it's buried out of sight.

Do you know if it's got any gearing between it and motor?

If it's all totally unknown, I'd set the steps/mm to 10 or 100. I'd probably try 10, and if you don't get much movement jogging, up it to 100, or maybe even 1000. You want to be able to jog at a reasonable speed. Too low a setting and it'll hardly move, too high and it'll be hard to control.

Then jog over a reasonable distance that you can measure accurately.
Then divide the commanded movement by the actual movement, and finally multiply the steps/mm by that figure.

So say you use 100 steps/mm. You jog 20mm, yet the machine moves 35mm. 20/35 = 0.571439 Now multiply that by 100, and your steps/mm should be 57.1439.

D-man
18-03-2017, 03:44 PM
Measure it would be the obvious answer, but I'm going to guess it's buried out of sight.

Do you know if it's got any gearing between it and motor?

If it's all totally unknown, I'd set the steps/mm to 10 or 100. I'd probably try 10, and if you don't get much movement jogging, up it to 100, or maybe even 1000. You want to be able to jog at a reasonable speed. Too low a setting and it'll hardly move, too high and it'll be hard to control.

Then jog over a reasonable distance that you can measure accurately.
Then divide the commanded movement by the actual movement, and finally multiply the steps/mm by that figure.

So say you use 100 steps/mm. You jog 20mm, yet the machine moves 35mm. 20/35 = 0.571439 Now multiply that by 100, and your steps/mm should be 57.1439.

It's a tad tight but the gearing is 1/1

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D-man
18-03-2017, 03:45 PM
I can just get in to measure it when I lower it, what am I measuring? I know the screw dia just need the pitch for the steps per

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mekanik
18-03-2017, 03:54 PM
You could get a rough indication with a pair of dividers, if you set them to the narrow groves between the ball ways, ie on the OD of the screw. Then do as M-C instructed and use a dial gauge to get the actual distance traversed.

m_c
18-03-2017, 03:56 PM
I can just get in to measure it when I lower it, what am I measuring? I know the screw dia just need the pitch for the steps per

For a metric screw, you measure the distance between each thread/ball track.
For an imperial screw, you measure the number of threads/ball tracks over an inch.

JAZZCNC
18-03-2017, 07:16 PM
measuring gaps won't help if it's multi start which often are. Best way is try to mark the screw and rotate 1 rev and measure distance. Chances are it will 5mm or 10mm pitch so easy to see which.

However if your still using mach3 then it's simple really just let mach work it out for you using Set steps per in the settings tab.

D-man
18-03-2017, 07:19 PM
measuring gaps won't help if it's multi start which often are. Best way is try to mark the screw and rotate 1 rev and measure distance. Chances are it will 5mm or 10mm pitch so easy to see which.

However if your still using mach3 then it's simple really just let mach work it out for you using Set steps per in the settings tab.

Bang on my mate! 5mm I took a chance and it was bob on!

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