The New Machine

Yippee my wait is over..:dance: the new machine has been delivered:naughty:
Attachment 4488

Just waiting for the ali stock now to start the conversion, Ive got some rolled ballscrews and nuts that will fit the bill for the time being, but i need these for another job so i will be purchasing some ground Ballscrews in the near future. All the design work for the conversion will be completed on V-Carve and machined with Mach3 i will upload files as and when they have been proven, with the odd video here and there.

My Initial opinion is the build quality is not as bad as i thought it would be in fact its very good, the supplier was very helpfull and it was delivered on time. :tongue: I will get some picks of the strip down as i do it.....:twisted:

Look forward to following this one!

Just a thought, will you be offering a conversion kit once proven or?

.me

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Originally Posted by Lee Roberts

Look forward to following this one!

Just a thought, will you be offering a conversion kit once proven or?

.me

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:naughty:I suspect you will.:whistling:

OK the first question... i will be gearing the steppers at 2.5:1 and I will be using T5 10mm pulleys to give me 0.01mm resolution per step i wonder what size is the smallest pulley available i know i can get a 10 tooth but do they go smaller?

I would be very surprised if you can get a pulley with less than 10 teeth. 10 teeth is the least I have ever seen anyway.

Ian

I would advise against getting a small pulley as I heard the belt wear is greater. Also you may struggle to get enough teeth meshed on a very small pulley.

Only disadvantage I can think of with a bigger pulley is the moment of inertia is greater, but that's probably negligible on a mill.

I would avoid belt drive, extra complexity is extra problems. They will also limit the maximum speed of the machine if you look at my convertion or the hoss machine you would be better to follow that template. The g540 is the way to go i have used some of the drives from the uk and they are not a patch on this setup. Keling was where i go my drive and motors from.

http://www.cnczone.com/forums/bencht...g_machine.html

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Originally Posted by Web Goblin

I would be very surprised if you can get a pulley with less than 10 teeth. 10 teeth is the least I have ever seen anyway.

Ian

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Cheers Ian:smile:, Me too, In fact many of the sites I checked started at 12 teeth.

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Originally Posted by Jonathan

I would advise against getting a small pulley as I heard the belt wear is greater. Also you may struggle to get enough teeth meshed on a very small pulley.

Only disadvantage I can think of with a bigger pulley is the moment of inertia is greater, but that's probably negligible on a mill.

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Thanks Jonathan:smile:, I did Intend to use a 10 and 25 tooth pulley to give me the ratio I needed, and going for anything smaller as you say may put too much load on the reduced number of meshed teeth. So 10 and 25 then.

So the pulleys will be as above.

For those people that are not aware of why I would like to use pulleys then let me explain.

:confused:Using 1605 ballscrews will give me a pitch of 5mm, that is to say 360 degrees in 1 rotation of spindle will advance the axis 5mm.

If i use a direct coupling stepper to screw,

The stepper will give full steps of 1.8 degrees.

360/1.8 will give me 200 steps per revolution.

5mm / 200 will give a resolution of 0.025mm per full step.

This is an odd measurement to use in my head, i have done it though..

Using a ratio of 2.5 to 1 ( 10 and 25 tooth pulleys) will give me a step resolution of 0.001mm per step.

and if i were to use half steps as the stepper is capable of doing, it would be 0.0005mm per step...

thats a fair bit of resolution/accuracy, there are however disadavantages to using pulleys.

its upto the individual who is designing/building and using the machine.

(a special thank you to i2i who educated me on this subject in the first place)

There you go clear as mud!!!!:confused:

Rick

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Originally Posted by Ricardoco

Cheers Ian:smile:, Me too, In fact many of the sites I checked started at 12 teeth.



Thanks Jonathan:smile:, I did Intend to use a 10 and 25 tooth pulley to give me the ratio I needed, and going for anything smaller as you say may put too much load on the reduced number of meshed teeth. So 10 and 25 then.

So the pulleys will be as above.

For those people that are not aware of why I would like to use pulleys then let me explain.

:confused:Using 1605 ballscrews will give me a pitch of 5mm, that is to say 360 degrees in 1 rotation of spindle will advance the axis 5mm.

If i use a direct coupling stepper to screw,

The stepper will give full steps of 1.8 degrees.

360/1.8 will give me 200 steps per revolution.

5mm / 200 will give a resolution of 0.025mm per full step.

This is an odd measurement to use in my head, i have done it though..

Using a ratio of 2.5 to 1 ( 10 and 25 tooth pulleys) will give me a step resolution of 0.001mm per step.

and if i were to use half steps as the stepper is capable of doing, it would be 0.0005mm per step...

thats a fair bit of resolution/accuracy, there are however disadavantages to using pulleys.

its upto the individual who is designing/building and using the machine.

(a special thank you to i2i who educated me on this subject in the first place)

There you go clear as mud!!!!:confused:

Rick

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And hurry up moderator.

But you should be using 8 / 10 mirco stepping for best performance of the motors and why are you worried about the interger as it is a cnc'd machine that will be controlling it.

As before i have done it with this machine, 0.001 res is pie in the sky, £200,000 machine tool struggle to get that with direct drive and servo's. 0.025 per step is what i run and gives me 1500mm/min rapid you would be lucky to get 700mm/min as you would be over spinning the motor and have not torque.

resolution and power work againest each other.

here a like to my Thread on cnc zone.

http://www.cnczone.com/forums/bencht...g_machine.html

Sorry for the delay and welcome fragger!