Few pics of my homemade CNC mill

[wiatroda]

There is web address with few pics of my DIY CNC. http://malamuterun.co.uk/cnc/homemade_cnc_mill.htm

[h4ppy-chris]

nice work mate lovin the web site.

[wiatroda]

I use T2.5x6mm Synchroflex timing belts to transfer power from stepper to lead screw.X and Y axes have two motors to rotate the screws. And yesterday the belt snapped, not for the first time I gotta say. So now I'm planning to replace two 2.5mm pitch belts with one 5mm pitch on Y axis but still leaving two motors to steer two lead screws. Of course I'll need to replace timing pulleys and make some tensioners. Stuff ordered,hope it will work.
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[Jonathan]

Looking good :smile:


I use T2.5x6mm Synchroflex timing belts to transfer power from stepper to lead screw...

I've used XL pitch belts, at least 1/2" wide and have never had any problems. Can also make your own pulleys for them with a bit of care which saves a bit.

What have you used for the nuts on, I think, the X axis? Is it just a brass/bronze bar tapped with the hole for oil or something more elaborate?

[wiatroda]

I don't have rotary table to cut the pulleys :( . Money are sometimes an issue so I went for smaller pitch, cheaper belts and pulleys. On all axis I've got M16x2 lead screws. Nuts I've made myself from 32mm dia steel bar. They are 60mm long with a grease nipple re-drilled to fit 4mm nylon tube for oiling. Very simple, good and cheap solution, with no backlash at all.

[h4ppy-chris]

you don't need a rotary table to cut the pulleys use your cnc to cut them out of plate ;)

[wiatroda]

You are right Chris. I've never cut timing pulleys, but some time ago I was messing with robotic arm gripper. All parts I've cut on my CNC from 3mm steel.
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[Jonathan]

you don't need a rotary table to cut the pulleys use your cnc to cut them out of plate ;)

That does of course depend on the profile. You'd need a very small cutter to get a decent XL pulley with that method.

[wiatroda]

Stuff have arrived. I managed to do some drawing . Hope tomorrow I'll find some time to put it together :)
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[primorc20]

Is this PM542 stepper driver? What voltage do you use?

[wiatroda]

I use PM752 supplied with 65VDC. Transformer is 500watt.

[primorc20]

And the beakout board you use is pcpps from zapp automation? Because in the manuals for this board is written that it supports only max 35V? But the board is using the same voltage as drivers?

[wiatroda]

Please see 1st picture on my website - Control box http://malamuterun.co.uk/cnc/homemade_cnc_mill.htm
There is two power sources.
1. Toroidal transformer with 25Abridge and capacitor at the top for PM752.
2. 25V power supply at the bottom for PCPPS-3 from zapp.
Two power suppliers share ground/negative.

[m_c]

Just looking at your proposed new drive system, isn't it bad practise to use two motors coupled together?

[wiatroda]

Just looking at your proposed new drive system, isn't it bad practise to use two motors coupled together?
So far the only problem I had it was when one of the belts snapped and then the other motor was pushing Y car's one side only eventually snapping the second belt or stalling the motor. That's why I decided to use one ,long, strong timing belt. Why do you think there may be any negative aspect of coupling the motors together ?? I've attached mounting plate pic. I'll try to produce it asap.
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[m_c]

Using two motors with one driving each side is ok, but I've seen it mentioned in various places that coupling two motors together can cause problems.

[Jonathan]

Is this PM542 stepper driver? What voltage do you use?

If you're deciding which driver to buy then get the PM752. The higher voltage will make the motors run with higher torque at high speeds, and thus faster overall.

Currently I use the PM752 on 75v, though that should change in a few weeks when I've finished prototyping my 120v driver design...

I'm also using a 500VA transformer with 4 of the 3 N.m motors.

[wiatroda]

jupi machine alive again :))))
First in order to cut proper steel motors mounting plate I've made "very sophisticated" 3mm MDF plate.
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I've put some corrections and CNC cut from 3mm steel plate, so far insides only.
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Some inside circle cut-outs are perfect to hold a material while machine cuts outside profile
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Just waiting for end result ;)

[h4ppy-chris]

i love it when a cnc makes it's self nice 1 mate keep up the good work. loving the pictures ;)

[wiatroda]

Thanks Chris
...and finished item
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[h4ppy-chris]

looks good to me mate nice to see some steel and not ally ;) and here's a thanks

[wiatroda]

Tensioner shaft
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with 3 pieces of 688z bearings each
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Job finally done :)
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[Jonathan]

That looks neat. I can't really think of a good reason why, but having both motors running on the same belt doesn't seem like a good idea. Why not just have one going to each ballscrew? At the very least that means shorter belts, so lower inertia (probably negligeble). I guess the only thing it gains is preventing racking occuring.