Author Topic: What's needed  (Read 2550 times)

Offline kayzed1

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What's needed
« on: July 19, 2016, 07:56:58 PM »
So, can some body who has done the convert on say...the sx2p or the like, mini mill. Do a list of the parts required to make this CNC thing happen
Please?? that would/could get the ball rolling, we just then need to find the kit and price it up ,then,then,then :doh:
Lyn.


Offline Imagineering

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Re: What's needed
« Reply #1 on: July 20, 2016, 04:29:06 AM »
OK 39 Reads and no replies, so here goes.

I've converted an SX3 to 4 Axes. I'll ignore the 'power of the fourth' for this reply.

Required Ingredients for 3 Axes;
3 BallScrews and Nuts. (preferably Metric, as it's easier to calculate Step/Distance ratios).
3 Stepper Motors. (as powerful as you can afford).
3 Stepper Motor Controllers. (Must match or exceed the Motor Specs).
1 Breakout Board. (Many on the market, I use the one from Gecko in the SX3 build.).
... An alternative is the Gecko G540 which consists of a 4 Axis Controller with a Breakout Board in one Package. (I have one of these on my 1200X1200X300mm CNC Router).
1 Power Supply Unit. (the more Volts the better. If you research the Gecko G540, there is a package deal with a PSU).
1 Computer with a native Parallel Card. (New Software/Hardware can run USB but I have no experience of it yet).
Mach3 or similar Software.
CAD/CAM Software or ability to write G-Code by hand.

You will also need;
6 Thrust Bearings.
3 Std Ball Bearings.
3 Stepper Motor to BallScrew Couplings.
If the Stepper Motors are not directly coupled to the BallScrews, Non-Backlash Belts & Pulleys are required, (AT5 Series Suggested).
You will also need Material to fabricate new ends for each Axis as the existing End Mounts for the LeadScrews will probably not fit.
You will also need some means to machine and fabricate stuff whilst your Mill is in pieces.
Assorted Wire, Cables & Connectors.

I hope that this helps.

Offline RobWilson

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Re: What's needed
« Reply #2 on: July 20, 2016, 05:14:47 AM »

Offline Brass_Machine

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Re: What's needed
« Reply #3 on: July 20, 2016, 01:46:31 PM »
This any help Lyn

http://www.fignoggle.com/plans/cncplans.htm

Rob :dremel:

I used those to convert my mill the 1st time around. I am actually using a different set of plans (that are free) for the next iteration of my X2
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Offline Will_D

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Re: What's needed
« Reply #4 on: July 20, 2016, 04:50:22 PM »
Oh I do like free!

Any updates/links?
Engineer and Chemist to the NHC.ie
http://www.nationalhomebrewclub.ie/forum/

Offline Brass_Machine

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Re: What's needed
« Reply #5 on: July 20, 2016, 05:25:08 PM »
Over on CNCZone, mduckett has a nice build going on. I got them from his thread. On Page 12...

http://www.cnczone.com/forums/benchtop-machines/168634-cnc-12.html

Science is fun.

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Offline PK

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Re: What's needed
« Reply #6 on: July 20, 2016, 05:34:11 PM »
One tip.
Save yourself some pain and leave the undriven end of each ballscrew unsupported.
On a small machine you won't see any rod whip and it makes it HEAPS easier to line everything up.
The screw manufacturer will have a table for the maximum unsupported length of screw for a given RPM... Look it up if you are unsure..

PK

Offline Imagineering

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Re: What's needed
« Reply #7 on: July 21, 2016, 02:10:51 AM »
One tip.
Save yourself some pain and leave the undriven end of each ballscrew unsupported.
On a small machine you won't see any rod whip and it makes it HEAPS easier to line everything up.
The screw manufacturer will have a table for the maximum unsupported length of screw for a given RPM... Look it up if you are unsure..
PK

I disagree with you on that one. I tried that and ended up with Screw related Harmonics which marred the finish of the item I was machining.

My method for lining every thing up;
Make sure the BallNut is secured in the intended centre of the BallScrew Axis.
When fabricating the End Plates which hold the Bearing, make the Mounting Holes a mm oversized. (eg 6mm Bolts, use 7mm Holes).
Bolt everything together so that the End Plates can move laterally.
Drive the Axis to the Motor end of it's travel and nip up the Mounting Bolts at that end.
Drive the Axis to the other end of it's travel and nip up the Mounting Bolts at that end as well.
Drive the Axis back and forth between limits and check that there is no binding anywhere.
If all is well, tighten the Bolts fully, and repeat for the other Axes.

I've converted two Mills and built a CNC Router from scratch, and have used this method with success on all three.

Offline PK

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Re: What's needed
« Reply #8 on: July 21, 2016, 07:47:22 AM »

I disagree with you on that one. I tried that and ended up with Screw related Harmonics which marred the finish of the item I was machining.
The number you are looking for is the critical speed for a given length of a screw. If you go faster than that then you get whip and the sort of harmonics you describe. Slower and it doesn't happen.
Nook has a couple of calculators for it on this page http://www.nookindustries.com/EngineeringTool/Index

PK


Offline kayzed1

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Re: What's needed
« Reply #9 on: July 21, 2016, 07:47:26 PM »
Thank you All, lots to read up on now. I must start to save some of my monthly pension and then i can  :zap:
#Lyn.