Author Topic: CNC concept "Molehillman"  (Read 336 times)

Offline Shonver

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CNC concept "Molehillman"
« on: July 10, 2018, 05:13:48 PM »
Guys, I have long wanted to build a CNC router.

I recently read through JimGore's thread about his MountainMan CNC machine that he had built. I was very much inspired by the revisions he had made to the original machine's specs.

I want to build my own smaller version, but not necessarily with the same level of customisation (though there will inevitably be that) and definitely with more bang for buck because the budget is tight. Due to budget constraints, I expect that it will take a long while to complete.

I would like get some input from those in the know with regards to getting a full spec down on paper, and also advice regarding what off-the-shelf materials are available.

As well as being a router, I would like to be able to upgrade it to milling machine level of performance later (hopefully with just a change of the spindle).


Aim: build a DIY 3-axis CNC routing/milling machine with 600mm x 1200mm work area.

Gantry: Light weight but stiff, with very low torsional deflection.

Linear bearings: TBD

Lead screws: TBD

Motors (I have 4 Nema 23 motors type PJB56H76B18):

X-axis motor: 1x Nema 23
Y-axis motor: 2x Nema 23 motors
Z-axis motor: 1x Nema 23

Controllers: TBD
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Offline PsyCLown

Re: CNC concept "Molehillman"
« Reply #1 on: July 10, 2018, 05:47:37 PM »
I will be following this for interest sake, see how it goes and how much of a mission it might be.

How much do you expect it to cost you all in if I may ask?
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Offline Timber_MG

Re: CNC concept "Molehillman"
« Reply #2 on: July 10, 2018, 06:19:19 PM »
Shaun, I would highly suggest going with a design that's already passed muster at the likes of CNCZone.com. There are so many variables and in the end it comes down to your material cutting and finish requirements determining your choice in structure, linear bearing choice and axis configuraiton. A gantry is the least stiff option when it comes to layouts (excepting single sided arm designs) but for many uses is adequate.

Offline Shonver

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Re: CNC concept "Molehillman"
« Reply #3 on: July 10, 2018, 07:38:02 PM »
How much do you expect it to cost you all in if I may ask?

I don't know, to be honest. I am just  throwing my idea out there and seeing what comes back. I am hoping to be shown the way ITO ways to minimise costs.

Shaun, I would highly suggest going with a design that's already passed muster at the likes of CNCZone.com. There are so many variables and in the end it comes down to your material cutting and finish requirements determining your choice in structure, linear bearing choice and axis configuraiton. A gantry is the least stiff option when it comes to layouts (excepting single sided arm designs) but for many uses is adequate.

Martin, I will in the course of events check out other designs (I am doing it). I don't just want to go with what is out there for the sake of safety (if, after sufficient learning, I discover a design that already does it better, I would not mind that, either). Some discussion here as to possible pitfalls is welcome. I do want to see what is the best I can do for as little money as possible, without ending up with a piece of junk. I know there is an abundance of mechanically-minded types here, so please chime in.
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Offline Shonver

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Re: CNC concept "Molehillman"
« Reply #4 on: July 10, 2018, 07:38:31 PM »
Martin, you were saying about gantries....?
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Offline 2wice

Re: CNC concept "Molehillman"
« Reply #5 on: July 10, 2018, 09:20:54 PM »
You might want to consider a moving bed design with a fixed gantry if you want to do any useful milling in future.
Pretty much cost equivalent, suits your table size and negates your gantry requirements which are virtually impossible. Also makes it easier to upgrade your spindle at a later date by over designing your gantry slightly for not much cash and zero negative impact on the immediate operation of the router.
Good luck and we're along for the ride.

Offline Shonver

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Re: CNC concept "Molehillman"
« Reply #6 on: July 10, 2018, 09:55:06 PM »
OK, guys. I'm convinced about the fixed gantry (is that what you were implying, Martin?).

https://www.youtube.com/watch?v=herMY_2WowM
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Offline Shonver

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Re: CNC concept "Molehillman"
« Reply #7 on: July 11, 2018, 01:02:37 AM »
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