After a coupla years of thought and compromises and decisions on how to make a rigid small CNC machine this is what I've come up with.
It will be cast solid aluminum which is the only real solution for the rigidity issue. If you could do it in cast iron it would be perfect. However this seems to me to be the best compromise after a lot of thought and trials.
This is a moving table design not a moving gantry design.
We plan to make the casting sometime after the 6th of January when I have help from the rest of my team here working on another project.
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Gary
Some other food for thought the "bosch router" uses a universal motor it will run quieter and smoother on DC rather than AC and you can also reverse it if you want.
It's not brushless of course but doesn't really mater it would have more torque as well.
You can get a 110v DC power supply on ebay you need to match the current to the rating on the motor. I saw one with 3.5 amps for $40
You could also use an old serial mouse take out the wheel and use it for an encoder attached to the motor shaft. There are some ready made programs out there for using one.
Pretty fiddily but might be fun.
Thank you for that video Monroe,
It was an excellent project and although I think I will do things a bit differently, the basic concepts are quite reasonable.
I like the idea of a simple self screwing collet changer.
Currently I am using a "Bosch router" which, of course would not work, but I will eventually switch to a VFD or brushless reversible spindle which would work fine.
I am not sure at this time whether I am going to upgrade my machine or just buy a new one, but I will definitely look to producing my own tool changer.
I really only need 3 or 4 tools and generally only change to each one once per job.
The pneumatic ATC systems with 30-40 taper tool holders are what I was referring to as too expensive, easily can be $10,000.00 or more for the auto change system itself, but a lot less fancy system could work just fine for my uses.
You have definitely given me some thoughts.
Best,
Gary
Gary here is an interesting tool changer for CNC Router
Gary
All you really need for a tool changer is some free space on one end of your table about 1 1/2 to 2" what kind of spindle do you have? I'm sure I can come up with a quick change holder and fixture for whatever you have.
Monroe
Hi Monroe,
Definitely interested in a tool changer.
The standard CNC quick change tool holders are themselves so expensive I hadn't considered it.
If you have or know of another acceptable solution I would really like to hear about it.
Best,
Gary
Making anything is fun! :) This machine will make things I can not make any other way. Every "maker" should have a 5 Axis CNC machine!
The cheap ones on ebay are just junk! If you want to make foam parts they might work for that (albeit not for very long) I want to make kits so you can build yourself one or offer a completed machine if you can afford one.
This machine will have an automatic tool changer as well so there is plenty of development left. Criticism and ideas wanted!
The Bosch routers are gorillas and pull some serious amps on 120vac.
Are they adaptable to the popular speed controller SuperPID? I suspect they are.
I think that one really needs to define the scope of what the tool will cut and how accurate it needs to be cut.
In my case, I want the accuracy for pcb routing and this should do well enough for model aircraft and other parts. The real motivation for building such a machine is having the ability to make another copy of a part with some degree of reproducible accuracy. Small runs of kits could be another motivation, but I have learned one thing in my Jack Headley research, the history of model aircraft kit offerings is littered with the dead and acquired. The long running companies have been few.
The history of 'drones' (I still avoid that term) is already showing us that product longevity is a very fickle thing.
The final motivation (and probably the best) for a machine build is the challenge and enjoyment it *can* bring.
Let us all build on!
-=Doug
Gary
I think you can find some ABEC 7 bearings you could try that?
Gary McCray said:
Hi Monroe,
I have seen that some of the Chinese spindles use four bearings and some of them even claim to use Japanese bearings, I will be very interested to see what your experience is.
The Bosch can actually get up to 25,000 RPM so max speed isn't a problem, However, the bearings are generally not as good as those found in a real spindle, the Bosch has 2 heavy duty bearings, but they are not as far apart as in a real spindle, so eventually some axial play does build up.
And RD, I really like the Precision Bits Collets, they don't give them away, but they are just what the Bosch router needs for CNC use.
Here are a few pics and diagrams of my machine who's only significant deficit in my view is only having one ball screw to drive the X axis - 2 would be better.
One of the things I really like about it is the PlanetCNC controller which is direct Windows USB operated, not DOS through a printer port, their software is right up their with Mach 3 and it has a good simulator as well.
You can see more information about it at my CNCisFun.com website as well.
Just finished building a new shop so should be doing more with it soon.
Best,
Gary
Gary, Yes, those are two other options, I think, and I do have the clamp patterns in my plans set for a Bosch.
It is a stock Momus 2.1 as seen at this site http://www.momuscnc.com . There is an active, mostly, group for the design at CNC Zone.
Precision Bits was the company that dropped support for the Rigid -- of course after I fabricated the mounts for it!
-=Doug
Gary McCray said:
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