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Discussion Starter · #1 ·
Guys and galls,

I've been looking at a desktop CNC router with 3 Axis milling. I have a few questions and wondered if anyone here used such a device.

First set of questions

How does the router cut out shapes if it does not use a vacume bend to hold it but used clamps ?

I want to try doing the following things, not all slot car related.

Milling wheels for slot cars
Cutting supports for track
Cutting borders
Cutting out complete picture frames with details on

what else could it do?

Thanks

Colin
 

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Hi Colin,
We have a couple of desk top routers at the school I work at and I use them regularly.
I'll try to answer your questions as best I can.

How to hold down the material being cut.
Vacuum beds are ideal but are not usually available for these small machines.
The most common way of holding material down on the bed is with double sided tape. You'd be surprised how strong this can be even when cutting parts out from a sheet of material. I like to screw the sheet to the bed outside the cutting area when cutting metal just for extra security.
The only metal I would recommend you machine is hard brass as it can be done dry. These machines are not powerful enough to cut steel, and aluminium really requires a cutting lubricant to cut well and this is not good for the machine.
For machining in 3D a self centering vice is a useful accessory as it enables you to machine both top and bottom of an object accurately.
When machining objects in 3D it is usual to leave uncut 'tabs' to be cut by hand after the machining is finished. A bit like cutting parts from the moulding sprue of a plastic kit.

Milling slot car wheels.
I assume you mean cutting the spoke detail etc on the wheel as the best way to actually make wheels is with a lathe (either CNC or conventional centre lathe).
It would certainly be possible to do this.
You would have to fix the wheel to the bed in an accurately known position. Probably best done with a screw through the axle hole.
Most of these small machines are not really designed for cutting metal though and you may run into problems with vibration and chatter.
Small milling cutters are very fragile and easily broken.
See also the comment above about machining aluminium.

Cutting supports for track.
Don't quite know what you mean by this but remember that most of these machines are limited to an area of about 300mm square, some much less.
They will happily cut plastics, MDF and wood within the limits of the bed area.

Cutting boarders. Cutting out picture frames.
Same constraints as above.

You biggest problem with any CNC machining is the design process.
You will need a vector drawing package that can be converted into the 'G' codes that run the machine.
Most of my experience is with Roland machines which can be run directly from Techsoft's 2D Design package.
This is relatively simple to learn but it's 3D capability is limited.

If you want to do anything clever in 3D you will need to become proficient with a 3D drawing package such as Solidworks.

What else can it do?
Limited only by your design capability and imagination.
Examples.
Printed circuit boards.
Engraving on trophies etc.
Parts for slot car chassis in plastic or metal.
Full 3D body mould for producing your own slot car bodies by resin casting or vac forming.

The parts for these brass and wire chassis were cut out on a Roland MDX20 machine.



Hope this is helpful.
Cheers.
****.
 

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Solidsworks?! oh please, lol (kidding) (I use Rhino and Inventor) - you can even use Autocad.
By the way how much is one of these table top CNC routers? Can they cut aluminum?
 

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We use Solidworks simply because it is compatible with various Techsoft programs which can be used to operate Roland machines.
It may not be the best but it works well enough for us and saves having to teach students about 'G' codes.
The smallest of the Roland machines sells for a little over £2000 (new) here in the UK.
I've seen them sell on ebay for less than half that price.

Will they cut aluminium?
Yes but!
They are not really powerful or rigid enough to cut metals of any kind.
I have used them to cut both aluminium and brass but you have to go really slowly and it will take a long time.
Aluminium also require some form of cutting lubricant which can encourage swarf to get into the workings. Not good.
Cutting lubricant can also be a real pain to clean off if you then want to machine some other material.

Cheers.
****.
 

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As mentioned most of the work is in the drawings so you need to be able to draw in DWG (CAD) files.

Rick
 

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Discussion Starter · #6 ·
One last question, well for now.

Can you use a router to cut glass?

Not sure if that is a stupid question or not!

For what I need, using a 3D package will not be an issue and as I improve then I'm sure I will increase what I can do on the router.

Thanks for everyones input as well.
 

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re: Can you use a router to cut glass?

I would say that acrylic is easy (watch for melting from heat buildup), polycarbonate could be best but more brittle and will crack easier,
glass would require a miracle *grin*

John
 

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Discussion Starter · #8 ·
That's a shame, I wonder what glass can be cut on if it needs to be cut into shapes without straight edges.
 

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Hi Colin,

On a well known on-line auction site that I have no dealings with is a Roland Modela MDX20, I have one at work and have managed to create loads of stuff with it.

Chassis made from HIPS (High Impact Polystyrene) layered together.
You Tube video of scratch built chassis

You Tube video of 4x4 chassis

Casting a chassis with low melting point alloy:
My blog of casting a chassis
Machining casting:
My blog of machining casting

I hope this gives you a few ideas of what you can do with a fairly low-level machine.

Regards,

Alan
 
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