DIY CNC

[paulp]

For a while now I've been looking around to try and find a realistic way of DIY CNC. I don't mean go out and buy a CNC for £2000 and work it at home, I mean construct a viable Desktop CNC machine on a realistic budget. Currently I am thinking as close to £600 as I can get.

It seems that if I were in the U.S. then this can be achieved by buying from a range of ready made kits that range from $500 upwards. As always though, very few of these ship to the U.K. or if they do then the cost is extremely high. One seller on ebay told me the kit was $699 and it would cost me $650 to ship it to the U.K.

Its mainly because the cheaper kits are MDF framed or something similar and its extremely heavy. Aluminium is a lot lighter but proportionately more expensive.

It also seems that manufacturers of the kind of hardware needed to do this in the U.K. know that they have you cornered. Leadscrews, Ballscrews, Linear Shafts and bearings all cost more here than abroad. Stepper motors and Controllers cost more but they can be imported for not too bad a cost from the U.S.

These for example are used a lot and recommended on many sites.
http://www.probotix.com/3_axis_stepper_motor_driver_kits/

Surprisingly, a similar solution can be bought here in the U.K.
http://www.diycnc.co.uk/html/driver25.html
http://www.diycnc.co.uk/html/stepper_motors.html

If anyone has any experience of building this kind of thing I would be interested in hearing from them.

[paulp]

Perhaps something along these lines...



By pajp at 2008-06-24

I've deliberately kept as many clean staright cuts as possible. My idea being that most suppliers of Acrylics etc are willing to do straight cuts at low prices. There's no way I could produce as good a cut as they can.

Here's the same thing in clear 20mm and 15mm acrylic. Cheap material and quite rigid. Also looks better than MDF on the table next to the P.C.


By pajp at 2008-06-24

[MetalSkullRobotics]

Hi paulp, I myself am working on a cnc-router as well.


I have been sniffing around on the internet for quite some time now and came by some very helpful sites. Don’t have the links on this computer as it’s my laptop but you will get these from me when I'm able to post them.

[Matt Denton]

Love the design Paul, In particular the use of the pre fabricated tubular sections as many of the se seem to use now. We should put our heads together on this once I have time, I think a pretty good kit could be made!

One thing I would say is that it would be a lot better in Aluminium, and probably wouldn't cost too much more. If your CNC'ing something, its always better to have a radius between to angles, this way the cutter does not have to come to a stop.

[paulp]

I was going to ask you about aluminium, its a material I've not worked with. Mainly as to its rigidity, for something like this I was thinking 10 - 15mm thick. would that be about right.

The idea of this design was that it could be made in either ali or acrylic possibly as an option.

When you've got some time let me know and we can exchange ideas.

[Matt Denton]

I was going to ask you about aluminium, its a material I've not worked with. Mainly as to its rigidity, for something like this I was thinking 10 - 15mm thick. would that be about right.

It depends on what job the plate is doing, looking at your drawing I think you could get away with some parts being dwon to 4/5mm thick in Ali.

The idea of this design was that it could be made in either ali or acrylic possibly as an option.

When you've got some time let me know and we can exchange ideas.

Definitely, must get the kits out the way first

[paulp]

O.K. Working in Aluminium.... and straight away into the trade-offs...

Firstly this is the ideal solution for the main Gantry support bearings.


By pajp at 2008-06-25

These sell at about £42.00 +VAT so about £50 each.

The second solution is..


By pajp at 2008-06-25

These sell at about £25.00 +VAT so about £30 each but would need 2 nice little brackets machining. The brackets could then be used as a brace between the gantry base and the upright.

The Third solution is ..


By pajp at 2008-06-25

This would require more bracketry and be a bit unsightly. The bearings cost £14.00 + VAT so is more expensive.

I'm assuming the brackets for option 2 would make it the cheaper option...

[paulp]

Like this....


By pajp at 2008-06-25

Though fastening to the lower Section might be an issue

[Matt Denton]

I'm itching to have a look into what can be done with this, but I'm swamped with other work.

I will take a proper look at the design as soon as I can.

[Matt Denton]

Forgot to mention, send me the igus part numbers you are using for the rails/linear bearings etc, so I have more details when I get to take a look.