[heavyweather]

I was thinking about building my own cnc machine for some years now so some weeks ago I started designing.
I am building boats at school and at home (raptor canoe) so it has to have some area. My father is going to do harps and I plan to mainly work with wood (boats, modelplanes, furniture and bikes) and XPS for plugs and surfboards.
Planning on running my Makita700C router before upgrading to a CNC Spindle. Should be enough for some plywood cutting.
My current design iteration has 1620mm*920mm*145mm working area from 1800mm*1000mm*300mm guide rails.

Some design inspirations are

EMS (Möderl/mixware.de) machines. There is also a lot of his design work available on his sites and on the webarchive pages.
http://www.ems-moederl.de/index.html


"Frida"
https://www.google.at/search?q=FRIDA+Fr%C3%A4se&safe=off&espv=2&biw=1600&bih=770&source=lnms&tbm=isch&sa=X&ved=0ahUKEwjpn5qV2rvPAhWBchQKHSgbAPAQ_AUIBigB

JRHarris
http://jrharris.co.uk/#section6

Welschoff's CNC-Wood
http://ww3.cad.de/foren/ubb/Forum502/HTML/000001.shtml
http://ww3.cad.de/foren/ubb/uploads/...d/DSCF2706.jpg

CNC14
http://www.cnc14.de/

and Openbuilds OX

Linear rails
20mm on Y (2 carriages on each), 20mm on X (one carriage on each rail) and 25 or 30mm on Z (one carriage).

The Y and X axis will be beltdriven (15mm HTD3M) where the belt is interfacing with a rack. Or belt on belt but it looks as the belts do not interface that great that way.
I am also here for some advice on Motors and controllers. At first I thought about buying a Longs Motors Set for 200€ (convenient as it ships from a German warehouse) but it is not well matched.
I guess they stepper motors should have a low impedance (<2mH) and I need a 48V PSU.

So here are some pictures of the current design.
http://docdro.id/z1xOSIY (PDF drawing, side view)



There will be a vertical vise on the front end of the table. Maybe a removable bed or a tilting part like on Frank Howarths cnc (Joe's Hybrid) and the CNC14.

Here are my previous design iterations. The one under the stairs was not a serious idea though concrete side walls would be cool. Initially I wanted to build in wood but aluminium extrusions and T-slots are just too convenient. I also thought about V bearings on steel but why when good linear components are available at good prices.

I already post on a German speaking forum but the reach of CNC-Zone is much higher and I figure more opinions can't hurt.

thank you,

[awerby]

That extruded aluminum T-slot material is expensive; there's no particular reason to use it unless you're trying to save weight. For structural parts that don't move, it's a waste of money in my opinion.

If you're talking about using a long piece of rubber belt as a rack, that's not a great idea. Just get regular steel racks, and use your motors to drive pinions spring-loaded against it.

A router designed for occasional use in a hand-held application won't work too well, or for very long, as a CNC spindle. I'd say budget for a real spindle and VFD, and keep your Hitachi in its un-destroyed state.

I'm not sure what that tilted fixture is supposed to do for you. Unless I had a special part that required machining at that angle, I'd wait on that until I really needed it.

[heavyweather]

The extruded Aluminum material is just easier to assemble. Otherwise I'd have to drill and tap a lot. What material would you suggest for the sides and the gantry?

I want to try the belt. It is used on the RAW CNC, the CNC14 and on the stainless OX in a double belt variant where the lower belt is glued down. There are also fast industrial servo drives that use timing belts.
the belts are reinforced timing belts and pretty rigid. I also use a belt drive (gates drive) on one if my bicycles.
Building CNC machines | Raw CNC

https://youtu.be/OdJoVh6DRPA?t=37s

Here's another belt machine
https://youtu.be/T9QU3YQe-Sc

Here is another one where you can see the belts reinforcement at the end where it is cut.
https://youtu.be/5L7NuSs9kJc

A lot quieter than steel racks.

I'll go with the spindle or at least a Kress motor.

The vertical vise is to machine longer pieces for furniture or edges of deeper pieces that you would otherwise need a horizontal spindle.

[Jeff0000]

The belts look interesting, and no doubt they are fast, but with a big gantry like that it seems like a lot of momentum for belts, is the flex in the belts and issue, both with movements and pressure from the spindle?