Proposed router design. comments please

[pavlo]

Hi I have wanted to build a router table for quite a while now and thanks to this forum I think I have a good chance of doing it.

I recently ordered ballscrews, rails, mounts and linear bearings from ebay so I guess I've got to get started.

Here is a couple of pictures of the proposed design.
http://www.cnczone.com/forums/attach...1&d=1242593418

http://www.cnczone.com/forums/attach...1&d=1242593458

The base and gantry will be welded steel. The z axis mount and router bracket will probably be aluminium although I may try mdf as a prototype.

The machine will have x axis travel of 600mm, y axis travel of 490mm and z axis travel of 170mm if I stick to this design.

I have tried to keep the design as compact as possible to reduce moments on the gantry.

Could you guys please have a look and offer any criticisms before I start cutting stuff up.

The three ballscrews are not shown but they are all 16mm dia 5mm pitch.

I could do with some with selecting the right motors too.

I hope to be able to upload the sketchup file to my webspace soon so if anyone wants to modify it they should be able to.

Many thanks

Paul

[Kipper]

Looks better than some of the commercial offerings! Get it made then.

[FandZ]

Nothing looks bad on it, just need to add on those motor mounts and ball screws to get an idea on how you plan to drive it.

[bad bearings]

It is a nice and simple design. On the gantry, are you using recirculating balls or bushings? There are some decent plastic bushings out there--Igus makes some. They work well with sawdust and tolerate misalignment better than balls. Also, for a router timing belts may work better than ballscrews--again they tolerate sawdust and dirt. There was an article in Machine Design about a year ago about a way to use timing belts with a differential carriage--sort of like a Chinese Windlass. This way you can get a large gear ratio without gearing down the input shaft--similar to a ballscrew. The article claimed that the inventor had obtained resolutions and repeatability similar to a ballscrew. Good luck.

[pavlo]

Thanks for the replies.

I have to be honest, I don't know what sort of bearings/bushes I'm getting. I ordered a bundle deal from ebay which was 3 pairs of rails (12mm 16mm & 20mm), 2 bearing mounts for each rail, 3 ballsrews with nuts, mounts and couplings. All coming from China. According to the order tracking, the items are currently with customs. No doubt I will get a hefty bill for duty and VAT but it should still be a good saving.

Thanks for the info on the timing belt but as you can see, I'm pretty much committed to using ballscrews now.

I can't wait to get started properly. I will of course post my progress on this forum.

[Kammo1]

Hey Paul that looks like it will be a fantastic machine bro,where are you based in the UK I'm in Nottingham

[pavlo]

Hi Kammo1

I am in Rochester, Kent. I'm hoping to find some cnc enthusiasts near me so I have someone I can call on when it all starts going wrong.

The bits have arrived today. They look great, only problem is the rails and bearings for the z axis were not in the delivery? An email is on its way to them.

[pavlo]

Well, I did it.

It took about 5 months of grabbing the odd hour here or there but it works.

here are a few photos.
















And finally, here's a video of it working

YouTube- ball in cube.wmv

YouTube- ball in cube.wmv

[Thazul]

Nicely done, Grats on the machine!

[Phife]

Looks great! did you go with a MDF Z axis?

That Ball in Cube looks fantastic, I'd love to try something like that, Willing to share some more details on how it was done? share the model?

[FandZ]

Hey hey, congrats! it really came out great. What are your IPM and all that?

[marzetti]

Nice machine! Just wondering what cam software you used for the ball-in-box and where you came up with the model.