Thread: Cnc2012

Are those just round rails on the X axis? could you change them to supported round rails?

Also I'd be moving them as far apart as possible.

Originally Posted by Ch4iS

Are those just round rails on the X axis? could you change them to supported round rails?

Also I'd be moving them as far apart as possible.

Thanks, Yes they are 20mm round rail, how much difference would having supported rails be?

Originally Posted by Bupton

Thanks, Yes they are 20mm round rail, how much difference would having supported rails be?

If you can bolt them to a solid piece of the machine I reckon it would help a-lot when machining aluminium. It's just that I have a 600mm long cutting area myself and I can't see it doing too good if I were to use round rails and tried machining anything other than wood.

use supported rails , and also try to strengthen the side areas of the x axis , and hang the supported rail off the table , so any vibration/deflection in the x axis table is also in the y,z axis , at the moment your x axis guilds and table can flex independently

I would also think about moving the rail for the Y axis to the rear of the cross member. This will allow you to either improve the clearance of the Z axis or to lower the height of the cross member by 40 or 50 mm.

Thanks guys. Will update my drawings soon.

Went and got the aluminium plate yesterday.
14 x 355 x 2100mm
Chance will be I wont use it all, but it was cheap. $45

Aluminium plate, 2100mm x 355mm x 14mm | eBay

Design is looking good. I would agree with the above on both changing out simple rod to a supported 16-20mm rail(depending on end use) as it will make the rigidity of the final machine much better and have less chatter during operation as well as changing the design slightly.

Gee thats a great find for aluminum. Wish something like that would appear a little closer to home as i need a couple small bits for my new z axis i am working on.

keep it up and look forward to seeing some more progress.
Daniel

Hi,
Here is the photos of the updated drawing, any further ideas let me know.
Thanks Ben

You appear to have put the supported rails underneath the body of the machine. If so, then I would strongly suggest that they be transferred to the top of the rails so that they are supporting the weight rather than having it depend from the bearings.

I would also like to see slightly wider uprights than you have. The wider they are, the better their stability will be when cutting forces are applied to the tip of the router.

Hi, here is my suggestion (attached image) I designed this one some time ago it's similar to what you already have but it uses 60x60 extrusion along each side to which a SBR20 rail easily bolts to, the extrusion would bolt to the main length of your aluminium and also to the end plates.

I have built a larger version (~1200x800) of this base from 80x80 and 6x120mm plate and the design seems very strong, unfortunately I needed the room so its in parts now so no pics.

** Its just a rough design.

Hi,
Thanks.
Chris, I have changed the design now, it is kind of like your idea, but I have just put the rails on the top.

Thanks Ben

Hello,
Could you please tell me what programs are used to create your drawing designs?

Cheers
Kym

Originally Posted by Kym A

Hello,
Could you please tell me what programs are used to create your drawing designs?

Cheers
Kym

Google SketchUp

Google sketch-up, I believe ben is also using sketch-up. If you find things a little tough to get started there are some video tutorials which can get you up and running within a night.

It is free and the full version, the only downside to the free version is you cannot export to DXF ect. formats.

Yes I am also using Google sketch, it is very easy to use with lots of online support.