Linear Guides

[rgillard]

Hi Guys,

Im trying to design a CNC Plasma/gas cutter and a wood router into one machine. I have been looking at some linear guides on a website and just wanted to get some expert opinions. They can be found at this link

http://www.automotion.co.uk/search.php?query=uni

I was looking at using the A75 for the side rails and the E75 for the gantry across the table. The use Belts for driving and I just wondered would this be good enough in terms of backlash and wear.

If anyone has time to give them a quick look I would appreciate it.

Regards,
Ronan

[Zappautomation]

That link does not go to a product page.
I have had a quick look around the site and cant find the product you mentioned.

Originally Posted by rgillard Hi Guys, Im trying to design a CNC Plasma/gas cutter and a wood router into one machine. I have been looking at some linear guides on a website and just wanted to get some expert opinions. They can be found at this link http://www.automotion.co.uk/search.php?query=uni I was looking at using the A75 for the side rails and the E75 for the gantry across the table. The use Belts for driving and I just wondered would this be good enough in terms of backlash and wear. If anyone has time to give them a quick look I would appreciate it. Regards, Ronan

[mackeym]

Are you choosing this type to avoid using ball screws or lead screws? I don't see why they wouldn't work as long as they have the tolerance and load capacity. This type is more commonly used: http://www.automotion.co.uk/products...near-rails.htm

[rgillard]

Thanks Guys,

I think I got quoted over 3,000 Uk Pounds for these components which I thought was quite expensive. I have been looking at the machines being build in the cnc plasma cutter forum and some of them are just using chains and skate board bearings. I am caught between spending a lot of money and getting guaranteed motion or trying to use the more homemade technique that the other guys are using. Have you any issues with using the chains? Here is a link to the thread (http://www.cnczone.com/forums/showth...t=16634&page=2)
Hope it works this time.

Thanks lads
Ronan

[Zappautomation]

Either the link is working now or i was blind before.
If you are using them on a gantry, they should be fine.
The loading is quite good, (75KG or 180KG Each side) and because they are running from belt, there will be no backlash only Hysteresis.
Using these on a gantry is good because you can quite easily link them together, but these belt type linear actuators can be quite expensive, when compared to using guided linear rails and a ball screw.
I donk know these ones, but have delt with parker and tolomatic, and they would normally cost about €1500-€2000 each for 1.5 meter long units.

Help that helps.

Originally Posted by rgillard Hi Guys, Im trying to design a CNC Plasma/gas cutter and a wood router into one machine. I have been looking at some linear guides on a website and just wanted to get some expert opinions. They can be found at this link http://www.automotion.co.uk/search.php?query=uni I was looking at using the A75 for the side rails and the E75 for the gantry across the table. The use Belts for driving and I just wondered would this be good enough in terms of backlash and wear. If anyone has time to give them a quick look I would appreciate it. Regards, Ronan

[rgillard]

What would be the approximate cost of ball screws and linear guides for a 5ft X 5 ft machine. I would like to have a screw on both sides of the X axis, one for the y axis and a short one for the z axis. Ball Park Figure? I was under the impression that these linear guides were cheaper than ballscrews. I dont think I will ever need to cut anything more than half a sheet of steel which is 4 ft by 4 ft. Building a smaller table means that it wont take up too much of my precious shed floor.

Ronan

[Zappautomation]

Without going into the fine details about your application, I have come up with the following:

4 x 20mm Profile Rail
- Carriage: Two per rail
- Length: 1900mm £612.12

3 x ZPSF2005 (Ballscrew)
- Mounting Block (Fixed End): BK-15
- Machining: None
- Ball Nut: Single (ZPSF)
- Length: 1900mm
- Mounting Block (Floating End): BF-15 £344.25

1 x ZPSF1605 (Ballscrew)
- Ball Nut: Single (ZPSF)
- Length: 200mm
- Machining: None
- Mounting Block (Fixed End): BK-12
- Mounting Block (Floating End): BF-12 £52.64

2 xSFC16 Precision Round Rail (16mm)
- Carriage: Two
- Length: 300mm £22.28

4 x SK Mounting for SFC
- Model: SK16 (for 16mm rail) £4.24

This works out to be
Sub-Total: £1,035.53
Shipping: £0.00 (Free)
VAT (17.5%): £181.22
Total: £1,216.75

This is for three axis Ball screws and bearings, mounting blocks, and assuming you will do the machining on the ball screws for the mounting blocks?

Originally Posted by rgillard What would be the approximate cost of ball screws and linear guides for a 5ft X 5 ft machine. I would like to have a screw on both sides of the X axis, one for the y axis and a short one for the z axis. Ball Park Figure? I was under the impression that these linear guides were cheaper than ballscrews. I dont think I will ever need to cut anything more than half a sheet of steel which is 4 ft by 4 ft. Building a smaller table means that it wont take up too much of my precious shed floor. Ronan

[schbrownie]

Ronan,

Depending upon the tolrance you're trying to hold... if you're looking for something better than +/- 0.005", then keep with the profile rail. If you can live with something in +/- 1/32" to +/- 0.005", then try a less expensive rail system like this one:

http://www.automotion.co.uk/products...mpact-rail.htm

This one is made by a comany called Rollon.. you can also find similar systems from Pacific Bearing and/or BWC... (all of which should be available to you in Ireland)

Good luck,

~Jon