Building a Rockcliff out of thin plastic

[jazzythumper]

Doew anyone see any problems with making the Rockcliff desktop CNC machine slightly smaller and making it out of plastic say 5mm or 10mm thick?
6nly we have a laser cutter at university and it would be easier to make the frame work out of this.

Here is the model for you to look at

http://cgi.ebay.co.uk/Build-a-CNC-Ro...QQcmdZViewItem

[jhowelb]

Originally Posted by jazzythumper Doew anyone see any problems with making the Rockcliff desktop CNC machine slightly smaller and making it out of plastic say 5mm or 10mm thick? 6nly we have a laser cutter at university and it would be easier to make the frame work out of this. Here is the model for you to look at http://cgi.ebay.co.uk/Build-a-CNC-Ro...QQcmdZViewItem

With machinery rigidity is the key. Plastic has been used, I've seen builds presented on the Zone. Don't know to what degree of success.

If that is the thickest you can cut, consider laminating several layers to get the degree of rigidity you need.

[Stepper Monkey]

I am probably going to be the minority opinion here and say, yes, you might be able to - but only if you do go as thick as possible with the material, you do significantly scale down the machine, you aren't using a heavy spindle, and are not doing heavy cutting.
It depends on the use it will be put to. Circuit boards, foam, and plastic sheet can be cut on some pretty light machines. Get much beyond that and lack of rigidity is fatal. Scale is the enemy of rigidity here too, as thickness of frame material relative to free span is NOT a linear equation - you are talking squares and cubes, so a little distance or thickness can be more critical than you think.
You'll just have to do the math in this case to determine optimal size for your material, as you don't have the luxury of just overbuilding like most. Also remember rigidity of the joints is the biggest failing point in most small machines as it is more difficult and you have fewer options for joining thin materials solidly.

[cpcapace]

I purchased the rockcliff CNC plans. Interesting, but overly complicatd design. Well that is to say. If you have only hand tools at home, some pieces would be a little hard to build.

Try the buildyourcnc.com web site. I've found that to be more straight forward.