scaling up cnc plans

[aspire2008]

hi guys

i am new to this forum
my first question is

is it possable to scale up the cnc plans to make a larger machine ?

thanks guys

[High Seas]

Hi and welcome aboard.
One of the BIG problems with just scaling is getting the engineering right.
The footprint of the machine and its work envelope all determine the size of; the linear ways (so they don't flex and give you crappy resolution), the size and style of the linear drive (screws/belts/chain/racks), and naturally the size of the power supply, motors and drivers.

You - probably knew all that. Quite a few of the folks here build a first machine - to spec -- than learn from it and then build a larger machine using it to get the parts built. How big are you looking? 8x4 (feet) or? There are some other plans out there that can get you to a larger machine on first go if your want to jump right in at a bigger size.

Pretty sure other guys will chime in here too.
Jim

[Don Kellogg]

Can you point me to the large plans. I looked into this about a year ago and now I think I'm ready to build. I'd like to make 4x4 or 4x8 machine.

[Kipper]

Do a search for Mechmate or Shopbot.....The owner/modifier of Mechmate doesn't like people changing "His" design so just pretend you're going to build it how he wants you to

[Gerald_D]

I saw that!

Actually, I welcome changes, provided that they are made with solid engineering thinking behind them.

[robashley]

Hello Aspire....

I have recently finished a scaled up rockcliffe, but I modified it. I used samic linear bearings instead of oilites (easier to fit and align) although slightly more expensive.

Motors are NEMA 23s ~ 200 ozin. I am now about halfway through reading the MACH 3 instruction manual...

Hope the build goes well
Rob

[wongster]

Any suggestion if I would like to scale down a model D (flying gantry)? I believe its more than just reducing the length of all the components by a factor.

Appreciate any help.

Regards,
Wongster

[Kipper]

Originally Posted by robashley Hello Aspire.... I have recently finished a scaled up rockcliffe, but I modified it. I used samic linear bearings instead of oilites (easier to fit and align) although slightly more expensive. Motors are NEMA 23s ~ 200 ozin. I am now about halfway through reading the MACH 3 instruction manual... Hope the build goes well Rob

What! "reading a manual" call yourself a man...Pah you'll be asking directions next!


I'll get me coat.......


@ Wongster, to scale down is reduce the size of all components....although you may not want a 3mm leadscrew if you're "really scaling down"

[wongster]

Originally Posted by Kipper @ Wongster, to scale down is reduce the size of all components....although you may not want a 3mm leadscrew if you're "really scaling down"

Hi Kipper,

Thanks for your reply. This is something I'm very new in. I'm trying to build a machine with footprint of 400mm x 4oomm. I'm concern about structural integrity if I scale everything down proportionally. eg. can the reduced x-axis bear the weight and movements of the z.

My guess is, though I'm reducing the overall length by a certain factor based on a plan, the thickness and width should be reduced by a lesser amount to maintain a certain level of stiffness.

Regards,
Wongster