CNC router 1

[kaizad]

Hi,

We are looking for a cnc router for machining and also polishing plastic (specifically acrylic). We have one at present (110"X110" table) but it does not have polishing capability. Please suggest routers out there that can accomplish both.

Also the present router has a limitation on facemill diameter (2.5"). Is this generally the size most routers can accomodate or can it be much larger (keeping within the allowable weight)?

Thanks!

 

[twinny]

The size of the facemill is limited by the size of the spindle.
A 40# taper spindle would typically take a max 100mm/4" face mill. But as you increase the rpm and cnc routers typically run at 18,000 rpm I would suggest keeping the diameter of the cutter to about 20mm max. Balancing of the cutter becomes critical if you do not want to damage your spindle bearings. Spindle rebuilds are expensive I would suggest that before you pick a final choice of machine to get quotes from the manufacturers for refurbished spindles as I have found this to be the highest cost of all the machine "consumables".
My choice would be any machine with a HSK type spindle as these are by far the best.
I ran cnc routers cutting ally sheet 24/7 for 10 years and spindles are the achillies heel of these machines.
As for polishing can you be more specific?

 

[kaizad]

We do have an HSK63A type spindle and are running the facemill (2.5" dia) at 11500rpm. However it takes a while to flycut a 72"X72" sheet and that is the reason a larger tool is being considered. This will however reduce rpm and surface finish.

Regarding polishing, the tool marks after flycutting have to be removed for the part to be optically acceptable. Hence polishing of the material is being considered on the router itself once flycutting is completed. Please let me know your thoughts on this.

Thanks.