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goldtop
06-03-2016, 10:27 AM
I'm a complete CNC/routing newbie and trying to work out what sorts of router/mill/bits I should be considering for PTFE work.

My experience of working with PTFE is using HSS drill bits in a pillar drill, running at about 1500rpm. This is very easy, and the PTFE swarf comes out in one flute-shaped piece for each hole (3mm thick PTFE sheet). It doesn't stick to the drill bit, and tends to get 'flung' sideways an inch or so as the drill is reversed out of the hole. Perfect.

I went for a quick demo of one CNC machine, and saw that the PTFE swarf was super-stringy (for want of a better word), and being so long and fine it entwined itself completely around the cutter. FWIW, this was just cutting vertical holes (DoC about 1mm at a time, I think) with no horizontal cutting. So this seems A Bad Thing, although the holes themselves were OK. I presume this was a general purpose end mill, and there would be a better choice for PTFE? And a more suitable feed/spindle speed?

In my application, I would be taking a board about 600x400mm making several patterns of 2.9mm, 3.5mm and 10mm holes (presumably using the 2.9mm tool on a path for all of them), and then cutting an outline around the holes to produce several rectangular boards (about 150x70mm).

Your suggestions?

magicniner
06-03-2016, 01:02 PM
A single flute or fast helix two flute cutter should work OK.
Peck drill to control swarf length, a ramped internal strategy for your 3.5 holes and outlines should generate chips not continuous swarf, the best path for your 10mm will depend on the strategies available in your CAM,
Regards,
Nick

goldtop
06-03-2016, 01:51 PM
Thanks Nick. I was looking at Vectric Cut2d Desktop, but am not entirely sure if that's the CAM software you refer to, or just the design software. (The multi-process nature of CNC is still a bit confusing.)

magicniner
07-03-2016, 05:07 PM
CAD - drawing, 2, 2.5 & 3D
CAM - creating tool paths to then convert to G-Code suitable for your machine.
With 2D you won't have too many strategies to choose from so I suspect it will not be too daunting.
I think Vectric is CAD/CAM and covers both.
Regards,
Nick