CNC  for  the  DIY'er

For Britain's Men's Sheds

 

Videos

The Proof Is In The Pudding
This is a well designed product that has a track history

Bubble Table

To give a flavour of SheetCNC’s capabilities, here’s some video of an early Mk3. This clip shows SheetCNC cutting 13mm MDF at very high speed – 5,000mm/minute – using a low-cost 6mm single-fluted cutter. This was also the first outing for the new Tornado vacuum dust collection head which now ships with all Mk3 kits.

Early SheetCNC Mk1 cutting a tiny printed-circuit board.
Feed-rate: 400mm/minute etching; 100mm/minute cutting-out
Cutters: 0.2mm 10° carbide mill; 0.8mm carbide end-mill
We include this one to show the very high level of repeatability which is achieved by a well-designed chain-drive CNC: the 1mm isolations are mechanically etched in perfectly parallel 0.2mm steps, 0.8mm holes are drilled dead-centre on 1.8mm octagonal pads, and crisp text is cut in a tiny 1.9mm font.
An astonishing achievement, for a budget large-format machine.

 

Early SheetCNC Mk1 shaping multiple complex parts from 26mm MDF.
Feed-rate: 3000mm/minute
Main cutter: economy 2-flute HSS upcut end-mill
There are 8 tool changes required. The automated touch-off probe makes changes quick and easy.
The 2-flute cutters used in this clip are exceptionally quiet. This makes them ideal in a shared workshop. But their chip clearance rates are quite low so deep cuts in thick material are made in multiple steps. There’s no need for a dust shoe when using these cutters: the heavier chippings settle on the workpiece for collection later while the lighter airborne dust is all removed by the very effective extract nozzle.

Early SheetCNC Mk1 cutting a simple engraved sign from uPVC facia board.
Feed-rate: 3000mm/minute
Cutter: economy 1-flute 1/8″ carbide upcut end-mill
uPVC cuts cleanly at a wide variety of speeds, up to a maximum of about 6000mm/minute. For this test-piece, a feed-rate of 3000mm/minute avoids any risk of melting and the chippings come away cleanly leaving no burring, even when cutting full-depth in one pass.

Early SheetCNC Mk1 creating a simple cogwheel gadget from 10mm uPVC facia board.
Feed-rate: 2000mm/minute
Cutter: economy 1-flute 1/8″ carbide upcut end-mill
A slightly lower feed-rate for this job, to avoid any risk of tearing out the delicate tips of the specially-shaped teeth.

Early SheetCNC Mk1 machining a 2″ smiley from 1/8″ brass plate.
Feed-rate: 200mm/minute
Cutter: economy 1-flute 1/8″ carbide upcut end-mill
SheetCNC was not originally designed for cutting metals, but we’ve found that the rigidity of the machine is suited to some, very modest, metalworking jobs. We produce instrument panels, brackets, and workshop jigs in non-ferous metals on SheetCNC. We even spot-drill 3mm steel components – though we don’t try to cut them. This is one of our early test-pieces.

Chordal Error

This is something we’re constantly asked about. Maybe it’s the fancy name that makes it stick in people’s minds? Anyway, here’s a video to show why it’s not an issue:

The video was filmed on a Mk3 SheetCNC which is about a year old and has seen some heavy use.
The machine has all-original mechanical parts, identical to those supplied in PembrokeshireCNC’s kit.

Backlash

Another popular question. Again, it’s really not an issue. Here’s the test:

 
 

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