[Zootalaws]

I’ve (almost) acquired an older Chinese CNC router - it’s been idle for about 4 years but I got it working pretty well after a few minutes. It’s only had a few hours use in the seven or so years since it was bought - the owner runs a laser sign business, but never got to grips with wood routing, so it’s sat idle for years.

It’s very heavy-duty machine with ~50mm cast rack and pinion drive system and a very heavy vacuum bed made out of what looks like so,e sort of engineering plastic. The vacuum pump is buggered, but everything else works fine. The effective cutting area is 2450 x 1250mm on a 3000x1500 bed.

Never having used a vacuum bed before, is it a sacrificial item, or do you make a matching spoil board to sit atop the channeled vacuum bed?

The existing bed is very thick - 40-50mm, so I imagine resurfacing quite a few times is possible before needing to replace the bed and carve new channels if it is a sacrificial item, but it seems a waste.

However, I am in the wilds of Borneo and the ability to get a replacement vacuum bed is both difficult logistically and expensive, whereas MDF is easily sourced so making a matching spoil board with vacuum channels seems the most logical approach.

I intend making items out of sheet goods - ply and mdf and acrylic.

Any operational advice gratefully received.

[ger21]

You put a sheet of MDF on top. Take a skim cut on both sides of the MDF sheet, removing about 0.25mm from each side. The vacuum will pull through the MDF.

[Zootalaws]

You put a sheet of MDF on top. Take a skim cut on both sides of the MDF sheet, removing about 0.25mm from each side. The vacuum will pull through the MDF.

Cool, thanks. I had no idea MDF was so porous. I’ve found a sizing guide for a replacement vacuum pump and it described using a plain sheet of MDF. would 18mm be too thick?

And I guess sealing the edges of the sheet will lessen any losses?

[ger21]

We use 3/4" MDF (19mm).
Yes sealing the edges will help. But it all comes down to how much vacuum you have.