Diode laser for cutting 3mm MDF?

I'm looking into buying a laser cutter, the main use would be cutting 3mm MDF and maybe plywood as well.

(Am I right in thinking MDF is more difficult to cut than plywood?)

I see lots of machines like this on eBay:

[www.ebay.com]

They claim to be able to cut 3mm wood "easily" but in the forums it sounds like it takes several passes at quite a slow speed to do it.

I don't have any experience with these things so I invite comments from the experts: What's the truth? Will one of those things cut 3mm MDF in a reasonable time and do it cleanly? "Cleanly" is more important than "fast", but ... I wouldn't want it to take hours and hours to cut something. I understand I might have to add air assist or something to get it to work.

nb. The reason I'm looking at diodes instead of a sensible K40 CO2 cutter in a proper metal box is that the K40 is only 300x200mm work area. That seems too small and the next size up from that is a lot more expensive (over $1000?)

Any input would be greatly appreciated.

Edited 2 time(s). Last edit at 01/29/2018 04:10PM by fungus.

... here, from 4:30 on, I'm "cutting" 3mm thick plywood with a blue 445nm 3,5W-diode - [vimeo.com]

IIRC, it took 2 passes to get through ... or maybe 3?

MDF has more density, so could need even more passes ...

Edited 1 time(s). Last edit at 01/29/2018 07:05PM by VDX.

---

Viktor
--------
Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]

Quote
VDX
... here, from 4:30 on, I'm "cutting" 3mm thick plywood with a blue 445nm 3,5W-diode - [vimeo.com]

IIRC, it took 2 passes to get through ... or maybe 3?

Timewise: That video's sped up 8x times, so maybe 10 minutes per pass? Half an hour to do that cut? I'm guessing MDF would be twice as difficult as plywood so it could take an hour to do something that a CO2 would do in a few minutes?

Cleanliness: It's not easy to see details in the video but the long straight lines on the left have a few wobbles, even with air assist.

Food for thought, thanks for the info.

PS: What's the packing tape for?

Edited 1 time(s). Last edit at 01/30/2018 02:04AM by fungus.

Quote
fungus
PS: What's the packing tape for?

... without it, the fumes will leave brown traces on the surface

---

Viktor
--------
Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]

In the end I decided to get a 40x40cm, 50W CO2 cutter. There's quite a few of them on Aliexpress.

Still not huge, but a lot bigger than the basic K40's 30x20cm. They cost about about twice as much as the K40 but I think it will be an order of magnitude more useful. Above this the price goes up quite a lot (also the physical size of the machines!)

The square format seems a good idea as well. A lot of things are circular so I'll be able to do a lot of things a 60x40cm cutter would do.

Another factor I thought about is the safety. An unenclosed 450nm laser (diode) vs an enclosed 10um laser (CO2)? No contest there.

Anyway, let's hope it doesn't take too long to arrive and that customs don't give me much grief.