[Things]

Hey guys, what kind of distance do you have between your cutting bed and the drop tray underneath? I'm building/designing my machine now and I'd have roughly 65mm between the top of my cutting bed and the top of my drop tray.

Regards,
Dan

[pontiacg5]

Hi Things! Long time no see

My catch tray is around 8" below the bottom of the cutting table, the catch tray is not the full size of the cutting table so it tapers up to the full table width. The smallest distance between the top of the cutting table and catch tray is less than two inches. I don't see any damage in the paint from the laser at that closest point, so you should be good.

Hope that helps!

[Things]

Hah, hey man! Long time no see indeed

This is my design:



Dan

[pontiacg5]

Hah, hey man! Long time no see indeed

This is my design:

Dan

You might want to make that bottom tray removable, cutting acrylic and plywood puts off a fine dust I could see catching fire. Unless of course you are going to enclose it and vent the table somehow.

Personally I would just use some aluminum sheet that's been scuffed or textured somehow, possibly sandblasted. Aluminum parts are very hard to mark because they spread the heat so fast, so I wouldn't see the base getting too terribly hot. It will reflect a lot of the energy, but it would be so defocused and diffused I can't see it messing with the back of whatever you are engraving or cutting.

Also, you are probably going to want some sort way to force air past the focal lens. They get dirty almost instantly without air especially when engraving, and it will crack the lens if it gets too dirty. Not to mention the extra cutting benefits, I went from 5PSI to 50 and I have no problem cutting 1/2" thick MDF anymore. Used to be hit or miss weather I could cut in one pass or not. Simply the best mod I've done to the laser so far, it kicks butt with all that air pressure! Plus it stops a lot of fires (flame2)

[Things]

Hehe yeah, my nozzle does have an air assist port. I bought a 45L/min air pump from eBay just the other day.

Also yeah, the whole entire thing will be under negative pressure and vented outside. I am a bit worried about it starting fires in the drop tray like you said. Suppose I'll just have to try it and see

Worse case I can probably get another 2cm onto the distance.

Dan

[Melody-gweike]

Hi, Dan,

Our design is a funnel under the cutting bed with a small drawer at the bottom. I think it is a good design. Because it will avoid the base to getting too hot as pontiacg said. And at the same time the air compressor connects the funnel to sunk the smoke away.

For your reference~

Melody
[email protected]

[Things]

OK Cool, I'll see about doing a funnel design

Dan

[pontiacg5]

This is going to be one cool laser when you get it finished, be sure to post pics!

The funnel is also nice because it catches parts that are cut free from the dross. If they sit too close to the laser focal point you may accidentally mark them while cutting other parts on the same sheet. I guess you could add tabs to keep stuff from dropping, but that's just extra post processing work that I hate!

[Things]

Yeah, didn't really consider that much. Will go for a funnel design then.

Here are some pics of my progress so far:









The Y carriage is basically the most complex part of the machine. Just waiting on a few bits from HK to get the X going as well.

Dan

[Things]

Beefed up that angle alu by doubling it up to try stop some flex. The belt tension was actually warping the metal. By doubling it up, I only get a few microns of movement in the carriage if I flex it.



I have started compiling this project on my website: NQLasers

Dan