stupid question

[MGardner]

I'm fairly new to the CNC plasma world (I got my machine in January 2014) and I have learned the hard way how much dust these machines create!!!!
I'm looking into a down draft system and also a water table and possibly using them both together?
I went and got the sheet metal to close in the sides today and that's when it hit me........ (here's my stupid question)

When cutting small pieces how do you keep them from falling thru the grates? or if they do fall thru the grates how do you get them back??

I didn't think about this until I closed in the bottom of the table. Currently when a piece falls thru I just reach under the table and get it but now that I have the table closed in I cant do that. Should I have made one of the panels hinged?? Or is there a trick I am missing??
Also If I decide to put a tray under the grates for a water table and the piece falls into the water how do you get it back??
I hope I don't get laughed at to hard for over looking a simple solution but I must admit I'm a little curious how everyone else does this??
Thanks
Mike

[Metriccar]

Auto parts stores will carry sticks with magnets on them. That's what I use to reach things that fall through the grates.
I have a down draft. I closed in the sides and purchased the fan off this site. No complaints, although I do have to cover the top of the table with metal sheets as well some times, especially when I'm cutting on the side of the table opposite the air inlet.

I prefer this over water tables. The downside to water tables is dealing with rust and gunk water. The downside to downdraft is hot air being pushed out of your shop. Being from Arizona I don't have to worry about that.

[jimcolt]

You can tab the parts so they stay attached by a small tab to the metal skeleton. Some of the better plasma cutting software packages make this very easy. I do it if I have a lot of small parts that will drop.

Jim Colt Hypertherm

[Gamelord]

You can also add in a slanted sheet underneath your table so that all the scrap/drops fall down and then slide to the front so you can easily retrieve them. Just put an access door or hinge or something. Then suck the air out of the back of the slanted sheet through a hole with a screen on it.

[CNCCAJUN]

TRACKER CNC PLASMA tables have hinged panels. Also there are several magnets on an extention available.

Steve

[suttoncnc]

I am currently experimenting with a side draft system that I designed for my table. My machine operates as a router and it is equipped with a vacuum table top so a downdraft system or a water pan is not a good option for me. I needed a way to eliminate the smoke and particles from the shop as I have a mill and a lathe within a few feet of the cnc machine. So far the side draft system is working great and has the side benefit of moving lots of air across the bottom of the sheet being cut and my warping issues have all but disappeared. I changed my cut operation so that all my cuts start farthest away from the vacuum source so that the sheet itself serves as a seal against the vacuum intake. In that way as the sheet is used up I still maintain a seal against the vacuum source. The vac manifold has a 2 inch slot cut across its fill length. I am using a 3500 CFM Dayton 8 inch Duct Blower that takes the smoke out the back of the shop. The burn plate just simply sits on top of the vac table with a sheet of hardibacker cement board under it to act as a thermal barrier.

Scott

SIDE DRAFT 1.JPG

SIDE DRAFT 2.JPG

Before adding the vac system I could not have cut this very well because of the massive amount of heat buildup under the sheet, I cut this yesterday and it came off flat and was only warm to the touch right after the job finished.

JOHN.JPG

[MGardner]

That's a very interesting design I've never heard of this way before?
How much of a problem do you have with sparks bouncing back up since your tray is so close? How much distance there between the cutting surface and the tray? Do you have any problems with heat on the tray?
Thanks
Mike

[suttoncnc]

That's a very interesting design I've never heard of this way before?

I have no idea if this has been done before or not so others may give info about that....it came about for me after much experimenting with air flow and the limitations of my machine being a CNC router with a vacuum hold down table.


How much of a problem do you have with sparks bouncing back up since your tray is so close?

I have not noticed that sparks bouncing have caused any issues, the sparks stay under the material and do not bounce back above the sheet. I am not experiencing any dross spatter buildup on the bottom of the material away from the cut line. I have only cut 18 gauge with this setup so far so still much to learn with it.

How much distance there between the cutting surface and the tray?
1.5 inches

Do you have any problems with heat on the tray?
The tray remains fairly cool, I am moving LOTS of air thru the tray. So far the tray is not showing any signs of heat distortion.

If I am cutting a piece of material that is less than 48 inches wide I have a set of foam rubber pads that I made that drops into the manifold and blocks air from that zone. That way only the material section gets the vacuum

[East German]

This is my system, works fine!

http://www.plasmaspider.com/viewtopic.php?f=87&t=13136

Regards Peter

[Gamelord]

Peter,

I seen your post earlier but never really clicked that you had dual side exhaust fans on that. Guess I need to examine the posts a little more detailed. That looks pretty slick! Nice job and great idea.

This forum is awesome because of the many ideas and designs that come from so many talented people.

Thanks to all for contributing.