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Laser for Layout

Posted: Tue Mar 12, 2019 8:30 pm
by TReischl
I am finding a small laser more useful every week.

This morning I was doing a part that was already cut to size. The big question was "Ok, am I going to run into the clamps or what?"

Then I had an "aha!!" moment. Just use the laser to trace out the cut lines. Presto! There is where the part is in the material!

One thing I never like is cutting large openings. I don't like tabs especially well either. Have to cut them, then get rid of the little bumpies they leave, etc. If I cut through a part with tabs or onion skin then the waste can become an issue real quick. Well, since I now knew where those openings were I could just drive a screw in and hold them down. So I did that and it worked like a charm.

Yup, it takes a bit more time but it is worth it with certain parts. These days I never cut a rectangular part out of a larger piece. I cut it to size before putting it on the router. It is way faster and the finish is better.

My machine is now setup with the router using G54 for the workpiece offset and G55 for the laser workpiece offset. The router post has a G54 in the header section and the laser post has a G55. The only thing I need to do "manually" is set the Z height for the laser.

By the way, another nice thing about this method is that you do not have to clamp the part down to laser engrave it.

If you set the feedrate correctly the line left by the laser is easily sanded out.

Re: Laser for Layout

Posted: Wed Mar 13, 2019 2:51 am
by 4DThinker
I've got a 1/4" spiral upcut pattern bit mounted in a router table right next to my CNC. A benchtop bandsaw stands nearby. When I've got tabs to remove I'll bandsaw through the tabs, then flush trim what is left over at the router table. The spiral upcut pattern bit typically leaves no trace of where the tabs were.

4D

Re: Laser for Layout

Posted: Wed Mar 13, 2019 12:38 pm
by TReischl
4DThinker wrote:I've got a 1/4" spiral upcut pattern bit mounted in a router table right next to my CNC. A benchtop bandsaw stands nearby. When I've got tabs to remove I'll bandsaw through the tabs, then flush trim what is left over at the router table. The spiral upcut pattern bit typically leaves no trace of where the tabs were.

4D
Oh, trust me, I have used the band saw and the router table. It is really tricky band sawing interior cutouts though. I haven't figured out that one yet. :shock:

Just an aside, years ago I read something by, I think it was David Pyel, who discussed something he called "the craftsmanship of certainty vs the craftsmanship of risk". Here is a link that contains what he discussed:

http://promotingprimitivism.blogspot.co ... nship.html

Essentially what I am practicing is craftsmanship of certainty. With everything locked down I know exactly what the result will be. It will also be repeatable part after part. Once the part is removed from the machine and a person starts manually handling it through other machines a certain element of risk enters the picture. Slip on the bandsaw and a ding appears on the edge of the workpiece. A void on the edge of the part will cause the flush trim bit to cut deeper.

I don't think everything needs to be made that way, I do a lot of stuff manually with a certain amount of risk involved. But since I am using a computer controlled machine I see no reason to add risk and more time when making a part on it.

All that said, when I need edge radii you can bet that I do it on the router table because it is faster to set that up than to do it on the cnc. And when the parts needs the edges on both faces rounded, it becomes obvious the router table is the better method.

Re: Laser for Layout

Posted: Wed Mar 13, 2019 1:46 pm
by Phil
Ted, excellent technique for those of us who have a laser attached. I have a plotter pen that I bought a few years ago. I have used it to help confirm that a workpiece that is a little too long for my 32" table will fit on a diagonal layout.

Phil