Table Flatness

Discuss Thermwood 3-axis Machinery, Controller, and Software.

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Rob Davis
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Postby Rob Davis » Thu, Mar 02 2006, 2:20PM

Bill, Thermwood does still sell wasteboards direct. We tried using regular grade MDF for wasteboards and have since gone back to Thermwood stuff. Commercial stuff curved up and and warped and created all kinds of wierd situations. For a few bucks more, get the right stuff and it pays. They ship it commercial carrier.

We always use a wasteboard and we make parts as small as 6\" x 7.5\" on our 5x10 table starting with a 5x10 MDF sheet. Wasteboard holds the parts more uniformly. Whenever we do not use a 5x10 sheet, we have laminate strips we place on the table to \"seal\" the wasteboard area not in use. Works great and is easy to move around and store.

We only fly cut every couple of months and only one side. Our wasteboard looks pretty ugly from time to time but as long as it works, we are happy. Make sure when you load sheets that you get table really clean of sawdust and the sheet sits flat. Bowed plywood should be loaded with corners down then let vacuum pull sheet flat in middle. Usually when we aren't holding we have junk under the sheet or under the wasteboard.

Just my 2 cents worth.
Rob

Bill OConnell
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Postby Bill OConnell » Fri, Mar 17 2006, 9:43AM

I have been reading this thread with great interest and have gotten a lot of good tips out of it. Thank you to all who shared their knowledge and experience.

As a result of reading this thread, I flycut my spoilboard on both sides 0.1\" on each. I then decreased the value between the top of the spoilboard and the automatic tool sensor stored in the M999 macro by 0.2\" I then flycut my waste board on both sides. The first pass was to a height above the spoilboard of 0.24\" and the flip side to 0.23\", thereby taking 0.1\" on each side. So far so good. :)

I verified the part position on the control screen and it read Z=0.23.

I thought that this process would reduce or eliminate the deep grooving in the wasteboard that I was getting. When I run a file generated in eCabinets I get a fairly deep cut into the waste board even though the Cut Through Depth in Control Nest is only set to 0.002\" How deep is the cut? I haven't measured it exactly, but flycutting off an additional 0.015\" sometimes doesn't eliminate all the grooves. The impact was that in a 32 sheet job, I was losing vacuum in some areas because of the grooving after 16 sheets. I had to stop and flycut again to finish the job.

Now here is the interesting twist. I had to run some simple parts that were easier to do in TurboCAD with a DXF output file. I was about a six sheet job cutting sixteen pieces. When I nested the four DXF files (there were multiple copies of each), and ran the job, it barely scratched the surface of the wasteboard and in some cases left a little skin on the part.

Question to the forum: Is there some parameter in eCabinets that causes it to cut through more deeply than would a DXF file? In both cases the material was measured and correct values entered in the program or part files before the jobs were run.
Woodworking the Way You Want It

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Jason Susnjara
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Postby Jason Susnjara » Fri, Mar 17 2006, 9:57AM

Hi Bill,

There is a setting in Rolling Nest called \"Cut Through Depth\". This is extra that the machine should machine into the wasteboard. Make sure that this number is small. Mine is set at .005. When I surface a spoilboard for the first time, I just surface the top side. I then record the depth of the cutter as it is cutting so I know exactly what the daylight should be. I then record that into the macro for that tool. I sometimes see a difference in cutting depth but I don't surface the wasteboard. I will measure the thickness on all four corners of the board and will then take the average and plug that in. It seems to work pretty good.


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