Unexpected Result from Slice

General MeshCAM Questions

Unexpected Result from Slice

Postby nath2099 » Thu Jul 20, 2017 5:54 am

Hi all, the attached file GSB.stl is a 3d model that I am trying to slice. When I use the slice function in MeshCam each layer has an extra surface in it, as attached. You can see in the slices, there is a face on the second half of the circle... kind of hard to explain. I have attached a screen shot as well. Am I doing something wrong?

Cant attach stl's, handy. Can anyone tell from the jpg's?


slice.jpg (162.64 KiB) Viewed 203 times

whole.jpg (203.57 KiB) Viewed 203 times
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Re: Unexpected Result from Slice

Postby larynx » Mon Jul 24, 2017 4:09 am

I am not positive - have actually never used the slice command - I just go deep.......or split it in CAD at equal heights or where the transition to detail requires, and run two cuts as one file with the "pieces" aligned next to one another. That way I can "flip" one over like the "top" of your file next to the "bottom" and its like cutting from inside out so there is no "shelf under what can not be cut - why you "slice" I assume. But, if you have any errant surfaces in your CAD stl, then yes they may show up, but should not at [would be a big coincidence] the exact level you slice at. So really - no I don't know.

Ok, so why am I stating ANYTHING........because, I would ask if you are doing a router air blast deflector that you will need to drill the center out of after cutting? If so you may wish to put a "post" on the front edge so your router can not be pushed all the way into the cavity - will block too much air flow - I did that the first time, just forgot it so glued in a block after the fact. Needed a hole for my "shaft lock" too. Left a "shelf" to slide on a dust broom skirt [separate - never did make it] Also "adjusted" my center hole to blow just enough air to clear the debris from cuts while diverting the rest. Also cut three smaller holes to allow the leds in the base to shine with the lights off in the room. Yeah, I know, too much information and ....................

If you want me to try, I think you may be able to attach the file - change the extension to "txt", but attaching files in this forum is becoming a hit & miss option. Be happy to share mine if you wish.

Anyway, attached pic is how I split and flip in CAD then export - I always add a "fake" surface to mimic the size of the block I am cutting so I do not have to adjust the size in MeshCAM itself and to allow me to clamp it by using an "include region" where the cut takes place - see pics.

The "deflect01.jpg" is the deflector halves, the "defelct02.jpg" shows the "include region dxf" in green as would be "cut area specified" and the blue "block" region which is output as part of the dxf [it is a surface of 0.0000 height] which is included in the stl output. I later eliminated the directed vanes in the pic - first thought was to direct more air agaisnt my Z rails, then decided I had more than enough output to keep them free of dust - I use a filter on the top of my router case to prefilter the air and keep the inner case & bearings clean and the output air clean against the rails.

Again, if there is anything you can use, great, if you have another method, I am interested in how you do it. For me, the layout in CAD seems to eliminate all the other stuff and I do not have to think so hard when running MeshCAM for gcode output or clamp options. I can clamp anywhere in the blue, and set the depth of cut in MeshCAM so I have a fine usually 0.030" flashing left I can sand or trim router off on the table.

Think I better stop drinking beer now.
DEFLECT02.jpg (27.69 KiB) Viewed 179 times
DEFLECT01.jpg (16.72 KiB) Viewed 179 times
I am not aligned with nor do I have any relationship with MeshCAM or its staff other than being a user [that sounds a little like I have a dependency problem]
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