Plane cut 3d model above a specific Z value

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Terry Williams
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Plane cut 3d model above a specific Z value

Post by Terry Williams »

I am making a tough case to protect my Son's (masonwilliamsmusic.com) guitars when shipping out of state for luthier service.

The outer case is 1/4" HDPE joined with aluminum 90deg extrusions with the interior consisting of pink extruded polystyrene foam (Foamular) that has been carved to accept the original hard case for his guitars. The guitar will be shipped in it's own case which is protected by the HDPE shell and carved foam insert.

I have scanned the Guitar case and cleaned it up a bit in some editing software and then imported to Aspire 11.03 as a double sided project.

I created a rectangular component that will contain the guitar case model and subtracted the scanned from the rectangular component to create the cutout area for the hard case.

In doing this, the combine mode of "add" for the box causes material to spike up above the top of the box component.
HamerCaseIsoView.jpg
I want to remove the excess "spiked" material (the yellow hi-lighted area on the pic) from the model.
HamercaseY.jpg
This is easy with some editing software using the "plane cut" function, but I don't know if Aspire has a similar function - At least I have not found anything like it other than the "replace values below Z with a plane" but that gets rid of whats below a plne instead of above.

Suggestions and advice would really be appreciated!
Terry
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martin54
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Re: Plane cut 3d model above a specific Z value

Post by martin54 »

Is this really a 3D job? Looking at what you have posted it looks more like a 2D profile/pocket job which firstly means you don't have to worry about the artifacts & secondly will machine a lot quicker :lol: :lol:

Terry Williams
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Re: Plane cut 3d model above a specific Z value

Post by Terry Williams »

It's 3D - I scanned the hard case and imported the .stl .

The cutout needs to fit the curved outer edges and the domed top of the guitar hard case. The domed top tends to get damaged when shipped in a flat bottomed box so I decided to build a custom shipping case so it doesn't happen again.

He has three of these guitars and they are very expensive and rare - they are no longer available except for an occasional eBay listing.

He makes his living as a professional guitarist and these guitars are his tools. Two are in service now and one is waiting for a fret job but they all get shipped out on a regular basis so the shipping box has to be GOOD!.
Terry
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Adrian
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Re: Plane cut 3d model above a specific Z value

Post by Adrian »

Have you added a zero plane?

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SteveNelson46
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Re: Plane cut 3d model above a specific Z value

Post by SteveNelson46 »

This is the procedure I use to plane the material to an exact thickness. It works for planing the spoilboard also.

In the job setup, set the material thickness to the desired finished thickness and z-zero to the machine bed
Create a pocket toolpath slightly larger that the material to be cut with a cut depth set to "0" (zero).
When you run the toolpath the machine thinks it's skimming the top but it is actually cutting away material.

For example, if your material is 2 5/8" thick and you want it to be 2 1/2" set the material thickness to 2 1/2" and the z-zero to the machine bed in the job setup. Create a pocket toolpath slightly larger than the material with a cut depth of "0". The machine thinks it's skimming the top of a 2 1/2" board but actually cutting away 1/8" leaving the board thickness to 2.5".

It sounds complicated but when you think about it it's pretty logical.
Steve

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Re: Plane cut 3d model above a specific Z value

Post by garylmast »

When you import a model as a double sided project, it will ask for an Overcut Distance. The figure will be a negative distance past the zero plane. If you later want to change the distance, click the zero (limit) plane and going into its component properties (crescent wrench icon) and you can adjust it there. If you want to limit the depth, put a positive value there. If you want it deeper, put a higher negative value. To get rid of any artifacts, change the component to merge.

Gary

Terry Williams
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Re: Plane cut 3d model above a specific Z value

Post by Terry Williams »

This is a two sided job and when you import an stl file 2-sided, Aspire automatically creates "Limit Planes" that are used to delineate the base of the 3d model on top and bottom sides.

I'm trying to find out how to trim a 3d model ABOVE a certain height - east to cut the part of a model below , but not so easy to cut what's above.
Terry
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Terry Williams
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Re: Plane cut 3d model above a specific Z value

Post by Terry Williams »

OK - I got it now.

I duplicated the "box" component and then used the combine mode "low" - that did the trick!
fixedprob.jpg
Terry
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adze_cnc
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Re: Plane cut 3d model above a specific Z value

Post by adze_cnc »

Terry Williams wrote:
Sat Jul 31, 2021 5:17 pm
It's 3D - I scanned the hard case and imported the .stl .

The cutout needs to fit the curved outer edges and the domed top of the guitar hard case.
The project is not 3D because of the STL model it is 3D because of the arched top of the guitar case, which was not in evidence from the screenshots.

Many jobs people think are "3D" are actually "2D" in disguise. This was a Rhinoceros 3D file that I was given:
2016-02-16_091652.gif
it looks 3D but I cut it entirely with profile and pocket toolpaths using the curves that the model was created from:
2016-02-16_092027.gif
using a round-over, a straight, and a v-bit.

Will you be chamfering or rounding over the 1/4" HDPE edges?

I ask because I still have a scar on the palm of one hand I got from moving a 1/2" sheet of HDPE without gloves ("I'm only moving it a little way"). I found out what heavy material + slippery surfaces + sharp edges can add up to.

Terry Williams
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Re: Plane cut 3d model above a specific Z value

Post by Terry Williams »

Right, the geometry represented by an .stl file does not dictate using a 3D toolpath when it represent planes that intersect other planes or planes joined by constant radius curves (although you could still choose to cut using 3D toolpaths if you want too). When the geometry represented by the .stl file contains features with compound curves of continuously varying radii in across all dimensions, you will have to use a 3D toolpath.

We use about 30-40 sheets of "Marine Board" a year and are well aware of the nasty nature of it. We use clamps with handles and drywall caddies to move it about so no one gets hurt. In this case there will not be any chamfers or round-overs since all edges of the HDPE are covered by the aluminum angle extrusions.
anglealum.jpg
anglealum.jpg (3.2 KiB) Viewed 1967 times
Anyway, the main thing I was looking for was a quick solution to modifying my 3D components to get rid of the unwanted spike and I figured that out shortly after posting so I'm good to go!

Thanks everyone for posting.
Terry
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