Help with model finishing pass

[bcombs510]

Hello,

I'm new to the forum and new to Aspire. I was able to follow one of the great Youtube tips and tricks videos on modeling guitar necks and was able to successfully model a ukulele neck. Now I'm on to doing test cuts in polystyrene so I can get the tooling and fixturing kinks worked out.

First issue - I was able to complete the roughing toolpath fine. I used 3D raster. The bits I'm using are long reach fishtail 1/4" endmill for the roughing and long reach 1/4" ballnose for the finishing. The fishtail has 3.25" of reach and the tallest point on the model is 2.75" so I was able to run the roughing pass fine. The ballnose has 2.5" of reach, maybe a bit less. So while the ballnose was running the finishing pass the collet was hitting the material. No big deal since I'm using polystyrene to test the cuts and work everything out.

I tried running the finishing pass as both raster and offset and had the same problem just on different sides of the highest point.

Here are two pics. You can see around the heel of the neck where the collet was rubbing:

Is there a way to work around this short of trying to find a longer ballnose? My understanding is that the two bits I have are used by many makers and pros to cut necks so I'm wondering if there is a toolpath solution.

Thanks!
Brad

[adze_cnc]

Could this be run as a double-sided job with the neck "lying on it's side"? Much less height needed that way.

[bcombs510]

Thanks. The job is two sided now but I see what you mean about putting it on its side. Now a really naive question - can I somehow take the project as is and turn it on its side? The model consists of basically five components which are two rail sweeps. I will need to re-create the vectors used in those sweeps to put the model on it's side or can I "rotate" as is?

Appreciate the response.

Brad

[dealguy11]

If you export your current components as stl files, then import them, you can rotate them during the import process.

[bcombs510]

Awesome, thanks. This is getting me very close. There is a strange artifact after the model is imported, it could be how the original model components were created, I'm not sure. The video that I followed to create the original model file is here -

The video was very straightforward with the exception of one aspect which was the "invisible bed" that he used to create the headstock angle. This consisted of creating a component that was a two rail sweep using the side line profile of the entire neck and then mirroring that on the other side. The "back side" had the component set to subtract so the result is an "invisible" ramp that the headstock shape lays on.

Could that be contributing to the issue? I've uploaded two pics below. The settings I'm using to export and the settings to import. In the import image you can see the excess that is creating a sort of hood around the headstock shape. Any suggestions on changes to the export or import that could address that? I don't want to keep just asking for help so if there is a term or section of the manual I should consult that's fine too, only way I'll learn.

Any ideas are appreciated.

Thanks!
Brad

[chemstock]

problem with deep cuts is the opportunity for the spindle to hit the work piece. I have tried hollow forms in maple and run into this problem. Something will break when the collet or spindle hits the work piece. hopefully it is only the work piece or the bit.
Long reach tools help, Amazon has some 1/4" long reach bits that can get to 3" but be careful. I have had a few explode on start up, vibration is a big problem. You will need to slow the spindle speed and reduce the cutting speed to keep side loads and vibration down.
Better to find a 1/2" bit with a 1/4" ball nose end. That will eliminate the vibration issue and allow a deeper cut. I have had some bits made through All Blade. Very expensive but the best way I have found for deep cuts.