@jim said:

Hi Tom,

Short answer is yes you may be able to use Sketchup depending on your needs as long as you understand its limitations.

If you need smooth curves, you need to use a high segment count when drawing arcs and circles in Sketchup.

Don't smooth or hide the edges in your model. The smoothing in Sketchup is an illusion and won't translate to smooth curves in the .dxf.

The biggest limitation is that SketchUp does not have true arcs or circles. Everything is exported as line segments, and unless you used a lot of them, the segments could be visible on the finished part. Of course, this does depend on other factors such as the radius of the curve and precision of the machine. A small radius will probably not have visible segments, for example.

The shop is going to take the .dxf and generate gcode to run on the cutting machine. The gcode ironically does support true arcs, but again Sketchup exports only line segments so that is what the machine will cut. The more segments you model with, the smoother the finished part.

CNC machines and 3d printing have become affordable at a hobbyists budget. It's really too bad because Sketchup seems like a perfect fit otherwise, but this lack of curves makes it hard to recommend Sketchup for applications like cnc and 3d printing.

Thank you Jim,

First of all, your Blog is EXTREMELY helpful and I've found it to be a great asset in this project and in future projects, I'm sure.

I sent the DXF to the machine shop with 50 sided "circles". We'll see how that turns out.

I downloaded an external DXF viewer to double check my exported model out and it seemed to me that a model based on poly lines was most stable. Is this normal? Is a triangular mesh favored?

Anyway, thanks for all your help, I'll let you know how it goes.

Tom

@mac1 said:

Tom, if so simple why not make drawing and just have it machined vs CNC?
Don't have any experience with 3D printing but for race car application and the vibration and shock I would question that is the appropriate application.
Just some thoughts

Hi mac,

I'm getting quotes from machine shop off of drawings as we speak, but it seems to be more expensive than a CNC job would be.

It's actually for a high end Sim racing rig so don't worry about vibration/shock factor. thanks for looking out for me though!

Tom

Okay so here's my noob post. I've designed a part in SU that i would like machined out of aluminum. It's not that complicated, no undercuts or anything and actually except for one spot that needs to be milled, could be done with a skill saw and a drill press.

Am I in way over my head here?
Is it even feasible to export a DXF that they will be usable? (I already have a few plugins but havent been able to export reliable DXFs)
And lastly, Maybe I'm barking up the wrong tree? Maybe more luck can be had in the 3d printing arena?

The part will be holding buttons and will only need to withstand the force of a thumb press at a leverage distance of about 1.5". I chose aluminum initially because it will sit directly behind a racing steering wheel that is made of the same Al.

Thanks for your time guys!
Tom