Part holding and milling 3D part on 2.5D Mill?

[john_t_h]

Hi everyone,

I'm in the process of teaching myself how to use CAD to design some small parts for radio controlled models in 3D. I don't have my mill yet, but at this stage I'll be getting a Syil X4 mill and will being using BobCAD for the CAM side of things and Mach3.

I finished drawing up my first part the other day and then I started thinking how I could hold a block of aluminum on the mill and machine the part out. I originally thought one side would be machined then the other. But then I couldn't visualise how the part would be held on the table. Perhaps there needs to be more steps?

What would be the best process of machining the attached part?

[cam1]

Hi: One of the biggest parts of the machining learning curve is fixturing...
You could machine it out of a "brick",and leave additional material at the ends of the part, that would be held by the vise, or by clamps.One side is machined, the part is flipped, and the other side machined. Afterwards the excess material is bandsawed,milled away. Alternately you have a feature there (the bore) that could be used to arrest some degrees of freedom, and be used to index the part.(You could create the bore as one of the first operations).
When designing, try to keep in mind the subsequent machining processes,if you cannot envision how you are going to be able to manufacture the final part, change the design until you can.

PS
nice looking part.

regards

regards

[neilw20]

Search for foiling
Recommedation on Vacuum table?
I use it all the time. Usually 0.2mm all round, and the last cut just skips the first and second corner by 0.1mm and goes below by 0.2mm the rest of the way. Break it out with your fingers. Be careful that Z moves don't leave marks. Usually better not to move z in the last pass and go around the foiled corners over a thicker area you leave for support.

[john_t_h]

Do you normally design the foiling into your drawings?

[neilw20]

Yes and no. Depends what you call a drawing.
I do all the tool paths and the registration holes for flipping the part(s) in the 3D CAD file, but don't bother to include foiling in the 2D drawn part.

[john_t_h]

Neil,

Is this the sort of thing I should be doing. I've only added one bridge in this one, but the finished one I guess would have five or six more?

[airforce1]

Neil,

Is this the sort of thing I should be doing. I've only added one bridge in this one, but the finished one I guess would have five or six more?

exactly, you can add more bridges but that will work.
i don't think i'd do foiling on that part, it is so thin i don't see the point. but yes i use it quite often, if it is posible i like to write programs that can run start to finnish with out human interference.