Question for the CNC/3D guys

[GAC05]

I have a customer needing some custom counter top, clear display racks.
They are not very big - 24"x18"x12.
I don't have a table so I'm just going to do the design and assembly and sub out the cutting.
Question I have is with the tolerances needed when you want two panels to fit together snug but not so tight that I'll end up with assembly problems.
The material will be 1/8th to 3/16 acrylic or polycarb. Do I build in some slack or let the CNC guy do it when he figures in the bit diameter offset and all those other things I don't know about?
I have not talked to him yet so I'd like to have some basic info before I do.
I've had him do some stuff before but it was mainly basic panels with shapes punched out of the center so there weren't any interference issues.

Thanks
wayne k
guam usa

 

[Techman]

Design them so they fit like you want. Let the cnc guy make the offsets to match his machine. Every machine is different. That even changes with the materials and the sharpness of the cutter bits.

 

[GAC05]

Design them so they fit like you want. Let the cnc guy make the offsets to match his machine. Every machine is different. That even changes with the materials and the sharpness of the cutter bits.

Thanks, I'll post the results once I get one made.

wayne k
guam usa

 

[johnnysigns]

I build the tolerances in.

You using adhesive backed extrusion to connect the sign header to your acrylic blades on top of the unit? Is this just a friction fit or are you dropping glue/solvent into joints for adhesion?

 

[4R Graphics]

build the tolerances into the file you send to the cnc guy.

The cnc will cut it within 1000's of an inch (if its any good) also it will be cheaper as the cnc operator only has to set your file for a profile cut (very quick and easy) if he has to start adding tolerance adjustments it takes longer and he will charge for it.

Think of it like this do you charge a design fee if I give you print ready art? You will if i give you art that needs to be adjusted samething for the cnc guy.

 

[rfulford]

You will definitely need to extend the slots by half of the diameter of the bit used to cut. Otherwise, you will need to go back with a file to make the interior cuts square. I would design everything else to be as perfect as possible and build a couple of test pieces into the file for testing the fitting. I would also recommend polycarbonate over acrylic. You want this as tight as possible and I can just see the pieces cracking as you try to slide them together.

 

[GAC05]

Thanks all for the additional information.
Next step will be to sit down with the CNC guy and see what he wants.
I am going to glue/weld the joints along with the header on top and maybe close off the back so the rear split sections are supported.
Polycarb is what I want to use. Guess it will depend on the final cost.

Thanks again

wayne k
guam usa

 

[fixtureman]

Ask the CNC guy what he wants.