CNC programme for Radius dish ?

[rusty999]

Hi Guys,
I am new to CNC but a friend does have a machine and has a basic knowledge of cnc work. Just wondering what he would need to build me a couple of radius dishes ?
I live in Europe and its very expensive for me to try purchase one in USA and ship it over as the shipping costs plus customs just puts them out of my reach unfortunately, so I thought about asking him to make one for me
If anyone has any advise about what software is needed I would be most greatful
Thanks
best regards
Rusty

[ken cierp]

Requires 3D software to draw and 2 - 1/2 D coding and CAM software to cut -- not sure what entry level programs can be use. We use, Rhino, Solidworks, Turbo Cad 3d Platinum, Artcam and a couple other of products, for the cutting flies, Mach 3 may be able to run the G-code? I think the trial version has limited allow code lines?

Bottom line unless you are going into the hobby seriously -- buy yourself some dishes or make a router sled and do it by hand, takes a long time is very messy but works -- there are a couple of videos on you tube.

Before you ask -- no we do not sell our machining files.

[Andy Birko]

Although it's not the best software for the job, freemill will get the job done for creating tool paths for you and it's free. It's very limited in what it can do but it will be able to generate a toolpath for you.

A radius dish is extremely easy to make with just about any 3D software. Just draw an arc of the radius you want and do a revolve operation. To do it on the cheep, see if sketchup has a plug in that will allow it to export a file format that freemill will read.

Because of the tool paths that freemill creates, I'd recommend modeling a rectangular plate with the dished area in the center. Not sure how freemill would handle the edges of something round like that. It might stop the tool paths at the edge of the part or it might plunge down to table level.

Good luck!

[rusty999]

Great Advise on this forum

Many thanks guys

Rusty

[Jay McClellan]

The Vectric V-Carve software that came with my CNC router won't create a usable radius dish directly, but I was able to do it by first creating a simple flat circle (zero depth) with a fairly tight raster pattern. Then I exported a TAP file for machining and used the free WarpDriver software to distort the TAP coordinates shape into the dishes I needed. WarpDriver works with the depth of distortion not a radius so I needed to calculate the sagitta and for 15' and 30' radius dishes with 24" diameter it worked out to a saggita of 0.4 and 0.2 inch respectively, i.e. that is the depth of the dishes at the center. WarpDriver then spits out a modified TAP file that drives the CNC with the desired curvature. It's a messy job so you'd better have good dust collection.

After routing the dishes into 24" square sheets of 3/4" MDF I found that they distorted due to the unequal stress, i.e. the back was noticeably not flat anymore. So I just screwed them back-to-back, which flattened them out and also happens to make (in my experience) a good weight for sanding rims without having to push down. Zoro Tools has 24" pressure-sensitive sandpaper discs (search for "PSA disc") way cheaper than anyplace else I've found them and I use the 50-grit, then smooth by hand with finer paper. For radiusing braces I shape them on the 50 grit disc and then just lay a sheet of 100 or 150 grit paper on the disc for a final smoothing, works great.