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View Full Version : Radius Dish CNC info needed



Timbuck
10-05-2011, 01:52 AM
I have the CNC m/c available and I'm looking for info ..So I can make Radius dishes..Up to now all machining weve done is in 2D..and I require 3D for a Radius dish ( I think)..can any one help :)

Rick Turner
10-05-2011, 03:20 AM
Ken, actually, most CNC machines work in 2.5 D...that is they go to a certain spot in the X, Y, and Z axes and then just work 2 D, move over, and work 2 D again line after line after line. It's like a scan in 2 D.

Timbuck
10-05-2011, 04:02 AM
Rick I know what you're saying but.. I'm hoping someone out there will just send a ready made file:o...My Son Mike is slogging away learning "Alibre" and "Solidworks" 3D CAD at the moment and it will be a few days before he starts to get somewhere with it

thistle3585
10-05-2011, 05:48 AM
I could ask my programmer to write the program for you but I know he'd want reimbursed. If you're interested then PM me. I think I paid around $45 for the drawing, machining and material to make a 15' dish with a 18" diameter, so I can't imagine the program would be all that much.

Timbuck
10-05-2011, 09:17 AM
Progress report..Mike (Timbuck Jr) says he's got the CAD sorted, and the dish is now drawn in 3D ..and now he's working on the CAM..We could be there within the next 24 hours.:)

Sven
10-05-2011, 09:21 AM
If so, please be prepared to recieve orders from the land of Vikings and eternal night...

Rick Turner
10-05-2011, 01:18 PM
Solid Works is good, very good. It integrates perfectly with "Visual Mill" for developing the CAM part...tool paths, tooling, and all that for outputting G code. We use Rhino with RhinoCAM which is an adaptation of Visual Mill. Rhino has fewer features, but all we need, and it's about 20% the cost of Solid Works.

Timbuck
10-05-2011, 10:39 PM
Timbuck Jr spent several hours on a CAM program he downloaded free on the web, called Meshcam ..and he got a lot of problems with it and gave up (He do's all this stuff without any manuals or anything "completly self taught".. My brain can't do that :eek:) ..I will recomend " Visual Mill" as per Rick and see how he gets on with that....He's not learning this stuff for my benefit..it's for his own business, he needs to make some new molds for forming plastics on his latest creation in "Electronic Drums"..and the Radius dish is a nice easy shape to start with.

Timbuck
10-13-2011, 06:48 AM
Success at last..Number one Son..has got it sorted....I asked for a boat curve 10ft Rad across by 5ft-2" Rad lengthwise so I can radius sand the backs of my sopranos with confidence...We dug out an old scrap piece of kitchen worktop to practice on..now we know it can be done i'll buy some decent MDF and make a decent one...The CAD used is "Solidworks" and the CAM is "ArtSoft Mach3"...It would be very difficult to make this without CNC
Here is the 3D drawing
http://i219.photobucket.com/albums/cc143/shiregreenbod/PICT0001-12.jpg
Here is the CNC in action
http://i219.photobucket.com/albums/cc143/shiregreenbod/PICT0081.jpg
Here is the roughed out sample.
http://i219.photobucket.com/albums/cc143/shiregreenbod/PICT0087.jpg

Moore Bettah Ukuleles
10-13-2011, 06:58 AM
I radius dish is so easy to make by fabricating a sled for your router. Don't need no stinking CNC.

tattwo
10-13-2011, 07:08 AM
I radius dish is so easy to make by fabricating a sled for your router. Don't need no stinking CNC.

We made a sled too. It took longer than to rout out the dish

Pete Howlett
10-13-2011, 07:10 AM
So how is it going to work Ken? A boat curve is a 'changing' shape isn't it? Does it mean the taper on the sides is straight or to the curve?

Timbuck
10-13-2011, 07:10 AM
You'd need two sleds to do this one 10ft rad X 5ft rad...and it can be done in less time than making a sled :)

Moore Bettah Ukuleles
10-13-2011, 07:29 AM
You only need one sled, not two. I'm just opposed to using a CNC or lasers in any part of my work.

Timbuck
10-13-2011, 08:06 AM
So how is it going to work Ken? A boat curve is a 'changing' shape isn't it? Does it mean the taper on the sides is straight or to the curve?
I'ts hard to explain..but the sides taper upwards into the curve the're not flat..I'll try and record the method when I put the next one together...
But the end result is like this one I did earlier "the hard way".. (I put a pencil on the back to show the detail of the arch)
http://i219.photobucket.com/albums/cc143/shiregreenbod/PICT0009-5.jpg

thistle3585
10-13-2011, 09:39 AM
Are you saying that you have a recurve around the perimeter of the top similar to how an arch top is carved?

Timbuck
10-13-2011, 09:51 AM
Are you saying that you have a recurve around the perimeter of the top similar to how an arch top is carved?
This is not the top it's the back..and there is no recurve.

Timbuck
10-18-2011, 09:38 AM
While waiting for number one Son to make my new dish.. I took the 1st roughed out dish unit..slapped some sandpaper on it and gave a try out..and it worked perfectly..as promised I recorded the method on camera and made a bit of a slideshow.
Click on the image to view it
http://s219.photobucket.com/albums/cc143/shiregreenbod/arch%20project/th_PICT0001.jpg (http://s219.photobucket.com/albums/cc143/shiregreenbod/arch%20project/?action=view&current=c3d86f6f.pbw)

Timbuck
10-20-2011, 08:17 AM
Experiment a success

All glued up and ready for next operation..I've discovered that a "radius dish" dosn't have to be circular (unless it's meant to rotate like Chuck's on his potters wheel).. a rectangle is an ideal shape if you sand back and forth and easier to fit the sandpaper..and also it can be a double radius like this one at 5ft rad lengthways and 10ft rad across...(You can't do that with a rotating one)
I found it very quick to sand down with 80 grit and I'll be using this method from now on.
ON the downside "Just to prove that i'm normal"..I accidently glued the back on with the bracing clamps left inside the uke???? (Oh Bollocks! I said, or words to the same effect) and then I had a devil of a job getting them out thro' the soundhole.

Here are the pic's of the finished job
Across the upper bout.
http://i219.photobucket.com/albums/cc143/shiregreenbod/PICT0006-6.jpg
Across the waist
http://i219.photobucket.com/albums/cc143/shiregreenbod/PICT0008-6.jpg
Across lower bout
http://i219.photobucket.com/albums/cc143/shiregreenbod/PICT0004-10.jpg
And lengthways.
http://i219.photobucket.com/albums/cc143/shiregreenbod/PICT0011-4.jpg

ulmis
02-21-2013, 10:54 PM
I found this old thread when searching for CNC-related info but those 3D softwares are difficult and expensive.
wolframalpha.com (with wikipedia) is great free browser based site to refresh your geometry studies.
An ellipsoid like Timbuck is actually making above (AFAIK) can be represented with equation
x^2/(2a)^2+y^2/a^2+z^2/a^2=1.
WolframAlpha solves z from it easily, see
http://m.wolframalpha.com/input/?i=x%5E2%2F%282a%29%5E2%2By%5E2%2Fa%5E2%2Bz%5E2%2F a%5E2%3D1&x=0&y=0
and with replacing a with real value (in millimeters) and moving origo 50 mm south you get plot
http://m.wolframalpha.com/input/?i=Plot+z+%3D+-sqrt%28-%28x-50%29%5E2-4+y%5E2%2B51840000%29%2C+x%3D-200+to+200%2C+y+%3D+-100+to+100&x=0&y=0
But if you are still interested and have access to CNC-router, you will need some CAD etc sw.

Timbuck
02-22-2013, 01:45 AM
I found this old thread when searching for CNC-related info but those 3D softwares are difficult and expensive.
wolframalpha.com (with wikipedia) is great free browser based site to refresh your geometry studies.
An ellipsoid like Timbuck is actually making above (AFAIK) can be represented with equation
x^2/(2a)^2+y^2/a^2+z^2/a^2=1.
WolframAlpha solves z from it easily, see
http://m.wolframalpha.com/input/?i=x%5E2%2F%282a%29%5E2%2By%5E2%2Fa%5E2%2Bz%5E2%2F a%5E2%3D1&x=0&y=0
and with replacing a with real value (in millimeters) and moving origo 50 mm south you get plot
http://m.wolframalpha.com/input/?i=Plot+z+%3D+-sqrt%28-%28x-50%29%5E2-4+y%5E2%2B51840000%29%2C+x%3D-200+to+200%2C+y+%3D+-100+to+100&x=0&y=0
But if you are still interested and have access to CNC-router, you will need some CAD etc sw.

Err? Yes!!...That should do it , I think:confused: ????:anyone:

Sven
02-22-2013, 01:51 AM
It's simply a matter of rolling an ostrich egg in glue and then in sand, then using the abrasive egg on a thick piece of mdf. Hey presto, the boat curve dish is done in minutes. Remember to ask the ostrich first.

ulmis
02-26-2013, 10:16 AM
Sven,
I couldn't find ostrich eggs from the local store, so I decided to try a donut. None so big in store either, so I installed OpenSCAD (a free 3D CAD sw from the net) and draw both objects on top of each others. See attached image. 49399
Now I wonder which one is the correct shape... somehow the donut feels more tempting. Computers are great, I could not live without them :)

Timbuck
02-26-2013, 10:56 AM
Computers are great, I could not live without them :)

Yes! you could...I managed 50 years without them.:)

ulmis
09-22-2013, 07:26 AM
I gave up CNC and built a sled with my son. This one is a duo-model for 12' back and 22' halftop. A lot of dust but result was OK.590055900659007