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Doug Griffith
06-21-2010, 11:24 PM
Recently I've been contracted to create some organically shaped injection molded parts. More specifically something that is edgy and needs to fit comfortably in the hand. This is not an easy thing to do with 3D software. Even if I could get it to look good, I wouldn't know if it "felt right". My solution was to sculpt out of clay > cast as urethane > hand smooth > scan > clean up > convert to parametric data > work the file typical to a 3D part. The laser came in handy by being the interface between the organic and geometric areas. I cut end pieces on the laser and integrated into the clay sculpture. After casting, I added more laser cut pieces to the part as run-off, made sure they were square and parallel, and blended in. Once in the computer, most of the laser cut areas will be replaced and blended in again (using the original laser files imported into the 3D software). After that, the internals will be added and the file is off to be rapid prototyped.

BTW the round ring and curvy swoop are both functional as they provide clearance for internal parts.

Bob Davis
06-22-2010, 12:08 AM
Sensational work Doug.
I really admire the way you've combined processes and tools to get an appropriate result - outstanding.

John Barton
06-22-2010, 1:13 AM
That's amazing! Has anyone here ever tried to make a ball? I have often thought about how fine the slices would need to be and how many of them I would need to make to make a ball that would require very little sanding to be round and smooth.

When I was at the machine show last year I saw a laser on a robot arm and it was cutting 3d objects out of blocks. Previously I had only seen that type of thing as a router bit on a robot arm.

Andrea Weissenseel
06-22-2010, 4:10 AM
very sophisticated, respect !

Frank Corker
06-22-2010, 4:10 AM
Great work again Doug. You do get some interesting stuff to do. Can't stop, got to go and wind the clock.

Dan Hintz
06-22-2010, 7:14 AM
Yeah, for organically-shaped objects, trying to do it completely in software is folly. I'd do the same as you. After the half clay, half plastic model was complete and shaped to my liking, the next step would be using a laser scanner to get the computer model. A little cleanup of the point cloud, then off to the SLA shop.

Cool...

Mark Ross
06-22-2010, 8:20 AM
I'm kinda lucky because in addition to having the laser at work, we also have a Dimension printer and print our own 3d parts. I can't wait for the cost on those to come down and we all have one on our desk like a big ol' laser printer.

Cool work, looks pretty darn ergonomic. I take it this product is something people are going to have in their hand alot?

Scott Shepherd
06-22-2010, 8:42 AM
I can't wait for the cost on those to come down and we all have one on our desk like a big ol' laser printer.


Google "makerbot" and look at the videos on there. You can buy the kit to make your own.

Doug Griffith
06-22-2010, 11:28 AM
Thanks fellow Creekers. I'm off to GrowIt (www.growit3d.com) this morning to drop it off to be scanned.

Here is a combo that is around what we paid for our lasers:
http://www.nextengine.com & http://tinyurl.com/yyjaozm

Dan Hintz
06-22-2010, 11:42 AM
That GrowIt company looks pretty new... curious at to their pricing structure. I've used ProtoMold in the past, but man are they pricey... doubt I would use them again because of that now that I have some experience under my belt.

The 3D printers still aren't anywhere near the sub-$5k prices they were promising even a few short years ago. And that's a real shame...

Doug Griffith
06-22-2010, 12:00 PM
That GrowIt company looks pretty new... curious at to their pricing structure. I've used ProtoMold in the past, but man are they pricey... doubt I would use them again because of that now that I have some experience under my belt.

The 3D printers still aren't anywhere near the sub-$5k prices they were promising even a few short years ago. And that's a real shame...

I'll keep you informed as to my experience there. They seem like a good company to work with.

Lee DeRaud
06-22-2010, 1:44 PM
Has anyone here ever tried to make a ball? I have often thought about how fine the slices would need to be and how many of them I would need to make to make a ball that would require very little sanding to be round and smooth.Well, sort of...half a 'ball' anyway: http://www.sawmillcreek.org/showthread.php?t=58025.
No 3D printer, just the laser and a lathe.

I can't remember what it's called, but there's a 3D rapid-prototyping process that glues up slices of laser-cut resin-impregnated paper. I assume the cutting is the easy part, but maintaining registration during glue-up is either a total pain or involves some tricky (and/or expensive) gear.

Dan Hintz
06-22-2010, 2:12 PM
Lee,

I know there's a system that uses layers of paper/resin and a knife, but I haven't seen one that uses a laser. It's very cheap to operate, at something like $0.10-$0.15 per cubic inch, and about as fast to operate as other non-laser-based layering systems.

Lee DeRaud
06-22-2010, 3:01 PM
I know there's a system that uses layers of paper/resin and a knife, but I haven't seen one that uses a laser. It's very cheap to operate, at something like $0.10-$0.15 per cubic inch, and about as fast to operate as other non-laser-based layering systems.I'm having trouble getting my head around the mechanical process: does it glue a layer on and then cut, or cut first and then glue?
If cut-then-glue, how does it keep each new layer's piece(s) lined up?
If glue-then-cut, how does it weed scrap from a larger underlying layer?

Doug Griffith
06-22-2010, 3:25 PM
I'm having trouble getting my head around the mechanical process: does it glue a layer on and then cut, or cut first and then glue?
If cut-then-glue, how does it keep each new layer's piece(s) lined up?
If glue-then-cut, how does it weed scrap from a larger underlying layer?

If I was to attempt it with my laser, I'd create an inner alignment piece that notched together and cut corresponding X shaped slots in each layer. I'd create two halves then glue together.

Lee DeRaud
06-22-2010, 3:39 PM
If I was to attempt it with my laser, I'd create an inner alignment piece that notched together and cut corresponding X shaped slots in each layer. I'd create two halves then glue together.Well, as it happens, that's how I did it in the thread I referenced.

But I assumed the commercial process used something a bit more high-tech:
the examples I've seen had rather complex interior voids that simply would not be possible with something like that.

Dan Hintz
06-22-2010, 6:51 PM
Lee,

Glue, then cut, if memory serves.

John Barton
06-22-2010, 9:55 PM
http://www.desktopfactory.com/ is a rapid prototyping 3d printer

Michael Hunter
06-23-2010, 8:21 AM
Years ago I saw a demo of a system that used Avery sticky label stock to make 3D objects.

The software divided the 3D design into label-thickness slices which were then cut on a vinyl plotter. The labels were built up on a board with dowels for (reasonably) accurate positioning. When finished, the object was hardened by painting it with superglue and then sanded to remove the ridges.

Very crude, but surprisingly effective!

Niklas Bjornestal
06-24-2010, 2:33 AM
That GrowIt company looks pretty new... curious at to their pricing structure. I've used ProtoMold in the past, but man are they pricey... doubt I would use them again because of that now that I have some experience under my belt.

The 3D printers still aren't anywhere near the sub-$5k prices they were promising even a few short years ago. And that's a real shame...

You can always make yourself a reprap (www.reprap.org (http://www.reprap.org)), it's a "free" 3d printer (the design is free, you still have to buy the material for it).

Dan Hintz
06-25-2010, 10:18 AM
I've kept my eye on the DIY printers since they first started hitting the scene, but they are still a long way off from the capabilities of a purchased machine. They're fine for a crude proto for someone working at home, but when it comes to a true business, they're not even close.

Doug Griffith
07-11-2010, 2:45 AM
After that, the internals will be added and the file is off to be rapid prototyped.

Following up:
The pic on the left is of the scan data (point cloud) converted to a mesh. The pic on the right is after a bunch of cleaning up and blending to the solid top and bottom. It went from the mesh to surfaces to a solid. Now it's a shell that I'm configuring the internal components within.

The cyan top and bottom solid models were extruded from the same vector files I used to cut the MDF on the laser. They have a bunch of run-off that will be chopped down.

andrew zen
07-12-2010, 2:25 AM
Create a 3D sketch of your model and then slice it up.

http://sketchup.google.com/


It has a "Slicer" plug-in
http://sketchupdate.blogspot.com/2010/06/slicer3-make-physical-site-models-fast.html


DXF Export

Doug Griffith
07-12-2010, 10:08 AM
Create a 3D sketch of your model and then slice it up.

http://sketchup.google.com/


It has a "Slicer" plug-in
http://sketchupdate.blogspot.com/2010/06/slicer3-make-physical-site-models-fast.html


DXF Export

Not for what I do. I've played around with it and consider it more of a toy. The slicing feature is nice though. Rhino can do that with ArchCut (http://wiki.mcneel.com/labs/archcut). It is a far more powerful program and priced on the low end.

Joe De Medeiros
07-12-2010, 11:23 AM
Lee,

I know there's a system that uses layers of paper/resin and a knife, but I haven't seen one that uses a laser. It's very cheap to operate, at something like $0.10-$0.15 per cubic inch, and about as fast to operate as other non-laser-based layering systems.

When I worked at ford we had one that worked like this (3d stereo lithography)

http://upload.wikimedia.org/wikipedia/commons/1/1e/Stereolithography_apparatus.jpg