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To: null and void

Not to be Johnny-rain-cloud, but it sound like “production” is over-optimisticly jammed in here.

I can see how it could be cheaper and faster than sand-casting for development prototypes, but I wouldn’t believe it for production runs.

The interesting thing, to me, would be the ability to make designs possible with no other process. Whole new concepts could be enabled that would make the slowness and expense worthwhile.


7 posted on 01/07/2013 10:44:19 AM PST by Empire_of_Liberty
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To: Empire_of_Liberty
Not to be Johnny-rain-cloud, but it sound like “production” is over-optimisticly jammed in here.

I think so too, but maybe not?

I can see how it could be cheaper and faster than sand-casting for development prototypes, but I wouldn’t believe it for production runs.

Me neither. Daimler should know what they are doing, shouldn't they? Shouldn't they?

The interesting thing, to me, would be the ability to make designs possible with no other process. Whole new concepts could be enabled that would make the slowness and expense worthwhile.

There are some parts you simply can't build any other way. I've held in my warm moist palm a chess-piece, a rook, with a full internal spiral staircase. You simply can't make a mold that goes around all those corners and curves, nor could any CNC machine work the internal surfaces.

9 posted on 01/07/2013 11:31:55 AM PST by null and void (The world is full of Maple Streets.)
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To: Empire_of_Liberty
I can see how it could be cheaper and faster than sand-casting for development prototypes, but I wouldn’t believe it for production runs.

The company I retired from used 3-D printing to produce temporary tooling for prototype castings. As testing revealed needed "tweaks" the changes were incorporated into the model and new match plates made for the jolt/squeeze machine. New core boxes were also made using 3-D models. Turnaround time was under a week, sometimes less depending on the nature of the change.

The actual model process was very rapid as instead of fusing plastic or PM, our machine used paper with a thermoset glue on one side. The paper handling system was a simple heated roller that advanced and retracted over a platen that used a ball screw to drop 0.005" with each pass. An X/Y gantry mounted laser would sketch the outline of the current cross section and then cross hatch the area outside the model shape into 0.25" squares. Every 50 layers the laser the laser would scan the entire "to be removed" material, creating 0.25" cubes. When finished the model looked like a big cube made up of 0.25" cubes. To release the "hidden" model you just rubbed the big cube and the little cubes fell away.

The resultant "paper" models were hard and dense as oak and could be used directly for patterns to produce about 100 castings before significant wear. When the development phase was over we only had to recalculate the up to date last version "math model" using a double shrink allowance to produce a pattern for our metal production tooling.

I suppose that you could skip the "paper model" and directly carve out a wood pattern with a multi-axis CNC mill and the time would be pretty close but the cost of our printer was way below a CNC mill.

Regards,
GtG

PS The speed increase mentioned is due to the media used to form the model. Defining a volume with paper means that you only draw the outline. When using plastic or PM you have to scan every bit of the area enclosed by the cross section in order to fuse the media into a solid layer.

11 posted on 01/07/2013 2:08:20 PM PST by Gandalf_The_Gray (I live in my own little world, I like it 'cuz they know me here.)
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