Re: 3D printing (Was: New early P&R steel.....)

Tom Madden

I worked for a 3D printing company from 1995 through 2016 and will back up Ryan's comments 100%. I'll also stress the point that parts that have to match or fit together have to be printed together, and in the same orientation. That's also true for resin casting because there is typically some small dimensional variation from batch to batch. 

These jet printers are touchy machines if you want the best surface quality, and the material is very expensive. I had access to two Stratasys Polyjet printers, a large Connex and a smaller, earlier model. For HO Pullman sides I had much better luck with the smaller machine, but only because the production folks would let me sneak in one "test" run right after a full nozzle alignment and purge sequence. After that first run the machine was fine for production printing for quite a while, but that first run gave the best prints.

I share Ryan's puzzlement about why anyone would use Shapeways' Fine Detail Plastic for production parts unless there was absolutely no alternative - i.e. very small and complex parts, figurines, etc. The material is expensive, has poor structural qualities, is dimensionally unstable and brittle, will cold flow if unsupported, and despite Shapeways' claim that it's "heatproof to 132 degrees F", it certainly softens at a considerably lower temperature. 

Shapeways works for me because I work with what they _can_ do, not with what I think they should do. And except for very small appearance items like the little pump and brake cylinder I showed earlier, everything they print for me is intended to be a resin casting master. All my jobs are also "print it anyway" so they bypass Shapeways' design audits and go directly to the printers. That means I get my parts faster but there are no free reruns if the print is unsatisfactory. Also I can't offer print it anyway parts to others, but that's OK because I don't trust the Fine Detail Plastic material enough to be comfortable selling such parts to others.

Tom Madden

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