I think it's important to evaluate on the usefulness of a tool, within the design scope of that tool. Due to the nature of our business (fast turn, low volume, high mix parts, often called "prototypes") we have a variety of tools in our shops, not just one hammer. I have a Mazak mill, a Tsugami lathe (retrofitted to LCNC), a small HF mini mill (also LCNC), a ULS laser cutter/engraver, and a Dimension 1200 FDM 3d printer, amongst other things. I use the 3d printer a LOT. We probably push about $5k in consumables a year through it. It's ABS material, relatively tough, and a good standin for passing quick prorotypes around the table. There are parts that one can draw in CAD and "click print" faster, not having to worry about fixturing, than one can push into CAM, create machining operations, figure out a workholding and tool strategy, monitor the cut, perform secondary operations, and hope you got it right. I do push what are considered the limits of FDM - in fact a lot of my parts are so organic in nature that the 3d printed parts become the actual production parts. An on-demand printed part 6 times a year doesn't justify creating injection mold tooling, and often where weight is an issue, cutting from steel or aluminum billet also isn't appropriate. I've used it to make single piece chain sprockets in a pinch where the needed part just wasn't available off the shelf. It ran for 5 days, which was 4 days longer than it needed to. That said, if the part demands material that isn't compatible with ABS, then 3d printing isn't appropriate. Agreed, you cannot take a micrometer to these parts and expect every feature to measure net zero accuracy. There is a learning curve to each machine on where to redraw a feature over or undersize, and to consider secondary operations. If you want a 0.3210" diameter hole, be prepared to ream it. Even grander however, is the large variety of 3d printing tools out there - I'm still very partial to SLA, but it's still incredibly expensive. (although DLP polymer is becoming reality). I've had the ZCorp "powder printers", but the post-processing is exhausting, messy, and very limited in application. FDM (such as Stratasys and the extruder rep-raps) is a nice middle ground that in many cases, I can produce parts that literally just pop off the tray and go to finishing. If I needed sintering, I sent it out. All two times. What I really like though is that I can use the laser cutter and the 3d printer together to produce workholding fixtures that can hold a part for machining in the mill or on the lathe. The largest distribution of parts that come out of our 3d printer are either custom fixtures or patterns for casting. It is however very true that although the hardware or technology in many units is close to "identical", the software or secondary features either makes or breaks a product. I have an early Darwin (reprap) from handmade parts, that has sat in a corner (probably smushed now) for a long time, because the software didn't keep up with the technology early on and the glitter wore off. Commercial technology came and filled the void. I wouldn't want to compare parts from the reprap to the Dimension - they're $50k apart in capabilities. The current crop of thing-o's with dual extruders will eventually catch up once builders copy the "tricks" that the commercial guys learned only through their own development. Some of those tricks relate to dimensional tolerances (you're adding physical fluid material, in a space that may already have material, as opposed to "machining to zero", so particular decisions have to be made on the order of laying down that material and physical offsets versus cooling time). Some are omissions to simplify a product - the heated enclosed chambers that Stratasys use I feel are an essential part of the process; the open frames of repraps don't allow the deposited filament to anneal slowly and reduce the layer artifacts. You can easily tell a commercial part form a "Hobby" one. But that's common to all fabrication technologies. Even then, 3dp isn't a "Fits all" tool.
Will a singular technology exist on the kitchen counter to make everything you need? Probably not. But then, I've never been one to stir my coffee with a hammer, either. Cheers, Ted. ------------------------------------------------------------------------------ Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
