52 in 52 – Week Thirteen Preview

Posted: March 29, 2010 in 52 in 52 for 2010
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This is a teaser for what’s in store for this week. This design is an exploration of the use of 3D printer work for creating form and providing structure in plastic. The first components (black) took over 30 hours to print, with the second set (red) half way through its 36 hour process time. While this sounds silly, the machine runs unattended –  all that is involved is designing the parts and letting it run, through the night and all day, so the hours are continuous, not restricted to working days. Part of the reason for the extreme build time is that the product is almost solid plastic,with only the voids needed to run wires and contain electronics. This drives the cost of material up to around $400. Sounds nuts, but this design is a research project to see just how far this can be taken. Besides the physical time it would take to create similar forms, using carved wood for example, would be impossible to consider. CNC machining from billet aluminum, wood or plastic could be used, but the process time would not be a great deal different, plus material cost, not to mention the pile of scrap created. CNC machining centers also cost many times that of the 3D printer and requires considerably more space – and cannot run unattended, so the point is moot. If I were to attempt to duplicate the design employing a shell design using welded or soldered materials, I would need to change the shape and invest so many hours in fab and finishing, that the $400 material cost seems outright cheap in comparison, not to mention the time required, all on my clock, since I don’t run 24/7.

In the fixture head created in week 12, the material cost was just $21, and the FDM (fused deposition modeling) process time only 6 hours total. For a one-off design and/or short run, this is certainly reasonable and an indication of what a smaller hollow shell involves.

The video here shows the machine at work, for those who have not seen one. This particular machine is a Dimension 1200es, which can build a volume of 10″ x 10″ x 12″H. What it does is lay down layers of .010″ of plastic by extruding it in a thin line tracing the form. It lays down both model material (in your choice of color for the part), and support material to allow it to create negative space and overhangs. The internal structure of the parts can be solid, semi-solid (small air spaces) or a semi-open structure of webbing to hold the part together. The material is ABS, and can be easily sanded and painted, as well as glued, and is available for this machine can be had in red, black, blue, yellow, green, white, ivory, and gray.

This is one of the coolest tools around – for product people anyway. It can be used to make working prototypes, finished parts, or for forms to be used with other processes, like sand casting, fiberglass layout or vacuum forming.

Since installing it on Friday, I’ve had it running continuously. The printer que, with parts for my projects and customer projects, extends will into the weekend. Along that time, I will have entered more work for it, meaning it is unlikely to see any idle time in the near future. The result is like having a production person making parts while I do other things.

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