Thanks, everyone!Heavy Melder wrote:
Will the entire catalog be making its way to the new site...or not?
Great question. Short answer: no, only those products whose geometry and size are suitable or whose print times are reasonable. The printer used to create models out of gray resin is best suited to printing objects like turrets and directors and other objects with similar geometry in 1/192 scale and smaller. Nameplates will not be offered in gray resin but will continue to be available in acrylic and metal through Shapeways.
Long answer:
1. Complex geometry. The printers used by Shapeways to create products in acrylic extrude a waxy material that supports overhanging features during printing. Shapeways melts the wax away in a low-temperature oven at the factory. The gray resin printer does not use any wax. Instead, this printer builds physical structural sprues during printing to support the model's overhanging features. Once the model is fully cured, these sprues are no longer needed. They must be cut away by the modeler. The gray resin printer creates products by first building a support tray that looks like a dish. The printer then builds physical sprues upward from the tray that support overhanging features during printing. Some superstructure designs, for example, have very complex shapes with lots of overhanging features. If the geometry is overly complex, too many structural supporting sprues are required to produce it. It would be covered in supports, inside and out. Their presence and their attachment point locations would spoil the appearance of the superstructure.
2. Size. Some existing designs are simply too big to fit in the printer. The model must have a footprint smaller than 14 cm x 14 cm, including the support tray, in order to fit in the printer. For example, most aircraft carrier islands in 1/350 scale will not be offered in the new material. Many designs in larger scales like 16" Iowa class turrets in 1/96 scale will not be offered in gray resin. They're just too big.
3. Reasonable print time. The printer creates a model by using a laser to harden a thin layer of liquid resin. The model is built up layer by layer. This is why 3D-printing is a very precise but excruciatingly slow process. A taller model requires more layers to complete than does a shorter model. Thus, a taller model takes longer to print; hardening more layers requires more time. Even though a design can fit in the printer and has suitable geometry, some tall models simply take too long to print.
For example, a pair of 1/72 scale PT Boat torpedo tubes have very thin walls and are quite weak and flexible until fully cured.* The material is somewhat soft during the printing process (when the process is complete, the model is hard and rigid). The tubes can sag and bulge during printing if not properly supported. Therefore they have to be oriented on end in the printer in order to be properly supported. Placing them on end eliminates sag and bulging or the need for excessive sprues. But the test print for a pair of those tubes took 15 hours to print nearly 4000 layers. Although the tubes easily fit within the printer space and have suitable geometry requiring few sprues, 15 hours is not a reasonable amount of time to commit the printer to create one model when other products (and customers) are waiting.
Hope this explanation makes sense!
* When the model is removed from the printer, it then goes into an alcohol bath to clean away any remaining liquid resin, then it goes into a UV light booth for final curing. Once fully cured, the model is strong and rigid. It is after the UV light booth treatment that the supporting sprues are no longer needed for printing purposes and can be cut away. They are left in place when shipped in order to provide added strength and rigidity during shipping.
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