Our shop has been working on a project that involves extensive use of 3D mechanical drawings. The scale model, an asphalt plant, will be 7 feet tall when completed. The size and structure of the scale model requires it to support its own weight and traditional model making materials would not be appropriate. Sheet metal will be used instead, and the parts need to be sent out of the shop to be laser cut and bent.
Model makers typically design a project as they build it, problem solving, adjusting and refining their techniques as they go. As craftspeople, they can transform a rough idea into something both accurate in design and beautiful to behold. The sheet metal parts are being sent to a laser cutter unfamiliar with the project’s nuances, so more precise, documented dimensions are needed.
Using a program called Autodesk Inventor, our model makers have drawn up the sheet metal parts on the computer to be sent to the laser cutter. Then the parts will be bent next door at Clad Industries. The finished pieces will arrive back to the model shop for assembly and detailing. Check back for pictures of the finished scale model!
The Patriot MIM-104 is a surface-to-air missile (SAM) system used by the United States Army and many other nations. The prime contractor for this system is Raytheon. You can read more about this system here.
This scale model was built mostly from scratch with one exception. The cab and chassis are a die-cast model that we used as a starting point for the truck in the pictures. When a high-quality mass-produced model is available in the proper size, we will often use it as a starting point for out model. Not only does this save a lot of time, a mass-produced kit often has small, high-detail parts included that would be cost-prohibitive for our customers. When a model is mass-produced (in the 10,000s or 100,000s) the small details can be injection molded. The injection molding process has high up-front capital costs but low per-piece costs for large runs.
Model Highlights
The tires were designed in CAD and then output to our in-house rapid prototyping machine. They were then molded in RTV silicone and cast with urethane resin.
We used 3D CAD geometry supplied by our customer to design and fabricate this model.
More than 50% of the parts on this model were drawn in CAD and output to our 36″x24″ laser cutter/engraver. We use this not only to cut the shapes we need in various plastics, but also to add details by engraving the surface.
Small parts, including the hand rails and round rods are made of brass and are often brazed or soldered for strength.
Structural parts of this model such as the trailer chassis are made from brass to create a strong base for the rest of the details.
