Aitkens Pewter started in 1972 when Martin Aitken, then 17, apprenticed with a well-known pewtersmith Dr. Ivan Crowell and set up his own shop in Fredericton, New Brunswick, Canada. In the early years, the company concentrated on making 2D products using the traditional method of exposing an ultraviolet-sensitive polymer to create the pattern. Around the turn of the century, the company decided to expand into 3D and selected Delcam's ArtCAM software as its primary tool to design patterns and provide CNC programs for pattern building.
ArtCAM has helped us develop a new generation of more realistic, more finely detailed and visually appealing products that have substantially expanded our business,"
...said Pierre-Luc Arseneau, Designer for Aitkens Pewter. The company has grown to the point where it has three studio stores and a thriving online business. Aitkens' store and studio in Fredericton have become a major tourist attraction and, largely due to Aitkens, Fredericton is now known as the pewter capital of Canada.
Aitkens produces a wide range of pewter products including medallions, lapel pins, vases, ornaments, etc. The company introduces new products on a regular basis, many of them with a Canadian flavor, such as spoons, cake servers, cheese knives and cheese planes with various carving motifs such as the maple leaf. Despite the visibility of its retail stores, a substantial portion of the company's revenues comes from custom orders placed by non-profit organizations and businesses. One of the company's biggest sellers is awareness ornaments for fundraising drives, such as a model of a building that will be built or restored with the funds that are to be raised.
Creating 2D Products
Aitkens produces 2D products using traditional methods. The company creates line art and then using a special camera, takes a black and white image. The negative film is then put into an ultraviolet sensitive polymer machine. Ultraviolet light is projected through the film onto a sheet of ultraviolet-sensitive polymer backed with a sheet of steel. The rubber that is exposed to the light hardens while the rest of the rubber remains soft and is washed away with water. The resulting pattern consists of a plate with raised areas that represent the shape of the finished part. The pattern parts are sandwiched in a soft rubber mold and then placed in a vulcanizer that hardens the rubber so it will remain strong and rigid during casting. The mold is used in a spin casting machine that rotates the mold while molten pewter is poured into the mold, ensuring that molten metal thoroughly fills the outer extremities of the mold.
Expanding with 3D Products
Arseneau's predecessor researched various 3D software programs on the market and selected ArtCAM because it enabled quick and efficient creation of manufacturable 3D models from 2D images and artwork. "We have been making 3D products ever since and 3D has in fact grown to make up the lion's share of our business," Arseneau said. He said that the process of designing a new standard or custom 3D product typically begins with 2D artwork such as a photograph or rendering of a building or a simple sketch of a product idea. Arseneau uses a 2D drawing package that he is more familiar with to create the artwork although he adds that ArtCAM also provides strong 2D drawing capabilities.
Arseneau imports the 2D artwork, whether line art or photography, into ArtCAM where his first task is to convert the flat 2D file into an eye-grabbing 3D image. With line art, he typically begins by creating a cross-section of the prospective 3D part. "ArtCAM makes it easy to develop cross-sections by giving me the ability to bounce back and forth between the 2D and the 3D images," Arseneau said.
The next step is extruding the cross-section to begin forming the 3D image. ArtCAM has a wide array of extrusion features. Arseneau frequently uses the two-rail extrude feature by creating two lines that intersect the cross-section and then extruding the cross-section along the path of the two lines. On the other hand, if the initial artwork is a photograph, Arseneau often uses ArtCAM's bitmap to vector feature to automatically convert the photograph to a 2D vector image that he then extrudes to create the 3D image.
Producing realistic building models
In the case of buildings, Aitken Pewter typically requests either a straight-on or a Â¾ view photograph or rendering. For a straight-on view, he converts the photo to vector art and adds details such as windows and bricks, then adds various extrusions to give the image depth. Arseneau takes advantage of the fact that most buildings are symmetrical around a vertical bisecting line by drawing and extruding only half the building and then creating a mirror image. The ¾ view is a more complicated design challenge and the company charges its customers extra for this service. In this case, Arseneau again converts the photograph to vector art and manually draws each detail on the sides of the building using vector art at the correct angle with perspective distortion taken into account.
When Arseneau is happy with the 3D model, he then simulates on the screen the machining operation to create the pattern. "The simulation shows the path of the cutting tool so I don't have to worry about collisions. It also shows the exact geometry of the finished part, including the surface finish, which I then compare to the 3D model," Arseneau said. After correcting any problems, he then generates G-code for one of the company's two Model Master Computer Numerical Control (CNC) machines. He uses both machines to cut out the patterns from high density urethane foam, also known as butter-board. The pattern is then used to produce the mold, which in turn casts the pewter product using the same method described for the 2D approach.
Producing A Leopard Tank
An example of the complex and high-margin products the company has produced with ArtCAM is a model of a Canadian Leopard tank. Arseneau obtained a 3D STL format model of the tank and brought it into ArtCAM. He created vector surfaces to match the external geometry of the tank. Then he separated the model into individual components as needed to enable moving parts on the finished model and to account for limitations of the CNC machines. For example, the turret of the tank is a separate assembly so it can swivel around the base.
The turret consists of eight individual pieces. Arseneau designed the assembly using the ArtCAM project assembly window that allows users to design parts individually and then combine them to see how they fit together and look fully assembled. Later the mold maker, Alan Grey, arranges the eight pieces so they can be produced in a single molding operation, removed from the mold and glued together.
ArtCAM has played a major role in our success by enabling us to design and build complex 3D models that allow us to create new products that fill market demands.
When potential customers come to us with a photograph they would like to duplicate in 3D or when someone in our company has an idea for a complicated product, I am confident I can produce a design that will meet or exceed their expectations."
For more information on Aitkens Pewter please visit their website - http://www.aitkenspewter.com/