Design for Manufacturing
Up until the advent of the computer, all fabrication depended on skilled machinists guiding tools such as drill presses, lathes, routers and mills. When microcircuits became available at a reasonable price, these types of machine operations were automated. The result was that parts could be fabricated quicker, at higher quality and at lower cost.
In broad terms there are two types of manufacturing: subtractive and additive. Subtractive manufacturing implies starting with a block of solid material and removing any unnecessary bits and pieces until only the desired object remains. Drills, lathes and mills remove material. Additive manufacturing works just the opposite. An example of this process is a mold which is filled with a liquid substance that hardens and becomes the desired end item. It is not uncommon to use both processes to achieve a desired result. Many pieces of hardware are made by molding an item (additive manufacturing) as the first step and then performing a machining operation (subtractive manufacturing) to refine the object into the final shape.
Typical Milling Machine
One of the more interesting additive manufacturing processes that is becoming more common is 3D printing. Although often more expensive than traditional techniques, 3D printing opened up an entire new range of possibilities. Objects that were difficult to manufacture with traditional processes became easier to produce. And pre-production prototypes could be made without having to invest in the expensive tooling needed for high rate production.
Typical 3D Printer
When a product is being developed it is important to design it so it can be manufactured economically. These design rules vary depending on the material being used and the processes used to shape the material.
A good designer understands the merits of different manufacturing processes and makes the customer aware of the alternatives for his product. A proper CAD model incorporates the constraints of the selected manufacturing process. And, as required, a responsible designer will work with a manufacturer to achieve a product that meets the desires of both the client and the end user.
Everything from the thickness of the material to the slope of a profile and the fillet at a corner must be consistent with the selected manufacturing process
