In 2014, we have a huge demand for prototypes in metal materials. There are different methods that can be utilized in order to achieve this goal. Factors to consider when deciding on the best method for your application include: cost, speed, design limitations, and resource considerations such as, labor and facility requirements.
In general, prototyping with metal materials drives the price up. On one side, you have the classic CNC (Computer Numerical Control) machining method for milling blocks of metal into your desired shape, also called subtractive manufacturing. There are different types of machining processes that can be used and combined to create your desired effect. The CNC method holds a moderate position on the cost curve for metal prototyping. You have a flexible range of materials to choose from. Some of the downsides to the CNC method are that it requires a significant amount of time in preparation and production. Machine purchase cost is quite high and depending on which machine you have, you may be limited in what you can produce. A skilled laborer is required to program and operate the machines. Because of the mechanical process limitations, certain geometries can be a challenge or even be impossible to create using CNC Machining methods for manufacturing.
On the additive manufacturing side, we have a couple of different options for working with metals. In the interest of time, I will discuss one process. If you would like more information about this process or any others, feel free to contact me. One example of additive manufacturing with metals is a process that ASTM has coined Powder Bed Fusion. Powder Bed Fusion consists of a bed of powdered metal that is fused together layer by layer in the shape of your design by an energy source. As with any additive metal process, the cost is high. You are either paying a lot for a machine in house, or you are paying someone else a lot to make your prototypes on their machines. Material choices are limited due to the process. The environment required for Powder Bed Fusion usually requires a high level of control, for example, a vacuum or inert gas area. Manufacturing speed is quick, enabling you to go from design to part in your hand within hours.
A third option to consider for manufacturing with metals is casting. A general explanation of casting is using a master pattern to create a mold which you then use to create your final metal part. As with each of these processes, there are multiple options. The one I will discuss with you today is called Lost Wax Casting. My favorite way of creating the master pattern is by 3D printing the mold master with a machine using a wax material. The casting is then done with a secondary process. The great thing about this option is that the machines used are more affordable than the others. Imagine metal parts in a matter of hours without having to spend a quarter of a million dollars on equipment. The environment for the wax printer is pretty flexible, requiring only a temperature controlled area. The casting area requires a bit more consideration. However, this process can be outsourced if facilities are limited. Operation of the wax printer can be done with a couple hours of training, as little setup is required.
In summary, if your application requires prototyping metal parts, there are numerous processes to consider. The best process for you is where cost, speed, and design requirements align.