What is PEP technology?
Our self-developed Powder Extrusion Printing (PEP) technology is inspired from traditional Metal Injection Molding (MIM) procedure and advanced 3D printing technology. MIM technology has been widely applied in industrial manufacturing since the late 1980s owing to its high productivity and well-understood debinding and sintering process, however, for every single metal part design, it requires one corresponding mold which requires a long lead time and a high start-up cost. On the contrary, 3D printing technology is free of using any mold so that green part can be formed layer by layer continuously within couple of hours. Once printed out, green part is ready for debinding and sintering which afterwards is similar to MIM process.
By combining MIM with 3D printing together effectively, our PEP technology can provide an innovated way for manufacturing metal parts in different applications, such as product design and development, tooling and industrial manufacturing, automotive and aerospace, etc.
STEP ONE: 3D Printing to Green Part
Based on our PEP technology, metal pellets are extruded and deposited layer by layer via 3D printer. From layer to layer, green part is printed out as whatever you design. 3D printing is typically applicable for prototype testing, complex geometry and/or low volume production. Typically, for our self-developed Uprise 3D printer, a variety of materials from metals to ceramics can be selected and printing performance is guaranteed to be stable and accurate.
After printing, the green part is then sent to debinding and sintering process.
STEP TWO: Debinding to Brown Part
The function of debinder is to remove most of the binder polymers from as-printed green part. The debinding process is relatively simple by immersing green parts into a proper debinding fluid for a certain period of time. Debinding equipment includes water debinding, solvent debinding and catalytic debinding. Typically, our debinder is designed to be more environmental friendly and much safer by using mild oxalic acid rather than nitric acid. Also, our debinder is available for batch processing and simply operation.
Once the binder polymers has been removed, the part is referred to as brown part and is ready to be densified into a fully metallic part via sintering.
STEP THREE: Sintering to Metal Part
In order to obtain final metal parts, sintering process is compulsory and critical. The sintering condition needs to be under vacuum atmosphere and high heating temperature. The furnace features for batch processing with high performance and simply operation. Through sintering, remaining binder polymers are the first to be removed at moderate heating temperature. As the temperature increases above the melting point of metal particles, these particles start to fuse and grow to densify reaching almost 98%. It is important to note that shrinkage will occur due to both the removal of binder polymers and the growth of metal particles during the sintering process, but the shrinkage ratio is constant. Metal part will be scaled up to compensate for shrinkage at 3D modeling step.
The as-sintered metal parts possesses good mechanical properties and is ready for variety of industrial use and applications.
STEP FOUR: Post-Processing (Optional)
As-sintered metal part is fully dense which are ready for use. But still, further post-processing method such as polishing and coating can be applied whenever requiring a better appearance. Typically, CNC milling is commonly applied for better accuracy. All these methods are well-rounded and the cost are affordable.