The Praxis Proprietary Process
Some of the biggest things we do are very, very small. Praxis can produce parts as thin as .04” and as thick as 0.5” with weights ranging from .02g to 150g. Our titanium injection molding process densifies parts to +99.5%.
TiMIM uses less material. Parts manufactured via Titanium Metal Injection Molding use nearly 100% of the metal powder, better material utilization translates to more cost savings. In many cases, components are net shape eliminating the need for any secondary operations.
Lower production expense. TiMIM is 20-50% more cost effective than other manufacturing processes like CNC machining, casting and additive manufacturing. With ideal volumes ranging from 10,000 to 10,000,000, the higher the volumes, the greater the savings.
Intricate features. TiMIM allows the freedom to design smaller, elaborate parts. Desired features such as ribs, bosses, grooves and threads are just the beginning of possibilities.
Secondary Possibilities. Praxis’ TiMIM parts behave identically to titanium conventionally manufactured and are compatible with all secondary operations such as CNC machining, surface finishing, passivation and anodizing.
Superior Materials. Our Ti-6Al-4V, Grade 5 material complies with the chemistry and mechanical property requirements of many ASTM specifications. Other titanium grades are available.
Consistency. With a validated TiMIM process and over 10 years of experience in powder metallurgy, Praxis provides TiMIM components that are extremely consistent in density, strength and dimension. Less variability means to lower costs and lower lead times.
The Metal Injection Molding Process
1. Feedstock Formation
Fine titanium powder and thermoplastic binders are combined at precise levels. The materials are mixed together and heated up to allow the metal powders to disperse within the melted binders. The mixture is then pelletized to form a feedstock suitable for injection molding.
Metal injection molding, like plastic injection molding, uses a conventional injection molding machine to form a molded part. In the case of MIM, feedstock is fed from a hopper into a heated barrel where the feedstock is melted however, only the binders are melted. Once the feedstock is molten, it is injected into a mold to form the desired geometry. Once the part is cool, the part is ejected and ready for debinding. At this point, the molded part is referred to as a “green part.”
The debinding process removes only a portion of the binder components. The remaining binder will stay to hold the part together during the first part of sintering. Debinding can be carried out in multiple ways, the most common routes are solvent extraction or catalytic decomposition.
4. Sintering / Thermal Processing
Debound parts are placed on ceramic setters and loaded into a furnace for high-temperature processing. During the early stage of sintering, the remaining binder is thermally decomposed. After this initial stage, the parts are heated to a high temperature where densification occurs, resulting is significant shrinkage of up to 20%.
5. Resulting Solid Component
The resulting solid component is nearly 100% dense and identical in chemistry to conventional titanium.
6. HIP’ing / Secondary Operations
To achieve full density, the component may be hot isostatically pressed (HIP’d). Secondary finishing options such as CNC machining, anodizing, passivation, surface finishing, and laser marking are also possible.