Machining Porous Calcium Polyphosphate Implants for Tissue Engineering Applications

The emergence of biodegradable bone substitute materials promises new breakthroughs in the field of tissue engineering. However, such materials like Hydroxyapatite and Calcium Polyphosphate (CPP) are relatively new in the world of manufacturing. Reliable processing data is required in order optimize the production of biomedical implants made from these materials. This paper investigates the machining characteristics of CPP.Milling studies are conducted to determine the suitable cutting speeds and conditions which produce accurately machined porous surfaces. This is required for the CPP material to fulfill its biomedical function. A force model is also developed by identifying the cutting coefficients, which helps to predict and limit the machining forces, thereby avoiding unwanted chipping of the implant. Results of these studies have been successfully incorporated into planning the 5-axis machining of a CPP construct for a tissue engineered tibial-plateu (lower knee joint) implant.