Machining PPSU MG

PPSU (polyphenylsulfone) is an amorphous high-performance plastic from the polysulfone family, alongside PSU and PES. It combines very high toughness and impact strength – even at low temperatures – with excellent resistance to repeated steam sterilisation and a heat deflection temperature of around 205 °C. The glass transition temperature is around 220 °C, with a continuous service temperature of up to 180 °C. In the MG (medical grade) version, the material is specifically qualified for medical technology applications and tested on the semi-finished product for cytotoxicity according to ISO 10993-5. Liedtke offers PPSU MG in several colour variants; the base version is black.

PPSU MG can be machined well with conventional machine tools – milling, turning and drilling are unproblematic. Before machining, the semi-finished product should be at room temperature and/or stored for at least 24 hours under normal ambient conditions so that internal stresses in the material are relieved. Finished parts can then be subjected to standard reprocessing cycles used in medical technology, such as steam sterilisation in an autoclave – though the specific approval for a given component always remains the responsibility of the manufacturer of the finished medical device.

PPSU MG is a good fit when several of these requirements come together: reusable medical devices that must withstand numerous steam sterilisation cycles, high requirements for toughness and impact strength even at low temperatures, heat deflection temperature up to around 205 °C, a material tested on the semi-finished product according to ISO 10993-5, and resistance against high-energy radiation (gamma, x-ray) for trial implants or sterilisation containers.

Because of its medical qualification and demanding formulation, PPSU MG sits in the upper price segment of technical plastics – clearly above standard materials such as PC or POM. The part price is mainly determined by stock form and dimension, material utilisation (waste), machining effort and batch size. We are happy to quote binding prices on request based on your drawing.

PPSU MG is not always the most economical or technically suitable solution: at lower temperature and sterilisation requirements, cheaper engineering plastics are often sufficient. Resistance to some aromatic and chlorinated hydrocarbons and polar solvents is limited. The material is not intended for permanent placement in the body – contact with internal tissue or blood for more than 24 hours. Where transparency is required, the black coloured version is unsuitable; a natural or light PPSU variant is better suited for that.

An honest assessment: Advantages: very high toughness and impact strength even at low temperatures, high resistance to repeated steam sterilisation, high heat deflection temperature up to around 205 °C, tested on the semi-finished product according to ISO 10993-5, good resistance against high-energy radiation, chemical resistant against many disinfectants and cleaning agents. Disadvantages: higher material cost than standard and many engineering plastics, limited resistance to some aromatic and chlorinated hydrocarbons and polar solvents, not intended for permanent body contact, no transparency in coloured versions such as black.