Arburg recently held an international conference to celebrate 50 years of its expertise in Powder Injection Moulding (PIM). The event saw presentations from worldwide PIM experts report on industry, applications and future prospects for the process. Here, the company looks back over the history of the process since the first ceramic part was produced on an Allrounder 200 S in 1963.
When the first moulded part made from ceramic powder with thermoplastic binder was produced on an Allrounder injection moulding machine 50 years ago, no-one could appreciate the potential contained in this process. Many of the visions of the time have since become reality, including automotive engine valve actuation systems, components for smartphones or grinding discs for coffee machines. Compared to conventional machining processes, the injection moulding of metal and ceramic materials (MIM, CIM) offers a wide range of design possibilities. With powder injection moulding (PIM), complex parts with internal threads, gearings or undercuts can be produced efficiently and cost-effectively in high volumes.
In 1963, the history of PIM processing began at Arburg with the production of the first PIM part on an Allrounder 200 – a geometrically complex pigtail thread guide for the German company, Feldmühle, for the textile industry. Instead of plastic granulate, an injectable moulding material made from ceramic powder and a thermoplastic binder were used. This feedstock was developed in-house by Feldmühle. In the subsequent years, demand for machines suitable for powder injection moulding as well as for the process itself grew continuously.
The processing of powder materials gained further impetus when BASF introduced feedstocks at the end of the 1980s and Hoechst launched a binder system onto the market. Arburg also developed its process in a targeted manner, including with an external consultant who created feedstock recipes for customers, as well as with the creation of in-house PIM laboratory. Together with the binder supplier, customer-specific feedstocks were developed and the injection units were adapted to the increased PIM requirements.
Upstream and downstream production steps such as material preparation, debinding, sintering and part analyses still take place today in the modern, in-house PIM laboratory. The equipment includes a shear roller extruder, debinding systems, sintering ovens and a device for simultaneous thermal analysis. Consequently, all production steps can be tested under practical conditions.
The product range, which is produced on Allrounders, extends from micro gear wheels with an external diameter of 1.4 millimetres to ceramic cores for stationary gas turbines weighing up to two kilograms. In 1992, the first two-component PIM part was a hard-metal milling cutter with an internal thread made from materials with a cobalt content of six and twelve percent.
Today, PIM parts can be found in many everyday items, including watches, spectacles, smartphones, lamps and orthodontic braces. One significant advantage of the PIM process is its suitability for high-volume production. For example, intermediate levers for an automotive valve actuation system for engines in unit volumes of five million per year are produced on Allrounders.