Although grinding is one of the oldest manufacturing processes in the world, for a long time it lagged behind other machining processes in terms of attention. This situation is now changing.

From finishing to high performance machining

Grinding has often been described as a nice finishing operation. This perception may stem from the fact that most people are familiar with sandpaper or hardware store angle grinders, while far fewer have experience with advanced five axis high tech grinding machines. It is therefore understandable that awareness of the capabilities of modern grinding technology is not yet widespread.

Modern grinding processes achieve high material removal rates, comparable machining times and significantly lower tool costs. Even more compelling is the fact that complex workpieces can be manufactured completely on a single machine. A particularly insightful example can be found in the tools of extrusion lines.

Extrusion technology as a demanding field for grinding

Extrusion is a highly complex process. The extruder continuously presses viscous material through a shaping opening. This principle can be explained using Play Doh. The material is pressed through a mold and different shapes emerge depending on the attachment.

Products produced via extrusion include chewing gum, hoses, foils, door seals, V belts, toothed belts, pencils, noodles, peanut flips, ceramic products, bicycle rims, meat substitutes, PVC, breakfast cereals, millet snacks, onion rings, garbage cans and pastries. The list can be expanded considerably.

Mixing and shear parts for melt homogeneity

Mixing parts increase thermal and mechanical homogeneity by repeatedly splitting and recombining the melt. Flow dividing elements ensure uniform distribution.

Common mixing geometries include:
Pins in the screw channel
Pineapple mixing section
Ring with bore

Shear parts increase homogeneity by applying controlled shear loads. Common shear geometries include:
Cylindrical shear part
Helical shear part
Maddock shear part
Troester shear part

The screw tip is also essential. As part of the non return valve RSP, it prevents melt from flowing back during injection. These components are subjected to extreme loads and therefore require demanding materials and alloys.

High performance plasticizing technology: Geometry and materials

Extruder shafts involve diverse geometries, demanding materials and high quality material designs, often in large lengths. These factors make them ideal candidates for complete machining on high tech grinding machines of the Multigrind series.

Traditionally, such workpieces are manufactured on several machines such as lathes, milling machines, whirling machines and polishing machines. This results in longer setup and machining times.

High tech grinding machines from the Multigrind series enable production in a single clamping. This reduces working time, setup effort and workpiece costs. Various turnkey solutions demonstrate the potential of Multigrind hardware and software for machining turbine components made of Inconel, optical components made of sapphire glass, precision tools made of carbide and prostheses made of special alloys.