To metallic or ceramic components in the molding process, it must be fixed first component material in powder form with a polymer / wax mixed system. These are the following points should be:
• a high Pulverfüllgrad to Schrumpfmaß component tolerance and to reduce
• a small particle size, the sintering process and surface components with good grades,
• a low viscosity for Spritzgießfähigkeit,
• and a high green strength, a defect-free removal of ge-währleisten.
These requirements are for each festival to develop new material.
Over the years, the range of materials in the powder injection processible are very aufgeweitet. Precious metals, copper, steel and titanium alloys are now for the metal powder injection molding are available. On the side of the ceramic materials can now oxide ceramics such as aluminum oxide or zirconium oxide, but also non-oxide ceramics such as boron nitride and silicon processed.
For the first Feedstockaufbereitung by filtering the powder, granulating, grinding, mixing and / or spray drying processed. Here, everyone has his own peculiarities manufacturers to batch tolerance as small as possible to keep. By Seven, stream or wind sifting can be eg Powder with more or less the same size filter out particles. In many cases, responded with bimodal or multimodal powder size distributions worked at a higher filling receive. Due to the different sizes of the powder particles, the spaces between the powder grains are easily filled. The particle sizes of commercially available powder batches according to the manufacturer's specifications are in the range of a few micrometers, but differ in this field.
In the first years of the powder injection molding binders were based on polyolefin wax mixtures. The disadvantage here is the long Entbinderungsschritt because the heat from the wax injection part must be removed. As a further development were teillösliche systems. It can be a part of the Binders by organic solvents are removed. An existing system is the standard Catamold binder system of the company BASF. It is based on the catalytic decomposition of polyoxymethylene (POM) by strong acids. A big advantage of this system is the high strength of the Green abgeformten components.
The mix of Feedstockkomponenten made in small quantities in a kneader and in larger quantities in an extruder. It must be ensured that the powder in the binder system is distributed homogeneously. After this mixing process, the feedstock in the process, either automatically or by using a mill in the form of granules, and it stands for the injection molding available.
Depending on the Mass of filler material is usually 45 to 65 percent by volume. Through the filler will shrink the size of the sintering determined. Increased filling leads to lower sintering shrinkage. Too high proportion of the powder feedstock due to its high viscosity no longer in the molding process.
One can say that all metal and ceramic materials in principle with the corresponding burden to a feedstock can be processed. If you have any questions, talk to us, we will answer your questions or give you an appropriate contact person name.