Injection Moulding of Metal Alloys – liquidmetal
ENGEL exclusive machine partner of Liquid-metal Technologies / Injection moulding of metal alloys – efficient and with maximum finish quality
With Liquidmetal, ENGEL opens the door to completely new classes of material and product characteristics; metal alloys can now be efficiently injection moulded.
As the exclusive machine manufacturing partner of Liquid-metal Technologies from Rancho Santa Margarita, California, USA, ENGEL is the only provider worldwide to offer system solutions for the injection moulding of Liquidmetal materials. The machine manufacturer will present this technology to the public at the ENGEL Symposium 2015 from June 16th to 18th in St. Val-entin and Linz, Austria, for the first time.
Components with completely new characteristics
Liquidmetal stands for a class of material with completely new characteristics. The zirconium alloys feature an amorphous, i.e. non-crystalline, structure, which is why they are referred to as metallic glasses. Components made from these materials are extremely hard, but at the same time very elastic, which leads to very good recovery behaviour. For example, the elas-ticity of steel is 0.2 percent and for titanium it is 1 percent, while the value for components made of Liquidmetal alloys is 2 percent. In addition, the materials are characterised by their low specific weight and excellent corrosion resistance. This range of characteristics predes-tines the alloys for use in precision components which are subjected to high mechanical stresses.
New machine technology with standard robotics
In order to process these materials using injection moulding, ENGEL has developed a new injection moulding machine based on the tried and tested all-electric machine series ENGEL e-motion. The difference between a Liquidmetal machine and a conventional injection moulding machine for plastics processing lies mainly in the injection unit. The Liquidmetal alloys are available in the form of slugs cut from round rods. These blanks are automatically fed into a melting chamber where the material is melted inductively under high vacuum condi-tions. Instead of a screw, the machine has a piston with which the molten metal alloy is in-jected into a thermo-regulated mould. Very rapid cooling under exclusion of oxygen leads to the forming of the amorphous structure, which is responsible for the outstanding characteris-tics. Standard robots – for example from the ENGEL viper series – are used to remove the finished parts. The sprue can for example be removed with the help of a water-jet cutting machine or mechanical shears.
Ready-for-use parts in a single step
With Liquidmetal, ENGEL is presenting an alternative to metal injection moulding (MIM) and CNC processing, which provide ready-to-use parts with a very high surface quality in a single step and in short cycles.
In CNC-processing, individual metal components are machined out of a metal block, for ex-ample by milling, drilling, grinding and turning. In this way, complex three-dimensional preci-sion parts with a high-quality surface finish can be produced. In comparison to injection moulding, however, this is a very time- and cost-intensive fabrication process.
The MIM process is also an injection moulding procedure, however, the materials processed are not metal alloys, but rather metal/plastic powders. The plastic is removed thermally after injection moulding and the finished component is obtained by a sintering process. Further-more, the surface is often rough from the sintering process and may require reworking. These additional process steps may take up a lot of time depending on wall thickness.
All these disadvantages are eliminated by the Liquidmetal technology. It provides highly effi-cient and economical ready-to-install precision components with a very high surface finish quality. The cycle times lie between two and three minutes and are thus significantly shorter than the processing time needed for CNC processing. Another advantage is that there is no waste accumulated in Liquidmetal processing because the sprues can be recycled.
From medical technology to aerospace
ENGEL sees good potential for Liquidmetal Technology in the field of medical technology, which is why at the ENGEL Symposium parts for medical forceps will be produced from a Liquidmetal alloy. Endoprostheses like hip joints or stents are also conceivable. Thanks to the excellent mechanical properties of the material, very robust components can also be achieved with very low wall thickness. Furthermore, there is a broad range of application in the fields of electronics, aerospace, military technology and sports equipment. It has already found a first area of application in the entertainment electronics and watch industries.
The licenses for the new method are obtained from Liquidmetal Technologies. ENGEL delivers injection moulding solutions to licensed partners. For individual presentations and initial sampling a Liquidmetal machine is available at the technology centre at ENGEL headquarters in Schwertberg, Austria.
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