Engel partners with Liquidmetal; alternative to metal moulding

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 elasticity of steel is 0.2% and for titanium it is 1%, while the value for components made of Liquidmetal alloys is 2%. In addition, the materials are characterised by their low specific weight and excellent corrosion resistance. This range of characteristics predestines the alloys for use in precision components which are subjected to high mechanical stresses.

In order to process these materials using injection moulding, Austrian machine maker Engel has developed a new injection moulding machine based on its 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 conditions. Instead of a screw, the machine has a piston with which the molten metal alloy is injected 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 characteristics. Standard robots – for example from the Engel’s 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.

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 example by milling, drilling, grinding and turning. In this way, complex three-dimensional precision 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. Furthermore, 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 efficient and economical ready-to-install precision components with a very high surface finish quality. The cycle times lie between 2-3 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.

Engel says it sees good potential for Liquidmetal Technology in the field of medical technology, which is why at the recent Engel Symposium parts for medical forceps were 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 while Engel delivers injection moulding solutions to licensed partners. A Liquidmetal machine is also available at the technology centre at Engel headquarters in Schwertberg, Austria.

(IMA)

  Home | Terms & Conditions | Privacy Policy | Contact | Webmail | Site Map  

Copyright (c) 2015 www.injectionmouldingasia.com. All rights reserved