Injection moulding of micro-parts
With annual growth rates of 20%, microtechnology is regarded as one of the key technologies of the 21st century. Injection moulding has established itself as the favoured technology for making tiny plastic moulded parts.
“Injection moulding of micro-parts” was one of the key topics of the two-day annual meeting on injection moulding technology held by the Association of German Engineers (VDI) in Baden-Baden in February last year, attracting more than 300 participants. The presentations under this heading showed that micro-moulding is a favoured manufacturing process which will play a major role in view of fast-growing demand for miniature polymer components. This in turn will open up new opportunities for plastics processors in a rapidly expanding market.
The “pursuit of tininess”
According to Christine Neuy from the Dortmund-based microtechnology association IVAM who gave a presentation in Baden-Baden on market trends and developments in miniature and micro-applications, miniaturisation and related technologies will have a major bearing on economic growth and jobs in Germany. Neuy, managing director of IVAM, sees the move towards miniaturisation as a mega-trend of growing technological importance. She said microtechnology offers more functions with high precision in minimum space, as well as lower energy consumption. This “pursuit of tininess” was of interest above all for areas such as the automobile, electrical, medical and environmental sectors as well as the entire telecommunications field.
Moulded in tiny dimensions with “X-Melt”: Ultra-small lens holders for laser heads in DVD players.
Miniature lens holders for laser heads are a key component of DVD players. They are manufactured, for example, by the expansion injection moulding process X-Melt, which was honoured with the annual innovation award of the VDI meeting in Baden-Baden. Developed by the Austrian equipment manufacturer Engel, the method cleverly utilises the compressibility of the plastic melt as an energy storage device. In conjunction with Engel’s “E-Motion” injection moulding machine, X-Melt can be used to achieve shot weights of 0.1 to 20 grams and wall thicknesses of between 0.1 and 1.0 mm.
Systematic approach to micro-moulding
Similar shot weights are claimed by the Demag Plastics Group, which has developed its own injection unit for the special requirements of micro-moulding: the so-called Microshot unit with a special screw of 14 mm diameter. The unit is installed on modified standard machines with up to 500 kN clamping force. This combination produces high-quality micro-moulded parts with shot weights of between 0.1 and 0.5 grams. Depending on application, the machines are available with hydraulic or electric drives.
Several “Microsystem 50” manufacturing units are in operation here.
The Microsystem 50, unveiled by Battenfeld at K 1998, was conceived as a complete manufacturing system with electric drive. The still topical concept uses a combination of screw pre-plasticising and piston injection to produce very low-weight components with high precision. A revised version will be on display at K 2007. A new drive for the system’s injection unit was already unveiled at the Fakuma fair in autumn 2005. According to the manufacturer, the dynamics of the injection unit were improved by a factor of three thanks to the development of a new electric cam. At the same time, deceleration and acceleration were enhanced, along with the user-friendliness of the system.
The corresponding machinery in its current version will once again be on display at K 2007. in Düsseldorf from 24 to 31 October 2007.
By: K 2007 Press Dept.