RESEARCH

ecoMold: Economic concept to produce moulds for the plastic injection moulding and the pressure die-casting

EcoMold is a project funded by the European Commission in the frame of the
5th framework programme ''Co-operative Research''

Project No:   CRAF-1999-70424
Contract No:  G1ST-CT2001-50096
Start at:   01-08-2001
End at:   01-08-2003
Duration:   24 months

Objectives

The object of the research is to enhance the applications of RP-processes, Lasersintering (SLS) and Lasergenerating (LG), to larger (prototype) tools. The target is to develop a process that will offer the possibility to build moulds in one third of the time, at 50 to 75 % of the costs, compared with conventional tooling. Therefore, the consequent use of CAD modelling together with simultaneous engineering (SE) project management would be also necessary.

Background

Industries must respond to the demands of markets worldwide for shorter product cycles and higher product quality. A fundamental objective for industries is to reduce time-to-market. Rapid prototyping (RP) technologies are now established in the early stage of the development process to verify the design, improve the communication within the company and help to accelerate the development. The properties of the parts produced by these common RP-technologies differ especially in the mechanical behaviour from the serial parts. For this account they cannot be used to make tests under realistic conditions. The properties of plastic injection moulded or pressure die casted parts depend strongly on the parameters of the production process. Therefore it is necessary to make moulds, which are used in the serial production process to manufacture these technical prototypes. The production of the moulds with conventional technologies is very time and cost intensive. To overcome this bottleneck it has been tried to develop the RP-processes Selective Lasersintering (SLS) and Lasergenerating (LG) of metal powders to produce more quickly moulds. A significant drawback of these processes is the low building rates of the actual available systems. Large parts with a high volume could not be produced economically. The range of reasonable applications is for these reasons limited to small, complicated parts. But also for medium and bigger sized parts there is a strong demand for quickly delivered technical prototype series.

Scientific aims

The approach is based on the lasersintering and lasergenerating of metallic powders, which is used to make prototype tools for the injection moulding and pressure die-casting. The technology is embedded in simultaneous engineering project management concepts, while competes with conventional technologies like milling and electrical discharge machining (EDM). It has been shown that such technologies are working well for small, complicated parts. Within this research project the field of applications of the lasersintering and lasergenerating shall be enhanced to medium sized moulds. The idea is to divide a mould into different modules, which are then built separately. Each module consists of a base geometry and a shape geometry. The base geometries are pre-manufactured milled standard elements, which are fit automatically into the geometry of the mould. The shape geometry is generated via lasersintering or lasergenerating onto the standard element. After finishing the different modules, they are assembled to the complete mould insert. This method saves time for the RP-process and reduces residual stresses in the part because the generated volume is small. The combination of milled elements and lasersintering resp. lasergenerating allows the fast production of larger (prototype) moulds at estimated one third of the time and 50 to 75 % of the costs compared to conventional tooling. The main focus in this project is put on the lasersintering RP-process, because it is the advanced developed technique. However, the modular approach will be also tested with the lasergenerating combined with a novel 3D positioning system.

Partnership:

IFAM (Fraunhofer-Institut für Fertigungstechnik und Angewandte Materialforschung)
Cybamatic ltd.
Legazpi Moldes Lda
Modelltechnik GmbH
Polyline SA