【K 2019】Thermoplastic Components Over-Moulded with Polyurethane
Abstract:
【K 2019】Thermoplastic Components Over-Moulded with Polyurethane
A Smart Engineering Solution from Yizumi
Combination Technology Injection Moulding and PU Over-Moulding
Injection moulding stands for the economical production of components in large quantities. Complex multi-component parts with high-quality surfaces can be produced in a separate production process using an injection moulding process with subsequent post-treatment. For economic reasons such processes are becoming less preferable.
High-Quality Surfaces with Short Cycle Times
Today, product surfaces have wide variety of requirements. These requirements can often no longer be met by simple injection moulding processes. Coated plastic components offer an economical and efficient solution. A thin layer with the intended optical and haptic properties is applied to a carrier material. Surface finishing is integrated directly into the process. Complex post-processing steps, such as painting or separate coating, are no longer necessary. The result is the production of a finished component in a single production step. This results in numerous advantages:
Highly efficient solution for the production of complex multi-component parts.
Combination of thermoplastic injection moulding with a high quality polyurethane surface.
Single step production.
Short cycle time.
High design freedom.
No overspray → Reduced material costs and increased environmental protection.
Economically attractive.
Global Competence
The complex combination technology of injection moulding and PU over-moulding requires expertise in various areas. In addition to the injection moulding machine and the polyurethane system, mould technology and material selec- tion also play a decisive role. In order to guarantee a high-quality product, all areas must be perfectly coordinated. A network of competent partners enables smooth process integration. Yizumi is a global company located in China whose core competences include injection moulding.
Frimo offers highly specialized solutions that are used in numerous areas. Under the brand name ReactPro Yizumi and Frimo develop systems for the combination technology of injection moulding and polyurethane over-moulding.
Intelligent Mould Concept
Mould technology plays a major role in the combination technology of injection moulding and polyurethane over- moulding. Yizumi relies on its long-standing partner GK Concept, who has 20 years of experience in product and component development, and 40 years of experience in mould making and process development.
Figure 1 shows a conventional mould technology for the combination technology of injection moulding and polyurethane over-moulding. First, a thermoplastic carrier is injected. A swivel unit brings the carrier into the polyurethane mould. In the next cycle, the carrier is over moulded with polyurethane, while a new carrier is simultaneously produced in the thermoplastic mould. The processing times of the thermoplastic carrier and the polyurethane coating are correlated.
moulding. Polyurethane systems operate at relatively low pressures compared to the injection moulding process. This
results in comparably low clamping forces. The InPUR mould concept uses two polyurethane moulds and one thermo-
Narrow mould design → low day light → small machine.
No need for complex machine technology.
Two polyurethane moulds allow for application with PU materials with long reaction times.
Economical solution.
Figure 1: Conventional mould technology for PU over-moulding
1 . Thermoplastic is injected into the right cavity.
2 . The swivel unit rotates. The thermoplastic carrier is now in the left cavity (PU cavity).
3 . Thermoplastic is injected into the right cavity. At the same time, the thermoplastic carrier is over-moulded with PU in the left cavity.
4 .The finished part is removed from the left cavity. Thereafter the swivel unit rotates. The thermoplastic carrier is then in the PU cavity.
Figure 2:InPUR
1 . Thermoplastic is injected into the thermoplastic cavity.
2 . The thermoplastic carrier is transferred to the cav- ity PU1.
3 . Thermoplastic is injected into the thermoplastic cavity. At the same time the thermoplastic carrier is over-moulded with PU in the cavity PU1.
4 . Mould PU1 remains closed. The thermoplastic car-rier is transferred to the cavity PU2.
5 . Thermoplastic is injected into the thermoplastic cavity. At the same time the thermoplastic carrier is over-moulded with PU in the cavity PU2.
6 . Mould PU2 remains closed. The finished part is taken out from mould PU1. The thermoplastic carrier is transferred to the cavity PU1.
Economical Solution
With ReactPro Yizumi, Frimo and GK Concept offer an economical solution for a complex product. With an intelligent mould concept, it is possible to produce high-quality two component products in a single step production on a small footprint. The project partners not only focus on quality, but also on cost-effectiveness. The mould concept functions without a complex machine technology. A rotary table, sliding table or swivel unit is not required. A narrow mould design allows for the use of small machines.
ReactPro is a smart engineering solution from Yizumi. A modular design further reduces the costs by using standardized components. The polyurethane module is connected to the front side of the injection moulding machine using a flange.
The safety guarding of the injection moulding machine is extended to include the polyurethane unit. An integrated solution that enables retrofitting of existing Yizumi injection moulding machines in just a few steps. ReactPro offers numerous advantages for the customer:
Small footprint.
No expensive machine technology necessary.
Due to two alternating PU moulds no negative influence of the cycle time by the polyurethane process.
Small machines.
Short cycle time.
High design freedom.
No rework required.
Economically attractive.
The technology was presented at the Chinaplas in Guangzhou in May 2019. Figure 3 shows an engine cover produced at the Chinaplas made of AKROMID B3 GF 20 2 RM-D (4164) (Akro-Plastic GmbH) with an over-moulded central decor made of Puriflow 911 (Votteler Lackfabrik GmbH & Co. KG). The solution will also be shown again in Germany's K 2019, the world's No.1 trade fair for plastics and rubber, with a higher level of integration.
Figure 3: Motor cover demonstrator made of AKROMID B3 GF 20 2 RM-D (4164) + Puriflow 911
References
[1]Burkle,E,Wobbe, H:Kombinationstechnologien auf Basis des Spritzgießverfahrens,Munich 2016.
[2] Bohme, A: Spritzgießen und PUR-Technologie – effiziente Verknupfung fur hochwertigeanwendungsoptimierte ¨Oberflachen, Leipzig 2017.
Yizumi at K 2019:
IMM booth: Hall 13 / D80
DCIM solution: Hall 12 / A27
RIM booth: Hall 14 / C59
