Engel and Cannon make clearmelt more flexible and cost-effective for automotive parts

Austrian injection molding machinery manufacturer Engel has developed a new machine concept for its clearmelt systems, based on the duo combi M two-platen injection molding machine. The company has worked in collaboration with Italian PU and thermoplastic molding machinery company Cannon Afros.

According to Engel, the design is intended to make clearmelt more efficient and easier to implement. The process floods plastic components in the mold with a transparent or colored polyurethane layer, giving them high-quality, scratch-resistant surfaces directly in the injection molding process. Functional films can also be integrated.

Engel said downstream painting or coating processes can be replaced in many applications. This is particularly relevant for automotive interior and exterior components, where manufacturers are seeking larger, highly designed and robust parts.

In the new concept, the thermoplastic component is injected from the moving side of the machine. The standard injection unit on the fixed platen side is omitted, with the polyurethane equipment positioned in its place.

This puts the PU mixing head closer to the mold, shortening the PU feed lines and making the system periphery more compact, easier to handle and faster to convert. Engel said the arrangement reduces flow paths and line volumes, lowering investment and installation costs because expensive piping is no longer required.

This effect is important for multi-color applications, where a separate pipe would otherwise be required for each color. The shorter lines also avoid the need for moving hoses, with hose connections only briefly disconnected when changing PU equipment.

Engel said the new system concept also enables more flexible use of color units. In the previous configuration, the units were permanently assigned to one machine, while unused color lines had to circulate continuously to prevent pigments and additives from settling.

This is no longer necessary with the new layout. Flushing processes to disconnect color units from the production cell are eliminated, enabling color change in less than 10 minutes.

The company said existing clearmelt molds can continue to be used and only need to be turned around. The system can also be used for standard injection molding applications, while retrofitting with an injection unit on the fixed side remains possible.

Engel said the new system layout saves around 25% of production space. The first systems based on the concept are due to go into operation in the fall. From November, a clearmelt production solution for large exterior parts will also be available for customer trials at Engel’s technical center in Shanghai.

The development follows Engel and Cannon’s work on in-mold PU coating for automotive exterior components and lighting systems. The process combines thermoplastic molding with PU coating in a single in-mold operation.

Cannon has said the technology can replace traditional painting on exterior surfaces such as front ends, hoods, door panels and roofs, reducing VOC emissions by 99% and CO₂ emissions by 60% compared with traditional painting. The company has also said the PU surface coating process is up to four times faster than subsequent painting.

“PU surface coating has been in use for years to produce aesthetic automotive interior parts, such as dashboard trimming,” said Stefano Andreolli, sales & marketing manager, Cannon Afros. “Today, thanks to the evolution of chemicals and processes, this technology can now also be applied to many exterior components.

“The Cannon and Engel partnership aims to provide automotive and appliances manufacturers with complete production plants, whereby customers can benefit from a worldwide network of well-trained and experienced technicians and engineers in both thermoplastic and polyurethane technologies, supporting those who are new to the technology and processes in taking their first steps toward a successful and efficient production.”

Photo: the new system concept for clearmelt, shown here on an Engel duo 5500 combi M injection molding machine, requires around 25% less floor space and operates with considerably shorter PU feed lines, according to the company. Credit: Engel

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