Maximum product utility

Inspiring Innovations – Enabling transformation

Optimum material identification for maximum product utility

When designing plastic components, a number of factors must be considered to ensure that just the right material is chosen. In addition to the mechanical properties, the type and duration of stress, the range of temperatures to which the component will later be exposed, and, often, also the surface quality of the chosen plastic must be analysed in detail. Economic considerations impacting the purchase price and cost-effective processing options usually add to the difficulty of the decision.

A wall bracket for a heating manifold was in the design stages at AFRISO-EURO-INDEX GmbH—a manufacturer of measuring, control and monitoring devices for building technology, industry and environmental protection headquartered in the German city of Güglingen/Baden‑Württemberg. To ensure optimal planning of the material requirements for the product, the component had to be moulded in one piece.

The wall bracket was originally to be made of 30% glass‑fibre‑reinforced polyamide 6 (PA6) due to its relatively high strength and elasticity. But after several tests with this material, it was determined that the film hinge, which was needed here to hold the pipe in place, cracked or broke off after just a few load cycles.

Then Hamburg-based plastics distributor K.D. Feddersen came up with an attractive alternative—the PP compound Hostacom from LyondellBasell Industries. According to Thomas Raithel, Customer Consultant at K.D. Feddersen: “The 30% glass-fibre-reinforced Hostacom G3R05 is not quite as tough as a PA6 with 30% glass-fibre reinforcement, but it is much better suited for use in a hinge. We were therefore able to offer the customer a good compromise between strength and hinge performance.”

The major advantage of film hinges is that they can be manufactured cost-effectively in one piece along with the rest of the component. Generally, however, these hinges have limited resilience. Shear stress and increased load on the hinge ends can result in breakage or cracking. In the event of a defect, they usually cannot be replaced.

“Use of a film hinge in this component is significant for us. It means that the clip and the bracket comprise a single part, and the clip is guided during closing so it cannot slip to the side,” explains Marcus Frey, AFRISO Development and Design.

Hinge operation: The manifold is positioned and the clip is closed over the pin joint and locked into place. A pin is then inserted to secure the joint.

The specifically modified PP compound used here is chemically coupled. Chemical coupling causes glass fibre to become more tightly bound to the matrix, resulting in improved tensile strength, flexural strength and notched impact strength compared to conventional glass‑fibre‑reinforced materials. Thus most properties of chemically coupled glass fibre in conjunction with an optimised polymer matrix are comparable to those of a long-glass-fibre material. By modifying the polymer matrix in Hostacom G3R05, greater impact strength with excellent stiffness—a flexural modulus of over 7 000 MPa (on test plaques)—was achieved.

 Uniform fibre length and extremely even fibre distribution throughout the component are further characteristics of this new generation of glass‑fibre‑reinforced plastics. This is beneficial for the component characteristics, and the material can also be used for injection‑moulded parts with complex geometry.

Close-up view of the film hinge on the wall bracket for a heating manifold, made of Hostacom G3R05 PP compound