From PEEK to HAVER AdPEEK®

One of the most popular and widely used high-performance plastics, Polyetheretherketone (PEEK), is highly resistant to nearly all organic and inorganic chemicals as well as radiation, making it suitable for applications across a wide range of industries. However, when overmolding a textile-based hybrid component used as a resistance heating element, processing technology reached its limits with this material.

The Challenge

The resistance heating element is manufactured from an extremely fine woven strip measuring just 5.4 mm in width, which is laminated with a tin foil and then overmolded with a very thin layer of plastic.

The specified wall thickness of 0.6 mm leaves virtually no room for error, particularly inside the component. Any plastic overflow into the heating zone is unacceptable, as only the fabric, not the plastic, may come into contact with the active heating area.

In addition to meeting stringent mechanical strength requirements, the component's surface quality had to remain flawless. These customer requirements were further complemented by HAVER & BOECKER's own goal of establishing a reliable, safe, and economically efficient manufacturing process.

A critical factor for achieving such thin-wall overmolding is the flowability of the plastic material, which in turn depends on achieving sufficiently high melt temperatures in the injection molding process.

Initial test runs using PEEK revealed significant drawbacks associated with the high processing temperatures required. The challenges began with material outgassing and deposits forming inside the mold. The consequences included high scrap rates due to excessive demolding forces, surface defects on the plastic component, and melting of the tin foil. Longer cooling times, combined with increased cleaning and maintenance requirements, further complicated efforts to achieve the desired performance in a continuous production environment.

Making the impossible possible

The issues resulted in long downtime, low production output, and defective components. Unfortunately, neither material suppliers nor renowned plastics engineering institutes were able to provide a viable solution.

HAVER & BOECKER, however, has a long tradition of developing its own solutions to complex manufacturing challenges. In this project as well, that innovative spirit proved to be the key to success.

A cross-functional team comprising specialists from the company's toolmaking department, R&D, engineering, and plastics processing experts evaluated a range of new concepts. Their work extended from optimizing tooling and equipment design to fundamentally improving the plastic material itself.

The solution: HAVER AdPEEK®

Following a series of successful trials, PEEK combined with a silicone-based additive delivered highly promising results at an early stage. The resulting compound, later named and registered as HAVER AdPEEK®, demonstrated improved flowability even at reduced melt temperatures.

The positive impact on the overall manufacturing process was immediately evident. Unlike the original material, outgassing and deposits inside the mold were reduced to a minimum, significantly improving process stability and cleanliness.

Ultimately, every previously identified disadvantage was transformed into a distinct advantage:

• More energy-efficient and resource-conscious operation of the production equipment.

• Low demolding forces that not only prevent component deformation but also reduce long-term wear on machines and tooling.

• Elimination of weld lines while achieving the required mechanical strength of the component.

To ensure the safe use of HAVER AdPEEK® across all industries, including medical applications of the heating element, comprehensive chemical and toxicological analyses were conducted during the heating of the hybrid component.

After iterative refinements to the tooling and careful balancing of the individual cavities, the final results not only exceeded the customer's expectations, but even surpassed HAVER & BOECKER's own expectations.

Reduction of the cicle times

Increased output capacity

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“Our drive is to achieve the best possible results and ensure customer satisfaction by finding the optimal product solution for every application.”

Detlef John
Technical Manager, Wire Weaving Division