Henkel delivers the right material and equipment solutions for time-sensitive electronics assembly application

Global adhesive technology supplier consults on design, materials, equipment and process; helps accelerate assembly and ensures quality and reliability.

The Challenge

An international manufacturer of electromechanical connectors and sensors with high-volume production in Europe was experiencing quality issues that needed a fast and permanent solution. Manufacturing was happening in a pilot plant, but would soon expand to a new high-volume production facility. Before manufacturing could fully expand, the company urgently needed to solve three production challenges.

Challenge #1:
The manufacturer was using a UV-cure potting material to fill gaps and ensure mechanical protection on an electrical connector. The UV-cure material was not fully curing in shadowed areas, so the part was consistently failing during inspection.

Challenge #2:
At the opposite end of the same connector were a series of soldered wire contacts. The manufacturer was using a low viscosity, UV-cure acrylic adhesive to protect the wire contacts from corrosion. But the adhesive was too thin to stay in place prior to cure, and could not offer sufficient protection post-cure.

The Solution Journey

Having worked with Henkel over the years, the manufacturer understood Henkel's broad line of product chemistries, global footprint, and wide range of equipment. So they reached out to their Henkel representative to collaborate on a solution.

Henkel engineers recognized that while UV adhesives cure in seconds, they were inappropriate for two reasons. A 100% light cure material could never fully cure on a product with shadowed areas. And a thixotropic material would offer better protection for wire contacts than a thin material regardless of cure.

Henkel engineers recommended two-part polyurethane materials to replace both UV-cure products.

For gap filling and mechanical protection, Henkel engineers recommended LOCTITE CR6130, a thin, two-part polyurethane potting material capable of flowing to fill gaps inside the connector. This product offers superior adhesion on metals and plastics, provides mechanical protection, and fixtures in just 2 minutes once mixed. Full cure occurs in 6 minutes.

To protect the wire contacts from corrosion, Henkel engineers recommended LOCTITE UK178, a thick polyurethane material that cures into a tough, resilient encapsulant that offers ideal performance.  UK178 didn’t cure quite fast enough for the application, so Henkel’s R&D team customized the product to mound over the wire contacts and fixture in 2 minutes with complete cure in 6 minutes.

Henkel chemists added a UV tracer to both polyurethanes to allow in-line quality inspection, ensuring the adhesives are placed appropriately on parts.

Once the manufacturer specified the polyurethanes, they needed the right equipment on the pilot line to dispense the new materials. The production process required a semi-automated machine, where an operator could place the part into the assembly system and the machine would dispense adhesive onto the part. For the pilot plant, the machine’s capacity had to allow production of a minimum 200,000 parts per year.

The most appropriate dispense equipment for this application was Henkel’s Sonderhoff DM402 dosing cell, a high performance, low-pressure semi-automatic mixing and dosing system that allows for quality inspection and features x-y-z axis dispensing. This equipment was capable of dispensing both materials onto the part at the processing speeds required. These machines ordinarily take many months to custom-manufacture. In the interest of time, Henkel located two preowned machines they refurbished and quickly delivered to the customer. Accessing like-new equipment saved time, allowing the manufacturer to meet their four-month deadline. Henkel fully tested and qualified the equipment prior to its installation.

Exceptional Results

At the outset of this project, the manufacturer was under massive pressure to achieve production of a highly-reliable connector within a very tight manufacturing timeline.

Henkel’s equipment and material solutions resolved the customer’s production problem and accelerated the overall assembly process. The newly-redesigned pilot line was specified, tested, set up and running within a four month timeframe. Henkel’s unique vertically-integrated global footprint and broad technical capabilities provided timely solutions for the customer.

Prior to process approval and installation, Henkel’s technical support team conducted machine programming, adhesive performance, and processing-time tests. These tests ensured the final production line would meet and exceed customer expectations.

Henkel introduced an entirely new adhesive chemistry with a unique cure profile.  The custom-engineered polyurethane materials achieved the same production speed as the original process. Product quality and reliability improved dramatically.

After the initial four-month pilot application, Henkel delivered a second set of custom-formulated adhesives for use in the company’s new high-production plant. Fermadur CR6130 and Fermadur UK178 were modified to increase cure speed and enhance performance in the high-volume production setting.