Challenge

A leading tool manufacturer in Australia was launching new model of pliers for electronic components. The customer considered press fits or brazing the pliers hands to the jaw. They found that all these methods were undesirable:

• Press fit involved expensive machining to maintain very tight tolerances.
• Brazing needed expensive brazing machines, which were dependining a lot on operator skills and was expensive too.

Solution

Loctite Retaining Compounds:

Loctite 609 is a low viscosity retaining compound that bonds rigid metal assemblies and was tested for this application. Ideal for gaps up to 0.1 mm diametral. Fixtures in 10 minutes and provides a shear strength of 3,000 psi after 24 hours.

• Due to the high cured strength over a wide range of gaps, Loctite retaining compounds allow the usage of clearance or light press fits - thereby eliminating the high costs of precision surface finishes and close tolerances between mating parts.
• Eliminating the processing costs involved in producing the press or shrink fits by avoiding using expensive machines such as presses, grinding / honing machines and heaters.
• Retaining Compounds fill into the micro gaps & surface irregularities. Ensuring 100% surface contacts.
• Consistency of load carrying performance is improved even over uncertain tolerances.
• Eliminating the fretting corrosion.

As the adhesive was applied in a blind hole, the adhesive needed an outing to ensure proper coverage and to eliminate any trapping of air bubbles. Loctite Engineering Team worked out a solution with the customer – a fine slot on one side of the jaw - to ensure proper application in the blind hole.

Results

Loctite 609 bonds jaws and pliers with gap to 0.02 mm. The bonded joint withstands a pull-out load of more than 150 kg (1.51 kN) much higher than the customer test requirement. Fixture / handling strength is achieved within 10 minutes improving the productivity. What’s more, by using Loctite 609 the customer can gain significant savings in machining and process costs compared with press fits or brazing.