Technodigm Innovation Technodigm Innovation
Technodigm Innovation
November 08, 2023

Case Study: Dispensing of Anaerobic Adhesives

Requirement & Task:

Traditional connection technologies, such as screw or welding connections are being more and more replaced by adhesive connection types. Therefore, the development of technically highly sophisticated glue recipes and formulations is advancing. Also, to reduce costs and improve profitability, engineering departments globally tries to develop innovative product designs and manufacturing efficiencies by using new technologies, including adhesives. The use of anaerobic adhesives has become increasingly popular in all manufacturing applications, such as consumer, electronic, automotive or general industry. In the past, the main reason to use anaerobic glue was to increase the seal or holding force of mechanically joined connections such as thread lockers, thread sealants, or flange sealings. Anaerobic adhesives remain liquid until isolated from oxygen in the presence of metal ions, such as iron or stainless steel. For example, when an anaerobic adhesive is applied between a nut and a bolt on a threaded assembly or screw thread, it rapidly starts to cure or harden to form a stable crosslinked plastic with a strong adhesion to many metals. The shear strength of this gluing connection is very high.

Typically, anaerobic adhesives are used to lock threaded assemblies together. Here, they prevent loosening and corrosion of the fastener, maintain proper clamping force, and offer controlled torque for removal of the assembled parts. Anaerobic gasketing materials are commonly used as formed-in-place gaskets (FIPG) that produce leakproof seals between flanges. At fixed cylindrical assemblies, such as joining a bearing onto a shaft, anaerobic adhesives known as retaining compounds enable manufacturers to glue these parts that once could only be assembled using press fits or shrink fits.

When it comes to the best suitable dispensing and dispensing equipment, there could be many mistakes and wrong systems to be used. The main issue is, when metal parts are used inside the dispensing systems, so – by definition – the anaerobic adhesive starts to cure at these metal parts. Passivation of these metals parts is one possibility to avoid this curing effect, but this process means additional costs, requires careful handling (damage of passivation layer) and also needs a renewal of this passivation process after some time.

Therefore, complete metal-free and precise dispensing system is needed to ensure the special gluing process and process stability and safety.

Solution:

The PCP-technology offers the best solution for dispensing anaerobic adhesive. We have developed a special rotor unit, made out of a special PEEK-material mixture to ensure a smooth dispensing of anaerobic adhesives. This rotor unit is truly completely metal free and offers a lot of advantages and benefits. Also, our rotor and unit use a special developed rubber and elastomer material at the stator, so that it can withstand the chemical features of anaerobic and increases the life time of this part tremendously. This combination offers a perfect solution for the dispensing of anaerobic adhesives.

A unique injection moulding process is combining the rotor and shaft as a single plastic part, without using a separate flexible unit for the eccentric movement of PCP-technology. This offers many advantages, new opportunities and application areas for PCP dispensers. In combination with a plastic housing, a complete metal-free dispenser ensures a smooth dispensing process of anaerobic adhesive.

We specialized in developing customized compounds for specific applications. The stator material is especially suitable for dispensing applications with chemically demanding materials (like anaerobic). The features of this rubber compounds guarantee a smooth and very stable dispensing process.

Advantages & Benefits:

The PCP-technology in general and the new rotor-plastic unit in particular offer tremendous advantages and benefits when anaerobic glue should be dispensed.  Up to now it was very tricky to use standard dispensing systems and technology, as the dispensing equipment was either technically not suitable or too expensive. The need of completely metal free components prevented the use of automated dispensing systems. With the new metal free plastic unit, this disadvantage could be eliminated and a perfect dispensing solution could be provided. By using the plastic rotor unit, the anaerobic adhesive could be applied process- safe and repeatable and without any risk of curing and hardening. New areas and applications for anaerobic adhesives could be defined. As the design of the plastic rotor unit is without any separate flexible part, a smooth dispensing process could be guaranteed.

In general, the PCP-technology offers a precise and accurate solution (accuracy and repeatability of +/- 99% could be guaranteed). The adjustable suck-back of the dispenser offers a clean solution, even for dispensing of anaerobic.

As of now an automatic & process safe dispensing solution for anaerobic glue could be offered, this help to reduce production costs and increase the yield and efficiency of the production by decreasing the cycle times.

Stable and reliable processes mean cost and time savings

For more information on Technodigm™ technologies, check out our automated fluid dispensing solutions as well as UV LED curing systems.