Dispenser for anaerobic adhesives tested in long-term tests

Anaerobic means something like "airless". Anaerobic adhesives are single components or 1K adhesivesthat cure due to the exclusion of air. This is one of the two mechanisms for curing when handling the 1K adhesives. Combined with the second mechanism, contact with metal ions, the material is polymerized quickly - a challenge for the dosing unit. Preflow by Viscotec has one for this Long-term test carried out.

Anaerobic adhesives are very popular because they are easy to use and cure quickly. The 1K solvent-free adhesives are used in a wide variety of applications such as screw locking, adhesives with the function of sealing in the Automotive industry, for the assembly of Engines and gearboxes or connections more rotationally symmetrical Joining parts.

Advantage of anaerobic adhesives as disadvantage

The advantage of anaerobic adhesives was also a disadvantage in the past Dosage for gluing. When touching with metal ions When components are occupied, the adhesive begins to react - sometimes very quickly. This reaction is quite desirable because in the automated Series production should be able to process joined and glued components as quickly as possible. Each adhesive reacts differently and there is a risk of unintentionally hardening material in the dosing unit.

The dispensers of Preeflow are very suitable for the exact dosing of the anaerobic adhesive. By using suitable materials for the Glue the manufacturer managed to master the challenges of the order. For this purpose, Preeflow works closely with the chemists in the elastomer department at Viscotec numerous endurance tests performed with anaerobically reactive adhesives. In this way, it was possible to identify the materials that do not trigger a reaction in the adhesives or that impair the dispenser performance.

The housing parts of the Eco-PEN dispenser that come into contact with the material are standard free of metal. The metal parts of the rotor strand that come into contact with the material also no longer offer a surface for hardening after a simple treatment. Even extremely fast-reacting high-performance adhesives can stay in the dispenser for three days without causing damage. Dosing breaks over the weekend, for example, are not a problem.

Pleasant side effect: The time-consuming cleaning on Friday afternoons is no longer necessary. This time saving and the avoided downtimes of the system due to unintentionally hardened material in the dosing unit bring the return of investment within a few weeks.

Speed-dependent dosing technology halves throughput time in series

Aerobic adhesives in the dosage test

The Eco-PEN450 dispenser was subjected to long-term tests with anaerobic adhesive with regard to resistance and start-up behavior in use. Preeflow has tested a total of 14 different anaerobic adhesives from seven adhesive specialists.

The dispenser was put into operation in accordance with regulations. After filling the dispenser with adhesive, the tester dosed approx. 3 ml dispenser content and vented the system. The adhesive remained in the Eco-PEN without dosing for a period of up to 32 days. After the time had elapsed, the start-up behavior was checked with a torque measurement, with the result: Even after 32 days of downtime, the dosing unit with the majority of the anaerobic adhesives tested achieved a perfect dosing result.

Results from the long-term test

Overall, more than half of the adhesives showed over the entire test period no abnormality. This means that the user can leave the adhesives in the dosing unit for 32 days without dosing. With three dispensers, the manufacturer recommends a cleaning step after the same number of days.

Another three materials showed the effects of one easy polymerization by the dispensing needle or, after a long period of inactivity, in the end piece of the dispenser. Anaerobic adhesives in particular, which begin to cure even when exposed to little light, pose a major challenge for the dispensing system.

The starting torque can be completely neglected if the recommendations are taken into account. It did not show any increased values ​​in the tests either. With all the results, nothing stands in the way of using anaerobic adhesives, provided that the commissioning and cleaning are carried out in accordance with the regulations.

Highly viscous materials can also be dosed

The Preeflow products also offer precise and repeatable dispensing results. Regardless of viscosity fluctuations, the result is a clean, process-reliable dosage. In addition to anaerobic adhesives, they can be used to dispense highly viscous materials such as grease or epoxy resins, as well as low-viscosity fluxes and many other critical fluids and pastes.