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One of the most important, yet often overlooked, factors that impacts the performance of a silicone dispensing machine is temperature. The knowledge of the temperature‑dispersion relationship is of paramount importance for manufacturers who need precision, uniformity and efficiency in sealing applications. KAIWEI is dedicated to seal technology for over 20 years and it is always temperature control that is in the forefront of our technological development.
The Science Behind Temperature and Silicone Viscosity
Silicone materials are temperature sensitive. The higher the temperature, the lower the viscosity of silicone, and the more easily it flows through the dispensing nozzle. On the other hand, as temperatures drop, the thickness of the material increases, and the dispensing becomes much more difficult. The temperature effect on silicone's viscosity has been demonstrated, but it is less pronounced with regards to elasticity. The droplet volume consistency, bead formation and overall sealing quality is directly affected by the viscosity‑temperature relationship.
Without an optimal temperature throughout the dispensing system, a silicone dispensing machine will not give accurate dispensing results. KAIWEI's equipment is provided with high‑temperature control system, such as constant temperature water circulation equipment, which can keep the adhesive and pipe at constant temperature to avoid high viscosity materials curing or solidifying during the processing, and ensure the smooth processing.
Problems Caused by Improper Temperature Control
Dispensing at Too Low a Temperature
If the temperature is too low to run the silicone dispensing machine, the following problems can occur:
Difficulty pumping – High viscosity limits pump flow and increases the pumping resistance.
Uneven nozzle flow – This results in an uneven nozzle, causing irregular bead sizes and poor seal.
Material buildup on the nozzle – excessive silicone buildup around the nozzle tip which will lead to dispensing (also known as "offset dispensing")
Stringiness – Thin silicone strands from the nozzle form a mess and material waste.
Reduced adhesive wetting – reduces bonding strength, poor wetting of adhesive.
Dispensing quality can be up to 50% different with only a 5°C temperature difference in the environment! It is a sensitivity which makes it even more crucial that any professional dispensing operation is carefully managed from a thermal point of view.
Dispensing at Too High a Temperature
While heat will lower the viscosity of the flow, excessively high temperatures present other problems:
Reduced tackiness - Dryers are added to lower the tackiness of silicone. Dryers are used to decrease silicon's tackiness.
Bead dragging – The material is too runny, allowing the bead to drop, or drag behind the nozzle.
Bubble formation – If air is trapped it will affect the seal.
Reduced pot life – The material will cure too soon reducing the working time.
Excessive fluidity – The flow of material being dispensed is excessive before it is cured.
Too long exposure to hot‑melt silicone formulation may cause the silicone formulation's material performance to be permanently impacted.
How KAIWEI’s Silicone Dispensing Machines Address Temperature Challenges
KAIWEI's silicone dispensing systems are designed to feature all‑inclusive temperature control. We offer wide operating temperature range (-15°C to 35°C) for our equipment to suit a wide production environment. Some of the main temperature control characteristics are:
Independent zone temperature control – The platen, hose, pump and nozzle are all independently controlled, resulting in uniform material properties throughout the system.
Precision thermoregulation – Closed loop systems regulate temperature and make adjustments accordingly to the environment changes.
High‑quality sealing components – Our patented KW‑800 mixing head and our six‑axis robotic integration ensures optimal rheological properties.
KAIWEI's temperature control system products are certified by CCC, CE, ATEX, IP66/67, RoHS & ISO 9001:2015, and ensure that our products meet the highest international standards in terms of safety and reliability.
Best‑Practice Operation Suggestion
When working with silicone dispensing machines, it is important to not only have good temperature practices, but also know the following:
Preheat silicone materials – If ambient temperature is below 23°C, preheat material before dispensing to ensure proper flow rates.
Maintain nozzle temperature - Use the lowest temperature for the nozzle that will give a steady flow, normally 120°C to 140°C for hot‑melt silicones.
Monitor ambient conditions - Check ambient temperature and conditions – drafts and temperatures below 18°C may have a negative impact on nozzle performance
Use intelligent temperature control systems - Employ intelligent temperature management systems that automatically compensate for viscosity changes as a result of temperature changes
Conclusion
Temperature is not a secondary variable, it is a primary element of success when it comes to silicone dispensing machine. The ideal silicone dispensing machine should be equipped with precise temperature control, rather than it being an optional extra. After 20 years of innovation in the field of intelligent sealing systems, KAIWEI has developed a sealing system which is excellent in controlling this critical parameter and achieves excellent results in over 60 countries around the world.
We are confident that KAIWEI's temperature controlled dispensing solutions are suitable for you to ensure product quality and production efficiency, whether you need to seal automotive battery covers, make electrical enclosures or air filters.
