Hot melt adhesive systems are a vital part of the set-up for many manufacturing, print, and packaging businesses. Hot melt tanks and dispensing equipment help keep the production line moving and produce top-quality products for their customers. As adhesive application equipment operates at high temperatures and under high pressure. However, they can sometimes experience issues and not work as intended.
This often results in spoiled products or machine faults – and the root cause is frequently a build-up of degraded adhesive or char around the pump or dispenser nozzle. Once recognised, the problem can be resolved by stripping back, cleaning, and rebuilding the machine to the original factory specs. The key to avoiding unnecessary downtime is to spot the signs of the problem early so it doesn’t slow your operation down. These are three of the most common visible signs that you may have an internal issue with your machine.
Problem #1 – Adhesive Splatter On The Inside Edge Of Products Or Containers
When adhesive is dispensed around the opening of large containers, furniture items, plastic consumer products, or packaging, in some cases, the adhesive splatters onto the inside of the item.
There are generally three causes for this.
1) Most commonly, there may be a char build-up in the dispensing nozzle or hot melt tank. This creates air bubbles in the system and interrupts the flow of adhesive, causing it to ‘splutter’.
2) Alternatively, you may have a problem with dry conditions causing static electricity. If this happens, the static electricity can cause the adhesive to jump up suddenly on exciting the dispensing needle. It will then not carry on dropping below the dispensing needle directly. In this instance, you could try looking at ways to deal with dry conditions and thus reduce static build-up, such as by using a humidifier in the production area.
3) The third common cause is stringing. This is when the adhesive continues to come out even when the dispensing needle pressure stops. This could be caused by char, but it’s just as likely to indicate a mechanical fault. The best solution is hiring a specialist company to assess the parts in your HMS and replace any broken or faulty components.
Problem #2 – New Adhesive Running Over Your Machine Parts When Used
This is a common problem seen when a new type of hot melt adhesive is used in a hot melt system without thoroughly cleaning it of old adhesive residues. You may find that the new adhesive runs over machinery and their parts – even though it is the same viscosity as the old one.
The answer to this riddle lies in the rate of flow. Just because two adhesives share the same viscosity, they may not share the same rate of flow. There are Newtonian Fluids (which flow the same in any conditions) or Thixotropic materials (which change viscosity depending on how fast they are stirred). It is, therefore, a good idea to check which type your new adhesive is before you buy. Additionally, it is strongly recommended to clean your HMS of the old degraded adhesive before changing brands, even if the two types of glue should be compatible.
Problem #3 – Dispenser Tip Keeps Clogging When Used With An Automatic Pressure Pot System
Many businesses now use an automatic pressure pot system for dispensing adhesive. One issue that sometimes comes up is the dispenser tip getting clogged. This, once again, is often the result of the dispenser becoming blocked by old and partially congealed adhesive. It can also arise from the adhesive being incompatible with the dispenser tip, e.g. through the viscosity being too high, in which case you should check with your HMS manufacturer about the best applicator to use.
Regular Maintenance Is The Best Solution To All Applicator Issues
The best solution to adhesive application problems is to keep your applicators regularly maintained and cleaned, and keep an eye open for the early signs of potential issues before they develop. A planned rebuilding and maintenance schedule will remove any degraded char from the hot melt tank and the applicator and keep them working as expected. It is essential to use a professional, experienced company to do this – which is where Adhesive Laundry comes in.
Find Out More
The Adhesive Laundry are hot melt adhesive application and service specialists. We can help with adhesive application issues and keep your machinery well maintained, and address emergency faults and shutdowns as required. Contact us at [email protected] today for more details.
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