800-235-8090

800-235-8090
sales@keystoneparts.com

Monday, March 19, 2018

How to Stop Hot Melt Adhesive From Smoking

While hot melt adhesives are an excellent solution for many industrial applications, the high temperatures of the process need to be carefully controlled to avoid problematic fumes. When hot melt adhesives are heated, they inevitably release some fumes. That is the odor you detect when working close to hot melt nozzles. While having some fumes is normal, excessive fumes suggest a problem with your process and require some attention.

Our team has seen examples of hot melt adhesive smoking and have some tips on how you can make adjustments to reduce the amount of smoking you have.

Check Your Process

To stop hot melt adhesive from smoking, take a look at your various hot melt process parameters:

  • Temperature: The temperature of your hot melt gun or nozzle is critical. Too low and your adhesive doesn't melt and flow properly. Too hot and your adhesive becomes too runny and can release annoying and irritating smoke. In some cases, burnt adhesive can discolor the final glue bead, and can also contribute to charring. Adjust your temperature setting according to the manufacturer's settings for your hot melt equipment as well as the manufacturer’s temperature recommendations for the specific glue you're using.

  • Orifice and mesh size: If the orifice size of your nozzle and the mesh size of your inline filter is not correct, you can have problems pushing your adhesive through and onto your products. An overly restrictive nozzle allows hot melted adhesive to back up and stay in the nozzle longer, which can lead to overheating. Verify that you have the correct flow through your nozzle at the indicated temperature and replace your nozzles and your inline filter assembly or filter cartridge if necessary. Our team can help determine if you have the right hot melt adhesive set up for your application.

  • Nozzle and work zone cleanliness: Adhesive residue buildup on your nozzles, in your applicator head and in the vicinity of your work areas can cause melt adhesive problems and smoking. An adhesive that has already been burnt and has dried will smoke more easily than fresh, unmelted hot melt adhesive. Accumulation of used, dried adhesive on your applicator head and nozzle is a common source of smoke.

While a small amount of smoking from your hot melt equipment is expected, if you are experiencing excessive smoking that causes eye or throat irritation, there are solutions. With years of experience as a leader in the hot melt adhesive market, here at Keystone Industries, we can help you understand why your hot melt dispenser is smoking. Always make sure that you are following manufacturer guidelines for your nozzles, modules and hoses as well as the glue that you are using.

Hot melt adhesives are suitable for a wide range of industrial applications, so get the most out of your system and avoid uncomfortable and annoying fumes. If you have any questions or need to replace any of your equipment, accessories or hot melt products, browse our catalog or contact our team for assistance.

Thursday, January 18, 2018

How to Stop Hot Melt Adhesive Stringing

Whether you’re using hot melt for packaging, automotive, print materials, or any other adhesive application, details matter. At best, inefficient use of adhesive can result in waste – at worst, it can cause issues with your system that add to costly downtime.

One of the most common issues encountered with hot melt systems is adhesive stringing. We’ve put together the following guide to help you understand what stringing is, how it happens, and how you can prevent it.

What is Hot Melt Stringing?

Hot melt stringing occurs when some of the adhesive material is left behind on the nozzle and pulled into a string, either automatically down the production line or manually when a handgun is pulled away from the applied surface. The string of adhesive that is left behind is sometimes called “angel hair”.

Hot melt stringing can affect any hot melt application, but it can be problematic for some in particular:

  • In food packaging applications, hot melt stringing can lead to pieces of adhesive breaking off and contaminating food products.
  • In pharmaceutical applications, hot melt stringing can break off inside packaging for medications, which could be mistakenly consumed.
  • In automotive applications, precision adhesive application on visible parts is an important part of ensuring a clean appearance for an automobile.
  • In Case and Carton closing applications , hot melt can appear on the product or case the product is put in.

What Causes Hot Melt Stringing, and How Can I Fix It?

There are various causes of stringing hot melt adhesive, including:

Application Temperature: When adhesive temperature is not high enough, the adhesive can become too viscous and thick, leading to stringing.

Solution: Consult your hot melt Material Data Sheet (MDS) to find the correct temperature settings. Standard hot melt adhesive is typically designed to be set at a temperature of 350° across all zones; however, your MDS may recommend a different temperature based on your adhesive & your application.

Late Shut Off: This is most commonly seen in older AO/SC module configurations, which can shut off slower than newer AO/AC configurations.

Solution: A support specialist at Keystone Industries is happy to help you determine if the age or configuration of your gun is a factor in your hot melt stringing issues.

Distance from Surface: If the distance between the nozzle and the surface is too great, this can allow air to cool the adhesive after it is applied, leading to stringing.

Solution: Try decreasing the distance between the nozzle and the application surface.

Nozzle Issues: The nozzle’s orifice diameter can contribute to stringing because of its effect on adhesive velocity.

Solution: Try replacing your nozzle. Keystone can help you determine what size could be a better fit for you.

Other potential causes: Over the years, we have seen a variety of different parts and issues contribute to hot melt stringing, including debris build up in hoses and other parts, solenoid issues prohibiting the proper cycling of the hot melt gun, and more.

Keystone is Here to Help

If you’re experiencing hot melt stringing, Keystone Industries can help you troubleshoot and get to the bottom of the issue. Simply call us at 770-586-5990 or contact us today.