It is Usually Always a Clog
The most common reason for your hot glue system acting up is because of a clog. Clogs are common because you are working with glue, which is sticky and chars over time. Below are some of the most common technical calls we receive, with the solution…and you guessed it, it’s usually always a clog.
Pump is not pumping
There are several reasons as to why your pump can stop up. Honestly, it is usually dirty oily air in your shifter. However, when it is not your shifter it is usually a clog. If your shifter is running fine, but it sucked something up into the hydraulics of the pump, the pump shifter will be stopped in the top position, unable to shift down. That is because you probably have some char or debris in your hot glue reservoir and while pumping, you sucked something up into the ball check valve. You have now clogged up your pump and need to send it in for a flush and clean. Another potential issue could arise if your pump is running but sluggish. If your pump is running mush slower than it used to, it is probably because you haven’t changed out your tank filter and it is clogged. The tank filter is located on the side of the tank and filters all glue before it runs into the hoses. If that filter is not regularly changed (every 500 – 1500 hours depending on how clean your glue is) then that clog can cause pressure to back up into the tank and not allow your pump to run at full capacity.
Gun is not firing
If your gun is not firing at all, it is probably your solenoid valve. However, if your gun is firing every other time or randomly, it is probably due to a clog in your in-line filters. The in-line filters filter the glue from your hoses into your gun. These filters are there to help filter our char or debris that was missed by the tank filter or that has built up in the heated hose. If the filter screens are not changed regularly, they will get clogged up and not allow for your gun to fire properly. For example, if you need to increase air pressure in order for your gun to fire, it is probably the in-line filter clogged up. Another clog can happen in the gun manifold itself. Typically, this is only in multi-module guns. If you have a multi-module gun and the last module in the line is not firing, there is probably a clog in the manifold.
Module Drips
If your module is constantly dripping glue, then you have a clog in your module. This is most common in air open, spring close modules. A piece of char will get stuck in the seat and not allow the piston to seal tightly, causing the glue to drip out. A clogged module will need to be replaced with a new module.
Nozzle keeps clogging
This one is fairly straight-forward. If your nozzles keep clogging there are a few solutions. First, you can change out your in-line gun filters. They are probably not clean and not filtering the glue through the gun. You can also increase your nozzle diameter. If you are running small hole nozzles such as .010 or .012 diameter, try a .014 or .016 and you will start to see less clogging. However, that will lay down a little more glue, so keep that in mind when reviewing your glue usage.
The best way overall to reduce the number of clogs in your hot melt systems is to do preventative maintenance. That means cleaning your tank every month or every quarter, depending on how many shifts your tanks are running. Universal Systems makes Purge Plus tank cleaner and we sell them in a 5-gallon pail so that you are set for at least 2 – 3 cleanings. Additionally, change out your tank filters and in-line filters. These 3 tips are the most inexpensive way to keep your hot melt system running smoothly.
The Lost Art of Troubleshooting
Troubleshooting is most definitely a lost art. In today’s throwaway society, we have lost touch with our ability to fix things ourselves. That is true in all aspects of business and most definitely prevalent in the packaging world.
For us, in the hot melt application industry, we have seen it get progressively worse over the last few years. Ever since the pandemic, it seems that most hot melt manufacturers no longer stand behind their equipment and help with troubleshooting. Industry giants, like Nordson, want you to buy new machines, they don’t want you to fix what you already have. Here at Universal Systems, that is the exact opposite of our company culture. We are here to help, we believe in our equipment, and that the art of troubleshooting isn’t something that should be lost forever.
That being said, troubleshooting a pump not running doesn’t mean hitting it with a wrench until it moves. There is an art to it. Using deductive thinking to pinpoint the cause of the issue versus just replacing each piece until it starts working again. For example, your line is running a multi-module gun, and the last module on the line isn’t getting glue. In order to figure out where the real issue lies you first need to make sure all of your key points are met. First, is your glue heated to the correct temperature? What is the consistency of the glue out of the first module in the gun versus the second, etc.? If the gun isn’t heated to temperature, your glue’s viscosity may not be correct to run through the manifold to all modules. Second, have you checked your in-line filters? There could be a clog in the filter not allowing enough glue to flow into the gun to get to all modules. There could also be a clog in manifold itself. Once you eliminate all potential variables, you will be able to deduct what your actual problem may be.
Training on equipment is also very important in practicing the art of troubleshooting. If you have line operators that understand how your equipment works, they will be better equipped to troubleshoot potential issues. If your line operators or floor managers are not fully versed with your equipment, you should be able to call the equipment manufacturer to go through troubleshooting steps with you. At Universal Systems, we pride ourselves in our customer service and ability to walk any customer through troubleshooting. If you have a manufacturer, like Nordson, that will not take that time with you, maybe it’s time for a change to USSE.