How to deal with glue and material leakage in the glue pot? Investigation and prevention of hot melt adhesive leakage in book and magazine binding machine

Leakage of glue/material in a glue pot refers to the leakage of molten hot melt adhesive from the sealing area, dispensing valve, rubber hose joint, and other positions of the glue pot body, rather than being applied to the spine of the book through the glue roller normally.It is exactly the opposite of ‘no glue output, poor glue supply’ – no glue output means no glue supply, and glue leakage means not following the right path and leaking out of the pot through gaps. Light cases can dirty equipment and floors, waste glue, and severe cases can cause glue to flow to electrical parts or burn, which must be dealt with as soon as possible.

Let’s say it in the order of ‘locate first, investigate the cause later, and handle later’.

1、 First, determine where the leak is

The leakage location is different, and the cause and treatment are completely different. Don’t rush to remove it for now:

• Leakage at the flange/sealing gasket of the pot bodyCommonly seen on the joint surface between the pot lid and the pot body, as well as the seam between the heating plate and the pot body;
• Leakage at the outlet valve/pump interfaceAdhesive seeps out from the pump body, valve, and measuring port;
• Rubber hose/connector leakageThe hose is aging and cracking, the quick connect is not locked tightly, and the glue drips from the pipeline;
• Overflow from the pot mouthIf the glue is too full, it will overflow from the pot after thermal expansion (strictly speaking, it is not considered a “leak”, but the phenomenon is the same).

2、 Common reasons

1. Sealing components undergo high-temperature aging.The glue pot works for a long time at 160-180 ℃ (according to the process card), and the sealing gasket and O-ring become hard and crack due to heat, losing their sealing performance. During the training, it was repeatedly emphasized that ‘90% of after-sales problems come from equipment temperature control failure’ – inaccurate temperature control leading to long-term overheating can accelerate seal aging and adhesive carbonization corrosion.
2. Excessive glue temperature leads to carbonization and corrosion.The temperature displayed on the glue pot does not match the actual temperature, and the actual temperature is too high. The glue is burnt and carbonized on the pot wall, and the carbonized layer corrodes the sealing surface and metal joints, resulting in more leakage.
3. Loose/loose assembly.Valves, hose quick couplings, and flange bolts loosen due to vibration, resulting in adhesive leakage in gaps.
4. Overflow due to high liquid level.The one-time addition of glue is too full, and it may overflow from the pot mouth during heating expansion or stirring.

3、 Troubleshooting and processing steps

1. Shutdown for cooling, power off before operationThe risk of burns from hot glue is high, so do not wear a thermal disassembly device;
2. Clean the remaining glue outside the potSee the real leakage point clearly (don’t be misled by the glue hanging);
3. Check the sealing gasket/O-ringIf aging and hardening occur, replace with temperature resistant seals of the same specifications;
4. Check the connector/valveRe tighten the quick connect and tighten the flange bolts;
5. Check the rubber hoseIf there are cracks in the hose, replace it directly, which is not acceptable;
6. Clear carbonization layerIf the pot wall has already burnt, follow this series’ How to clean the glue pot when changing the glue or line ‘to remove the carbonization layer and reinstall it to avoid further corrosion;
7. Control liquid levelAdd glue below the calibration line and leave a thermal expansion allowance.

4、 How to prevent (maintenance checklist)

• Regularly replace sealsReplace the heat-resistant sealing gasket/O-ring according to the equipment maintenance cycle, and wait until it leaks before replacing it;
• Temperature control and carbonization preventionRegularly calibrate the actual temperature of the glue pot with a thermometer to avoid long-term overheating;
• Not exceeding the liquid level, not mixing glueLeave a surplus amount of glue, and be sure to clean the machine when switching between different formulas to avoid carbonization accumulation and corrosion of the sealing surface;
• Daily inspectionTake a look at the seams, valves, and hoses of the pot in each class, and deal with any signs of leakage as soon as possible.

5、 What can Sunlife do to help

The leakage of glue in the glue pot is a maintenance issue of the equipment, but the link of “temperature control misalignment → overheating → carbonization → glue leakage” is directly related to the temperature setting of the glue used. Sunlife provides recommended working temperature ranges and supports temperature measurement and calibration guidance when delivering hot melt adhesive for books and magazines; Specific temperature and seal specifications are as followsEquipment manual and accompanying process cardTo be accurate. If there is repeated glue leakage and accompanied by weak adhesion and wire drawing, it is recommended to first discharge the temperature control and then the sealing to avoid only replacing the gasket without solving the root cause.

Explanation: This article only provides troubleshooting instructions for the sealing leakage of the glue system on the book and magazine gluing machine. The specific working temperature and seal specifications are subject to the equipment manual and accompanying process card; Not to extend unverified statements such as’ all products have passed a certain test ‘.