List of 6 high-frequency problems and corresponding solutions for avoiding pitfalls in hot melt adhesive for book and magazine packaging

#List of 6 high-frequency problems and corresponding solutions for avoiding pitfalls in hot melt adhesive for book and magazine packaging

The glue packaging problem reported by book and magazine factories is most likely not due to “glue not working”, but ratherTemperature, process or selectionNot right. Sunlife has repeatedly verified one point in the after-sales service of book and magazine hot melt adhesive (back/edge adhesive, production base Foshan Jucai, specializing in book and magazine binding for many years):About 90% of on-site problems are rooted in equipment temperature control failure(For example, displaying 160 ℃ actually only shows 100 ℃).

Below is a list of the 6 most frequent problems as a “pit avoidance checklist”, with directions provided for each category and corresponding deep text entry points for you to easily follow the map.

1、 Page dropping and glue opening – first check the “paper temperature glue amount”

The most common and headache inducing. The first reaction is often strange glue, but there are three things that need to be checked first:Is the paper suitable, is the temperature of the glue pot in place, and is the amount of glue applied sufficientEspecially, it is necessary to confirm whether the displayed temperature of the glue pot is consistent with the measured temperature.

→ For in-depth investigation, please refer to “Is the binding glue of books and periodicals not dry or firmly adhered? First check the three items of paper, temperature, and glue amount”

2、 Drawing and tailing – starting from three aspects: opening time, temperature, and adhesive amount

The glue is stretched too long, which not only stains the pages but also affects their appearance. The core isThe opening time is too long or the glue temperature is too highLet the glue spin out before it forms a film after coating; Excessive glue application can also worsen. Returning the temperature to the optimal range of 160-180 ℃ and matching the opening time according to the speed of the model can usually hold it down.

→ For further processing, please refer to “How to adjust the glue drawing and trailing on hot melt adhesive? Starting from three aspects: opening time, temperature, and glue amount”

3、 Uneven book back and raised spine – glue and craftsmanship are adjusted together

The bulging and angular back of a book often occurs when it is thick or unevenly milled. must start fromMilling depth, degree of roughening, adhesive layer thicknessTake a look at several aspects together, rather than just changing the glue. Thin book cores are actually the strongest, and the thicker the adhesive layer, the better.

→ For in-depth analysis of the reasons, please refer to “What are the reasons for uneven back and raised spine of adhesive bound books? How to adjust hot melt adhesive and process”

4、 Sticky knife, slow curing – cutting before drying will cause deformation

After cutting, the pages of the book are often stuck with a knife or scatteredThe curing process was not completed before moving on to the next stepThe curing time given in the training is generally 3-5 minutes, and pressing and cutting before it dries will cause the knife to stick and deform. Align the rhythm with the curing rhythm of the glue first.

→ For further processing, please refer to “Why does hot melt adhesive stick to the blade and cure slowly? Reasons and treatments for sticking to the blade and cutting loose pages in book pages”

5、 The book back has “empty glue” and the glue layer is not full – the glue roller is attached to the book back

The adhesive layer is intermittent and the back of the book is empty, so the bonding force naturally cannot go up. Key investigationIs the pressure of the glue roller, the fit between the book back and the glue groove, and whether the glue temperature is too low causing poor fluidity。

→ For further processing, please refer to “What are the reasons for ’empty glue’ and insufficient glue layer on the back of the adhesive book? How to handle it”

6、 The temperature of the glue pot looks accurate but actually deviates – calibrated with a thermometer

Many pages fell off, glue opened, and finally it was found thatRubber pot temperature sensor driftThe panel displays 160 ℃, but the actual measurement shows only 100 ℃. Using a thermometer for actual measurement and regular calibration is the most cost-effective way to avoid pitfalls.

→ For calibration methods, please refer to “What should I do if the temperature of the glue pot is not accurate? Use a thermometer to calibrate+display 160 ℃ and determine the actual temperature of 100 ℃”

Attachment: Selection should also avoid pitfalls – based on machine speed rather than “the more expensive the better”

There is a huge difference in speed among different models, and the opening time requirements are completely different: low speed is about 15-20 seconds, medium speed is 5-10 seconds, and high speed is 2-7 seconds (specific subject to the accompanying process card). Using the wrong opening time glue, no matter how expensive it is, it cannot do a good job.

→ The selection method can be found in “How to choose hot melt adhesive for book and magazine packaging according to machine speed? Matching opening time with production pace”

General principle of avoiding pitfalls

1. Measure the temperature first, then blame the glue——Temperature measuring gun is a standard equipment in book and magazine factories;
2. Selection for rhythm——Match machine speed with opening hours;
3. Moderate adhesive layer——Thin book cores are the strongest, not the thicker the better;
4. Small batch samples——Make a sample before bulk production, don’t bet on the whole batch.

By wrapping these few pieces together, the vast majority of adhesive problems can be solved on the production line without having to wait for finished product quality inspection before rework.