Analysis of Quality Control Points for Glueless Binding

In recent years, with the change of book binding technology, more and more books have adopted wireless glue binding technology, the wireless flat glue binding process has been simplified, the quality is relatively stable, the cycle is short, the labor intensity of workers is low, and the bookbinding is beautiful in appearance. . However, at present, there are not many manufacturers that form a complete, systematic, and standardized process in the production of adhesive books and adhesives. The various binding problems caused by this problem have caused great inconvenience to readers. The main problems are page breaks, broken glues, skewed backs, empty backs, and shrinking pages. How to use the correct process to effectively control the above-mentioned quality problems requires a systematic consideration of the whole process from prepress to printing.

One, fundamentally g garment quality issues

Stapling is not an isolated processing process. Many unreasonable ones in the upper process will bring construction difficulties to the binding. Therefore, from the beginning of product design, it is necessary to push the process forward with the binding requirements.

1.32 binding book binding book

32 pairs of books, in the past when the wire is generally used when the first day of the peace 4mm, 6mm in the seam, 2mm foot cut, in the three-cutting machine, use the dual push book car to complete the previous and next Cut separately. In the adhesive bonding production process, using the above operation, it will produce a lot of days, breaking the ground.

This is mainly due to the hot-melt adhesive curing, the overall hardness is much greater than the previous hot pack books, in the process can only take the method of sawing the knife, the first double glue adhesive book divided into two before Cutting, and saw blade thickness, usually about 3mm, if you still use the size of the previous incision, it is obviously difficult to achieve the cutting requirements, if you add the size of the middle seam to 9mm, lithographic products due to the edge and mouth Occupied by the size, the printed product is incomplete. According to the actual situation, the size of the middle seam can be set to 8mm, which not only ensures the integrity of the printed product during printing, but also guarantees the quality of the bound and cut.

2. Milling back thickness design

In order to ensure that the signature can be completely milled at the milling cutter, the thickness of the general milling back is 2—2.5mm, the thicker books can reach 2.5—3mm, and the thickness of the coated backsheet is generally 0.6—1.2mm. . The average back-to-back thickness is 25mm, the average thickness of the coating is 0.9mm, and the size of the normal outside cut is 3mm. For example, the external cut after milling is only 1.4mm. If a normal folding tolerance is generated, the outer cut may be There is a phenomenon of shrinking pages; if only the folding size is enlarged, there will be phenomena such as a serious shift of the layout center, an edition center, and a contiguous page number exceeding the standard, which will cause great inconvenience for reading and will also seriously affect the aesthetics of bookbinding. If you want to add a 15mm milling mouth at the milling back when you make a make-up, this will ensure the cutting size requirement, eliminate the shrinking phenomenon, and will not affect the beauty of the book.

3. Order problem

Some people think that glue books do not have an order, so the final version of the finished book is not centered on the layout. This problem is especially noticeable in practical work, especially in books with title pages. This is mainly due to the fact that gluebooks are not likely to bind books like the sewing thread. They can open the book pages to the back of the book, because the groove depth of paperback glue is generally 1.0-1.2mm. The author concludes in practice that when the mouth is set to about 3mm, the heart of the edition happens to be centered. This is basically in line with the dimensions of the milling back and the drawing groove.

4. The book is not centered

The lack of centering of glue-backed books is a very vexing problem. This is a prominent problem that arises from the development of hand-bags to mechanized bags. In the past, printing was mostly done by single and double-color offset printing machines. Due to the problem of overprinting, the machine attached great importance to the front gauge and the pull gauge. Nowadays, due to the continuous transformation of equipment, the market is pursuing a short cycle, and the requirements for cover matching are fast, so most of them are printed on a four-color machine. Since there is no problem with overprinting, this largely ignores the problem of rules, making Book backs are prone to skew when mechanically sealed in bindings. For this reason, we adopt a black â–³ before and after 3mm of the outer crosshair at the time of imposition of the pull surface, and the black â–³ is 3mm, so that the printed product can see the accuracy of the front gauge and the pull gauge at a glance, in practical work. Has also achieved very good results.

5. Trapezoidal inspection

Because the gumbooks were cut by a single mold, the trapezoidal process of the previous old craftsmanship was reduced, which resulted in the misprinting of individual books caused by the oversight of the pagers, resulting in a major quality story. As for the trapezoid on the back of the book block book, it is impossible to perform interstitial inspection. In this regard, we have adopted the sky-headed and trapezoidal marking method. The size of the trapezoidal trapezoid is set to 3mm (width) x 4mm (length), and a hair is established. This inspector checks the trapezoidal trapezoids during the production process, and uses the page search method to add pages when manually adding pages. This can basically eliminate the situation of the wrong posts.

6. Post-press binding of signatures

To make a paperback glue book have a more stable quality, it must be bundled before binding. This not only makes the book beautiful in appearance. The back of the book can eliminate the phenomenon of large books, and it can also reduce the probability of misprints, change the scene environment, improve the efficiency of the use of the machine, and greatly improve the bookbinding quality. In the glue binding products, the binding of the signature is a very important link.

Second, the correct use of raw materials

1. Strictly control hot melt temperature

At present, all EVA hot melt adhesives are used in the production of adhesives for paper binding. The actual use temperature of the hot melt adhesives must be strictly controlled. Generally, the adhesive temperature should be controlled between 150-1 70°C. The temperature should generally be controlled between 100-120°C.

This is because when the temperature is too high, although the flowability and permeability of the hot melt adhesive are increased, the viscosity and strength of the hot melt adhesive are decreased, and the adhesive layer is not formed on the back of the book very well, and the binding strength of the book is also reduced. In serious cases, page breaks and loose pages may occur. Broken glue and other phenomena; if the temperature is too low, the hot melt adhesive will thicken, and its coating will not be very uniform, especially the pull groove part can not fully inject the hot melt glue, and can easily cause page drop and loose leaf.

The above mainly refers to the problem of adhesive, the side adhesive also has a great relationship with the temperature change, the temperature is low, the adhesive layer is thick, after the bracket is clamped, the back of the book is thick, there are defects such as glue overflow, and the temperature is too high. There are defects such as weak bonding, no side glue, etc. These are due to changes in the fluidity and viscosity of the hot melt adhesive when the temperature changes. Specifically, the temperature and viscosity are inversely proportional to the fluidity. It is proportional. For the specific changes in the environment to analyze the specific issues, can not be impersonated, to adjust the actual glue temperature, such as the glue temperature used in winter and summer is certainly a difference.

2. Choose the right hot melt adhesive

Before the use of hot melt adhesive first visual inspection, good hot melt adhesive film should be bright, semi-transparent, with two hands back and forth after folding will not have a large deformation, with a small hammer will not be too much deformation .

Secondly, cold and heat testing should be carried out. Cold testing is mainly conducted in an environment of -10 to 20°C. After a period of time, it can be seen whether it has its own toughness and can adapt to the cold in winter; thermal inspection is mainly conducted at 40 to 50°C. In the environment, to see how the degree of curing, can adapt to the summer heat.

Finally, the specific gravity test is performed. The simple method is to add hot melt adhesive to the graduated measuring cup, and then add water to measure the specific volume and weight. Practice has proved that when the hot melt adhesive specific gravity test result is 0.7 to 0.72 ton/m3, the use effect is better. At this time, the hot melt adhesive formula is also reasonable.

Third, improve the operating level

The level of the bookbinding glue binding process operator is directly related to the stability of the glue-binding product quality, so it is very important for the operator's skill training to allow the operator to fully understand the performance of the glue-binding equipment. Operating procedures, maintenance principles and methods to solve practical problems. In the form of forums, they can communicate with each other, learn from each other, and sum up their experience, gradually and systematically. For example, milling back knives on the glued-glued link line, if used for a long time, there will be ridges in the paperback glue binding book. The problem of quality problems such as uneven coating, practice found that grinding once in two weeks will effectively avoid the occurrence of the above situation. If the wrapped semi-finished products are cut, they will stick to the heat due to continuous cutting. Melt, lightly coated with a layer of silicone oil can effectively avoid the above situation and ensure the cutting quality.

In addition, more than 1/2 overlapped conveyor belts should be used for glue-binding line, which can effectively increase the condensation time. Generally from the beginning of gluing to three-sided knife cutting machine, the time should not be less than 3 minutes, so as to ensure the quality. Of course, the use of new materials is also a factor to improve efficiency and ensure quality. For example, the use of razor steel blades greatly reduces ineffective labor and is about 3-4 times more expensive than ordinary alloy steel knives. In short, improving the personnel factor is also crucial to the implementation of the glue-binding process.

(Text / Hao Tiankai Gansu Tianshui Xinhua Printing Factory)

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