The perfect binding line is linked with one machine, which can complete the entire process of wireless perfect binding into a book online. This kind of production line has high degree of automation and high unit output, so it is very important to implement effective whole-process quality monitoring. This article combines the practice of the author's company to talk about the programmatic operation of quality monitoring of the binding line.
1. What is the programmatic operation of quality control
The programmatic work method is a management method that regulates the operation behavior of production staff. It adopts scientific classification and compilation methods, and compiles all the work contents of the relatively independent working surface operators into a set of standardized work procedures according to the inherent laws of controllable factors. Each program has corresponding working standards and schedule requirements, and through field inspection, evaluation and Other means to ensure the implementation effect, to the greatest extent avoid the negative impact of different operating habits caused by different people. The programmatic operation of quality monitoring is to apply the programmatic work method to the implementation of quality monitoring to ensure the full realization of the monitoring target. There are two major types of programmed working methods: time series and process. According to the flow production characteristics of the quality monitoring and glue binding line, we adopt a process-based work method, that is, in order to complete the glue binding work process, divide the monitoring stage according to the quality monitoring steps, determine the key control points, and mark the monitoring warning , Prepare monitoring operation procedures, standards and acceptance procedures.
2. Quality Control Project
In accordance with the requirements of comprehensive and complete quality control, we list the quality control items of the binding line as Table 1.
3. Implementation of quality control projects
This article focuses only on the implementation of several quality monitoring projects for raw and auxiliary materials, milling back, and glue application.
Raw materials
This refers to the processing object, that is, the signature and cover. The captain of the main engine and the collator of the collation should carefully check the handover, compare the samples and samples, carefully review the designated book, master the title, opening number, algebra, the starting and ending sequence of the page number of each generation, the thickness of the back of the book, the rules of the cover, and confirm that the binding The product should be complete and correct.
Monitoring and early warning:
(1) The signature is critical to the quality of the appearance of the finished book back. Folding must be in place and accurate without hollows or wrinkles. Otherwise, the end signature may be milled continuously, so that the back of the signature cannot be coated with glue Cause the page to drop. The signatures with thick paper and many folding times should be cut into small format and then folded. For this reason, when arranging printing, you should consider printing the relevant rule lines. The folded signatures should be tied together tightly, and the setting time should be no less than 2 days to prevent springback and falseness after unbundling. The signatures should not be too dry or damp. Excessively dry, poor permeability, the adhesive adheres to the surface, affecting the bonding strength; excessively moist, slow curing, affecting molding and cutting quality. In winter, the temperature difference between indoor and outdoor is large, and the signatures to be processed must be placed in the workshop in advance, so that the signatures can be processed after adapting to the room temperature. Otherwise, because the temperature of the signature is too low, the adhesive layer will be cold after application, the surface temperature will drop suddenly, and the fluidity and permeability will decrease, which will affect the bonding strength. When stacking and transporting the folded signatures, care should be taken not to deform them. Make sure that the signatures are flat and flat after unbundling. Bookmarks that are instantly flattened using a flattening machine should be neatly placed. Each layer should be placed on the platen for more than 2 days before it can be bound on the machine.
(2) Cover rules should be as consistent as possible, and cutting marks should be printed. When the cover is sealed, the marked cover is the regular cover. If there is no mark, it can be picked out in advance and handled separately to avoid waste and waste. When cutting the cover, the upper and lower knife errors should be minimized to ensure the consistency of the rules. Each cut should be about 250 sheets, and too thick covers should be less. Cover cutting must ensure a vertical angle. The color printing cover should not use too much thinner or powder spraying, so as not to affect the adhesion fastness. The linkage line is automatically sealed, and it should be printed with quick-drying ink, and there is no knife on all four sides; it should be loose before sealing to prevent adhesion, and the size error should be less than 0.2mm. When the cover is printed, without affecting the opening of the paper, the size of the head and feet should be appropriately increased to prevent glue overflow during encapsulation.
Main accessories
That is, hot-melt glue binding. Its quality is directly related to the book fastness. The main component of hot melt adhesive is EVA (ethylene vinyl acetate copolymer). At present, the quality and price of hot-melt adhesives vary greatly among manufacturers on the market, mainly because the raw materials are different. For example, hot melt adhesives rely on paraffin as a diluent to adjust the fluidity. Some manufacturers use imported synthetic wax, and some use the lowest paraffin. Another example is tackifier resin, which is imported hydrocarbon resin and EVA resin, and the lowest grade is also used rosin resin and added plasticizer. Due to the oxidation of rosin in the air and the precipitation and transfer of plasticizers, the aging and embrittlement rate of the glue is accelerated. If this kind of low-end, low-cost hot-melt adhesive is used for binding books and magazines, the adhesive strength can be imagined. Talc powder is also added to the hot melt adhesive to increase the hardness, and the color of the adhesive is changed by titanium dioxide. The various materials in its constituent components are themselves a contradictory combination group. In the binding process, the infiltration of the book block depends on the fluidity at high temperature, and the high temperature accelerates the aging of the glue, reduces the bonding strength, and deteriorates the low temperature resistance.
Monitoring and early warning:
(1) The paper of the book block has different requirements on glue. If the book block is newsprint, books and periodicals paper, ordinary hot-melt adhesive can be used; the book block is coated paper, double-coated paper, because its surface is coated or large-area ink, it has fast heat dissipation, poor absorption, low penetration, high-grade Glue; textbooks, reference books, account books, the slotting depth is not allowed to increase, and it can withstand frequent folding, and high-grade glue is needed; for some products that need to be torn apart during use, low-grade glue can be used.
(2) The glue used should be different in different production seasons. Especially in the north, when winter is cold, you must ensure the temperature of the production environment, and choose a glue with a slower curing speed. The temperature of the glue should be adjusted 3 ° C to 5 ° C higher than in summer, or use a halogen lamp or a tungsten iodine lamp above the upper rubber wheel. Bake to ensure the glue temperature. In summer, the glue that cures faster should be selected to prevent the book block from loosening and rebounding after binding, resulting in loose pages.
Under normal circumstances, the glued hot melt adhesive meets the conditions in Table 2 before it can be put into use.
Milling back
According to the thickness of the signature, adjust the milling depth. To make the innermost page of the signature all milled into a single sheet. The edges of the milling back should be smooth and clean, the back of the book should be level, the grooves are not hairy, and the spacing and depth are the same. If the back is milled into a bevel, the thickness of the adhesive layer is uneven, and the spine is difficult to uniformly wear, and the bonding strength is also greatly affected. The edges of the milling back and the milling groove are fluffy, and the glue cannot be poured into the groove, and the pages are folded back and forth, which is easy to break up. The spacing also affects the bond strength. Under the same conditions, the milling slot spacing is changed from 10mm to 5mm, and the initial tensile strength can be increased by about 1.5kg (see Table 3 and Table 4 for the technical parameters of milling back and milling slots).
Monitoring and early warning:
(1) The depth and width of the milling grooves of the coated paper and double-coated paper book blocks should be appropriately increased to ensure the bonding strength.
(2) Milling cutters and slotting cutters should use thickened carbide blades specially used by professional famous brand manufacturers. This blade is wear-resistant, has a sharp blade and a smooth milled surface.
Glue
The glue temperature should be controlled within a certain range. Adhesive temperature is too high, such as above 170 ℃, although the fluidity of the adhesive is good, but there is much foaming, easy to throw the glue, and will make the adhesive aging and brittle; too low adhesive temperature, such as below 140 ℃, the glue does not melt Thoroughly, the permeability is reduced, the bonding strength is low, and it is easy to cause loose pages and page drops. Generally, due to the high ambient temperature in summer, the glue temperature can be lowered by 3 ℃ ～ 5 ℃, but not lower than 150 ℃; in winter, it should be raised by 3 ℃ ～ 5 ℃, but not higher than 170 ℃. Continuous heating under static conditions will lead to the aging and failure of the adhesive. Therefore, when the machine is shut down for a long time (such as more than 2 hours), the temperature of the adhesive should be reduced by 30 ℃ ~ 40 ℃ to delay aging. Long-term storage under natural conditions will cause the glue to age and become brittle, so special attention should be paid to the production date and shelf life (see Table 5 for technical parameters of the glue application process).
Monitoring and early warning:
(1) Pre-melting should be adopted for patching, which should be added less and more frequently to keep the temperature of the glue relatively constant.
(2) There is often a big difference between the glue temperature display and the actual glue temperature. It should be equipped with a 50 ℃ ～ 300 ℃ thermometer to test the glue temperature frequently.
In recent years, wireless perfect binding has become the main method of book binding. In particular, the continuous introduction of the bookbinding linkage line is gradually changing the traditional situation of extensive manual labor binding. Therefore, it is of great significance to explore and improve the perfect binding process and continuously improve the quality management level of perfect binding. This article throws a brick to attract jade, hoping to give more advice to peers.
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