Fifth, preheating of hot melt adhesive
Hot melt should be warmed up before use. Preheat the solid hot melt glue into the preheated glue pot, heat the temperature around 160°C～200°C, preheat for 1～2 hours, wait until the heating temperature and have good fluidity, and then Put the preheated hot melt adhesive into the plastic tank with the green machine at 160°C～180°C, before it can be used normally. The heating temperature of the hot melt adhesive is closely related to the fluidity and adhesive strength of the adhesive. Therefore, when the hot melt adhesive is heated, the temperature must be strictly controlled. The heating temperature should not be too high or too low, and the temperature range should be strictly controlled within the technical parameters provided by the manufacturer. Generally, the heating temperature and the sizing temperature of the hot melt adhesive are controlled within a range of 170°C to 180°C. If the temperature is too high, the fluidity is good, and the permeability to the pages is also strong, but the bond strength will drop; the temperature is too low, the bond strength will rise, but the fluidity of the glue will decrease, and the pages will not be firmly connected. Bonding, degumming, loose-leaf quality problems. If the hot-melt adhesive temperature exceeds 200°C, the hot-melt adhesive may be carbonized and cracked. Hot melt adhesive should not be put for a long time, try to avoid repeated melting and solidification.
Sixth, the glue on both sides of the back and back of the book block
The glue glue is glued on both sides of the back and back of the book block. After the book block is milled back and grooved, the hot melt glue can bind the book page to the book page. The binding between the book block and the cover becomes a Book. The adhesive has the difference between adhesive and side adhesive. Their fluidity, open time, and curing time are all different. The adhesive temperature should be controlled at 170°C to 180°C, and the thickness of adhesive glue is generally controlled between 0.6 and 2mm. The adhesive layer should be even, and the thin glue on the back can affect the bond strength. The back glue can be thick and increase the cost. The length of the adhesive should be slightly shorter than the cover size of 1 to 2mm. If it is too long, it will cause the remaining glue to accumulate the mechanical transmission components, causing it to malfunction. If the length is too short, it will cause the back of the book and the legs to become empty and affect the quality. When upper side glue is between the book block and the cover, the side glue must use hot melt adhesive with good flowability, long opening time and curing time, and strong bonding layer. The temperature of the side glue is controlled around 160°C~180°C. The width of the glue is generally about 4 to 6mm. The thinner the glue on the side, the better, and the firm bonding is required to ensure the quality of the book and the cutting requirements. Do not use gum as a side glue, otherwise it will make the book cover on the cover line, affecting the quality of the product.
VII. Causes and elimination of common breakdowns of bookbinding
1. Book degumming, loose leaflet
(1) The depth of book block milling back is not enough, and the book page is not completely milled into a single page, causing the book not to be degummed or loose, and the depth of the back should be increased. (2) The distance from the groove is not proper, the depth of the groove is not enough to cause the degumming and loose pages of the book, and the distance and depth between the grooves should be adjusted; (3) The temperature of the hot melt adhesive is too low, and the fluidity and permeability of the glue cause the debonding of the book. , loose leaf, should be heated to about 170 °C ~ 180 °C hot melt adhesive. (4) The book back hot melt adhesive is too thin to cause the degumming and loose pages of the book, and the thickness of the back glue should be controlled. Generally, it is controlled between 0.6 and 2 mm. (5) If the use of the hot melt adhesive model causes improper degumming and loose-leafing of the book, the hot-melt adhesive of the guide type and season matching should be selected.
2. Books are not square
(1) The use of an unsharpened milling back tool causes the back of the book to be out of squareness, and should be replaced with a sharp milling backing knife; (2) Uneven backing caused by uneven backing of the book is not square, and the glueing mechanism should be adjusted so that the back rubber is uniform on the upper limbs. (3) Improper setting of improperly established institutions causes the back of the book to be out of squareness, and it is necessary to adjust the established institutions.
(4) Uneven finishing of the signatures causes the back of the book to be out of squareness. It should be sorted out to ensure the quality of the signatures.
3. The cover is uneven and the cover is clearly visible
(1) The amount of side glue is Dawen, which causes the cover to be uneven, the cover line is obvious, and the amount of side coating should be controlled; (2) The humidity of the side glue is too low and the uneven side coating causes the cover to be uneven and cover. The squall line is obvious, and the temperature of the side glue gluing should be increased. Generally, the temperature is controlled at about 160°C to 180°C.
4, book cutting size is not accurate
The cutting size of the book is inaccurate, and the three-side cutter cutter dimensions should be adjusted.
In short, as long as we continue to grope and sum up experience from practice, conscientiously understand the material's performance, master the appropriate process parameters, and strictly operate on the process, we can obtain satisfactory glue-binding products.
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