1 The quality requirements for hardcover shells include the specifications of the cover cardboard, medium-diameter cardboard, and soft cover materials and their technical specifications.
2 The various materials and production requirements for the production of book shells are different according to the thickness of the book block, the size of the open book, and the shape processing. The regulations are as follows:
3 Middle seam size: When the thickness of the cardboard is 1.5-3.0 mm, the width of the middle seam is 7-10 mm.
4 Middle diameter width: When the book shell is round back, the middle diameter width is the arc length plus the width of the two middle seams. When the back is squared, two widths are added for the back width of the book. Add two cardboard thicknesses to the back ridge.
5 floating mouth width of 2-4 mm.
6 Wrap width 12-16 mm, width 10-15 mm.
7 cover cardboard: the length is equal to the length of the book block plus the width of the two flaps, and the width is 2-4 mm shorter than the width of the book block.
8 medium diameter cardboard length: equal to the length of the cover cardboard. Medium-diameter cardboard width: when the book shell is square back, it is the same thickness as the book block; when the book shell is a square back artificial ridge, the thickness of two cardboard should be added; when the book shell is round back, it is the same as the arc length.
9 interface book waist: the length is equal to the length of the cover cardboard plus the width of the two hem. The width is equal to the width of the middle diameter plus the width of the two joining edges.
10 Then the surface material of the book case: the length is the same as the length of the book's waist, or 3-5 mm larger, and the width is about 7 mm wider than the cardboard.
11 The surface material of the entire book cover: the length is equal to the width of the middle, the width of the two cardboard shells and the width of the two hem. The width is equal to the length of the cardboard in the bookcase plus two edging widths.
12 Book pouches: The length is about 5 mm less than the length of the book block, and the width is the width or arc length of the back of the book.
13 The length and width of the bookcase inner paper should be within the envelope of the bookcase cover, with an error of 3 mm.