BS ISO 16763:2016 pdf download – Graphic technology — Post-press — Requirements for bound products Perfect binding In perfect binding, the folds of the gathered signatures shall be milled off. If single sheets are being bound, then they can be built up to form the block without the need to grind anything off. Depending on the paper thickness and the number of pages per signature, the depth of milling shall ensure the separation of the block into individual sheets. Notching and roughening may be applied to improve the adhesion. During all these processes the alignment of the signatures shall be kept. The milling shall be even across the spine. There should be no printing, varnishing or previously applied glue in the area reserved for gluing, which should also be free of dust. Application of spine and side glue The coating layer of the adhesive should be bubble-free and uniform with a thickness in accordance with the technical specification of the glue manufacturer. The operating temperature of the adhesive and any other operational requirements shall be in accordance with the technical specification of the glue manufacturer. Glue penetration of more than 1,0 mm on a significant number of pages should be avoided. The thickness of the side glue should be kept as low as possible. Excess glue shall not be visible anywhere in the final product.
4.5.2 Thread sewing Thread sewing should be used for products of high durability, frequent usage and also for papers with a high basis weight. The thread used shall be stronger than the substrate. The stitches shall be evenly distributed on the spine fold. The stitching holes shall align with the centre fold with a deviation tolerance of ±0,5 mm. The tension in the thread should be such that the signatures are bound tightly together without there being any wrinkles or tearing. Any torn thread or missing stitches shall be avoided. Any signature of the thread sewn book block shall be aligned to the head with a tolerance of ±0,5 mm. For a good bonding of the signatures of a book block, the number of stitching groups should correspond to the spine length, the stitching arrangement in Table 2 is recommended. Staggered stitching should be used to avoid spine build-up, if necessary. The thread sewing process shall be followed by the process of gluing-off the spine. The requirements of apply.
4.5.3 Thread sealing Thread sealing is carried out following the folding process, where thread staples with a thermoplastic coating shall be pushed from the inside to the outside of the sheet prior to the last fold and then the thread ends shall be laid out backwards and fused to the spine of the sheet by pressure and heat. The staples shall align with the binding edge with a tolerance of ±0,5 mm. The staple length should be more than 12 mm, the spacing between the staples should be less than 38 mm. The thread sealing process shall be followed by the process of gluing-off the spine with a lining stripe. The requirements of apply.
NOTE Thread sealing is considered as an alternative to thread sewing or perfect binding.
4.5.4 Lock-stitching Lock-stitching (saddle or side) should be used for combining a low number of signatures or sheets with a maximum spine thickness of 6,0 mm. Although thread is used in these methods, the methods are not described as thread sewing. There should be three to four stitches per 10 mm. For side lock-stitching, there should be a space of 4,0 mm ± 1,0 mm between the centre fold and the stitching line.
4.5.5 Saddle-stitching Saddle-stitching may be applied to the binding of single-layer blocks. The maximum block thickness is related to the staple format. Blocks stitched with flat staples should have a maximum thickness of 8,0 mm. Blocks stitched with Omega staples should have a maximum thickness of 6,0 mm with a loop diameter of 6,0 mm. The gauge of the wire used for the staples should be dependent upon the block thickness (see Table 3). The distance between each staple (outer staples if there are more than two) and the nearest edge a or c should be equal with a tolerance of 3,0 mm (see Figure 4). The distance between the two staples b should be greater than one third of the height of the product. For the Omega format, the position tolerance should be ±2,0 mm and the Omega staple formation tolerance should be ±1,0 mm.BS ISO 16763 pdf download.