When a customer complains about the binding quality of certain folded products, folding is one of the important processes in the binding process, and it is often easy to be the focus of accusations. In fact, the various defects and deficiencies manifested in the binding process of products are not entirely the responsibility of the folding department, and sometimes they are totally irrelevant. The following quality failures all seem to be related to the quality of folding, but this is not necessarily the case.

Broken line position and color line do not coincide

When designing a folded product, the effect of paper thickness on the quality of the fold must be taken into account. In general, in multiple foldings, the size of the folded-in pages must be slightly smaller than the outer pages, that is, the design department must give a certain amount of cutting compensation in order to increase the actual cutting amount. If the compensation amount is too small. The internal pages will interfere with other pages due to their large size. The pages are in a collision with each other, making the external pages arched, and the entire book is less flat. Therefore, for multiple folding, it is better to clearly give the compensation amount in the design process. Otherwise, once the document with this design defect is sent out, the binding department as the last line of defense will have to compensate for the cutting amount of the page in the folding process. At this time, if the folding line position of the product is exactly the same as the color When the boundaries are overlapped, actual misalignment will result from cutting compensation.

Inflation page size is small

Normally, the standard crop compensation amount for a single page is 1.5mm to 3mm. However, if multi-layer paper or thick paper is used, it is necessary to appropriately increase the cutting compensation amount of the inset page. However, if the compensation amount is too large, the actual size of the infolding page will be too small due to the large amount of actual cutting. In reality, we often see this practice: the design department did not specify or set the amount of cutting compensation in the design sheet, but instead tried to save time and directly required the binding department to solve the issue of cutting compensation. This type of practice is especially common in some simple folding operations. For example, when designing a direct mail envelope for sending bank statements, the shorter page should be about 2mm smaller than the other two long pages. However, most practices bypass the design process. Cut the size of the third page directly to a relatively short size. In order to fundamentally prevent the inner folding page from being oversized due to the actual cutting amount, the problem of small size is caused. It is best to directly specify the cutting compensation amount in the design sheet. In general, it is necessary to specify that the cutting compensation must not exceed 3mm.

The paper cracks at the fold line

When the fibers of the paper are stretched too far apart. Paper cracking will occur. If this happens in the field, the result is particularly bad. There are many reasons for the occurrence of paper cracking, such as indentation before folding; the moisture content of the paper is too low; the folding roller is not set correctly. Among them, the first reason is the most common. No matter what kind of print product. Customers want the cost to be as low as possible and the added value of the product can be as high as possible. In the case where the customer recognizes the importance of product added value and appearance effects, the relevant department of the printing and processing unit needs to advise the customer to carry out indentation processing before the folding, allowing the customer to willingly increase the cost input. Under normal circumstances, if the folding direction of the paper is perpendicular to the direction of the silk, the area where the fold line passes through the ground, the thicker ink layer, the larger amount of paper, or the cover of the book, etc., the fold line must be indented in advance. Get clear and accurate polylines.

Paper creases at corners

In multiple vertical folding. The corners of the page (near the intersection of the fold lines) are easily wrinkled. To avoid such phenomena, we must take appropriate preventive measures. Common reasons are:

The 1 folding sequence is unreasonable, so that the folding pressure is too high and the paper at the hinges is wrinkled.

2 folding process is unreasonable. The air is trapped inside the signature and cannot be discharged smoothly, affecting the folding effect. For example, two parallel folds are performed on the page first, and then two parallel folds in the vertical direction. This solution can easily cause air stagnation inside the signature.