With the development of the packaging industry in China and the needs of the market, the printing slotting die-cutting process and the post-press line process in paper products have become the common production of the carton industry due to its high production efficiency, simple and convenient operation, and good carton forming. Process. Its integrated production equipment is widely used by cartons, and its technology is increasingly valued by people. This production process is unmatched by general printing slot machines. This production process allows printing, slotting, and die-cutting to be completed on one device at a time.
However, if the good production equipment is poorly controlled, quality problems will occur at different levels. In this paper, the paper only analyzes the problems such as inaccurate dimensions, broken vertical lines, incomplete slotting, burrs, broken lines, broken lines, and inconsistent line widths during the carton forming process.
Inaccurate size of the problem causes and solutions
Raw paper tightness, causing cardboard warping
The tightness of the original paper is not good, that is to say, the base paper is relatively loose, and the heat shrinkage is severe, resulting in warp and deformation of the cardboard, which is one of the reasons for the dimensional inaccuracy. Excessive moisture or warpage of raw materials and corrugated board is also a cause for inaccurate dimensions. Under normal circumstances, the lower line of corrugated board moisture is basically about 10% to 14%, but if the off-line moisture is 14% -18% or higher, it is more humid. If the cardboard is printed directly after the thread is cut, the size is more accurate. However, for a period of time, when the water content is less than 10% after the water is dispersed, the cardboard will be retracted, the overall paperboard size will be smaller, and the size of each part will be different. The 1m-long paperboard will shrink by about 4mm~6mm. Therefore, it is very important to grasp the moisture of paper and board. Each batch of cardboard must be measured with a quick moisture meter moisture content, depending on the size of the water to arrange the printing slot cutting time. If the moisture is too large, it must be placed in the cardboard for 4 hours after the line is dried and then the next process of production, the general factory delivery of water in the 10% ± 2. This is also the reason why the size of an ordinary carton company when it is produced is accurate, but the reason why the size becomes smaller after putting it under natural conditions for a certain period of time.
Carton size is not allowed
The size of the carton is inaccurate when the production size is down or the adjustment error when changing the order, which is mainly caused by the operator is not serious. This problem will be avoided if the normal production is carefully examined.
The vertical line breaks the problem reason and the solution
Vertical line pressure is too large
When the board enters the pinch roller operation, the pinch rolls smash the board, causing the board's inner or front paper to break in the corrugated direction. To solve this problem, it is necessary for operators to adjust the pressure of the vertical line pressure roller according to the thickness of the paperboard. Under normal circumstances, the depth of the three-layer paperboard roll line is preferably 2mm-3mm pressed into the paperboard. However, during normal production, the operator should adjust the pressure according to the quality of the base paper, so as not to crush and fold
Unreasonable pressure roller
The most commonly used in cardboard press lines is convex to concave. Because of the different paper quality, production environment factors, and the thickness of the paperboard, the structure of the pressure roller used is also different. The main parameter is that the width of the upper and lower pressure roller should be appropriate, and the step transition arc of the pressure roller should be adjusted according to the depth of the pressure line and the applicable cardboard. In general, the thicker the cardboard, the corresponding larger width of the pressure line, for the three-layer paperboard can also use the arc surface of the pressure line wheel. Therefore, there is no uniform structure for the reel, and the length of the carton is required to find the suitable reel structure according to its actual situation.
Solution
1 The structure of the pressure roller is improved, and the structure of the pressure roller is adjusted, and the step transition arc radius of the pressure roller can be appropriately increased;
2 The pre-compression failure method is adopted, and the pre-compression is performed before the formal pressure line. The disadvantage is that it forms a relatively obvious pressure line trace;
3 requires that the quality of the base paper is better, for the relatively high requirements of the paperboard should use good quality paper and paper;
4 The moisture content of the base paper and paperboard should be appropriate. The worse the quality of the base paper, the drier the paperboard, the higher the chance of cracking the pressure lines;
5 properly control the depth of the pressure line. According to the thickness of the processed paperboard, the gap between the upper and the lower pressure roller can be controlled so that the paperboard can obtain the proper pressure line;
6 control the alignment of the center line of the upper and lower pressure wheel to prevent misalignment of the pressure wheel;
7 For the paperboard with poor quality paper, touch the threader with a threader;
8 If it is due to the paperboard drying caused by the cracking of the pressure line, you can use water spray to increase the water content of the cardboard.
The cause of paperboard burr and its solution
Loose tool
The looseness of the tool is mainly caused by human factors. When the tool is adjusted, the tool is not fixed firmly or the screw is loose, causing a "runner". The solution is relatively simple, just recalibrate and solidify the tool.
Tool wear
This problem is generally a natural wear. Just check the tool in time and change the tool in time.
There are several reasons for the dampness of paperboard. First, the high moisture content of the base paper, the high machine speed, and the insufficiency of moisture in the production line; the other hand, caused by the rapid recovery of paperboard after the output of paperboard; High humidity, caused by bad weather. To solve the above problems, we must start from the following aspects: first, replace the base paper, use the base paper with a moisture content of 12% to 14%, and suspend it beyond 14%; second, reduce the machine speed and improve the dryness of the board. The third is the replacement of the base paper, the use of tight raw paper for production; Fourth, increase the industrial fan and other dehumidification equipment, and strengthen the artificial dehumidification.
Hand pressing process problems and solutions
The problem of the problem of not folding double lines and the solution
Under normal circumstances, the indentation line that is manually operated by the crimping machine (or called the line-impacter) is double-lined when folded in the direction of the facing paper. The so-called non-double-line is that the folding line is not straight and the two-indented indentation Not obvious or imbalanced, resulting in no double line. The reasons are: First, the normal wear of two knives, the two ends and the pressure caused by the inconsistency; Second, the lower ridges are not centered, resulting in indentation line offset, the formation of a reflex is not double; Third, the device itself is not adjusted , The pressure at both ends is inconsistent, while the large side is small, causing the refraction not to appear double.
Solution
According to the wear condition of the two knives, cutting and grinding are performed in time to balance the two sides with the middle;
According to the double-line situation of reflexion, timely adjustment of the lower rib to make it in normal condition;
According to the operation of the equipment, please ask maintenance personnel or operating technicians to adjust the equipment so that it is in the best condition.
Even after the above measures are taken, during the operation, attention is also paid to spot checks in the course of operation to avoid the correctness at the beginning, and the above problems occur slowly. Therefore, the operator is required to perform necessary and regular spot checks during normal operation.
The specifications are inaccurate, the causes of the pressure lines and their solutions
Under normal circumstances, the pressure line specifications should be accurate. However, this is not the case during actual operation. With the vibration of the crimper, some tightening wires will loosen, and there will be problems with inaccurate specifications and pressure lines. It is normal to have such a problem, but as long as the reasons are carefully analyzed, there will be solutions. The reasons for its formation are: First, the loose or loosening of the fastening wire leads to inaccurate specifications, and the pressure line runs. Second, the operator does not reach the position when pushing the paperboard. Third, the operator does not use the baffle high enough. Pushing the baffle results in inaccurate specifications. Fourth, the technicians are not careful when adjusting, and the specifications are adjusted incorrectly, resulting in inaccurate specifications.
Solution
When the operator adjusts the specifications, the fastening wire is fastened firmly, and the worn fastening wire is replaced in time;
When pushing the cardboard, the operator must use even force and push it in place to prevent unnecessary loss;
To adjust the height of the baffle, in general, 50*50*5 angle steel or 70*70*7 angle steel can be used as the rule baffle, which can effectively avoid the specification inaccuracy caused by push offside and thus cause unnecessary Loss;
Require technical staff to strengthen the sense of responsibility, adjust the specifications, should first use a bad cardboard pressure test, review the pressure line specifications to ensure that the specifications are accurate.
The reason for the inconsistency of the line width at both ends and its solution
Under normal circumstances, the line width of the pressing machine is the same. According to the standard, the width of the three-layer box is 10mm-12mm, and the width of the five-layer box is 16mm-18mm. Of course, the width of the press line is sometimes adjusted according to the customer's requirements. For example, some customers require the press line width of the three-tier box to be 8mm. The company must adjust this standard in order to meet customer requirements. The line width at both ends is inconsistent. That is, one line is narrow and one line is wide. The main reasons are: First, the technicians adjust the inconsistency when the width of the line is adjusted; second, the fixed line that controls the line width is loose.
Solution
After adjusting the line width, the technician should first test the pressure with a bad cardboard, and review the width of the pressure line to ensure that the line width at both ends is consistent;
Periodic review of the width of the pressure line to ensure that the control line width of the fixed wire during normal production is not loose, even if loose and can be found in time to avoid unnecessary losses.
The problem of cracking on the paper or liner in the press line and its solution
Under normal working conditions, when the line is pressed, the cardboard of the line is folded, the line is straight, and the folding angle is a rounded arc angle; when folded, it is double lined and the box is good. However, when there is a crack or a crack in the paper or paper, it will affect the quality of the box. The reasons are as follows: First, the surface paper or the paper fiber is short, and it is not resistant to folding; second, the cardboard is too dry when going offline; thirdly, the pressure is higher when the line is pressed; and (4) the width of the pressure line is too narrow.
Solution
Replace some good quality facial paper or paper;
Adjust the moisture content of the cardboard off-line, and solve the problem of the paperboard that has gone offline through spray and other resurgence;
According to different types of corrugated cardboard and three, five, seven cardboard thickness adjustment of the pressure of the press;
The line width of the three-layer box should not be less than 8mm. If it is lower than this standard, there will be cracks in the best surface paper or inner paper.
At present, there are many carton enterprises that have adopted automatic pressure line equipment and the efficiency has increased exponentially. However, these problems still exist in the carton forming process. This requires the cartons to effectively control these issues during processing. It is normal for these problems to appear once, but it is abnormal to have no effective control after they appear. The key to the improvement of product quality is the self-control of the process and the perfect process.
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