Die-cutting and indentation process

First, the outline of the processing process <br> The process of the general die-cutting indentation process is:

On the plate → adjust the pressure → determine the rules → adhesive rubber → pressure die-cutting → formal die-cutting → cleaning and scrapping → finished product inspection → point packaging.

Second, the processing process

In the case of a carton, which is the main object of die-cutting and indentation processing, the process of blanking, printing, surface processing, die-cutting, indentation, and box making is generally required.

A die plate is to be made before the die-cutting indentation. The position of the die-bonded plate must conform to the printed space. Then, the post-printed cardboard is processed on the die-cutting machine using a die-pressing process.

The prepared impression plate will be installed and fixed in the plate of the die-cutting machine, and the initial adjustment of the position will obtain the initial die-cutting indentation effect as the upper plate. Before the edition, it is required to proofread the die-cut indentation plate and confirm the compliance with the requirements before starting the plate-making operation.

Then adjust the layout pressure. It is generally divided into two steps. First adjust the pressure of the steel knife: After padding, first press the print several times in order to flatten the steel knife, close the plate, and then use the cardboard with an area larger than the die-cut version (usually used 400 ~ 500g/m2) pressure test, according to the steel knife cut in the cardboard cuts, the use of partial or all gradually increase or decrease the number of layers of paper, make the layout of the knife line pressure uniform to achieve; then adjust the steel wire The pressure; general steel wire 0.8mm lower than the steel knife, in order to make the steel wire and steel knife get the ideal pressure, according to the nature of the molded paperboard pressure on the steel wire. The adjustment is based on the thickness of the board as the main factor to consider, generally based on the thickness of the paperboard being pressed, using the theoretical calculation method or a test-based empirical estimation method to determine the thickness of the paper.
The formula for calculating the potential paper thickness using theoretical calculations is as follows:
X=(steel blade height - steel wire height) -h

In the formula: X is the thickness of the pad; h is the thickness of the pressed cardboard.

The rule is the basis for determining the position of the processed board relative to the stencil in die-cutting and indentation machining. After the layout pressure is adjusted, the stencil should be fixed to prevent misalignment in the press. When determining the position of the rules, a reasonable selection should be made according to product specifications. Generally, the principle of centering molded products should be as far as possible.

After confirming and pasting the positioning rules, several test pressures should be taken and carefully examined. For folding cartons, inspections of specifications, quality, etc. should also be made.

Eraser sticks in the main steel blade of the stencil. On both sides, the role of Renan Rubber's elastic restoring force can push the die-cut cardboard out of the cutting edge. The rubber should be 3 to 5mm above the knife edge, as shown in Figure 13-12.

Figure 13-12 Sticking eraser

1- lined empty material 2- steel knife 3-rubber

After all adjustments are ready, proofs should be molded first and a comprehensive inspection should be conducted to see if the product's specifications meet the requirements. After confirming that all items in the inspection are up to the standards and leaving proofs, you can officially start production. Every working day, the requirements of the product should be reviewed once more so that problems can be detected and dealt with early.

After the die-cut indentation process, the excess edge material should be removed, which is called stripping, also known as blanking, chip removal, tearing, and pushing the core. The core is removed from the bad material and cleaned. The cuts of the cleaned product should be smooth and smooth. If necessary, the cuts should be sanded or scraped with a spatula.

After clean-up and inspection of finished products, after the product quality inspection is qualified, the number of points will be packaged, and the defective products will be removed from the points. The error shall not exceed 2/10000 to 3/10000.

Third, process parameters and their effects

The main process parameters in die-cut indentation processing are die-cutting pressure, working web size and die-cutting speed.

The size of the molding machine's working ability is determined by the size of the die-cutting pressure. In the molding process, due to the different processing objects and requirements, it is generally necessary to calculate the force required by the molding press to select and adjust the machine and guide the molding process. .

There are several ways to determine the size of die-cutting pressure. The formula for the calculation of die-cutting pressure is as follows:
P= KσA

Where: P is the force required for molding; σ is the shear stress value per unit area in the molding, its reference value is shown in Table 13-l; A is the actual area of ​​the press-separation surface and can be calculated according to the thickness and perimeter of the die-cut material; K is a factor that considers the actual conditions of the molding process and various technical factors. The value of K ranges from 0.76 to 1.34.

In the actual production at the factory, the test method is used to determine the value of the cutting force F on the length of each unit, and then the size of the die-cutting pressure is calculated, that is, a certain length of steel knife is installed on the press used for the test material. Steel wire, put the paperboard to be processed again, pressurize the paperboard until the required line marks are cut off and pressed; record the pressure only reading at this time, repeat 10 times, take the average, and then measure the Pressure P; divided by the total length of the incision and the pressure line l, you can find the average cutting force per unit length F = P1/l.