A simple method to improve the traditional hot stamping machine, the hot stamping efficiency has increased by 20%

As we all know, hot stamping can improve the grade of paper packaging products and increase the added value of products. It is a popular post-printing process. Temperature, pressure, and speed are the three core elements of hot stamping. If they are not well controlled, it will greatly affect the quality of hot stamping. In this paper, the author mainly made innovations and improvements to the traditional hot stamping machine in terms of temperature control, and improved the hot stamping suitability of paper packaging.

Heating method of traditional hot stamping machine

At present, the heating method used by the roll paper hot stamping equipment (roll paper round press round hot stamping machine or roll paper flat pressure flat hot stamping machine) is to fix the hot stamping plate (circular plate, flat hot plate) on the heating honeycomb plate seat Conduction heating on the upper surface (generally 50-250°C, adjustable), and then through the temperature and pressure of the hot stamping plate, the fusible thermoplastic glue in the anodized aluminum adheres to the printing material, thereby completing the transfer of the anodized aluminum.

1. Defects of traditional heating methods

In the actual production process, due to the difference in the temperature control performance of the equipment itself, the difference in the quality stability of the anodized aluminum, the change in ambient temperature, the fluctuation of the tension on the surface of the printing material (such as varnish, ink) and other characteristics, the actual hot stamping process often occurs due to electrochemical changes. Quality problems such as blooming and incompleteness caused by poor aluminum stripping affect the hot stamping efficiency.

2. Traditional solutions and their problems

To solve the above-mentioned problems, methods such as raising the temperature of the bronzing plate, reducing the production speed, and replacing the anodized aluminum are generally used to solve them. However, these methods have the following limitations and cannot be completely solved.

(1) Generally, the maximum temperature of the current bronzing equipment can only reach about 250℃, and it is more difficult to heat it up.

(2) The overall heating method of the hot stamping plate is not flexible, and it is not possible to accurately locate and raise a certain position independently. Some positions that just adapt will cause new hot stamping problems due to the increase in temperature.

(3) Will increase energy consumption, thereby increasing costs.

(4) The purpose of reducing the machine speed is to extend the hot stamping time and transfer more anodized aluminum, but it will significantly reduce the production efficiency.

(5) The method of replacing anodized aluminum has high requirements on the quality of anodized aluminum, and frequent replacement will cause multiple downtimes, which in turn will generate a lot of waste.

improve proposals

Produce a set of online pre-heating device, including 3 to 6 movable plug-in hot air generators, infrared temperature feedback sensor, 1 set of fixed bracket, temperature controller, before the printing material (paper) enters the hot stamping plate cylinder, pre-align The position of the paper to be hot-stamped is controlled by preheating.

1. Warm-up purpose

(1) Increase the surface temperature of the paper. Generally, the surface temperature of the unpreheated paper is between 22-28 ℃, while the surface temperature of the pre-heated paper can reach 50 ℃, which is equivalent to the temperature of the hot stamping plate at about 0-20 ℃. The increase can effectively compensate for the problems of the hot stamping plate temperature cannot continue to rise and local temperature unevenness.

(2) By preheating, the surface tension of the paper to be hot stamped can be changed, so that when the printing material enters the hot stamping station for hot stamping, the anodized aluminum glue layer can better bond with the paper surface, thereby reducing the loss of anodized aluminum. Quality defects such as blooming and incompleteness caused by poor film.

2. Precautions for paper preheating

Generally, it is recommended that the preheating temperature be around 50℃ or below, too high will cause the paper to deform; multiple independent preheat generating devices can be made, which can be moved and selected flexibly. Each preheating unit can also carry out individual temperature control according to the actual situation to prevent reasonable control when the equipment temperature is uneven.

Improved effect

After the device is used on the Stoner Web 820 round press round hot stamping machine, compared with the current single hot stamping plate heating method, it solves the temperature limit of the hot stamping plate, changes the surface characteristics of the printing material, and improves the anodized aluminum glue layer and the printing paper Adhesive firmness reduces the problem of hot stamping. It is estimated that the machine speed can be increased by 5-10m/min, and the efficiency can be increased by 20%.