Detailed Introduction to the Process Flow of Coffee Filter Production by Rotary Die-Cutting Machines

The production of coffee filters by rotary die-cutting machines is a continuous, efficient and standardized process, which is mainly composed of six sequential links, each of which is closely linked and indispensable. The whole process adheres to the principles of food safety and production efficiency, ensuring that the produced coffee filters meet the requirements of precision, air permeability and safety.

First of all, raw material preparation and inspection is the foundation of the whole production process. Food-grade filter paper is selected as the raw material, which is mainly made of natural wood pulp, bamboo pulp or their mixture, and some high-end products will adopt composite filter paper with waterproof layer to prevent breakage during brewing. Before entering the production line, the filter paper must go through strict quality inspection, focusing on detecting key indicators such as thickness, grammage, air permeability and surface flatness. Only qualified raw materials can be put into subsequent production to avoid affecting the die-cutting effect and product quality.

After the raw materials are qualified, the second link is unwinding and tension adjustment. The filter paper is loaded onto the unwinding device of the rotary die-cutting machine, and stable tension must be maintained during the unwinding process to prevent the filter paper from wrinkling, stretching or tearing. The tension value is flexibly adjusted according to the thickness and tensile strength of the filter paper, generally controlled between 5-10 N. At present, most advanced rotary die-cutting machines are equipped with automatic tension control systems, which can real-time monitor and adjust the tension, ensuring the stability of filter paper feeding and laying a good foundation for subsequent die-cutting.

The third link is optional preprocessing, which is mainly aimed at special coffee filters such as hanging ear coffee filters. Common preprocessing steps include creasing and gluing. Creasing is to press clear folding lines on the filter paper to facilitate subsequent folding and forming; gluing is to apply food-grade adhesive on the edge of the filter paper to ensure that the filter can maintain a fixed shape after die-cutting. The preprocessing is completed by the auxiliary rollers on the equipment, and the crease depth and glue application amount must be strictly controlled to avoid affecting the use effect and appearance of the filter.

Rotary die-cutting forming is the core link of the whole production process. The die-cutting roller equipped with a customized die and the pressure roller rotate at the same speed, and the filter paper passes smoothly between the two rollers. Under the action of pressure, the die on the die-cutting roller cuts the filter paper into the preset shape and size. The design of the die is determined according to the type of coffee filter: fan-shaped filters need a die with fan-shaped cutting edges and central holes, while hanging ear filters need a die that can cut the main body, hanging ears and ventilation holes at one time. During this process, the synchronization of die-cutting speed and feeding speed, the pressure between the two rollers and the alignment of the die are key parameters, which directly affect the cutting effect and product precision.

After die-cutting, the fifth link is waste removal. There will be waste edges left on the filter paper after die-cutting, which need to be removed in time to ensure the cleanliness of the finished product. The waste removal work is completed by the waste collection device on the rotary die-cutting machine: the waste edges are rolled up by the waste roller, and the finished filter paper is separated from the waste edges and sent to the next link. In this link, it is necessary to adjust the tension of the waste roller and the distance between the waste removal device and the die-cutting roller to ensure that the waste edges are separated smoothly without damaging the finished filter paper.

The last link is finished product inspection, folding and packaging. The finished filter paper after waste removal is first inspected for quality, focusing on checking whether there are missed cutting, burrs, uneven size and damage. Unqualified products are manually removed, and qualified products are folded into the required shape by the folding device. Then, the folded filter paper enters the automatic packaging machine for packaging. The packaging materials must be food-grade, and the packaging process must ensure that the filter paper is neatly arranged and the packaging is tightly sealed to avoid pollution. Finally, the packaged products are labeled, coded and stored in a clean and dry warehouse to complete the whole production process.