In the structure of electronic products, the protective film is an indispensable part of it. Whether it is a mobile phone, a camera or a tablet computer, a protective film is attached to protect the product screen before leaving the factory. The transparency, flatness, and cleanliness of the protective film affect the consumer's impression of the electronic product. A good quality protective film will also enhance the external image of the electronic product. Therefore, the die-cutting factory has strict protection for the production of the protective film. Process control.
Protective film material selection
When producing protective films, there are several points to be noted in the selection of materials. First, we must choose materials that are more suitable for printing and die-cutting on the basis of satisfying customer requirements, such as good scratch resistance, good ink adhesion, and not easy to use ink.
Protective film production environment control
There are two key points in the quality control of protective film products. It is important to avoid scratches and dirt. To meet these two requirements, we must first have a good production environment. The die-cutting plant is equipped with an independent dust-free purification plant for protective film production. Clean room is also called clean room, clean room, and clean room. It refers to the removal of particulates, harmful air, bacteria, and other contaminants from the air in a certain space, and the temperature and cleanliness of the room. Pressure, airflow speed and airflow distribution, noise, vibration and lighting, and static control are all within a certain range of requirements and are given to specially designed rooms. Regardless of how the external air conditions change, it is required that the cleanliness, temperature, humidity, and pressure parameters that were originally set in the dust-free purification plant be maintained. According to the requirements of production products, the cleanliness of the dust-free purification plant is of the 100, 1000, 10,000, 100,000, and 300,000 different levels.
In a dust-free purification plant, in the dynamic case, the largest source of bacteria and dust is the operator. Therefore, when the operator enters the clean room, he must wear clean clothes and blow air in the air shower room with clean air for 15 seconds to remove the dust particles attached to the clothes surface.
Protective film printing process control
Most plastic films (such as polyolefin films) are non-polar polymers and have a low surface tension of 29-30 mN/m. Theoretically speaking, if the surface tension of an object is lower than 33mN/m, it is currently known. Both the ink and the adhesive cannot attach firmly on the surface, so the surface is corona treated. Most of the protective film material is polyolefin, corona treatment is required before printing, usually corona power is 4.0W, speed 30m/min. After corona, it takes 5 minutes to print on the machine, and if it takes more than 10 minutes, it needs to be re-corona to be on the machine. During the printing process, the surface of the material is scratched due to the contact of the protective film material with the embossing roller.
Protective film cutting process
After the printing of the protective film is completed, a circular knife cutting machine should be used for die-cutting. During the die-cutting process, care should be taken to avoid scratching and chipping. The concrete manifestation of the collapse of ink is that the edge ink layer of the product should be covered and smoothed. There is no local ink phenomenon.
The main reason for the collapse of the ink in the die cutting process is that the ink and the protective film are not firmly attached. When cutting the edge of the product, the ink layer and the protective film are separated, and a jagged edge is generated. Therefore, after printing the protective film, the adhesion of the ink should be checked to ensure that the ink adheres well before die cutting. In addition, when the thickness of the ink layer is too thick, the phenomenon of ink collapse occurs.
There are many reasons that can easily cause scratches in the die-cutting process. The most common is the uneven rotation of the nip roller, which causes scratches due to relative sliding of the material and the nip roller. Therefore, before the die cutting, the rotation of the nip roller should be inspected to ensure that the nip roller in contact with the material is flexible. In addition, foreign matter on the nip roller can also scratch the protective film and cause scars. Therefore, clean the nip roller with a clean cloth before cutting to ensure that the nip roller surface is clean and free of foreign materials. .
The die cut shape of the protective film is generally designed according to the customer's drawing requirements, and is mainly based on the screen size of the customer's mobile phone product, usually rectangular with rounded corners, and a handle in the lower right corner of the rectangle. The handle is printed on the back, and then covered with a PET film to facilitate the assembly of customers, but also to facilitate consumers to remove the protective film from the screen. All kinds of shapes of protective film are circular cutters when die-cutting, but the number of circular cutters used in complex crafts will increase. For example, two round cutters and one cut handle are needed to put the protective film on the handle. Another cut shape.
Protective film packaging process control
The protective film is usually roll-shaped after die-cutting is completed. The film is first cut into single pieces and each 500 pieces is packaged. When wrapping, the protective film is wrapped with a wrapping film and then placed in a plastic bag. The main concern in packaging is the degree of cleanliness. Therefore, the operator is required to wear the fingertips for manual operation. For example, there is a protective film product that requires manual post-grip handles. The operator is required to place the handle in the exact position of the protective film with the adhesive surface (ie inside), and to ensure that the product cannot be contaminated and there is no foreign matter. All the above processes are required to be completed in a dust-free purification plant.
The mobile phone protection film looks simple and the production process is not complicated, but each link is more stringent. In general, always pay attention to the degree of cleanliness, and avoid bending and scratching the protective film. It is the above details that determine the product's grade.