1. Raw material mixing and plasticization
The production of Color Vest Bag must first prepare the raw materials. Polyethylene (PE) is usually selected as the main raw material because PE has good flexibility, stretchability and chemical stability. If you want to make a colored vest bag, the masterbatch is mixed with the polyethylene raw material in a certain proportion. Masterbatch is a particle containing a high concentration of pigment, which can make the final product present the desired color. Then the mixed raw materials are put into the extruder. The screw inside the extruder rotates under the drive of the motor to heat and extrude the raw materials. In this process, the raw materials gradually melt under the shearing and heating of the screw, and the temperature is generally controlled at about 150-200℃. Different polyethylene models may have different temperature requirements. The key to this step is to ensure that the raw materials are fully melted and evenly mixed, laying the foundation for the subsequent molding process.
2. Blow molding
The plasticized raw materials are extruded through the die head of the extruder to form a continuous tubular parison. At this time, the blow molding equipment is used to blow air into the inside of the parison. At the same time, under the action of the external mold, the parison begins to expand and fit the shape of the mold. The design of the mold plays a decisive role in the shape and structure of the Color Vest Bag. It not only determines the main shape of the bag, but also the shape and size of the handle part. The pressure of the blown air needs to be precisely controlled, generally between 0.2-0.8MPa. The appropriate blow molding pressure can ensure that the wall thickness of the bag is uniform and avoid the situation of being too thin or too thick in some parts. During the blow molding process, the parison gradually cools and shapes to form a prototype of the Color Vest Bag with a certain shape and size.
3. Printing (optional)
If the Color Vest Bag needs to be printed with patterns, text or logos, a printing process is required. Common printing processes include gravure printing and flexographic printing. Gravure printing has the advantages of bright colors, clear patterns and high resolution, and is suitable for printing complex patterns and high-quality images. Flexographic printing is relatively environmentally friendly and low-cost, and is suitable for printing simple patterns and a large amount of text information. During the printing process, the ink is transferred to the surface of the bag and then dried by a drying device to ensure that the ink is firmly attached to the bag. The printing process requires strict control of parameters such as the quality of the ink, the pressure, speed and temperature of the printing to ensure the consistency and quality of the printing effect.
4. Cutting and post-processing
Blow-molded (if there is a printing process, it is printed) Color Vest Bags usually exist in a continuous form and need to be cut to get individual bags. The cutting equipment cuts the continuous bags according to the pre-set size. After cutting, some post-processing processes may also be carried out, such as checking whether the bags have defects, counting and packaging the bags, etc. When packaging, a certain number of Color Vest Bags are usually packed into bundles or cartons for easy storage and transportation. The entire production process requires strict control of the quality of each link to ensure that the produced Color Vest Bags meet the relevant quality standards and customer requirements.
