How to make a Disposable lunch box?
How Disposable Plastic Lunch Boxes Are Produced at High Speed!
Preliminary Preparation: Careful Preparation of Materials and Equipment
Raw Materials: PP - The Core Foundation of Lunch Boxes
Equipment: Professional Equipment Is the Guarantee of High - Speed Production
Core Equipment - Haijiang High - Speed Injection Molding Machine: In the high - speed production of disposable plastic lunch boxes, the Haijiang high - speed injection molding machine is definitely the well - deserved protagonist. As mentioned before, the walls of lunch boxes are very thin, so a large injection pressure is required to ensure that the PP material can quickly and evenly fill the mold cavity. The Haijiang high - speed injection molding machine precisely has such an advantage. It is equipped with a larger oil pump that can provide strong power support. At the same time, it is equipped with a servo motor, making the injection molding process more accurate and efficient. Moreover, during the production process, the Haijiang high - speed injection molding machine can also make the surface of the lunch boxes more smooth and beautiful.
Auxiliary Equipment:
Dryer: Although PP materials do not absorb water strongly, they will still absorb a certain amount of moisture in a humid environment. If PP with moisture enters the injection molding machine, the produced lunch boxes may have defects such as air bubbles and silver streaks, affecting product quality. The function of the dryer is to remove the moisture in the PP materials and ensure the smooth progress of production. Generally, the drying temperature is set between 80 - 100 degrees Celsius, and the drying time is 2 - 3 hours.
Feeder: It is responsible for accurately conveying the dried PP raw materials and the mixed color powder or masterbatch into the injection molding machine. The feeder realizes automated feeding, which not only improves production efficiency but also reduces errors and labor intensity that may be caused by manual operation. Just imagine, without a feeder, workers would have to pour the raw materials into the injection molding machine bucket by bucket. How tiring and inefficient that would be!
Crusher: During the production process, some scraps, unqualified lunch boxes, or waste materials generated during machine debugging are inevitable. This is where the crusher comes in. It can crush these waste materials into small pieces and put them back into production, which is both environmentally friendly and saves raw material costs. It's like turning "garbage" into "treasure", recycling and reducing the production costs of enterprises.
Color Mixer: This is an important equipment for adding colors to lunch boxes. Put the PP raw materials and color powder or masterbatch into the color mixer according to a certain proportion. Through actions such as stirring and tumbling, they are fully and evenly mixed. The mixing proportion and time are crucial. Different proportions will produce different color effects. Generally, the mixing time is about 15 - 30 minutes, and the specific time needs to be adjusted according to the actual color requirements and the performance of the color mixer.
Chiller: The injection molding machine generates a large amount of heat during operation. If it is not cooled in time, it will affect the performance of the machine and the quality of the products. The chiller provides low - temperature circulating water for the cooling system of the injection molding machine to ensure that the injection molding machine operates stably at an appropriate temperature. It's like a "small air conditioner" for the injection molding machine, always keeping the machine "cool".
Mold: The lunch box mold that can withstand high - pressure injection is the key to determining the shape, size, and quality of the lunch boxes. A good mold can produce lunch boxes with high precision and stable dimensions. The design of the mold needs to fully consider the usage function and production efficiency of the lunch boxes, such as the shape of the box body, the sealing performance of the box lid, and the convenience of demolding. Moreover, since it needs to withstand high pressure during the production process, the material and manufacturing process of the mold are required to be of high quality. It must have sufficient strength and wear resistance to ensure stable operation during the long - term production process and produce high - quality lunch boxes.
Production Process: Multiple Processes to Create High - Quality Lunch Boxes
Raw Material Preparation
Drying PP Raw Materials: Put the purchased PP pellets into the dryer and carry out the drying treatment according to the previously mentioned temperature and time. After drying, the PP pellets should be promptly transferred to a sealed container to prevent them from absorbing moisture in the air again. This step is like giving the PP pellets a "bath" to remove the "moisture" on them and prepare for subsequent processing.
Color Mixing (Optional): According to the designed color scheme, put an appropriate amount of color powder or masterbatch together with the dried PP pellets into the color mixer. Start the color mixer and let them mix fully. During the color - mixing process, you can judge whether the color mixing is uniform by observing the color change of the materials in the color mixer. If the color distribution is uneven, it may cause the lunch boxes to have color streaks or inconsistent color blocks. Therefore, this color - mixing step must be taken seriously to ensure that each PP pellet is evenly colored.
Injection Molding
Mold Installation: Install the carefully designed and manufactured lunch box mold onto the Haijiang high - speed injection molding machine. The installation process requires great care. It is necessary to ensure that the mold is firmly installed and in the correct position. The installation accuracy of the mold directly affects the injection molding effect. If the mold is not firmly installed or the position is deviated, it may lead to problems such as flash, inaccurate dimensions, and mismatch between the box lid and the box body of the lunch boxes. After installation, the mold also needs to be debugged to check whether the mold opens and closes smoothly and whether all components are working properly.
Parameter Setting: Adjust the various parameters of the injection molding machine according to the characteristics of the PP material, the structure of the lunch box mold, and product requirements. These parameters include injection pressure, injection speed, holding pressure, holding time, and cooling time.
Injection Pressure: Due to the thin walls of the lunch boxes, a large injection pressure is required to ensure that the PP material can quickly fill the mold cavity. Generally, the injection pressure is between 120 - 200MPa, and this pressure needs to be appropriately adjusted according to the complexity of the mold and the size of the product. If the pressure is too low, it may lead to incomplete filling of the lunch boxes and the appearance of material shortage. If the pressure is too high, it may cause the mold to be impacted too much, affecting the service life of the mold, and may also lead to problems such as flash and deformation of the lunch boxes.
Injection Speed: One of the major advantages of the high - speed injection molding machine is its ability to achieve rapid injection. The injection speed is generally fast, so that the PP material can be injected into the mold cavity in a short time, improving production efficiency. However, the injection speed cannot be too fast, otherwise, the PP material may generate turbulence in the mold cavity, resulting in defects such as air bubbles and cavities inside the lunch boxes.
Holding Pressure: Usually, it is 60% - 80% of the injection pressure. The role of the holding pressure is to continuously supplement the plastic during the cooling and shrinkage process of the PP material to prevent the lunch boxes from having defects such as shrink marks and depressions. The setting of the holding pressure and time needs to be adjusted according to factors such as the thickness and shape of the lunch boxes. For thin - walled lunch boxes, the holding time is relatively short, generally about 3 - 8 seconds.
Cooling Time: The cooling time depends on the thickness of the lunch boxes and the cooling efficiency of the mold, generally between 8 - 15 seconds. If the cooling time is too short, the lunch boxes may be ejected from the mold before they are fully set, and it is easy to deform. If the cooling time is too long, it will reduce production efficiency. To improve the cooling efficiency, cooling water channels can be set in the mold, and heat can be removed through circulating water to accelerate the cooling speed of the lunch boxes.
Injection Molding Process: After everything is ready, start the Haijiang high - speed injection molding machine. The dried and color - mixed (if any) PP material is heated and melted in the barrel of the injection molding machine. Then, under high - pressure, it is quickly injected into the mold cavity. In the mold cavity, the PP material gradually cools and solidifies to form the shape of the lunch boxes. This process is like casting a spell in the "magic box" of the mold, turning the PP material into the lunch box shape we want. During the injection molding process, the large oil pump and servo motor of the Haijiang high - speed injection molding machine work together to ensure the stability and efficiency of the injection molding process. The produced lunch boxes have a smooth surface and accurate dimensions.
Post - processing
Demolding and Deburring: After the injection molding is completed, the mold opens, and the formed lunch boxes are ejected from the mold. The newly demolded lunch boxes may have some burrs. These burrs not only affect the appearance but also may scratch the users. Special deburring tools such as scissors, sandpaper, and trimming machines can be used to remove the burrs on the surface and edges of the lunch boxes, making the surface of the lunch boxes smooth and clean. For some fine parts, such as the edges of the box lid and the buckle parts, more careful treatment is required to avoid damaging the lunch boxes.
Quality Inspection: This is a crucial link to ensure product quality. Conduct a comprehensive quality inspection on the produced disposable plastic lunch boxes, checking for issues such as cracks, deformations, dimensional deviations, and uneven colors. For unqualified products, they need to be classified and processed. Repairable products are repaired, and non - repairable products are crushed by a crusher and put back into production. Only through strict quality inspection can we ensure that every lunch box that enters the market is qualified and of high quality. The inspection methods can include a variety of ways such as manual visual inspection, dimensional measurement, and sealing performance testing. For example, by filling the lunch boxes with water and checking for any water leakage, the sealing performance of the lunch boxes can be tested.
Packaging: The lunch boxes that have passed the quality inspection can be packaged. Select appropriate packaging materials and packaging methods according to the sales positioning and market demand of the lunch boxes. Single plastic film packaging, stacked carton packaging, or large - package plastic bag packaging can be used. Reasonable packaging can not only protect the lunch boxes from damage during transportation and storage but also facilitate handling and sales. For example, some merchants will stack the lunch boxes in a certain quantity and then put them in a carton. This is both beautiful and convenient for storage and transportation.
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