Research on Comprehensive Technology of Ordnance Maintenance Equipment Packaging Reform(3)

DXDT480 fully automatic body packaging machine is a newly developed electromechanical integration new automatic body covering machine, with a programmable controller as the core control unit, using advanced detection, control elements and pneumatic actions to perform components, the work is stable and reliable. It can automatically complete the function of pull film, clip film, film, film, vacuum body, air-cooled, automatic bottom film, seal, cut, automatic counting. It has a higher degree of automation than a conventional body-fitting machine and has a high speed. It can form an automatic water-flowing operation, and the bottom paper sealing bottom moisture-proof innovative is novel and suitable for packaging special-shaped ordnance maintenance equipment.
3.3 Shrink-wrap technology Shrink-wrap shrinkwrap A product that wraps a product or package and then heats to shrink the film to wrap the product or package.
Shrink packaging is used in the field of ordnance maintenance equipment packaging mainly packaging blister, body and vacuum three kinds of methods difficult to package large pieces of equipment, parts, boxes of kits and kits, etc. The specific dimensions are: the length is not more than 1200mm, width Not more than 600mm and height not more than 400mm.
Shrink packaging has good protection performance, transparent gloss, low processing costs; its own light weight, suitable for pallet collection packaging, suitable for mechanized production and other characteristics.
3.3.1 Shrink film is the most important material in shrink packaging. According to the characteristics that the thermoplastic plastic is restored under the heating conditions, during the process of forming the film from the plastic raw material, it is heated and stretched in advance and cooled to make a shrink film. The manufacturing method includes a secondary film stretching method in which a sheet-shaped film is formed, and then stretched along the longitudinal axis and the transverse axis, and a primary stretching method simultaneously performing stretching in two directions. Stretch or one-stretch method.
Currently used more shrink film material is: polyvinyl chloride, polyethylene and polypropylene, followed by vinylidene chloride, polyester, polystyrene, chlorinated rubber film and nylon resin. The main considerations in selection are shrinkage, shrinkage ratio, shrinkage tension, shrinkage temperature, and heat sealability.
After comparison, the shrink packaging of ordnance maintenance equipment used polyethylene (PE) and polyvinyl chloride (PVC) transparent shrink plastic film as shrink packaging material.
3.3.2 Method selection Shrink packaging operations are generally performed in two steps. The first is pre-packaging, packaging the product with a shrink film, heat-sealing the necessary mouth and seams, and then heat-shrinking to heat the pre-packaged product in a heat-shrinking device.
a. Pre-packaged work. When pre-packaged, the film size should be 10% to 20% larger than the size of the device. If the size is too small, the infilling is inconvenient, and the shrinkage tension is too large, and the film may be broken. If the size is too large, the shrinkage tension is insufficient, and the package is not tight or uneven. The thickness of the shrink film used can be determined according to the size and weight of the equipment and the required contraction tension;
b. Heat shrinking operation. The equipment used for heat shrinking is called a heat shrink tunnel (also called heat shrink tunnel) and consists of a conveyor belt and a heating chamber. The heat shrinking process is: placing the prepackage on the conveyor belt, the conveyor belt running at the specified speed, sending it into the heating chamber, blowing hot air to the package for heating, and leaving the hot compartment after the heat shrinking, naturally cooling, Remove from the conveyor belt. After comparing the above methods, the process of contracting and packaging the ordnance maintenance equipment is: using a thick o.25mm PE Film or PVC plate (sheet) plastic to make the container → charging → heat shrinking machine heating → shrinking → sealing → cooling → inspection → Labeling.
The main parameters of commonly used shrink film and contraction channel are shown in Table 1.
Table 1 Main parameters of commonly used shrink film and heat shrinkage channel

Film thickness (mm) Temperature (°C) Heating time (s) Wind speed (m/s) Remarks
PVC 0.02～0.06 140～160 5～10 8～10 Because the temperature is low, it is more suitable for food and the like
PE 0.02～0.04 160～200 6～10 15～20 Strong tightening
PP 0.03 to 0.10 160 to 200 8 to 10 6 to 10 Longer shrinkage time 0.12 to 0.20 180 to 200 30 to 60 12 to 16 Stop heating when necessary

3.3;3 Machine selection The shrink packaging machine is a machine that heats the product after it is wrapped with a shrink film and shrinks the shrink film to wrap the product tightly. There are many kinds of shrink packaging machines at home and abroad. Small shrink packaging machines are mainly used to pack small parts and components, and are mostly used for pillow-shaped bag packaging. L-type sealing packaging machines and plate heat sealing packaging machines are suitable for various sizes of packaging; Shrink packaging machines are mainly used for corrugated cartons and large bags of product packaging. After repeated investigations and studies and repeated trials, the RS600/400 dual-use heat shrink packaging machine was selected.
RS600/400 dual-use heat shrink packaging machine is used for sealing packaging of large parts and packages. It is mainly used for the packaging of ordnance maintenance equipment for polyethylene (PE) materials with a thickness of 0.12mm, 0.18mm and a width of 1000mm.
The machine is composed of furnace body, cold box, heat and power supply. With the characteristics of long furnace length, sufficient heat, high power, and fast cooling, it is an ideal packaging equipment for shrinking various large and heavy equipment. The machine uses quartz tubes for heat generation as a heat source. Adjust the pressure up and down, and keep the temperature at room temperature up to 250 degrees Celsius, suitable for all kinds of films with different thickness. Transmission using electromagnetic frequency variable speed motor, great power, smooth operation. The upper box adopts a flip type, and the lower box bottom plate can be pulled out to one side for maintenance and cleaning. A vortex fan is installed in the drying tunnel to ensure uniform heat in the drying tunnel. The mouth cooling box is designed with the characteristics of the film that is hot or cold, ensuring the quality of the packaging.
3.4 Vacuum packaging technology A vacuum packaging product is packed into an airtight packaging container and the air inside the container is drawn so that the sealed container can reach a predetermined degree of vacuum.
Vacuum packaging used in the field of ordnance maintenance equipment is mainly used for electromechanical parts, electrical components, rubber parts and tools that are not more than 410mm in length, not more than 410mm in width, and not more than 200mm in height.
Vacuum packaging technology has good protection, reliable sealing, suitable for long-term preservation of the contents; high vacuum, less residual air, to avoid mildew and corruption of the contents of oxidation; packaging speed, simple operation, low labor intensity; small size, in The storage and transportation process takes up less space and reduces costs.
3.4.1 The material is selected for trial and analysis. The vacuum packaging container for military maintenance equipment should be made of 0.05 mm thick polyethylene (PE) transparent shrink film and polyvinyl chloride (PVC) board (sheet) according to the size of the equipment. Or use aluminum foil plastic composite film.
3.4.2 Method selection The vacuum packaging method includes pouches, hoses, semi-rigid containers and body packs. Semi-rigid containers: Generally, a cup-shaped container is pressed with a composite of a semi-rigid plastic sheet and an aluminum foil. After filling, a vacuum is evacuated in a vacuum chamber and covered with a flat similar material and then heat-sealed. The resulting package has a flat, wrinkle-free appearance. If the inflation package is blown, the operation is simple and the oxygen that is not easily removed by other methods can be removed from the package.
After repeated trial and analysis, the ordnance maintenance equipment vacuum packaging has chosen the way of loading semi-rigid containers. The process is: using a PE film or PVC plate (sheet) material to make the container a load a vacuum seal a test + trimming edge attach a label. (To be continued)