The principle of vacuum automatic blister packaging machine

　　Blister molding machine principle of vacuum automatic blister packaging machine: Blister molding is also called thermoplastic molding. This molding process mainly uses the vacuum suction generated by the vacuum pump to heat and soften PVC, PET, PETG, APTT, PP, PE , PS, and other thermoplastic sheets are molded into various shapes of vacuum covers, blister trays, blisters, etc. At present, the common products on the market are: daily necessities blister packaging, small hardware blister packaging, automotive supplies blister packaging, electronic product blister packaging, food blister packaging, cosmetic blister packaging, computer peripheral equipment blister packaging, toys blister packaging Packaging, sporting goods blister packaging, stationery blister packaging, etc. Its main structure is composed of feeding material, pulling material, upper and lower electric heating furnace, lower gate, multi-functional adjustable size, lower mold plate, upper mold, upper gate, knife gate, slicing, releasing and equipped with vacuum device; The pneumatic device is the main power source, and the pulling and feeding of the film adopts electric, reducer, time relay, intermediate relay, travel switch and other electrical appliances to form a fully automatic control system. The requirements for the control system of the blister machine are to ensure convenient operation, high precision of mechanical action and temperature control, short production time, and save the power consumption of the machine as much as possible under the same production conditions.

　　The composition and function of the automatic blister packaging machine: 

       1. Clamping equipment When the plastic sheet is formed, the sheet is fixed on the clamping device. Clamping devices that are convenient for fixing sheets of various sizes are often used on thermoforming general-purpose and composite thermoforming machines. Some are equipped with a clamping frame for the whole molding machine. The clamping device can be divided into two categories: one is the frame type, and the other is the split type. The frame type clamping device is composed of upper and lower frames. The sheet is sandwiched between two frames. When the frame is opened, the lower frame generally remains fixed. The lower part of the upper frame of various types of single-station molding machines is directly fixed on the molding chamber. On the manual and semi-automatic molding machines that load the parison by hand and take out the finished product, when the frame size is very large, there are safety operating devices in the frame opening range. For parisons with high slippage, it is required that the clamping force can be adjusted in a relatively wide range. For this reason, two rubber-coated rollers are used, pressed against each other by springs, and equipped with a pressure adjustment device. The clamping of the continuous tab forming machine is the joint action of the zippers on both sides and the front and rear gates. The clamping device is preferably automatically controlled in order to move quickly, which can help improve the quality and efficiency of the workpiece.

　　2. Heating equipment One of the main processes in the vacuum forming process of thermoplastic sheets and films is sheet heating. The duration and quality of electric heating depend on the structure of the heater, the thermal inertia of the temperature transfer after the radiant surface, the distance between the sheet and the heater, the radiant energy absorption coefficient, the characteristics of the heater surface and the thermophysical properties of the material. Commonly used heaters include electric heaters, crystal radiators and infrared heaters.

　　3. Vacuum equipment The vacuum system consists of vacuum pumps, gas storage tanks, valves, pipelines, and vacuum gauges. In vacuum forming, a separate type of vacuum pump is often used. The vacuum degree of this pump should reach 0.07~0.09Mpa (520mmHg) or more. The gas storage tank is generally a cylindrical box welded with thin steel plates, and the bottom is oval. The capacity of the gas storage tank should be at least half larger than the capacity of the largest molding chamber. On the vacuum pipeline, appropriate valves must be installed to control the vacuum narrow capacity. The rotation power of the vacuum pump is determined by the size and molding speed of the molding equipment, and the equipment with larger or faster molding speed is usually as large as 2-4KW. The size of the vacuum central system depends on the specific production and development requirements of the factory.

　　4. Compressed air equipment The pneumatic system can be composed of the molding machine itself with a compressor, an air storage tank, a workshop main road set, valves, etc. The molding machine needs compressed air with a pressure of 0.4-0.5MPa, and various vacuum blister molding machines widely use piston air compressors. It can also be supplied by a large screw air compressor in the whole plant. In addition to a large amount of compressed air being used for molding, part of it is used for demoulding, external cooling of the initial product, and power for manipulating the mold frame and moving sheets.

　　5. Cooling equipment In order to improve production efficiency, vacuum-absorbed molding products often need to be cooled before demoulding. Ideally, both the inner and outer surfaces of the part in contact with the mold are cooled, and it is best to use a mold with a built-in cooling coil. For non-metal molds, such as wood, gypsum, glass fiber reinforced plastics, epoxy resin and other molds, because water cooling cannot be used, air cooling can be used instead, and water mist can be added to cool the outer surface of the vacuum forming part. If natural cooling is used in production, annealed parts can be obtained, which is conducive to improving the impact resistance of the parts. Although water cooling has high production efficiency, the internal stress of the workpiece is relatively large.

　　6. Demoulding equipment Demolding is to remove the product from the mold. Generally, no matter whether it is a concave mold or a convex mold, most of the time it is because the product cools and shrinks and sticks to the mold, so it is demoulded through the vacuum suction hole or blowing in the opposite direction. Especially for molds with a small demoulding slope or with a concave mold, use the demoulding mechanism to bump or vibrate to demould, and sometimes apply a mold release agent on the sheet and the mold or spray Teflon on the surface of the mold.

　　7. Control equipment The control system generally includes the control of various parameters and actions of instruments, meters, pipelines, and valves in the process of vacuum forming and finishing. Control methods include manual, electrical-mechanical automatic control, computer control, etc. The specific selection should be based on factors such as initial investment in labor costs, technical requirements, raw material costs, production and maintenance equipment costs, etc.