Automatic blister machineIt is mainly to blister PVC, PET, PETG, APTT, PP, PE, PS and other thermoplastic sheets into vacuum covers of various shapes with molds, or paste them on the surface of various shapes of products, and use vacuum pumps to produce blister effects. According to the thickness of the sheet, it can be divided into blister and sheet.
When the plastic sheet is formed, the sheet is fixed on the fixture. Clamping devices that are easy to fix various specifications of plates are often used on the hot mold general-purpose and composite hot mold machines. Some are integrally formed frames equipped with fixtures.
The clamping mechanism can be divided into two types: one is a frame type, and the other is a split type. The frame clamping device is composed of upper and lower frames. The plates are sandwiched between the two racks. When the frame is opened, the lower frame usually remains fixed. The lower end of the upper frame of different models of single-sided molding machines is directly fixed to the molding chamber. On manual and semi-automatic molding machines, the parison is loaded by hand and the finished product is taken. When the frame size is large, it is equipped with a safety operation device within the frame opening range. For parisons with large molding slip, it is required that the clamping force can be adjusted in a wide range. For this reason, two rubber-coated rollers are used to compress each other with springs, and a pressure adjustment device is equipped. The double-sided zipper and the front and back gates clamp the continuous pull sheet forming machine.
2. Heating device.
In the thermoplastic vacuum forming process of sheet and film, heating of the sheet is one of the main processes. The duration and quality of electric heating depend on the structure of the heater, the thermal inertia of the temperature heat transfer after the radiant surface, the interval between the plate and the heater, the radiant energy absorption coefficient, the surface characteristics and the thermophysical properties of the material. Electric heaters, crystal radiators, and infrared water heaters are commonly used heating equipment.
3. Vacuum device.
The vacuum system consists of a vacuum pump, gas storage tank, valves, pipes and vacuum gauges. In the vacuum forming process, a single vacuum pump is often used. The vacuum degree of this pump should reach 0.07~0.09Mpa (520mmHg). The gas storage tank generally adopts a thin plate welded cylindrical box with an oval bottom. The capacity of the gas tank must be at least half the capacity of the moulding chamber. On the vacuum pipeline, appropriate valves must be configured to control the narrow vacuum capacity.
The rotational power of the vacuum pump depends on the size and molding speed of the molding equipment. Larger or faster molding equipment usually requires 2-4KW of power. The size of the decompression center system depends on the specific production and development requirements of the factory.
4. Compressed air device.
The pneumatic system can be composed of a compressor, a gas storage tank, the main circuit set of the workshop, and valves. The molding equipment requires compressed air with a pressure of 0.4 to 0.5 MPa, and various vacuum suction molding equipment widely use piston air compressors. The complete machine supply of a large screw air compressor can also be used.
In addition to a large amount of compressed air for molding, there is also a part of the power used for demolding, external cooling of the initial product, and mechanical actions such as operating the mold base and running the plate.
5. Cooling device.
In order to improve production efficiency, it is often necessary to cool the vacuum blister product before demolding. Ideally, the inner and outer surfaces of the part in contact with the mold should be cooled, and a cooling plate inside the mold can be used. For non-metal molds, such as wood, plaster, glass fiber reinforced plastic, epoxy resin and other molds, since 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 molded part.
The natural cooling process is adopted to produce annealed parts, which is beneficial to improve the impact resistance of the parts. Although the production efficiency of water cooling is high, the internal stress of the parts is also very large.
6. Demoulding device.
Demolding is to remove the product from the mold, usually a concave mold or a convex mold. In most cases, it is because the product cools and shrinks to compress the mold, so it is demolded by vacuum suction holes or blowing in the opposite direction.
Especially for molds with small demolding angles or concave molds, the demolding mechanism can be used to press or press to demold at the same time, and sometimes a mold release agent can be applied to the sheet and the mold or the mold surface can be sprayed with Teflon.
7. Control device.
The system generally includes the control of various parameters and actions of instruments, meters, pipelines, and valves during vacuum forming and finishing. The control methods of the system include manual, electromechanical automatic control, computer control, etc. The specific selection should be comprehensively considered based on the investor's initial installation fee, technical requirements, raw material consumption, use of production equipment, and equipment production and maintenance.