Do you know what kind of mechanical equipment a blister machine is?

Have you ever heard of the blister machine? Do you know what kind of mechanical equipment it is?

The blister machine (also called thermoplastic forming machine) is a machine that blister heats and plasticizes thermoplastic plastic coils such as PVC, PE, PP, PET, HIPS, etc. into various shapes of high-end packaging boxes, frames, and other products. The vacuum suction generated by the vacuum pump is used to blister the heated and softened thermoplastic plastic sheets such as PVC and PET through the mold into various shapes of vacuum covers, blister trays, bubble shells, etc.

Function composition

Folding clamping equipment

When the plastic sheet is formed, the sheet is fixed on the clamping device. The universal and composite thermoforming machines for thermoforming mostly use clamping devices that are convenient for fixing sheets of various sizes. Some are equipped with a set of clamping frames for the entire forming machine.

Clamping devices can be divided into two categories: one is frame type and the other is split type. The frame type clamping device consists of two frames, upper and lower. The sheet is clamped between the 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 forming machines is directly fixed on the forming chamber. Manual and semi-automatic forming machines that manually load and remove the preforms are equipped with safety operating devices within the frame opening range when the frame size is large. For preforms with large forming slip, the clamping force is required to be adjustable within a relatively wide range. For this purpose, two rubber-coated rollers are used, which are pressed against each other by springs and equipped with pressure regulating devices. The clamping of the continuous pull-tab forming machine is the combined effect 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 product.

Folding heating equipment

One of the main processes in the vacuum forming process of thermoplastic plastic sheets and films is sheet heating. The duration and quality of electric heating depends 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 radiation energy absorption coefficient, the characteristics of the heater surface, and the thermophysical properties of the material. Commonly used heaters are electric heaters, crystal radiators, and infrared heaters.

Folding vacuum equipment

The vacuum system consists of a vacuum pump, a gas tank, valves, pipelines, and a vacuum gauge. A single vacuum pump is often used in vacuum forming. The vacuum degree of this pump should reach 0.07~0.09 Mpa (520mmHg) or above. The gas tank is generally a cylindrical box welded with thin steel plates, and the bottom is elliptical. The capacity of the gas tank should be at least half the capacity of the largest molding chamber. Appropriate valves must be installed on the vacuum pipeline to control the vacuum capacity.

The rotation power of the vacuum pump is determined by the size and molding speed of the molding equipment. Larger or faster molding equipment often uses up to 2-4KW. The size of the vacuum central system depends on the specific production and development requirements of the factory.

Folding compressed air equipment

The pneumatic system can be composed of a molding machine with a compressor, a gas tank, a workshop main pipeline, a valve, etc. The molding machine requires compressed air with a pressure of 0.4-0.5MPa. Various vacuum blister molding machines widely use piston air compressors. It can also be supplied by a large screw air compressor throughout the factory.

In addition to being used in large quantities for molding, compressed air is also used in part for demoulding, external cooling of the initial product, and for operating the mold frame and the operation of the sheet and other mechanical parts.

Folding cooling equipment

In order to improve production efficiency, vacuum blister molded products often need to be cooled before demoulding. Ideally, both the inner and outer surfaces of the parts in contact with the mold are cooled, and it is best to use a mold with a built-in cooling coil. For non-metallic molds, such as wood, gypsum, glass fiber reinforced plastic, epoxy resin, etc., since water cooling is not possible, air cooling can be used instead, and water mist can be added to cool the outer surface of the vacuum blister molded parts.

If natural cooling is used in production, annealed parts can be obtained, which is beneficial to improve the impact resistance of the parts. Although water cooling has high production efficiency, the internal stress of the parts is relatively large.

Folding demoulding equipment

Demolding is to move the product out of the mold. Usually, whether it is a concave mold or a convex mold, in most cases, the product is pressed against the mold due to cooling and shrinkage, so it is demoulded through vacuum suction holes or blowing in the opposite direction.

Especially for molds with small demoulding slopes or concave molds, demoulding is performed by knocking or vibrating the demoulding mechanism at the same time. Sometimes, a demoulding agent is applied to the sheet and the mold, or Teflon is sprayed on the surface of the mold.

Folding 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 blister molding, finishing, etc. The control methods include manual, electrical-mechanical automatic control, computer control, etc. The specific selection should be based on the initial investment labor costs, technical requirements, raw material costs, production and maintenance equipment costs and other factors.