The processing and application of plastic moulding machine is an engineering technology, which touches on various processes of changing plastics into plastic products. In the process of modification, one or more of the following situations often occur, such as polymer rheology, physical and chemical function changes, etc.

Binding molding

The primary equipment for compaction moulding is press and moulding. Presses are mostly self-contained hydraulic presses, ranging in tonnage from tens to hundreds of tons. There are down press and up press. Moulds used for compact moulding are called binding moulds, which can be divided into three categories: overflow moulds and semi-overflow moulds. The primary benefit of compact moulding is that products with larger plane can be moulded and many products can be produced. The defects of compact moulding are long production cycle and low power.

Injection molding

Laminating machine is commonly used for laminating. There are many layers of buoyant hot-pressing plate between the dynamic pressure plate and the fixed pressure plate of this kind of press. The commonly used reinforcing materials for lamination are cotton cloth, glass cloth, paper, asbestos cloth, and resins are phenolic, epoxy, unsaturated polyester and some thermoplastic resins. Extrusion blow moulding by injection blow moulding Extrusion blow moulding Extrusion stretch blow moulding film coated by hot cladding, fluidized spraying, flame spraying, electrostatic spraying and plasma spraying.

Extrusion molding

Extrusion moulding, also known as kneading moulding or extrusion moulding, is a method of moulding in which materials are heated and pressurized in the extruder and then continuously passed through the die moulding under the condition of movement. The extrusion method is mainly used for the forming of thermoplastic plastics, and also for some thermosetting plastics. Extruded products are contiguous profiles, such as tubes, rods, filaments, wire and cable cladding, etc. In addition, it can also be used for mixing, plasticizing, granulating, coloring and blending of plastics. The extrusion moulding machine is composed of extrusion equipment, transmission organization, heating and cooling system, etc. There are two types of extruders: screw extruder (single screw extruder and multi-screw extruder) and plunger extruder. The former is continuous extrusion process and the latter is intermittent extrusion process. The basic structure of Single Screw Extruder mainly includes transmission equipment, feeding equipment, barrel, screw, die and so on. The auxiliary equipment of extruder includes three categories: material pretreatment equipment (such as material conveying and monotony), extruder treatment equipment (shaping, cooling, traction, cutting or roll) and production condition control equipment.

Extrusion forming

Extrusion forming is one of the forming methods of thermosetting fiber reinforced plastics. Used for producing profiles with fixed section shape and unbound length. The forming process is to pull the continuous fibers impregnated with resin glue out by heating die, and then further solidify the resin through heating chamber to prepare one-way high strength continuous reinforced plastic profiles.

The resins commonly used for extrusion forming are unsaturated polyester, epoxy and silicone. Unsaturated polyester resin is used more. Extrusion machine is generally composed of fiber arrangement equipment, resin groove, pre-forming equipment, die and heating equipment, traction equipment and cutting equipment.

Maintenance and Defect Solution of Molding Machine

1. The forming machine is roughly divided into three main parts:

1) Electronic control part:

Traditional ejectors use contact relays to switch various actions. They often fail due to loosening of contact screw and aging of contacts. Generally, new products should be replaced after one million applications to ensure the stability of electronic control. Special environmental factors such as dust attachment and air humidity also affect the machine.

Modern emitters use Contactless integrated circuits, which greatly reduces the connection of wires, obviously improves the bad phenomenon of wire formation, and advances in parallel stability.

Controller

2) Organizational part:

Tissue should be kept smooth on time to reduce friction coefficient and wear. The nuts and locking screws on the head plate shall be inspected on time to prevent the cracking of the columnar column due to uneven force.

Mould thickness adjustment organization should check on time whether there is offset or relaxation in big gear or chain of transmission shaft. Whether the screw of the upper pressure plate of the gear is loose, whether the smooth grease is satisfied, etc.

3) Oil pressure part:

In hydraulic system, attention should be paid to the cleanliness of hydraulic oil in order to maintain the quality of hydraulic oil. The hydraulic oil with good stability and high quality should be used. In addition to timely replacement, the working temperature should be properly controlled below 50C to prevent the stability of hydraulic action due to deterioration.

When the injection moulding machine is in operation, the controller will alarm when there is any abnormality in the system, and a line of anti-white message will appear below the screen of the battalion, as shown below.

Analysis and Solution of Defects

modify

The reason of machine defect is often due to improper operation and setting. It can be easily removed by analysis.

Adjustment process of clamping force and low pressure maintenance:

1. Set the clamping pressure at 135 bar, 10%, the low pressure speed at 20%, the low pressure azimuth at 100 mm, and the low pressure time at 5 seconds.

2. Establish the clamping force by adjusting the die forward and backward; refer to the oil pressure contrast table of the clamping force when the pressure of the pressure gauge of the system rises greatly when the pressure of the pressure gauge is close.

3. Set the low pressure orientation to zero after opening the die.

4. Put the die close until the die contacts and spreads out immediately. At this time, the orientation of the moving die is assumed to be "X", and the orientation of the low pressure is set to "X+1" mm.

5. Then set the low-voltage maintenance width: the low-voltage maintenance width is the distance from low-speed to low-voltage.

6. Setting low-voltage maintenance time is generally 1.2 seconds.