1 Seven Elements of Plastic Forming of Plastic Molding Machine

A pressure

B speed

C time

D temperature

E measurement

F material

G mold

2. Programmable manipulation

It is well known that the injection rate controls the filling condition of the resin in order to improve the quality of the product, especially to improve the appearance and specifications.

Especially in the range, the shooting method of arbitrarily controlling the resin ejection rate is the representative work. In view of the requirements of various quality, different ejection speed is given in the process of ejection. This shooting method can avoid the bad appearance of the product, such as rough edge, shooting indeterminacy, bubbles and cracks. Besides, it can also improve the precision of the standard and reduce the internal stress, so as to make the strength of the product. Increase.

B. The connection between quality and ejection condition is that the surface of the product is solidified during filling, so the bad phenomena on the surface of the product occur depending on whether the shape of the surface layer is correct or not during filling. Therefore, proper control of the ejection speed has a good effect on the following bad phenomena. 1. The flow marks formed by the sharp increase of the area around or across the ejection exit are caused by the jet phenomena. The activity of the resin becomes turbulent, and the irregular epidermis is formed in this condition, which decreases the ejection speed, and the pressure is placed on the movable basis. Most of it can be dealt with.

2. The phenomenon of ambiguity, roughness, silver bars and burning around the emitted products are mostly triggered by thermal decomposition and gas emission at the initial stage of the emitted products and the outlet of the emitted products. Because the plastic is always filled and the exhaust function of the back end is poor, the gas performance pressure will occur. In this way, the velocity of the initial emitted products will be reduced and the pressure of the emitted gas will be reduced.

3. Joint line marks are formed by the joints of the cured epidermis. It is difficult to make them disappear properly, to change the method of movement, to change the direction of attack where they can not be seen, or to accelerate the ejection speed when the outer layer is joined, so that the surface layer is thinner, and to reduce the joint marks appropriately.

Other causes of joint line seizures are: during filling process, the direction of movement changes dramatically, the flow of resin occurs turbulence, or the temporary diversion also occurs. At this time, reducing the speed of movement of this part will have different effects on avoiding irregular flow rate.

4. Fur edge: It is composed of bad moulds or short mechanical clamping force, but it may also be helpful to control the injection speed. That is, when resin moves to the place where the fur edge occurs, the injection speed will decrease, which will make the local cortex thicker. Because of the cured cortex, although there are some voids in the moulds, the inflow of resin will become more difficult.

5. Gas burning (discoloration): Gas gas (GAS) is contained in the air or resin in the hole of the die. When the air is sealed, it will be high temperature because of the adiabatic contraction. Therefore, when the air is sealed, the following reduction of the ejection speed will be helpful to avoid.

6. Concave: In the process of cooling and hardening, if we want to avoid appropriate difficulties, but at the moment of filling, the ejection speed decreases and the hair edge is more difficult to attack. When cooling, the pressure-retaining process will be improved to a proper extent. The die or product with pinholes will be far away from the ejection outlet. Because of the poor pressure-retaining effect, the concave will occur more easily, and the ejection speed through the thick meat part will be reduced. This part of the epidermis becomes thicker. When it is cooled and hardened, the inner core layer forms a concave nest, and the concave surface is less visible.

7. Shrinkage: Shortening is a common phenomenon in poor injection moulding products. For products with longer runners and thicker runners, and products with uneven glue level, it often occurs. For injection moulding, melted plastics have begun to harden when they touch the exterior of the mould, while the density of plastics in heating and curing is different at the beginning, so shortening is at the beginning, especially for products with irregular glue level. Too thin to thick body, injection pressure can not be compensated, shrinkage is more obvious.

The shrinkage of all crystalline plastics will be reduced if glass fibers and other filling materials are needed. Otherwise, the shrinkage rate of all crystalline plastics will be appropriately large and the shrinkage will be very simple after downstream flow. Therefore, the plastics will be adjusted by pressure before hardening, but the pressure will be cracked if the pressure is too large, so the pressure will increase and decrease at any time. When the runner is larger or the thickness difference is reduced, the shrinkage will be reduced. Water also helps properly.

8. End blackening: The air in the die cavity is compressed and high temperature occurs, while machine filling is always carried out. If the ejection pressure travels and the ejection speed moves, the ejection pressure will be blackened. This condition can improve the blowhole or decrease the ejection pressure/the ejection speed of the finished product and the plastic temperature, avoid using materials with better thermal stability. Of course, the increase of the runner, the decrease of the ejection speed or the improvement of the exhaust hole will help to improve the unfinished product. Burn black.

9. Silver strip: The appearance of the moulded product is caused by the white stripe phenomenon caused by plastic activity when it is ejected. This is the phenomenon that the moisture in the plastic is compressed and gaseous. Under the pressure of the nozzle, it can not be transpired and attached to the hardening process. Therefore, the monotonous moisture in the material can stop the attack shamefully.

10. Welding Wire: When plastic flows through holes, it is combined after cutting, which is blocked by air, or there are too many release agents. Therefore, it is helpful to raise plastic temperature or speed of plastic through holes, to move mould temperature, to stop using materials with good mobility and release agents.

Problems often occur in injection moulding machine

A. The supply of moulding materials is not smooth

Under normal rolling condition, plastic can not supply screw properly and has idling phenomenon.

The reason is that the material temperature does not correspond to the material practice, and the machine screw caking occurs. The machine is long-term.