One

Seven Elements of Plastic Forming Machine

A Pressure B Speed C Time D Temperature E Metering F Data G Mould

Two

Programmable manipulation

A. Improving appearance by manipulating the ejection process

It is known from experience that the appearance of the product depends on the first half of the forming process, i.e. the closure of the resin filling injection outlet, etc. It is well known that the size of the resin injection rate is closely related to the appearance of the product.

The injection rate controls the filling condition of the resin in order to improve the quality of the product, especially the appearance and the accuracy of the specification.

Especially in the range, the shooting method of controlling the emittance of resin arbitrarily is the representative work. In view of the requirements of different quality, different shooting speed is given in the process of shooting. This shooting method can not only avoid the bad appearance of the product, such as hair edge, shooting indeterminacy, bubbles and cracks, but also improve the precision of the standard and reduce the internal stress, so as to make the strength of the product. Add to.

B. Connection between Quality and Emission Conditions

Because the outer layer of the product is solidified during filling, the adverse phenomena occurring on the surface of the product depend on whether the shape of the outer layer is correct or not during filling. Therefore, proper control of the injection rate has a good effect on the following adverse phenomena.

A. The flow marks formed by the sharp increase of the area around or across the exit of the jet are caused by the turbulence of the resin activity caused by the jet phenomena, and the irregular epidermis is formed in this condition. The jet velocity is lowered and the pressure is placed on the basis of the activity. Most of them can be dealt with.

B. The occurrence of ambiguity, roughness, silver bars, burning and other phenomena around the ejected products, most of which are thermal decomposition and gas generation in the initial stage of the conflict with the ejected outlet. Because of the constant filling of plastics and the poor exhaust effect at the back end, the gas performance pressure will occur. Thus, the initial ejection speed will be reduced and the ejection pressure will be significantly improved.

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

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.

D. Edge: It is composed of bad moulds or lack of mechanical clamping force, but it may also be assisted by controlling the injection speed. That is, when the resin moves to the place where the edge occurs, the injection speed will decrease, which will make the local cortex thicker. Because of the cured cortex, although there are some vacancies in the moulds, the inflow of resin becomes more difficult.

E. 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.

F. 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 break out. 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.

G. Shrinkage: Shortening is a common phenomenon in poor injection moulding products. For products with longer runner and thicker runner, and products with uneven adhesive level, it is more common to occur. For injection moulding, melted plastic has initially hardened when it touches the exterior of the mould, while the density of plastics in heating and curing is initially different, so the shortening is preliminary, especially for products with irregular adhesive level. Too thin to thick body, injection pressure can not be compensated, shrinkage is more obvious.

When needed, the shrinkage of all crystalline plastics will be reduced if glass fibers and other materials can be filled into composite materials. 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 decrease with time. When the runner is larger or the thickness difference decreases, the shrinkage will be reduced. Water is also properly assisted.

H. End blackening: The air in the die cavity is compressed and high temperature occurs, while the machine filling is always carried out. If the injection pressure travels and the velocity of the entry and exit presents blackening, this condition can improve the blowhole or decrease the injection pressure/the velocity of the drop-out and the temperature of the plastics, avoid using recycled materials and materials with better thermal stability. Of course, the runner is enlarged, the velocity of the drop-out or the exhaust hole is improved. Help to improve the blackening of the end.

I. Silver bars: The appearance of the moulded product is caused by the white stripes of the plastic during injection. 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 data can shame the attack.

J. Fusion wiring: When plastic flows through holes, it is combined after cutting. It 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, mould temperature, good activity information and discontinuous use of release agents.

Three

Problems often occur in injection moulding machine

A. The supply of forming materials is not smooth

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

The cause of seizure is data temperature.