plastic mould, injection mould

Injection molding processes are discovered - injection compression mol

 Injection compression molding (injection compression moulding / icm) is a traditional form of injection molding of a high.
It increases the flow of injection molding parts length / thickness ratio; use a smaller clamping force and injection pressure; reduce stress within the material; and improve their productivity.
Injection compression molding thermoplastic engineering plastics for various products produced.
The main features of injection compression molding process compared to traditional injection molding, injection compression molding the significant feature is that the mold cavity space can be automatically adjusted according to different requirements. For example, it can be injected into the cavity before the material is not to be closed mold-oriented parts, while the cavity space is expanded to twice the wall thickness of parts completed. In addition, the operation according to the different ways in the material injected during or after completion of the corresponding control in the injection cavity space size, so match with the injection process, pressure to maintain an appropriate state of polymer, and to compensation for material shrinkage effect.
According to the geometric shape of plastic parts, surface quality requirements, and different conditions of injection molding equipment, injection of contraction Protection Division has four options.
They are: sequential; of-action; breathing and partial pressure.
Sequential icm (seq-icm) sequential injection compression molding process, the injection operation and the mold cavity in order to promote cooperation is carried out. Initially, some die-guided slightly closed, and a part wall thickness of about twice the cavity space. When the resin into the mold cavity after the mold is to promote the activities of some completely closed up, and to polymer in the cavity is compressed. In this process, because to start from complete compressed into a polymer melt flow will be suspended and the static moment, which may be in part a flow line formed on the surface traces of polymer materials depends on their visible color, as well as forming part when the texture and material type.

The ways of operation. Crank rod device can be used to carry out such icm.
 Total fixed-type icm (sim-icm)
 with the same sequential icm, icm of-action start, guided in part when the mold closed slightly different starting materials into the cavity at the same time, the mold began to promote co-Shi pressure. The extrusion feed screw and the mold cavity in the joint campaign period, there may be a delay of s2 or s2. As the polymer flow front has maintained a steady flow state, it does not appear as seq-icm process of suspension and surface streamline traces.
 Since these two methods are in operation at the beginning left room for a larger cavity, the cavity in the molten polymer into the direction of pressure has not yet met, it may be because of gravity and the first into the cavity of the lower side of the and may not be able to withstand the pressure due to a temporary state in which there do not want any foam. Moreover, the greater part wall thickness, cavity space will be larger, while the streamer length of the extension will increase the mold completely closed period of time, which may cause the accelerated.
 Breathing icm (breath-icm)
 with breathing icm, the beginning of the injection mold is completely closed state. Therefore, once injected into the polymer will remain in the state of compression. This two ways to overcome the above potential problems that may arise. Injected into the cavity in the polymer, the mold is gradually opened to form a large cavity space, and the cavity of the polymer that is always kept at a certain pressure. When the material close to the full cavity, the mold has begun to push back together until it is closed, the polymer further compressed and needs to be completed by the thickness of parts. The movement between the mold cavity expansion can be injected into the cavity by means of the outgoing polymer injection pressure or injection molding machine preset exercise program to achieve.
 Local pressure-type icm (select-/com-icm) or using a local pressurized line compression icm, the mold will be completely closed state. Has a built-line pressure head in the polymer injection or after injection, from a local location of the cavity pressure to the cavity, so that part of a larger entity and is part of local compression pressure thin.
 This partial pressure, injection equipment or through a separate pre-built outfit hydraulic device procedures to control it.
 Injection molded parts and mold design is suitable for injection molding injection compression molding of parts with surface appearance, such as mobile computer casings, car tailgate, dashboard, and more flat so the car fender. Note that choosing to be part of the entrance channel and streaming live here, so to fill cavity with good results. Some commercial injection molding filling process can be used to detect the pushing force and injection pressure. For the development of some of the standard rules of plastic can also be used, such as strengthening the rib / wall thickness ratio, and some combination of technologies.
 Note the orientation of the die out of orbit and guide the core edge, and the Department of the cavity. With a tight tolerance to prevent polymer leakage overflow cavity. To have a nozzle with a backstop switch to prevent the polymer back into the injection molding machine. Mold can also install a check valve with thermal injection nozzle to replace the nozzle.
 For through-hole parts, it should be so fixed on the mold side of the nail penetration of the other side of the mold and with a good slide to prevent the mold cavity campaign to force pin loosening or stuck. In addition, because the icm injection molding process, the cavity pressure is lower when compared to traditional injection molding, so do not like a traditional injection mold structure as a solid when heavy.
 Injection equipment
 as icm of pushing force and the feed screw clamping movement of the corresponding conventional injection molding operation is different, it is necessary to increase the number of software features injection molding machine. In order to obtain such sim-icm and breath-icm of the mold and screw the same time exercise, injection molding machine hydraulic fluid flow must be improved. In addition, the main hydraulic equipment for the seq-icm injection, you can use for traditional injection locking of the hydraulic valve, to achieve the mold of pushing movement.
 Most hydraulic injection molding equipment can be used for large parts of the injection compression molding. But the closed cavity should use pre-programmed exercise program to control the pressure, otherwise they will experience difficulties.
 Should pay attention to the mold cavity is linear, because non-linear flow of polymer mold Games temporary effect occurs, leading to strange parts appear shiny surface appearance.
 As the icm to have longer than the traditional injection flow injection length and lower locking force and injection pressure, it can use smaller than conventional injection molding equipment to produce large parts.
 Noryl gtx964 on tests conducted in the same wall thickness and part geometry conditions, icm injection than the traditional 75 percent reduction of clamping force, and reduce 30% of injection pressure. While making use of sim-icm body panels of the test is that, when the mold cast by the Central Road and part wall thickness of 1.5mm, the length of the streamer growth of 200 percent compared to traditional injection molding.
In addition, the clamping force reduction to a large extent also depends on when the closed mold, clamping too quickly or too slowly will increase the injection pressure and clamping force.
 Conclusion
 injection compression molding has been successfully applied for years, and its operation is also relatively easy. With proper design specifications, and the use of appropriate materials and processes, it is entirely possible for the existing injection molding equipment with some adjustments to the software to achieve operation.
 icm compared with traditional injection molding, the advantage is a larger proportion of the flow injection length of the wall thickness; clamping force and injection pressure can be reduced, and smaller production of large parts injection devices; it also within the lower material stress, this process can also try out for the circuit package, but by the practice to verify, just think ah.



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