Today is July 11, the time is really like a white horse clearance, flashed by, did not give us the opportunity to retain. Recently busy day, are to wait until the evening only to update the article. Today, Dongguan Plastic mold factory editor for everyone to introduce the plastic mold filling speed and pressure.
The die filling speed is the linear velocity at which the melt is injected into the mold cavity, and the firing rate of the melt must be controlled during the filling phase of the injection to achieve the optimum performance of the product. The injection speed should be set at the time the product is designed and a faster rate of fire should be designed in the case of product wall thickness design and plastic properties. In general, thin-walled injection parts require fast injection speeds to ensure full filling;
While the wall thickness of the need for slow injection rate to prevent the formation of holes. But too fast to shoot too easy to make raw materials overheating. When the plastic parts gate or exhaust is not good, the melt to speed injection through the gate, the melt produced a large shear stress, so that the melt combined with the mold cavity difficult to discharge the air, and even produce combustion and carbonization Turn black. While the slow speed of the product will appear filling fill dissatisfaction and other defects.
In actual production, regardless of the value of the use of the injection speed, should be as far as possible in a larger range, in order to facilitate production. According to different experience of the students, the same product injection speed is not the same. However, segment injection can be used to inject the melt into the mold cavity at different speeds during the filling phase, which often avoids defects in the plastic parts. Such as serpentine, flash, burr, burning and so on. And with the control of the melt segmentation rate can also affect the product of the molecular arrangement and the size of the internal stress, or even improve the production rate and efficiency.
In order to ensure that the injection speed of the injection molding machine to achieve and maintain the required value, requiring adequate injection pressure. If the injection pressure is too low, the melt into the mold, the resulting resistance so that the injection rate can not reach the set value. Therefore, when setting the injection pressure, the value should be higher than the resistance generated by the melt 1.5MPa, melt into the mold when the resistance generated by the injection rate can not reach the set value, from the injection molding machine cylinder pressure gauge Know that The low injection pressure causes the injection cycle time to change. Therefore, if the injection force and speed are set, the time period of the injection cycle will not exceed 0.8s.
Note: The above information is chaired by Jiezheng on the Internet, welcome reproduced, indicate the source!