Injection device and maintenance of injection mold

The injection device is a device which makes the resin material melt and then inject into the mold. As shown in the figure, the resin is squeezed into the barrel from the material head, and the melt is transported to the front end of the barrel through the rotation of the screw. In that process, the resin material in the barrel is heated under the action of the heater, and the resin becomes molten under the action of the screw shear stress. The molten resin equivalent to the molding product and the main channel and the shunt channel is retained in the front end of the barrel (called metering), and the material is injected into the mold cavity with the continuous forward of the screw. When the molten resin flows in the mold, the movement speed (injection speed) of the screw must be controlled, and the pressure (holding pressure) is used to control after the resin fills the mold cavity. When the screw position and injection pressure reach a certain value, we can switch the speed control to pressure control.
How to maintain the injection mold?
1. Processing enterprises should first provide each mold with a resume card to record and count its use, care (lubrication, cleaning, rust prevention) and damage in detail, so as to find out which parts and components have been damaged and the degree of wear, so as to provide information for finding and solving problems, as well as the molding process parameters of the mold and the materials used in the product, so as to shorten the test run time of the mold To improve production efficiency.
2. Processing enterprises should test the various properties of the mold under the normal operation of the injection molding machine and mold, and measure the size of the final molded plastic parts. Through these information, the existing state of the mold can be determined, and the damage of the cavity, core, cooling system and parting surface can be found. According to the information provided by the plastic parts, the damage state and maintenance measures of the mold can be judged.
3. It is necessary to track and inspect several important parts of the mold: the function of ejection and guide parts is to ensure the opening and closing movement of the mold and ejection of plastic parts. If any part of the mold is stuck due to damage, it will lead to production stop. Therefore, the lubrication of the ejector pin and guide pillar of the mold should be maintained regularly (the most suitable lubricant should be selected), and the deformation and surface damage of the ejector pin and guide pillar should be checked regularly Once it is found, it should be replaced in time; after a production cycle, professional anti rust oil should be applied to the working surface, moving and guiding parts of the mold, especially the protection of the elastic strength of the bearing parts of the mold with gear and rack and the spring mold, so as to ensure that they are always in the best working condition; with the continuous production time, the cooling channel is easy to deposit scale, rust, rust, etc Sludge and algae make the cross section of the cooling channel smaller and the cooling channel narrower, greatly reducing the heat exchange rate between the coolant and the mold and increasing the production cost of the enterprise. Therefore, attention should be paid to the cleaning of the channel. For the hot runner mold, the maintenance of the heating and control system is conducive to preventing the occurrence of production failure, so it is particularly important. Therefore, at the end of each production cycle, ohmmeter should be used to measure the belt heater, rod heater, heating probe and thermocouple on the mold. If there is any damage, it should be replaced in time, and compared with the mold resume, so as to make records, so as to timely find problems and take countermeasures.
4. To pay attention to mold surface maintenance, it directly affects the surface quality of products, the focus is to prevent corrosion, therefore, the selection of a suitable, high-quality, professional anti rust oil is particularly important. When the mold has finished the production task, different methods should be adopted to carefully remove the residual injection molding according to different injection molding. Copper rod, copper wire and professional mold cleaning agent can be used to remove the residual injection molding and other deposits in the mold, and then air dry. It is forbidden to clean iron wire, steel bar and other hard objects to avoid scratching the surface. If there are rust spots caused by corrosive injection molding, it is necessary to use a grinder to grind and polish, spray professional anti rust oil, and then store the mold in a dry, cool and dust-free place.