What are the effects of excessively high injection molding processing temperatures?
The adverse effects are mainly reflected in the following aspects:
1. Excessive temperature will reduce the viscosity of the oil: When the injection molding processing temperature is too high, the viscosity of the oil will decrease and leakage will increase. At this time, the volumetric power of the pump and the power of the entire system will also decrease significantly. If the viscosity of the oil decreases, the oil film on moving parts such as slide valves will become thinner or trimmed, frictional resistance will increase, and wear will increase.
2. Accelerate oil oxidation and degradation: Excessive heating during injection molding will accelerate oil oxidation and degradation, break down asphalt substances, and reduce the service life of hydraulic oil. Analytic substances will block the damping holes and gap valves, causing the pressure valve to get stuck, and the metal pipe to stretch and bend. , or even break up.
3. Lead to poor quality of injection molded parts: If the heating of injection molding is too high, it will lead to poor quality of injection molded parts. Oil dissolves and air escapes, resulting in air pockets, which reduces the performance of the hydraulic system.
4. Mechanical thermal deformation: Components with different thermal expansion coefficients in hydraulic components should be combined with practice, resulting in operational failures, seriously affecting the transmission accuracy of the hydraulic system, and resulting in poor quality injection molded parts.
5. Excessive injection molding processing temperature will cause the rubber seal to deform, accelerate aging and failure, reduce the service life of the sealing performance, and cause leakage.
Injection mold processing is to first add plastic to the mold, and then the mold is continuously rotated along two vertical axes and heated. Under the action of gravity and heat energy, the plastic in the mold is gradually and evenly coated, melted and adhered to the entire mold cavity. On the surface, it is molded into the required shape and then cooled and set. The drive and driving force of the injection mold processing movement are provided by the power of the forming processing machine tools and equipment through the transmission mechanism.
1. Electromechanical drive
For example, stamping machines, friction presses, roll forging machinery, etc. are all powered and rotated by electric motors to drive the transmission mechanism, and are connected to the moving parts of the mold through sliders, etc. to drive the directional movement of the mold and transfer the transmission. The driving force acts on the mold, causing the mold to shape the material.
2. Electro-hydraulic drive
That is, the injection molding motor drives the hydraulic pump or water pump to generate hydraulic pressure and water pressure, and through the liquid hydraulic transportation and control system, a certain rated pressure is generated to drive the hydraulic cylinder or piston connected to the moving part of the mold (such as the movable mold). The movable mold is driven to perform directional translational movement relative to the fixed mold, and the material is further compressed, so that the material becomes a finished product after forming processing.
3. Air pressure forming
It is mainly used for suction molding and blow molding processing. That is, when the mold is in a fixed state, the air pump generates a certain negative pressure to directly suck the plastic sheet onto the mold surface to form a product. Blow molding uses The air pump generates gas with a certain pressure and blows it into the cavity of the hot-melt plastic part or hot-melt glass part blank, causing it to expand and deform, and stick to the surface of the mold cavity to form the part.
4. Injection mold processing driver For example, aluminum alloy profiles, plastic profiles, sheets or films generally use the extrusion forming process. The mold is fixed on the machine head, the material passes through the mold in the form of extrusion, and various parts are formed by relative movement of the mold. For example, plastic profiles rely on the spiral motion of the screw of the continuous extrusion machine to squeeze the plastic into the mold and pass through the mold surface, and then the molded material is shaped after cooling. The extruded profile is pulled forward by the traction mechanism for continuous forming processing.
When assembling the stamping mold, it is necessary to ensure a certain gap between the concave and convex molds, and the gap needs to be even, so as to extend the service life of the mold and ensure the quality of the stamping parts.
1. Direct measurement, use measuring tools to directly measure the gap between the concave and convex molds. Due to the complex structure between the concave and convex molds, the measuring tool can only be used on stamping molds with a single-side gap of more than 0.02mm. If the gap is too small, it will be difficult to Measurement.
2. According to the reference measurement of the gasket, insert a paper or metal sheet of uniform thickness into the gap between the concave and convex mold mating parts. Use the thickness of the gasket as a reference standard to ensure that the fitting gap of the concave and convex molds is even.
3. Measurement by light transmission method, using light to illuminate the fitting gap between the concave and convex molds, and judging whether the gap between the concave and convex molds is uniform by the size of the light gap.
4. Apply a layer of paint on the punch with a thickness equal to the matching gap between the concave and convex molds, and then insert the concave mold. This method is simple and practical, and is more suitable for stamping molds that cannot be tested and adjusted with gaskets.
5. Copper plating method: Plate a layer of copper on the working end of the punch, with a thickness equal to the matching gap between the concave and convex molds, and then insert the concave mold. This method is similar to the coating method. During the use of the stamping die, the copper layer can automatically fall off.
