Failure analysis and troubleshooting methods: (1) Improper control of process conditions. Should be adjusted appropriately. (2) Injection capacity of injection molding machine is less than weight of plastic part. A larger injection molding machine should be used. (3) Cross section of runner and gate is too small. Should be increased appropriately. (4) Flow distance of melt in cavity is too long or there are thin-walled parts. Cold slug should be set. (5) Poor mold exhaust, and residual air in mold cavity causes insufficient injection. Exhaust system of mold should be improved. (6) Fluidity of raw materials is too poor. Resin with better flow properties should be used instead. (7) Temperature of barrel is too low, injection pressure is insufficient, or injection time of replenishment is too short, which will also cause short injection. Control amount of related process parameters should be increased accordingly.
When we adjust machine, we often sigh: If mold is transparent, it will be fine! In this way, you can see entire filling process of melt, see how and when defects occurred. When we design a certain glue injection process, whether glue injection process is actually completed according to envisaged requirements, whether starting point is set correctly, we hope to be able to see.
Add granular or powdered plastic into hopper of injection machine. Plastic is heated and melted in injection machine to keep it flowing, then injected into a closed mold under a certain pressure. After cooling and shaping, molten plastic solidifies into desired plastic part.
When plastic part has external thread features, demolding generally adopts opening cavity, ejecting plastic part from core to realize automatic demolding, which is conducive to simplifying mold structure; When demoulding is required in same direction as axial direction of external thread or in vertical direction, a special side core pulling mechanism needs to be designed for side core pulling and demolding. Layout of plastic part to be molded in mold opening plane is closely related to selection of mold release method. In the case that demolding can be completed, ayout of plastic part to be molded in mold should be considered in favor of simplifying mold structure, so as to reduce mold manufacturing cost and ensure reliability of mold mechanism.
Door body of a household refrigerator is mainly composed of a door shell, an end cover, a column, a door liner, a seal, an insulation layer and a stop mechanism. Built-in door handle is a plastic part that integrates column and door handle, is connected with door shell, end cover and inner tank. For double-door refrigerators, door handles of refrigerator compartment and greenhouse are required to be beautiful and harmonious. In actual injection molding process, usually 1 mold and 2 pieces are produced as a set, which can improve production efficiency and reduce manufacturing costs. At the same time, in order to pursue a good appearance, formed plastic parts are required to have neat seams and flat joint surfaces. Design points and working principle of injection mold for streamlined refrigerator door handle 1-mold with different cavities are described.
In some consumer products, in order to meet needs of product functions, some buckles and undercuts are often designed on product. Some products not only have undercuts on the outside and inside, but also have some special undercuts and deep reinforcing ribs inside product. Front mold cavity is also very deep, external structure of product is complex and there are many undercuts. How do we design mold structure when encountering such a product? Today I will share with you a set of car mold structure, hoping to give you some inspiration.
With rapid development of green travel industry, major auto companies have entered new energy field. Motors are core components of new energy vehicles, and their market demand continues to rise. Aluminum alloy motor end caps are an important part of motors. Its stable production quality can ensure supply of complete motors, production and sales of entire vehicle market. Die-casting mold is an important equipment for producing motor end caps. Whether molded parts can be demolded smoothly is an important factor affecting die-casting production, it is also an issue that must be considered in design and development of die-casting molds. Following introduces die-casting forming of aluminum alloy motor end cover. Parts formed during die-casting test mold are easy to be stuck in fixed mold. Reasons are now analyzed.
Need to produce small and light parts has made thin-wall injection molding the most in-demand performance of injection molding machines. "Thin wall" is usually defined by lightweight electronic parts with a wall thickness of less than 1mm. For large automotive parts, "thin wall" can be 2mm. In short, thin-walled products require changes in processing technology: higher pressure and speed, shorter cooling time, changes in product ejection and gate arrangement. Following are requirements of thin-wall injection molding for injection machines and molds.
How to produce shell products with no melt marks, no flow marks, no flow lines, no sink marks, and high gloss surface is particularly important for flat-panel TVs, computer LCD monitors, air conditioners, and automotive interior parts. Use of high-gloss injection molding technology can solve this problem well.
Melt glue usually flows from nozzle into nozzle, but in some molds, nozzle is part of mold because it extends to bottom of mold. There are also two main types of nozzles: open nozzles and closed nozzles. In injection molding, open nozzles should be used more because they are cheaper and less likely to stay. If injection molding machine is equipped with a pressure-removing device, this nozzle can be used even for low-viscosity melts. Sometimes a closed nozzle must be used. This nozzle acts as a stop valve to block plastic in injection cylinder. Make sure that nozzle is correctly connected to nozzle sleeve. Top hole is slightly smaller than nozzle sleeve. This makes nozzle easier to withdraw from mold. Hole of nozzle sleeve is 1mm larger than that of nozzle, that is, radius of nozzle is 0.5mm smaller than radius of nozzle sleeve.