Cast iron parts are being used for manhole covers on urban roads. Although cast iron manhole covers have many advantages, they also have the following problems: cast iron manhole covers often get lost during use, resulting in frequent accidents; Some cast iron manhole covers with larger surface areas have poor impact resistance and are prone to breakage due to the impact of moving vehicles; Cast iron manhole covers are greatly affected by climate, and in areas with significant temperature changes in winter and summer, the thermal expansion coefficient of cast iron manhole covers is high, resulting in loose cooperation and easy overturning by moving vehicles; Although the self-locking structure can only change certain functions from a structural perspective, it is easy to lose; It is difficult to overcome phenomena such as breakage caused by impact.

Therefore, people began to explore the replacement of cast iron products with polymer composite materials. There are also many manhole covers made from waste plastics or other polymer composite materials on the market. Using polymer composite materials to produce a series of manhole cover products,

It is necessary to possess the following strengths: ① having high strength and stiffness; ② Not deformed or broken under heat and stress conditions; ③ Has high wear resistance and heat resistance; ④ Good molding process, low shortening rate, and good scale stability; ⑤ Low molding pressure, simple manufacturing process, extensive data sources, and low price; ⑥ It has non recyclable function and anti-theft (non recyclable use). The manhole covers produced using SMC materials quickly became the mainstream of this type of product due to their excellent functionality. This type of product has been tested in many cities, with various functions reaching the level of manhole covers. It is both environmentally friendly and anti-theft, and has a huge market. It is a product worth promoting. Therefore, SMC data has an outstanding market in the application of manhole covers for urban roads.

The article originates fromSMC molded products http://www.jmlicheng.com