模压复合井盖就是将模塑料加入钢筋在一定温度和压力下压制成型。这种复合井盖因增强材料采用的是短纤维(30-50mm短纤维形成复合材料的强度只有连续纤维20-30%)，复合井盖结构上采用的是平板底部加肋，这种增强材料及复合井盖结构导致复合井盖承载能力严重不足，只能加入钢筋以增加荷载。而钢筋的加入，形成材质具有两大缺陷：①钢筋表面有锈，往往导致材料界面结合不好(如果复合材料界面结合不好，就不会产生1+1>2的效果);②钢筋是金属材料，SMC/BMC是非金属材料，两种材料因热膨胀系数的差异。在不同温度下(早、中、晚、冬天、夏天)材料界面将会形成应力，加之车辆反复碾压，会导致钢筋与SMC/BMC脱离，最后导致复合井盖失去承载能力(具体多长时间失去承载能力，取决于企业制作过程中复合工艺和使用条件，也许2-3年，也许更长)。优点：A、防盗;B、外观精致;缺点：A、承载能力不够;B、因加入钢筋，界面脱离后会导致失去承载能力。2、分层复合井盖这种复合材料复合井盖是用不饱和聚酯树脂作基体材料，用玻璃纤维作增强材料，辅以一定刚性材料。结构上采用锅底结构，底部抗拉材料受力均匀;材质上分上下两层，上部采用耐磨、耐老化材料，产品的使用寿命长。下部采用连续玻璃纤维增强，可以使复合井盖具有足够的承载能力，而不需任何钢筋增强。是几种复合材料复合井盖中综合性能较好的一种材料复合井盖。优点：A、防盗;B、承载能力高;C、外观漂亮。缺点：A、表面硬度高、而脆性稍高;B、价格稍高。
模压井盖：是用不饱和树脂作基本材料，用30-50mm短纤维和钢筋作增强材料，用碳酸钙作填充材料，在一定温度下压制而成。由于钢筋是金属材料，而BMC是有机材料，BMC的热膨胀系数是钢筋的两倍，且因钢筋表面生锈，而使BMC与之复合时界面结合不牢，温度发生变化时，钢筋与BMC材料之间界面会形成应力，加之车辆反复碾压，会导致钢筋与BMC界面分离，最后复合井盖丧失承载能力。并且表面为BMC和碳酸钙材料混合物，因而耐磨性较差。玻纤增强复合井盖：从结构采用锅底型结构(均匀承载)，这种结构与加肋型(集中承载)相比，底部受力面积增大几倍;其次，多层加筋，层层相扣，受力均匀，因此，结构上使产品承载能力更强;从材质方面，耐磨层采用多色彩石英沙作耐磨材料并加入稳定剂，使产品耐磨性能使用寿命成倍提高;采用连续增强纤维骨架，确保了产品的高承载能力，而其他复合井盖有的不用纤维增强，即使使用纤维增强也是使用短纤维(短纤维的强度仅为连续纤维的20%-30%)，强度不够时，只好用钢筋弥补，产品整体材料为有机材料，在复合井盖不同部位使用不同增强材料，从材质上避免了其他复合材料产品因使用钢筋等增强材料而出现的分离、脱落现象。采用分层复合工艺，满足机构创新和材质创新的要求，在复合井盖不同部位使用不同增强材料，使复合井盖不同部位使用不同增强材料而出现的分离、脱落现象。
Molded composite covers with reinforced plastic is to die at a certain temperature and pressure compression molding . This result covers the composite material used is of short reinforcing fibers ( strength of the composite 30-50mm staple fibers are formed only continuous 20-30 % ) , a composite structure using a bottom covers stiffened plate , such a reinforced composite material , and manhole covers bearing capacity of composite structures lead to a serious shortage , only adding reinforcement to increase the load . The steel joined to form the material has two flaws : ① steel surface rust , often resulting in poor interfacial bonding material (if the composite interfacial bonding well, it will not have an effect of 1 +1 > 2 ); ② reinforcement is metallic materials , SMC / BMC is non-metallic materials , the two materials due to thermal expansion coefficient differences . At different temperatures ( early, middle and late winter, summer ) will form a material interface stress , coupled with the vehicle rolling again , will lead to steel and SMC / BMC detachment, leading to loss of carrying capacity of composite covers (specifically how long to lose carrying capacity, depending on the production process complex business processes and conditions of use, maybe 2-3 years , maybe longer ) . Advantages : A, anti-theft ; B, the appearance of fine ; Disadvantages : A, carrying capacity is not enough ; B, by adding steel, the interface will result in the loss from carrying capacity . 2 , layered composite covers this composite material composite covers are made with unsaturated polyester resin matrix material reinforced with glass fiber materials, supplemented by some rigid material . Structures using structural pot bottom material tensile force uniform ; divided into two layers on the material, the upper part of long life wear, anti-aging materials, products. The lower part of a continuous glass fiber reinforced composite covers can have enough carrying capacity, without any reinforcement enhanced. Is one of several composite materials composite covers in a better overall performance composite materials covers. Advantages : A, anti-theft ; B, high carrying capacity ; C, beautiful appearance . Disadvantages : A, high surface hardness , brittleness and higher ; B, higher prices .
Molded covers : unsaturated resin as a base material , with 30-50mm staple fibers as a reinforcing material and reinforced with calcium carbonate as filler , at a temperature of repression. Since steel is a metal material, and BMC is an organic material , the thermal expansion coefficient is twice BMC steel , and because steel surface rust , leaving the BMC interface when combined with the composite is not strong, when the temperature changes , reinforced with BMC material will form the interface between stress , coupled with the vehicle rolling again , will lead to reinforcement and BMC interface separation , the final composite covers loss of carrying capacity. BMC and the surface of the material and a mixture of calcium carbonate , which is poor wear resistance. Glass fiber reinforced composite covers : from structure using pot -type structure ( uniform load ) , this structure with ribbed type ( centralized load ) compared to the bottom of the force area increased several times ; secondly , multi- reinforced layers interlocking , even by force , so that the structure of the product bearing capacity; multi color quartz sand from the material, the wear layer for abrasion-resistant material and add a stabilizer so that the product wear life doubled ; continuous reinforcing fiber backbone ensure high bearing capacity of the product , and not some other fiber-reinforced composite covers , even when also using short fiber reinforced fiber ( short fiber strength of only 20% -30 % of the continuous fibers ) , the intensity of when not enough , had to use steel to make up the overall product material is an organic material , in different parts of the reinforced composite covers the use of different materials , to avoid the separation of other products due to the use of reinforced composite materials such as reinforced material appearing from the material , shedding phenomenon . Layered composite technology , innovation and material innovation to meet the agency 's requirements, to enhance the use of different materials in different parts of the composite covers , so that different parts of the composite covers the use of different materials to enhance the emergence of separation , shedding phenomenon .