BMC manhole covers are the the abbreviation of bulk molding compounds manhole covers.People in China often called unsaturated polyester dough molding compound. The main raw material of GF (chopped glass fibers), UP (unsaturated polyester resin),MD (filler) and various additives made by mixing dough prepreg material.
In 1960s and 1970s,BMC and SMC (sheet plastic) with the solutions of some key technology are growing rapidly,and its products are of the advantages of high precision,fiber without exposion, good surface appearance, and better product stability. In recent years,BMC products with the rapid development have been widely used in the electrical, instrumentation, chemical, transportation, military and other fields.
What are the advantages of using the BMC material to manufacture manhole covers ?
1.The production process is simple
BMC molded covers are resin,fiberglass,filler material to form BMC.Firsty in the bottom of the mold,put a small amount of BMC material,into steel bars, and then put the rest of BMC material, suppress heat-cured . Process characteristics: All the material is uniformly reinforced material except of steel bar material,simple production operations,a compression molding.
2.Less investment and start fast
Renting a few hundred square meters of factory,hiring a few working people,purchasing 2-3 sets presses (100-300 tons) and a BMC kneading machine,opening a few sets manhole covers molds,you can creat a BMC molded manhole covers plant without capital threshold and technological barriers only by invest usd30,000 even in a month.
3.Good quality appearance
With exquisite appearance,BMC manhole covers can be made into a variety of colors.
4.Temporary load ability relatively high
BMC molded manhole covers have temporary higher load ability than steel fiber reinforced concrete covers and magnesite cement covers. However,the using life of BMC manhole covers are very short,which will not beyond 2 years. Currently,the crack of heavy loads generally on BMC covers could be up to 24 tons.
5.The cost is relatively low
BMC manhole covers comparingly save material because its structrue uses flat bottom plus ribbed bars.There are many companies in China that use recycled old steel reinforcement with less production staff,low management costs. Therefore,the production cost of BMC molded covers is relatively low. The price of BMC manhole covers are of very very cheap price comparing to other SMC and FRP/GRP manhole covers.
6.Easily can make scale production
BMC molded covers products can be increased accordingly by simply copying the expansion of large-scale production if there are market.BMC molded covers factories in China based on the above advantages are springing up throughout the country by the Zhejiang area development.