95% of composite manhole covers factories in China are producing BMC manhole covers with very poor quality. That’s why so many customers always give us the same feedback ‘The load ability of composite manhole covers from China is very bad’.For the BMC covers, the maximum load ability for actual is 10tons, but the BMC manhole covers factory likes to sell you at the load ability D400(40TONS). You should imagine what’s going to happen when you use this type of sewer covers on your road system. Please kindly take a few minutes to read details of the following differences for BMC, SMC & FRP/GRP manhole covers to know what is the real plastic manhole covers.
BMC Manhole Covers |
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Material:
- Unsaturated polyester resin
- 10-15mm short glass fiber
- Calcium carbonate
- Low-profile additive
- Trasys
- Steel Bars
Technology:
- Put A, B, C, D, E into a kneader to shape as bulk molding compound (BMC)
- Put BMC into the mould, add some Steel Bars, and then press them under a certain temperature and pressure
- Demoulding, trimming, test
- Homogeneous materials, cheap
- Simple production
Function:
- Smooth surface
- Uniformitarian color, like plastic
- Low load capacity, can only produce A15, B125 grade product
- Friction surface
- Relatively lower cost
SMC Manhole Covers |
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Material:
- Unsaturated polyester resin
- 30-50MM short glass fiber
- Calcium carbonate
- Low-profile additive
- Trasys
Technology:
- Put A, B, C, D, E into a make-up tank, stir evenly and then put them on B to shape as a sheet molding compound (SMC)
- Put SMC into the mold, add some Steel Bars if necessary, and then press them under a certain temperature and pressure
- Demoulding, trimming, test
- Homogeneous materials, not cheap
- Relatively simple production
Function:
- Smooth surface
- Uniformitarian color, like plastic
- Can produce A15, B125, C250,D400 grade product
- Friction surface
- Higher cost
FRP Manhole Covers |
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Material:
- Unsaturated polyester resin
- Continuous long glass fiber
- Quartz
- Additive (a)
- Additive (b)
Technology:
- Put A, B, D to prepare continuous fiber reinforcement; Put A, C, D to prepare aggregate; Put A, C, E to prepare surface abrasion resistance, etc.
- Put different materials into the different part of mold (without Steel Bars)
- Press them under a certain temperature and pressure
- Demoulding, trimming, test
- Different materials, different formulations
- Complex production
Function:
- Good surface
- Characteristic color & logo
- Can produce A15, B125, C250, D400, E600 grade products
- Good wear-resistance
- Favorite price for C250, D400, E600 grade products