BMC & SMCMolds · Compression & Injection Molded Parts
Comparison
BMC vs SMC: differences, properties and applications
BMC and SMC use similar ingredients but differ in form, fiber length and how they are molded. SMC is a sheet with longer fibers, compression molded into larger, stronger parts. BMC is a dough with shorter fibers that flows further, and is injection or compression molded into smaller, more detailed parts.
Side-by-side comparison
| SMC | BMC | |
|---|---|---|
| Form | Sheet between carrier films, cut into a charge | Dough or log, weighed or fed by a stuffer |
| Fiber length (typical) | About 25 mm | About 3–12 mm |
| Glass content (typical) | Often about 25–30%, higher for structural grades | Often about 10–30% |
| Molding process | Compression molding | Injection, compression or transfer molding |
| Typical part size | Medium to very large | Small to medium |
| Detail and thin walls | Good | Very good |
| Strength and impact | Higher | Lower |
| Typical parts | Enclosures, panels, battery covers, water tank panels | Reflectors, breaker housings, motor parts, insulators |
Values are typical industry ranges; the supplier’s data sheet gives the figures for a specific grade.
BMC vs SMC FAQ
Is BMC or SMC stronger?
SMC, in general. Its longer fibers and the compression molding process give higher strength and impact resistance than BMC of a similar formulation.
Which is better for small, detailed parts?
BMC. Its shorter fibers let it flow into fine detail, thin walls and small features, and it can be injection molded efficiently.
Which is better for large panels and enclosures?
SMC. The sheet is easy to cut and stack into a charge for a large part, and it gives the stiffness and impact strength those parts need.