When Is the Best Time to Demold GRC Components? Qinglong's Precise Control Technology for GRC Demolding Process

Accurate timing of demolding is a key process node for ensuring the quality of GRC components. Demolding too early causes component deformation and breakage, while demolding too late reduces mold turnover efficiency. Through 28 years of process data accumulation, Qinglong GRC has established a scientific demolding timing determination system centered on strength development with environmental conditions as correction factors.

In the production of large decorative components (projected area 8.5㎡) for a super high-rise project in Guangzhou, real-time monitoring of specimen strength determined the demolding strength threshold to be 15MPa. With steam curing (constant temperature of 40℃), the demolding time was shortened to 16 hours; under natural curing conditions, it needed to be extended to 36 hours. Through precise control, mold turnover on this project increased to 50 cycles, and the component yield rate reached 99.5%.

Core Indicators of the Strength Control Method

Demolding strength for flat panel components ≥10MPa; cantilevered components ≥15MPa; large special-shaped components ≥20MPa. Compressive strength testing of companion-cured specimen blocks shows that the strength development rate curve reaches 40%-50% of 28-day strength at 24 hours at 20℃.

Ambient Temperature Correction Coefficients

A temperature-strength development mathematical model has been established: for every 10℃ increase in temperature, the strength development rate doubles. At 5℃, the time must be extended to 48 hours; at 30℃, it can be shortened to 18 hours. Temperature sensors are used for real-time monitoring of core temperature.

Component Characteristic Adjustment Parameters

Thin-walled components (thickness <20mm) require a 20% increase in demolding strength; components with decorative moldings should delay demolding by 2-4 hours; curved components require verification of demolding adhesion force. Standard demolding times are corrected using characteristic coefficients.

Mold System Influence Factors

With steel molds, demolding strength can be reduced to 8MPa; GRP molds require ≥12MPa; silicone molds require strength to reach 20MPa. A demolding strength parameter database has been established for different mold types.

Demolding timing requires scientific determination. The demolding decision system developed by Qinglong GRC has achieved a demolding pass rate of 99.8% and extended mold service life by 30%.