Causes and Practical Solutions for Fast Drying Cracks in Brick Green Body

2026-09-11

Brick green body cracking during the drying process is one of the most common quality defects in the automatic brick setting system production line. Excessively fast drying speed is the core trigger for green body cracks, which severely affects brick product yield and finished brick quality in the brick and tile manufacturing industry. Reasonable control of the drying process is the key to eliminating such industrial defects.

There are two primary root causes for rapid drying-induced green body cracks in brick setting systems.

First, sudden and drastic fluctuations in the drying system parameters, including sharp changes in temperature and humidity curves inside the drying chamber. Unstable drying conditions break the balanced water loss rhythm of the brick green body, resulting in irregular shrinkage and structural cracking.

Second, the drying speed is excessively high before the green body reaches the drying critical point. The green body does not form a stable internal structure in the early drying stage, and accelerated dehydration will directly damage the body integrity.

Drying medium temperature is a critical indicator that determines the water-carrying capacity of drying air in brick production. Higher medium temperature enhances water evaporation efficiency and speeds up the dehydration of uncured brick green body. However, excessive temperature or sudden temperature surges will cause an imbalance between surface and internal water migration. The surface moisture of the green body evaporates rapidly and shrinks sharply, while the internal moisture moves slowly with minor volume shrinkage. This inconsistent shrinkage generates strong internal tensile stress on the green body surface.

When the tensile stress exceeds the surface structural strength of the brick green body, permanent surface cracks and even deep structural cracks will occur. For industrial brick drying operations, maintaining stable and gradual temperature and humidity adjustment is essential to avoid rapid drying cracks and ensure stable production of high-quality bricks.

FAQ

Q1: What is the drying critical point of brick green body?

A: The drying critical point refers to the key stage where the free moisture inside the brick green body is completely evaporated and the internal skeleton structure is initially stabilized. Drying speed must be strictly controlled before this point to avoid cracking.

Q2: How to stabilize the drying system parameters of brick setting machines?

A: Adopt gradual temperature and humidity rise and fall procedures, avoid sudden parameter adjustments, and equip the drying system with intelligent constant-temperature and constant-humidity control modules.

Q3: Why does uneven internal and external shrinkage cause brick cracks?

A: Rapid surface shrinkage and lagging internal shrinkage produce mutual tensile stress. Once the stress exceeds the green body’s bearing strength, surface and structural cracks will form.