Analysis and Prevention of Common Defects in Finished Bricks (such as Cracks and Chipping)

Analysis and Prevention of Common Defects in Finished Bricks (such as Cracks and Chipping)

Cracks and chipping in bricks not only affect their appearance but also severely compromise their strength and durability. These problems are not accidental; they usually point to control errors in one or more stages of the production process. By systematically analyzing the causes and taking targeted preventive measures, these defects can be effectively eliminated.

I. Cracks (Surface Cracks or Through Cracks)

This is one of the most common defects, mainly caused by improper moisture control and external stress.

Cause Analysis:

Rapid Drying (Main Cause): After the brick blanks are formed, if they are directly exposed to strong sunlight and wind, the surface moisture evaporates rapidly, causing rapid shrinkage. However, the interior remains wet and shrinks more slowly, leading to uneven shrinkage between the inside and outside, generating tensile stress that "pulls" the surface apart, forming fine cracks.

Improper Curing: Low environmental humidity during the initial curing period (especially the first 3 days), or inadequate moisturizing measures (such as not covering or not watering), leads to insufficient cement hydration and insufficient strength development in the brick body, also easily causing cracks.

Raw Material and Mix Proportion Problems: High clay content in aggregates (such as sand), or excessive fine powder in the raw materials, will increase the drying shrinkage rate of the brick blanks. Excessive water content makes the brick blanks too soft, resulting in large shrinkage and deformation, which also easily leads to cracking.

Improper Operation: Rough handling during demolding, or collisions and compression during handling and stacking of wet blanks, cause internal damage, which later manifests as cracks.

Preventive Measures:

Strict Moisture Curing: After the brick blanks are formed, immediately transfer them to a shaded and wind-protected curing area, and maintain a humid environment for at least 5-7 days by covering them with plastic sheeting and regularly spraying water mist.

Control Drying Speed: Avoid outdoor curing or exposure to strong sunlight and wind.

Optimize Raw Materials and Mix Proportions: Use aggregates with low clay content and strictly control the amount of water added.

Standardize Operations: Handle wet blanks gently during demolding and transportation to avoid external damage.

II. Chipping and Edge Damage

These defects mainly occur at the corners of the bricks, affecting their regularity. Causes of Defects:

Mold Wear or Damage (Main Cause): The edges and corners of the mold wear down or deform due to long-term use, or the mold itself has defects, resulting in incomplete or uneven edges and corners of the formed bricks, or adhesion between bricks.

Difficult Demolding: The demolding mechanism is inaccurate or jams, or the release agent (separator) is used improperly, causing the bricks to be scratched or torn by the mold edges during demolding.

Insufficient Brick Strength: If the bricks are handled or subjected to impact before they have gained sufficient strength (not fully cured), the corners are easily chipped.

Handling and Stacking Collisions: Improper handling and stacking of finished bricks during transportation and storage can lead to hard collisions between bricks.

Preventive Measures:

Regular Mold Inspection and Replacement: Regularly inspect the mold, especially the integrity of the edges and corners. Repair or replace the mold promptly if wear or deformation is found.

Ensure Smooth Demolding: Adjust and maintain the demolding mechanism to ensure smooth and accurate operation. A small amount of special release agent (such as diluted waste engine oil) can be applied to the mold surface, but the amount should be carefully controlled to prevent contamination of the brick surface.

Ensure Brick Strength: Ensure that the wet bricks have sufficient curing time (usually 12-24 hours) before moving them.

Standardize Handling and Stacking: Use specialized tools for handling, and handle and stack bricks gently and securely.

In summary, the key to solving brick defects lies in "prevention first, systematic control." Most cracking problems can be solved by "proper moisturizing and curing" and "avoiding exposure to direct sunlight and wind"; while corner chipping problems require focusing on "maintaining the molds" and "standardizing demolding and handling." Establishing a quality control awareness throughout the entire process, from raw materials and molding to curing and handling, is the fundamental guarantee for continuously producing high-quality bricks.