Blast / Explosion Defect in Ceramics: Causes & Analysis

Blast / Explosion Defect in Ceramics: Causes & Analysis

A blast or explosion defect happens when a ceramic product bursts or breaks apart during the kiln firing process. This is a serious defect because it not only destroys the affected product but can also damage other ceramic products nearby in the kiln.

Why Is This Defect Dangerous?

When a ceramic product explodes inside the kiln, the broken pieces can hit and damage the surrounding products. This leads to more losses than just one defective piece. It can also damage the kiln shelves and furniture, which adds to the cost of repair and downtime.

Main Causes of Blast Defect

1. Moisture in the Body

The most common reason for blasting is moisture trapped inside the ceramic body before or during firing. If the product is not dried properly before going into the kiln, the water inside turns into steam when heated. This steam builds up pressure inside the body and causes it to burst open suddenly.

2. Air Pockets in the Body

Air trapped inside the ceramic body during the casting or shaping process can also cause blasting. When the kiln temperature rises, the trapped air expands rapidly, creating pressure that cracks or explodes the product.

3. Fast Heating Rate

If the kiln temperature is increased too quickly during the early stages of firing, the outer surface of the ceramic product heats up faster than the inside. This uneven heating creates stress in the body, which can lead to cracking or blasting.

How to Prevent Blast Defect

• Make sure all ceramic products are fully and evenly dried before loading into the kiln
• Use a slow and controlled heating rate during the early firing stages to allow moisture to escape slowly
• Check for air pockets or poor slip preparation during the casting process
• Maintain proper drying conditions in the drying room to avoid uneven drying

Impact on Production

Blast defects cause direct product loss and may also damage other good products and kiln equipment. Prevention through proper drying and controlled firing is the most cost-effective approach for ceramic factories.