Vertical Cracks

Description
Cracks travelling from top to bottom of the die bore.

Causes

• Mechanical stress caused by die bore drilled off center.
• Die misaligned when mounted.
• Insufficient diamond wall thickness due to oversized entrance or die bore.
• Drill bit contact with diamond table when casing was opened.
• Residual stress relief from cobalt pool in the diamond table.
• Hole bored before mounting of nib.

Horizontal Cracks

Description
Cracks travel around the bore diameter.

Causes

• Development of wear ring serving as a stress riser.
• Gaps in braze alloy after sintering cause mechanical stress.
• Gaps from press fit cause mechanical stress.
• Nib abrading steel casing during mounting operation.
• Overheating during laser drilling or sintering process.

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