What is Blisters on the External Surface Glass Defect?

What is Blisters on the External Surface Glass Defect?

By: Berlin Packaging Specialist
Date: November 11, 2019

Blisters on the External Surface is a type of glass defect during the manufacturing process of glass bottles.

Usually elongated, they may be:

Cracked (C) > the outer surface is broken

Not Cracked > but with a thin skin, the severity level is:

> 4 mm (M+) = 4 mm (M-) < 4 mm (m)

Problem

  • Cracked problem: potentially hazardous for the operator.
  • Not Cracked: ≥ 4 mm > risk of breakage during bottling and handling. Dangerous with carbonated beverages. < 4 mm > not very dangerous, considered mainly an aesthetic defect.