to develop a custom 700ml glass liquor bottle for their signature product. The client sought a sleek, modern design with a sturdy yet elegant structure to enhance their brand’s luxury appeal.
Challenge
After production, the bottles exhibited four inward-facing dents (concave deformations), compromising both aesthetics and structural integrity. The issue was identified in the early production batches, requiring immediate resolution to avoid delays in market launch.
Root Cause Analysis
Our engineering team conducted a thorough investigation and identified the following key factors:
- Mold Design & Cooling Imbalance
- The four-panel mold structure created uneven cooling, causing differential shrinkage and inward deformation.
- Insufficient venting led to vacuum pressure pulling the glass inward as it cooled.
- Glass Distribution & Thickness Variations
- The sidewalls were too thin in certain areas, making them susceptible to collapsing under atmospheric pressure during cooling.
- Inconsistent glass gob weight resulted in weak spots along the bottle’s body.
- Annealing (Stress Relief) Process Issues
- The annealing oven temperature curve was too aggressive, leading to rapid cooling and internal stress buildup.
Our Solution
- 1. Mold Redesign & Adjustments
- Improved Venting: Added micro-venting channels along the mold seams to equalize pressure during cooling.
- Optimized Cooling System: Adjusted cooling airflow to ensure uniform temperature distribution.
- Reinforced Wall Thickness: Slightly increased sidewall thickness in critical areas while maintaining the bottle’s sleek profile.
- Stable Gob Weight Control: Ensured consistent glass distribution by fine-tuning the feeder system.
- Modified Annealing Cycle: Slowed down the cooling rate in the annealing oven to minimize residual stress.
- Implemented automated optical inspection (AOI) to detect early signs of deformation.
- Conducted pressure resistance tests to validate structural integrity before mass production.
Result
After implementing these adjustments: