Case Former Downtime Stabilization
Improving Packaging Material Flow to Eliminate Chronic Equipment Downtime Losses on Yogurt Line
Challenge
A yogurt manufacturer experienced chronic downtime on its case former due to inconsistent cardboard tray materials, improper inventory rotation, and seasonal variability in board quality. Vendor fixes were temporary because the underlying material-handling issues were never addressed.
- Persistent case-former downtime appeared as a major cause on the downtime Pareto chart.
- Vendor technicians could temporarily resolve issues, but downtime always returned, indicating systemic material problems.
- Cardboard trays varied significantly in pliability, rigidity, and break points depending on age, lot, and supplier curing conditions.
- Packaging materials were stored and used in a LIFO pattern, causing older, degraded trays to reach production last.
- Seasonal supplier variability—especially during harvest season—further reduced board consistency and worsened machine performance.
Solution
The team implemented a structured packaging-material management system, reorganized warehouse storage for FIFO rotation, and updated case-former operating parameters to align with material characteristics and seasonal variability.
- Added cardboard trays into the Warehouse Management System and treated them like perishable items with age thresholds.
- Designed and enforced a FIFO rotation process to prevent over-aged tray stock from entering production.
- Reconfigured warehouse storage so the oldest lots were easy to access and consistently pulled first.
- Adjusted case-former parameters based on tray pliability and break-point characteristics for seasonal and material shifts.
- Eliminated most age-related variability through controlled rotation, leaving only normal supplier variation to be addressed by parameter tuning.
Results
Case-former downtime was reduced from a major Pareto category to a minor contributor, revealing the true bottleneck on the line and freeing resources to address changeovers and unlock additional capacity.
- Case-former downtime moved from a major-but-few, to minor-but-many category on the Pareto chart.
- Stabilized performance allowed the team to identify the case former as the previous bottleneck across several lines.
- With the constraint removed, changeover time emerged as the next major improvement opportunity.
- Resources were redeployed to reduce changeover time using SMED, shifting sequential steps into concurrent ones.
- Overall operational flow improved as material consistency and machine reliability increased.