Formulas and worked example
For one label supply, let N be bottles, K labels from this reel per bottle, R labels on a new reel, W unavailable labels per new reel, and S usable labels already loaded.
- Label demand = N × K.
- Usable count per new reel = R − W.
- Remaining demand = the greater of zero and (N × K − S).
- New reels required = remaining demand ÷ (R − W), rounded up to a whole reel.
- With a usable reel already loaded, each new reel is an in-batch change. Without one, the first new reel is initial setup, so in-batch changes equal new reels minus one, with a minimum of zero.
Example: 10,000 bottles, one label each, 2,000 supplied labels per reel and 40 unavailable labels per reel leave 1,960 usable labels per reel. Starting without a loaded reel requires six new reels and five changes during the batch, leaving 1,760 usable labels after the batch.
At the example operating rate of 30 bottles/minute, a full usable reel represents about 65.3 minutes of bottle production. Five four-minute changes add 20 minutes to approximately 333.3 minutes of running, giving about 353.3 minutes for running plus those changes only.
Initial setup, breaks, cleaning, inspection holds, material faults, upstream interruptions and other losses are not included. Use the throughput calculator to assess the broader time allowance; avoid counting the same planned stop twice.