Define the purchasing question
Tape purchasing starts with a sealing pattern and strip lengths, then adds observed process waste and whole-roll rounding.
Carry measured metres per box into roll quantity and recurring cost calculations. Ask suppliers to quote usable length and the qualified tape specification.
Collect measurements that match the calculation
Measure the seam and cross-strip dimensions on the closed carton. Record the extension at each end of a strip. Confirm whether both top and bottom faces are sealed.
Count top and bottom centre seams. H-seal adds two cross strips on each face. Extension is added at both ends of every strip.
- Carton seam length (mm)
- Carton cross-strip width (mm)
- Extension per strip end (mm)
- Sealing pattern
Work through an illustrative case
Centre seal = 2 × (Seam + 2 × Extension); H-seal adds 4 × (Width + 2 × Extension)
400 mm seams with 50 mm end extensions use 1 m for centre seals; 300 mm cross strips give 2.6 m for H-seal.
Replace these illustrative inputs with measured data or a quotation for the same scope. Change one assumption at a time so that a difference can be traced to a dimension, quantity, charge or process change.
Avoid the expensive comparison error
Adding extension once per box understates six-strip H-seal usage. Quoted tape thickness or roll length alone does not establish adhesive performance.
- Geometry only; order tools add process loss.
- Sealing pattern and tape specification require qualification.
Common questions
What should I verify before using this result?
Measure the seam and cross-strip dimensions on the closed carton. Record the extension at each end of a strip. Confirm whether both top and bottom faces are sealed.
Does this calculation approve the packaging?
No. It estimates only the stated quantity, conversion or cost boundary. Technical performance and any required test or supplier approval remain separate.