The useful purchasing measure is the cost of producing labels or codes that meet the job’s requirements. Roll price matters, but it does not describe usable length, rejected output or the cost of changing a process. A transparent comparison is more persuasive than a supplier’s unqualified claim of lower total cost.
Start with a narrow, reproducible model. Compare the same printer application, label construction, artwork and required production rate. Keep the quality threshold fixed so a cheaper but unacceptable image cannot improve the apparent economics.
Establish the consumption basis
For ordinary label printing, record how much ribbon the printer actually consumes during a measured job. Include startup and the unusable remainder left when a roll is changed. Do not assume that nominal roll length divided by label height gives the final accepted-label yield; label pitch, feed behaviour and the actual printing mode matter.
TTO requires particular attention because consumption can depend on the machine’s ribbon-saving functions and print layout. The Videojet DataFlex 6330 operator manual describes an interleaved mode as a lower-quality printing option. A consumption claim therefore needs the corresponding print mode and quality result, rather than a savings percentage borrowed from a brochure.
Measure a representative production run and retain its start and finish counts. Where only an estimate is possible, label it as an estimate and show the assumptions separately. A precise spreadsheet cannot make uncertain inputs more reliable.
Calculate the basic comparison
A practical first measure is:
Ribbon cost per accepted label = ribbon cost consumed during the trial divided by the number of accepted labels produced.
Use the landed ribbon cost on a consistent basis for both candidates. If freight, taxes or duties are excluded, state that explicitly. Do not compare a small trial shipment’s delivered unit cost with a bulk order price unless the difference is intentional and visible.
For a broader process measure, add attributable label waste, additional labour, cleaning materials and downtime according to the organisation’s costing method. Avoid double counting. If labour is already included in a machine-hour rate, adding it again inflates the cost.
Keep the basic ribbon measure beside the broader process measure. This allows a buyer to see whether a difference comes from purchase price, consumption or operational assumptions.
A small example with transparent assumptions
Consider two hypothetical trials that each consume one whole roll, including any discarded remainder. These are illustrative figures, not measured product results:
- Ribbon A costs US$18 landed and produces 4,500 accepted labels: US$4.00 of ribbon per 1,000 accepted labels
- Ribbon B costs US$22 landed and produces 6,000 accepted labels: approximately US$3.67 per 1,000 accepted labels
B has the higher roll price but the lower ribbon cost for accepted output in this example. The calculation does not tell us why the yield differs. The rolls might have different usable lengths, the job might consume them differently, or one trial might reject more output. Those causes matter when deciding whether the result is repeatable.
Now suppose B also requires a production-speed reduction that the operation cannot accept. Its lower ribbon-only cost does not clear that constraint. Conversely, if the trials used different label artwork, the figures are not a fair material comparison in the first place. Keep this simple calculation as one part of the decision, with its inputs visible.
Count failures consistently
Define “accepted” before the trial. It may include correct data, required barcode verification, legible text and the application’s durability checks. Record rejects even if an operator catches and reprints them before dispatch. Otherwise a process that creates more hidden rework can appear as efficient as a clean run.
Separate causes. A label rejected because the wrong job was selected should not automatically be attributed to the ribbon. Record the event and explain whether it belongs in the comparison. Unknown causes should remain unknown until investigated.
Use the same treatment for changeovers. Measure how many changes the production schedule actually requires and which minutes are incremental. Avoid crediting a longer roll with removing downtime that already occurs for an unrelated material change.
Test the assumptions that could change the answer
Run a simple sensitivity check: what happens if reject rate, usable length or changeover time differs from the trial? Use plausible ranges based on observed data, not a dramatic worst case invented to favour one option.
A candidate with a small purchase-price advantage may not justify a major validation programme for a low-volume SKU. Conversely, a high-volume application may justify careful trials because a modest, repeatable consumption difference accumulates. These are arithmetic consequences of the chosen inputs, not general performance promises about a ribbon grade.
Zebra describes separate durability and print-quality testing in its ribbon programme. Preserve that separation in a cost review: a ribbon must meet the application requirement before its operating cost becomes a meaningful comparison.
Present a decision someone can audit
Show the trial conditions, approved quality threshold, accepted count, consumption, unit-cost basis and assumptions. Identify costs that could not be measured. Include the operational changes needed to reproduce the result.
If the candidates are economically close, say so. The decision may then depend on supply reliability, stock complexity or support, which should be evaluated openly rather than hidden in a speculative savings figure.