Keep the nominal carton and the filled envelope distinct
A carton drawing can specify a nominal outer size, while the closed filled case can have a larger envelope because panels, flaps or contents change its shape. Measure the object in the condition that will be palletized and label the observation separately from the drawing. Do not declare every difference a manufacturing defect or invent a universal carton tolerance. The relevant acceptance requirement must come from the actual packaging and operation.
The rectangle model needs a chosen outside envelope. Record which panel or feature controls it and whether the observed dimension varies across the shipment. A single dimensional value is a modeling decision, not proof that every filled case is identical. If the load contains materially different envelopes, one identical-case calculation may be an approximation. Explain that approximation instead of replacing the larger observations with the nominal value to recover a desired count.
Use a one-millimetre threshold example
Assume a nominal closed case footprint of 400 × 300 mm on a 1200 × 800 mm deck, with zero gap and edge clearance for comparison. Three 400 mm sides require exactly 1200 mm. If the measured first side is 401 mm while the second remains 300 mm, three require 1203 mm and cannot form that row. One millimetre per case has changed a complete integer count because the earlier grid had no residual along that direction.
Without rotation, the nominal grid gives three positions by two, or six cases. The measured 401 × 300 mm grid gives two by two, or four. With horizontal rotation allowed, the nominal grid gives four 300 mm positions along and two 400 mm positions across, or eight. The measured rotated grid has four 300 mm positions along but only one 401 mm position across, because two require 802 mm. Its count is four, so the best uniform measured grid is four.
| Footprint | Fixed-orientation grid | Rotated uniform grid | Best uniform count |
|---|---|---|---|
| 400 × 300 mm | 3 × 2 = 6 | 4 × 2 = 8 | 8 |
| 401 × 300 mm | 2 × 2 = 4 | 4 × 1 = 4 | 4 |
| 402 × 300 mm | 2 × 2 = 4 | 4 × 1 = 4 | 4 |
| Outside width not measured | Incomplete input | Do not assume nominal fit | Unresolved |
Do not convert the change into a proportional capacity rule
The first side increased by only 0.25 percent from 400 to 401 mm, but the best uniform count changed from eight to four. That does not imply that every one-millimetre bulge halves capacity. It describes this exact deck, case and zero-spacing comparison. Other dimensions can remain away from thresholds, and a mixed layout search can find a different candidate. Fit changes discretely; an area percentage or generic reduction factor cannot predict every lost row.
The configuration engine’s mixed search is finite and has its own proof status. A valid best-found candidate with more than four cases would be an improvement over the uniform grids under the same measured inputs, not permission to use the nominal footprint. Keep the uniform comparison for explaining the threshold and the returned mixed result for its actual geometric proposal. Neither establishes packaging strength or compression under stacked cargo.
Investigate the physical condition that produced the measurement
Record whether cases were filled, taped, strapped and ready to ship when measured. If a flap had not been closed, the measurement may describe a temporary assembly state rather than the final outside envelope. If a bulge is normal in the completed shipping condition, it belongs in the relevant fit record. Ask the responsible packaging party when the intended measurement state is unclear. Do not flatten or compress the carton solely to match an input unless the real approved process does that.
Preserve the nominal drawing revision, observed envelope and the selected planning value. If the chosen value comes from a particular inspected group, record which group it represents. Avoid claiming a universal instrument precision or a standardized inspection plan from this worksheet. When the measurement uncertainty is comparable to the three-millimetre row failure, obtain the information needed to resolve the boundary rather than relying on a rounded number.
Make a nominal-versus-filled-case record
Write packaging revision, outside nominal dimensions, normal filled and closed condition, measured maxima, observation range, measurement method and relevant precision. Record which feature determines the 401 mm side and whether the 300 mm side was also measured. Keep rotation permission, gap and edge clearance unchanged when comparing scenarios. An unknown side stays unresolved until measured or supplied.
Reproduce the threshold without changing other fields
Open the nominal 400 mm case example, confirm the fields and record its uniform count. Change case length to 401 while retaining the same deck, second side and rotation. Use the configuration calculator for explicit gaps and edge clearances, preserving each result’s model and status. The link is a numeric comparison, not evidence about your carton’s allowed variation.
If a new packaging batch measures differently, update the calculation and the measurement record together. A shared eight-case screenshot can hide the fact that it used nominal 400 mm cases rather than the completed 401 mm envelopes. Before production or shipment, review the chosen arrangement with the actual packaging, height, mass and handling conditions. The useful result is a traceable fit scenario, not a tolerance inferred from a calculator.
Reference and example scope
EPAL 1 reference supports the 1200 × 800 mm deck dimensions; the nominal and bulged carton dimensions are assumed example measurements. The examples use explicitly stated measurements or assumptions; they are not instrument standards, tolerance rules or approval of your load.