Measure several representative products in their complete shipping condition before specifying the cells of a cardboard divider. A nominal dimension on a drawing does not describe manufacturing variation, a raised label or an accessory added during packing. Establish the product envelope first, then check the proposed clearance through assembly and testing of the complete pack.
Start with the version that will actually be packed
A bare bottle and a labelled bottle do not necessarily make the same contacts. A pump can also project beyond the outline of its container. List the relevant configurations: product, closure, decoration, individual protection and orientation in the box. Photograph each configuration beside its reference. This prevents a prototype being approved with a different version from the one subsequently supplied to the packing line.
Mark where the divider may touch the product and where clearance must be maintained. A decorative feature, moving component or appearance-critical surface should not be treated like a robust body wall. Show these areas on the drawing even when they do not increase the maximum overall width. The contact requirements are part of the specification, not an optional note added after dimensions have been agreed.
Build a useful measurement sample
Where available, select products from several manufacturing batches. Include suppliers, moulds or variants that could affect dimensions. There is no universal sample size suitable for every product: agree a sampling approach based on known variation and the consequences of a packing failure. If only a few development samples exist, record that limitation instead of describing them as representative of full production.
Keep a table containing the product identifier, measurement, measuring position and condition of the decoration. A dimension without a defined position can be difficult to reproduce. For an irregular shape, measure several sections and record the orientation of the widest part. A diagonal may matter more than the width seen from the front, particularly when a product can rotate within its cell.
Separate the product envelope from working clearance
The largest observed dimension describes product size. Working clearance answers a different question: how much space is needed to insert, remove and protect that product in the proposed arrangement? Too little clearance can hinder insertion or load a delicate finish. Too much can allow unwanted movement. Validate the clearance with the intended board, assembly method and handling sequence.
Consider a purely geometric example. A product measures a maximum of 62 mm in one direction, and the preliminary study proposes a clear cell opening of 66 mm. The difference is 4 mm overall, or 2 mm on each side when centred. This calculation does not prove that the clearance is suitable. It establishes the measuring convention and prevents total clearance being confused with clearance per side.
Connect cell dimensions to the inside of the box
The assembled divider also has to fit its outer box. Measure the usable internal dimensions with the base, flaps and any extra protection present. Do not automatically infer them from the outside size printed in a catalogue. FEFCO lists a procedure for determining internal box dimensions, illustrating the value of a common measuring approach between supplier and user.
Specify the clear cell opening, divider thickness and overall assembled size separately. The manufacturer can then check whether the layout is consistent. If the required product quantity makes the box too tight, reconsider the arrangement or box size rather than reducing every clearance arbitrarily. The drawing should make clear which dimensions are functional requirements and which remain open for design development.
Check large and small products, not only an average sample
A successful fit with an average-sized product is not enough. Use the largest samples to check insertion and the smallest to observe possible movement. Include the most sensitive decoration. Ask the people who will pack the products to try the arrangement: they may identify awkward access or an ambiguous orientation that is not apparent from a drawing.
Observe the final cell as well as the first one. Loading neighbouring cells can alter access or the position of a divider wall. Record whether an operator has to press, twist or reposition the product to complete the pack. These observations help distinguish a genuine design clearance from a fit achieved through an exceptional handling technique that would be difficult to repeat in production.
Freeze the references used for approval
Retain the dated drawing, product references, divider material and box dimensions. Keep a representative approved sample where practical. A change to a pump, decoration or container supplier should trigger a review of its effect on this definition. The measurement file then supports change control rather than serving only as an attachment to the first quotation.
- Identify every product variant that will be shipped.
- Measure contact areas and projections as well as the main body.
- Distinguish observed dimensions from proposed clearances.
- Measure the assembled box with all relevant components.
- Trial the largest and smallest representative products.
- Define which changes require a further fit check.
Estic-Maillot develops custom cardboard partitions around the product application. To prepare a study, send representative samples and your measurement table together with the intended insertion method and distribution conditions.
Frequently asked questions
Can the product drawing be the only input?
It is a useful starting point, especially when tolerances are stated. Add representative physical products when they become available, including the closures, decoration and accessories that will actually be shipped.
Should the clearance be identical in every direction?
Not necessarily. Geometry, orientation, permitted contacts and the loading movement may justify different clearances. Show them clearly on the drawing and validate them together in the complete arrangement.