Start with what the interior needs to do
A sewn luggage liner may include two shell linings, a divider, pockets, zipper tape, binding and attachment details. The phrase does not establish which of those items is included. Begin with an annotated drawing of the open suitcase and assign a part number to every component that the supplier is expected to deliver.
Mark how a user reaches each compartment. Does the divider open on three sides or detach completely? Is the pocket accessible when the case is packed? Must the liner allow a repair technician to reach the telescopic handle fixings? These decisions affect openings and assembly, so they belong in the first brief rather than a comment after the sample is sewn.
Custom work requires internal shell dimensions, buyer patterns or a physical sample. Nominal suitcase size is insufficient. Include the shapes around wheels, handle channels, hinges and fixing points, then confirm the sewn prototype in the actual shell.
One component schedule prevents different interpretations
Give dimensions for finished openings as well as the underlying cut parts. A pocket that measures correctly on paper can become difficult to use after its edges are bound or sewn into another seam. Identify the measurement points on the drawing and agree tolerances during development.
The schedule below is a brief template, not a fixed construction specification. Complete it for each shell model; a larger case may need more than a scaled copy of the smaller liner.
| Component | Details to put on the drawing |
|---|---|
| Main lining | Finished shape, fabric face, shell attachment and service opening |
| Divider | Hinge edge, opening path, material, edge finish and closure arrangement |
| Opening width, finished depth, position, closure and intended contents | |
| Zipper | Specified chain and slider, length reference, stops and pull direction |
| Binding or reinforcement | Material, finished width, location and stitching detail |
| Packing set | Included parts, model identifier, handed pairs and bundle method |
Test the zipper and seam together
Specify the zipper as a matched component, not just a colour and an approximate size. Ask the component supplier to confirm the chain, slider, stops and length convention for the selected item. Record whether the closure needs one or two sliders and which direction each pull should face when the divider is installed. A brand name alone leaves these decisions unresolved.
During sampling, operate the zipper with the liner fitted, empty and with the agreed representative contents. Watch the corners, the end stops and the gap between the fabric edge and the slider. Record any snagging, fabric trapping or opening distortion. A flat piece lying on a table cannot show every problem created by the installed geometry.
Coats' seam-puckering guidance identifies several possible causes, including thread tension, fabric structure, dimensional changes and uneven feeding. For a rippled divider seam, ask the sewing team to trial the actual fabric, thread, zipper tape and seam construction together. Do not turn a trial adjustment into a universal needle size or stitch setting for every fabric.
Photograph the accepted seam in both a relaxed condition and its installed position. Keep a physical approved sample if appearance is important; a written instruction such as 'smooth sewing' gives the inspector too little to compare.
Release the liner only after an installed sample review
Have the suitcase assembler install the sample using the intended fixing method. Close the case, reopen it and inspect whether fabric is caught, pulled tight or left loose around obstructions. Review the fit in each shell model being ordered. Record the shell revision as well as the liner revision so that a later mould change does not disappear from the paperwork.
Use a short approval sheet with one decision for each issue: accepted, revise and resubmit, or excluded from supply. Confirm pocket placement, divider access, zipper operation, seam appearance, part count and repair access. Any durability or load test needs an agreed method and acceptance criteria; this functional review is not evidence that the whole suitcase has passed a luggage performance standard.
The production file should contain the final component list, patterns, approved materials and sample comments. State who supplies the zippers and other trims, who installs the liners, and who checks the completed suitcase. Keep one marked sample available to both purchasing and assembly.