A luggage liner is part of a complete case structure. Choose its geometry and material using the sleeve, frame, handle, wheel and packing loads that it actually supports. There is no universal thickness or cutting tolerance that makes every suitcase stiff, light and durable.
Identify what each panel does
Mark the back, base, front and divider panels on the assembled drawing. Record where each is supported, how it is retained and whether hardware loads pass through it. A liner that only holds the fabric shape has a different duty from a part carrying a wheel housing or handle attachment. Do not assume the largest panel is always the principal load-bearing member.
| Detail | Specification to agree | Sample check |
|---|---|---|
| Panel outline | Dimensions, datum points, holes and corner geometry | Fit in the actual sleeve or frame |
| Sheet construction | Grade, thickness, mass per area and channel direction | Mass, stiffness and deformation under the agreed load |
| Attachment | Fasteners, inserts, backing pieces and bearing areas | Local crushing, loosening and fabric damage |
| Fold or hinge | Location, direction, formed geometry and retained section | Repeated folding in the assembled case |
| Contact edge | Radius, trim, chamfer or sleeve construction | Snagging, abrasion and edge exposure |
Calculate mass from the actual cut parts
Use the area of the actual outlines and the measured mass per area, then include trim, fasteners, inserts and adhesives. Nominal sheet thickness alone does not establish panel mass or stiffness.
For a hypothetical example, three rectangular blanks measure 0.55 × 0.40 m, 0.55 × 0.20 m and 0.50 × 0.35 m. Their total area is 0.505 m². At an assumed 800 g/m², their bare mass is 404 g; at an assumed 1,000 g/m² it is 505 g, a difference of 101 g. These are assumed calculations, not recommended material grades or quoted product values. Cutouts reduce area while attachments add mass.
Weigh the approved assembled case and assess stiffness with the intended packing and load. A lower blank mass is useful only if the finished case meets the agreed requirements. Increasing grammage does not by itself improve every hinge, fastener or edge detail.
Set tolerances from the assembly
Specify the drawing revision, measurement datums, conditioning and inspection method. Determine the required clearance from the actual fabric sleeve, seam variation, hardware and manufacturing process. Do not copy a generic plus-or-minus-one-millimetre tolerance onto every feature; holes locating hardware may have a different functional requirement from a free edge.
Measure the sample after the agreed conditioning and compare parts from the intended cutting process. Sheet temperature, tool condition, distortion and measurement technique can affect results. Approve a production inspection plan, including features that are checked during the run, rather than relying only on a first article.
Qualify hinges and edges together
A fold is not universally correct only across, or only along, the channels. Its behaviour depends on channel geometry, skins, scoring or forming, fold radius and how the assembled part constrains it. Trial the proposed orientation and process, and compare alternatives when repeated movement is required.
Specify the residual section and permitted damage where material is scored or routed. Removing material can weaken the part as well as make it easier to bend. Agree the folding cycle, temperature, load and failure criteria with the product designer; a convenient crease cannot establish a service-life claim.
Inspect internal corners, holes and contact edges for crack initiation, stress concentration and fabric wear. Select radii and edge treatment from the geometry and load rather than a universal radius. Test the selected trim, chamfer or fabric interface in the complete case, since it can shift, wear or expose a hard edge.
Test the bag or case, not just the blank
Define the finished-product trial with the buyer: packed load, handle and wheel use, repeated opening, impacts, temperature exposure and appearance or fit limits. Record the exact assembly and material lot. A successful sheet bending test does not qualify the handle, wheel attachment or stitched sleeve.
Agree any destination-specific material declarations and restricted-substance evidence for the finished construction, including colourants, coatings and adhesives. Virgin or recycled content is a material specification; neither label alone establishes product safety or regulatory compliance.
Request luggage-liner sample review. Send the part and assembly drawings, supported loads, target finished mass, fold details, hardware interfaces, inspection criteria, destination and order quantity. Review panel materials and approve fitted samples before committing to cutting tools or bulk production.