Stretch film is a highly stretchable LLDPE (Linear Low-Density Polyethylene) wrap that secures pallet loads through elastic recovery rather than adhesive bonding, and is manufactured via two distinct extrusion routes: cast (chill-roll quenched flat die) and blown (annular die air-inflated tube) [S3].
Specifying the wrong gauge-width combination or over-stretching beyond the film's elastic limit is the single most common cause of load failure in warehouses, and this guide walks the four gates a packaging engineer must clear before a roll goes on the dispenser [S3][S5].
Film Type Selection: Cast vs Blown vs Pre-Stretched
Cast stretch film is the volume workhorse because the chill-roll process yields excellent clarity, two-sided cling, quiet unwind, and roughly 20-30% lower unit cost than blown film, but it carries less load-holding power and lower memory after stretch [S3]. Blown stretch film costs more and unwinds with audible noise due to crystalline haze, yet delivers higher tear resistance, stronger memory, and superior holding on loads with sharp corners or irregular profiles [S3]. Pre-stretched 80-gauge film is a specialty option already elongated at the factory, and is used for banding 2-5 inch light uniform loads where a thinner, lower-force hand wrap is acceptable [S3].
For a single SKU running more than 20 pallets per shift on a turntable wrapper, blown machine-grade film at 80-120 gauge is the typical baseline; for under-10-pallet manual hand-wrap stations handling mixed retail cartons, cast hand-grade at 70-90 gauge is the standard pick [S3][S5]. Specialty variants — UV-stable, vented, anti-static, and colored opaque — extend the same base resin to specific duty cycles like outdoor storage, produce pallets, electronics, and theft concealment [S2][S3].
Gauge, Width, and Core Sizing Gates
Stretch film thickness is expressed in gauge (or micron: 1 gauge ≈ 0.254 µm, so 80 gauge ≈ 20 µm), and width runs from 2-inch bundling banding up to 20-inch machine-grade rolls, with 12-20 inch hand-grade filling the middle of the catalog [S3]. A standard load-size matrix maps 37 gauge to pre-stretched light banding, 60-80 gauge to standard 12-20 inch hand wrap, and 80-120 gauge to 20-inch machine-grade pallets, with heavier or unstable loads stepping up to 120-150 gauge [S3].
Core inside diameter (ID) must match the dispenser: 3-inch cores fit most hand-roll holders, while machine-grade rolls use 3-inch or 2-inch extended cores depending on the turntable or rotary arm wrapper carriage, and a mismatch here causes core slip, film snap-back, and operator injury risk [S3][S5]. When the pallet weight exceeds 1,500 kg or contains abrasive edges like crating lumber, move at least one gauge band thicker and verify the film passes a 250% stretch test on the pre-stretch carriage before locking the spec [S3].
Pre-Stretch Ratio and Application Overlap
Pre-stretch is the mechanical elongation applied between the brake roller and the film carriage, and a properly set pre-stretch carriage delivers 200-300% elongation at the film web — meaning a 1-metre film length becomes 2-3 metres of wrap on the load [S3][S5]. Operating below 150% pre-stretch wastes film and gives weak containment; operating above 300% pushes most LLDPE films past their yield point, triggering neck-down, gauge loss, and tearing at the corners [S3].
Apply the film with a 50% overlap on each revolution so every pallet edge is covered by two layers, and start the wrap at the pallet deck with a minimum of 3-4 anchoring wraps before climbing to the top — this locks the load to the deck and prevents the "pancake shift" failure mode seen when wrappers begin at mid-height [S3]. Top-wrap count should be at least 2-3 revolutions to seal the load against dust and forklift damage, and the final tail must be tucked or self-adhered, never knotted, to avoid snag points on conveyor transfers [S3][S5].
Equipment, Tension, and Operator Gates
Hand-grade rolls are applied with a tension-controlled dispenser that maintains 8-15 N of brake force at the core; under-tension produces loose loads that shift in transit, over-tension crushes top-layer cartons and reduces effective stretch ratio on the film itself [S3][S5]. Machine-grade turntable and rotary arm wrappers require a calibrated pre-stretch carriage with percent-stretch readout, a film delivery speed of 10-15 rpm on the turntable, and a climb speed that lays 1.5-2.0 metres of vertical film per pallet revolution [S3].
Vented pallet wrap is mandatory for any produce or hot-fill load cooling on the dock, because unvented LLDPE traps moisture and accelerates spoilage; this is one of the few cases where hand-grade is preferred over machine-grade because manual operators can spot and pierce visible condensation pools [S2][S3].
Failure Modes, Reject Criteria, and Escalation
The three most common stretch-wrap failure modes on an inbound receiving dock are: corner tears from gauge under-spec (replace with blown film one gauge band thicker), load shift from under-tension or insufficient bottom wraps (re-set dispenser brake to 12 N minimum and add two anchor wraps), and film snap during pre-stretch from over-elongation (re-calibrate the carriage to 250% max and replace the roll if carriage rollers are glazed) [S3][S5].
Reject the entire roll and escalate to the supplier if you observe: random gauge bands visible to the eye (indicates die lip wear), cling failure between layers (additive depletion beyond shelf life), or audible hissing during unwind (pinholes from contamination) — none of these are correctable in the field [S3]. For loads headed into long-term outdoor storage beyond 90 days, switch from standard LLDPE to UV-stabilized film rated for 6-12 months of UV exposure, since standard LLDPE loses 40-50% of its tensile strength in the first 6 months of direct sunlight [S2][S3].
Sourcing, Sustainability, and Standards Signals
The global stretch film supply base includes dedicated extrusion specialists like Thong Guan Industries (Malaysia, exporting to multiple countries with an integrated R&D centre and 80+ years of packaging heritage) and China-based converters such as Lihe offering machine, hand, and mini roll formats [S1][S4]. Sourcing directly from a manufacturer rather than a distributor can cut per-roll cost by up to 50% on standard gauges, according to one regional converter's published pricing note, though freight and minimum order quantity typically offset this at sub-pallet volumes [S2].
For a broader look at how stretch film integrates with upstream load units, the engineer's material-vs-load breakdown on plastic pallets is a useful companion read, while turnover box types covers the matching reusable container that often rides under the same wrap.
For component-level specifications, see stretch film, linear guide, and crossed roller guide.