Introduction
Here’s the basic problem: small parts move, rattle, and get damaged when they’re handled in bulk. Shrink wrapping can give a tight, neat package, but heat and residue aren’t always acceptable. Bundling stretch film is great for grouping parts quickly, but it doesn’t provide a sealed, conformal finish. Using water soluble shrink wrap together with bundling stretch film solves both problems. You get tight protection that disappears cleanly when needed, plus targeted bundling that keeps small items from scattering during handling.
This article explains when to use each film, how to sequence them on the line, and how to avoid the common pitfalls that slow packing or create rejects. I’ll keep it practical so you can pilot the idea without guessing.
Why small parts need a two-layer approach
Small parts come in all shapes: precision machined pieces, small textile components, electronic modules, or kits of mixed items. The risks are similar. Parts shift inside boxes, get scratched against each other, or fall out during sorting. A simple bundle might reduce loss, but it won’t stop abrasion or dust.
Water soluble shrink wrap conforms to the item, limiting internal movement and protecting surfaces. Bundling stretch film holds groups together and prevents scattered parts from escaping before they’re boxed. When used together, you get the benefits of both: sealed protection at the item level and flexible grouping for transit and handling.
How water soluble shrink wrap protects delicate surfaces
Water soluble shrink film is PVA-based and shrinks neatly around items when heated. That conformal fit eliminates pockets where parts can slide and collide, and it keeps dust out. The key advantage is what happens at disposal: the wrap dissolves in water, leaving no sticky residue or harmful microplastics on the part or downstream equipment.
That makes this film ideal where parts will enter wet processing later, or where customers demand residue-free unpacking. It also preserves finishes because the film is smooth and snug rather than crinkly and abrasive.
Why bundling stretch film is still essential
Bundling film is narrow and applied quickly by hand or dispenser. Use it to group kits, secure small sacks, or bind assemblies onto trays. It is affordable, fast, and lets you focus wrapping only where it’s needed. Bundling film keeps parts together while workers or automated systems move them from bench to box.
Because bundling film is targeted, it reduces waste compared with wrapping entire trays or boxes and is gentler than heavy tape or staples that can damage edges.
A simple, effective workflow
Start at the finishing station. For any small part that needs extra surface protection, place it inside an appropriate fixture or nest and run it through a shrink tunnel using PVA water soluble shrink wrap. Let the unit cool and stabilize. If the parts are fragile to heat, test low-temperature settings so the film shrinks without damaging adhesives or finishes.
Next, group the shrink-wrapped units as required and apply bundling stretch film around the group. This protects the group during handling and prevents units from shifting before they’re boxed or palletized. Then box or crate the bundles and secure them on pallets with your usual pallet film.
This sequence keeps the shrink step and the bundling step discrete and easy to incorporate into an existing line.
Practical machine and handling tips
PVA requires a shrink tunnel calibrated to the product. Start with the minimum temperature that achieves proper shrink and test for any adverse effects on coatings or adhesives. Allow items to cool before stacking so condensation does not form under the film.
For bundling, choose the right width and gauge. Narrower widths are better for small kit straps and give precise control. Standardize wrap counts so operators know how many passes achieve a stable bundle without crushing.
Store the water soluble film in dry conditions. It’s sensitive to humidity. Apply it as late as practical to reduce exposure and avoid premature softening. Bundling film is more tolerant, but keep rolls clean so thin films don’t snag on debris.
Damage prevention and padding
If internal movement is still an issue after shrink wrapping, use soft spacers or foam pads inside the nest before shrink application. That gives cushioning without defeating the tightness of the shrink. For items with sharp edges, add light corner protectors before bundling so the film doesn’t cut or concentrate pressure.
Cost and sustainability considerations
PVA shrink wrap costs more per meter than general-purpose shrink film, but the reduced handling, fewer returns, and residue-free disposal often justify the expense. Bundling film is inexpensive and lowers the need for extra boxing or inner packaging. Together they can reduce total packaging weight and waste because you avoid over-wrapping and you use targeted protection instead of bulk materials.
If sustainability matters, choose PVA formulations with clear dissolution profiles and pair that with recyclable bundling film if available.
Testing and quality metrics
Run a pilot. Pack identical SKUs using traditional methods and using the combined PVA shrink plus bundling film method. Measure damage rates, packing time, film usage, and return frequency. Also perform a dissolution test on sacrificial parts to confirm the PVA leaves no residue. Small, objective metrics here give you the evidence to scale or adjust.
Conclusion
For small parts, the combination of water soluble shrink wrap and bundling stretch film is pragmatic and efficient. Shrink wrap gives conformal, residue-free protection at the unit level, while bundling film keeps groups secure through handling and staging. Sequence them correctly, control heat and humidity, and run a short pilot. If you do, you’ll reduce damage, speed handling, and improve the customer experience without adding heavy or wasteful packaging.
