The Cartons Were Fine, but Every Product Surface Was Scratched
A Guide to Interior Packaging and Scuff Damage Prevention - Why Products Arrive Working but Scratched or Dented, Reading the Damage to Find the Cause, Comparing EPE Foam, EVA Foam, Corrugated Dividers, Bubble Wrap and Non-Woven Pouches, What to Put in Your Inner Packaging Spec, Void Space and Stacking Pressure, Request Wording, Real Cases and a Checklist

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A small home appliance brand imported 3,000 high-gloss white cordless humidifiers from a Chinese factory. The pre-shipment inspection passed on both appearance and function, and the cartons reached the warehouse without a single dent. Yet within a week of shipping parcels to customers, complaints poured in: “It’s brand new, but the top is covered in fine scratches,” and “The corners are scuffed white.” Nothing was wrong with how the units worked, but returns and exchanges for cosmetic defects passed 4% of units shipped.

Opening the cartons left in the warehouse made the cause obvious. Each humidifier was wrapped in a single thin PE bag and sat between top and bottom EPE foam end caps. But there was a gap between the foam and the body wide enough to slip a finger into. Shake the carton and the unit rotated slightly inside the foam, and every time it did, dust and foam crumbs trapped inside the bag rubbed against the glossy surface. The only packaging requirement on the purchase order was one line: “单个PE袋+珍珠棉+五层瓦楞纸箱.”

Nothing broke, so you could say the packaging did its job. Looking only at the carton and the function, that’s true. But when appearance is the product, a mark on the surface is as good as a breakage. This post looks not at the outer carton but at what’s inside it: the interior packaging (内包装) that wraps and holds the product, and how to design it and write it into your spec, from a practical buyer’s point of view.

Cosmetic damage usually comes less from one big impact than from small rubbing repeated thousands of times. Hold the product so it can’t move inside the carton, choose the materials that touch its surface, and write both into your spec.

1. Why the Product Works but the Surface Is Damaged

If the drops and impacts covered in Episode 127 are what break products, cosmetic damage usually starts with small movements inside the carton. Trucks and containers vibrate the whole way, and on parcel sorting lines cartons are pushed and tumbled dozens of times. If the product has any room to move, its surface gets rubbed by that much. These are the causes we see most often:

• Void space: The foam insert is cut larger than the product, or empty space is left in the carton, so the product shifts.
• Materials touching the surface: Corrugated board, rough recycled EPE or the sticky side of tape touches a glossy or painted surface directly.
• Product-to-product contact: Several units go into one carton stacked without dividers, or parts are packed together in one bag.
• Load from above: The carton top rests directly on the product, so the weight of the cartons stacked above passes onto the product surface.
• Handling before packing: It’s not unusual for products to be scratched before they’re even packed, from being piled on packing tables or handled with bare hands.

For a factory, interior packaging is an easy place to cut costs. The sample is wrapped carefully by hand by the staff member in charge, but in mass production packers handle hundreds of units an hour. Without a set spec, bag thickness, foam density and cutting dimensions gradually drift toward whatever is easiest for the factory.

2. The Shape of the Damage Points to the Cause

Look closely at the marks on returned products and you can usually tell roughly where they came from. Thickening the cushioning without knowing the cause only adds cost, and the same marks come back.

When a surface turns sticky or stained, the problem is less about rubbing than about incompatible materials. A PVC bag left against a painted or rubberized finish for a long time can transfer plasticizer and make the surface tacky, and condensation inside a container can get trapped in the bag and leave stains. Moisture control is covered in Episode 118.

3. Cushioning and Interior Packaging Materials Compared

Interior packaging materials fall into two groups: those that wrap the surface (pouches, bags, film) and those that hold the product in place (foam, board, molded pulp). They do different jobs, so they’re usually used together. We’ve included the names Chinese factories use as well.

The basic approach is to wrap the surface once in a soft material, then hold it from the outside with a firmer material so it can’t move. Simply keeping rough materials off glossy surfaces cuts fine scratches dramatically. How to reduce cost by changing your packaging mix is covered in Episode 15.

4. What to Put in Your Inner Packaging Spec

A single line like “珍珠棉保护” doesn’t tell the factory what foam to use, how thick, or at what dimensions. Set interior packaging in numbers too, with drawings or photos attached.

Make one set of the approved packaging into a sealed reference sample (包装封样) and keep one each with the factory. If production packaging differs from the reference, that alone is grounds for rejection, and there’s no clearer standard than that. For spec writing in general, see Episode 59; for writing cosmetic defect liability into a quality agreement, see Episode 103.

5. Void Space in the Carton and Stacking Pressure

Void space

Even a gap of a few millimeters between insert and product means the product keeps moving back and forth inside it through the constant vibration of transit. Checking is simple. Hold a packed carton in both hands and shake it front to back and side to side. If you hear rattling or feel movement, it moves far more than that in real transit. Cut inserts to measured dimensions, not drawing dimensions, and for products with dimensional variation such as injection-molded parts, finalize only after fitting a few production units.

Stacking and warehouse pressure

Cartons get stacked several high in containers, on warehouse racks and on pallets. Whether the outer carton can bear that weight is the job of the compression test covered in Episode 127, but even if the carton holds, you need to look separately at where the load goes inside it. If the product is almost as tall as the carton’s interior, the carton top presses directly on the product and the full weight above rests on its surface. Left that way in a warehouse for weeks, foam patterns can imprint on glossy surfaces and thin panels can warp.

• Design so the load is carried by the carton walls, corners and board posts, not the product.
• Put a foam cap or board pad between the product top and the carton lid to spread the pressure.
• For heavy products or delicate surfaces, print a stacking limit (堆码层数) on the carton and tell the warehouse and forwarder.
• A glossy surface facing up takes the load directly, so consider packing the product upright.

For container loading plans and pallet stacking, see Episode 101.

Checking with a packed sample first

Before mass production, the most practical check is to have a sample carton packed with the actual interior packaging sent to you once. Send it back and forth by parcel once or twice, or carry it in a car for a few days, then open it, and you’ll quickly see whether rubbing marks appear. For a more systematic check you can also run a lab vibration test; test types and steps are covered in Episode 127. Also add an item to the pre-shipment inspection to open a few random cartons and confirm the packing matches the reference. For pre-shipment inspection, see Episode 100.

6. Sample Request Wording for the Factory

Putting the wording below into your purchase order or packaging spec makes it clear what the factory needs to order from its packaging supplier, and leaves a record if cosmetic defects occur.

"本产品为外观件，包装须防止划伤、磕碰和压痕。每台产品须先装入无纺布袋（或珍珠棉复合袋），禁止使用PVC袋；顶面高光面须贴低粘PE保护膜，撕除后不得残胶。内衬使用全新料珍珠棉，禁止使用回料，密度不低于○kg/m³，按产品实测尺寸裁切，单边间隙不超过2mm，请附内衬图纸供我方确认。高光面和喷涂面不得直接接触瓦楞纸、纸浆模塑或胶带。配件须单独包装，不得与主机接触。箱内顶部须加盖板，堆码压力不得直接作用于产品表面。量产前请按大货包装方式打包样箱寄到韩国确认，确认后的包装作为封样。如需变更包装材料、供应商或尺寸，须事先取得我方书面确认。"
(This product is a cosmetic-critical item, and packaging must prevent scratches, dents and pressure marks. Put each unit first into a non-woven pouch (or foam-laminated pouch); do not use PVC bags. Apply low-tack PE protective film to the glossy top surface, with no adhesive residue after removal. Use virgin EPE foam for inserts, not recycled material, with a density of at least ○kg/m³, cut to the product’s measured dimensions with no more than 2mm clearance per side, and send the insert drawing for our confirmation. Glossy and painted surfaces must not touch corrugated board, molded pulp or tape directly. Pack accessories separately so they don’t touch the main unit. Add a top cap inside the carton so stacking load doesn’t rest directly on the product surface. Before mass production, send a sample carton packed exactly as for bulk production to Korea for our confirmation, and use the confirmed packaging as the sealed reference sample. Any change to packaging materials, suppliers or dimensions requires our prior written confirmation.)

7. Three Real Cases

These are anonymized versions of patterns we often see in consultations. Amounts and figures are examples.

Case 1 — High-gloss cordless humidifier

This is the case from the start of the post. From the next production run, the PE bag was replaced with a non-woven pouch and low-tack protective film was applied to the top surface. The EPE inserts were also recut to measured dimensions, bringing the gap under 1mm. A sample carton packed the same way was sent back and forth by parcel twice, and production started only after confirming no marks. Packaging cost rose by about 1.2 yuan per unit, but cosmetic returns fell below 0.5%.

Case 2 — Flat-pack solid wood side table

Four legs, a tabletop and steel brackets went into one carton. Because the four legs shared one bag and the brackets and screw pack were wedged into the empty space between them, every unit arrived with small dents scattered across the painted legs. After switching to corrugated dividers giving each leg its own slot and moving the metal parts to a separate compartment under the tabletop, dent claims all but disappeared. The carton size stayed the same.

Case 3 — Anodized aluminum laptop stand

The first production run had no issues, but from the second run claims for fine scratches and small white marks came in. On investigation, the factory had switched packaging suppliers and the EPE foam had changed to a greyish recycled material, with debris in the foam scratching the surface. Cartons lower down in stacks of more than eight in the warehouse also showed worse foam texture marks. After adding a virgin EPE requirement and a packaging change approval clause to the spec and printing a six-high stacking limit on the carton, the same claims didn’t come back.

8. Common Mistakes

• Writing the packaging requirement as a single line: “bag + foam + carton”
• Assuming production packaging will match the hand-wrapped sample sent by factory staff
• Responding to marks by making the foam thicker without looking at the cause
• Letting accessories be wedged into empty space next to the main unit
• Concluding that stacking load is fine because the cartons weren’t crushed
• Applying protective film without specifying adhesion and dwell time, leading to residue claims

9. Interior Packaging and Cosmetic Protection Checklist

Spec and contract stage

• Identified the cosmetically critical surfaces of the product (glossy, painted, display)
• Wrote primary packaging, protective film, and insert material, density and dimensions into the spec
• Included a condition that rough materials must not touch cosmetic surfaces directly
• Included conditions for separate accessory packing and dividers in multi-unit cartons
• Included a prior approval clause for changes to packaging materials, suppliers or dimensions

Sample and verification stage

• Received a sample carton packed with production materials, shook it and opened it
• Checked for rubbing marks with a parcel round trip or vibration test
• Kept the approved packaging as a sealed reference sample

Production and shipment stage

• Opened cartons during pre-shipment inspection and compared the packing with the reference
• Printed a stacking limit on cartons and informed the warehouse and forwarder

Wrapping Up - Start by Shaking One Carton

Cosmetic damage looks minor next to functional defects, but to a customer, one scratch on a new product is a defect. Add up return shipping, repacking, refurbishing and review management, and the cost of adding a pouch and recutting foam is usually small.

What to do right now is simple. If you have stock in a warehouse, pick up one carton and shake it, then open it and check the gap between product and insert and the materials touching the surface. If it rattles, rework your interior packaging spec before the next order.

StartMade supports you on the ground in China: designing interior packaging that suits the product’s surface finish, writing the packaging spec, checking packaging suppliers, verifying packed sample cartons, and inspecting packing condition before shipment. If you already have cosmetic damage, we start with root cause analysis; if you’re preparing a new product, we start with the packaging spec.