Common Defects in PP Industrial Dunnage and Handling Trays for industrial equipment and How to Prevent Them

Most quality claims on thermoformed parts trace back to a handful of root causes. Learn to recognise them on the drawing, in the tool and on the finished part.

The notes below come from day to day production and export work with overseas buyers.

Product Overview

This category covers a family of products rather than a single item. In practice a buyer defines industrial dunnage and handling trays by three things: the base resin, the format or dimension, and the performance or certification level it has to meet. Typical options in this category include ESD and conductive grades; stack and nest geometry; custom cavity layouts. Materials most often specified are High Density Polyethylene, Polyethylene Terephthalate, Acrylonitrile Butadiene Styrene, Polypropylene, and the choice between them changes stiffness, temperature resistance, chemical behaviour and price.

In the industrial equipment sector the decision is usually driven by thick gauge capability and flare and fire rating, with paintability as a secondary requirement. Typical end uses include twin sheet panels, protective guards, equipment covers.

Key Material Properties

The table below summarises the values that usually decide the material choice.

Polypropylene is frequently the default selection here: PP is the lightest mainstream packaging resin and keeps its shape under repeated flexing.

Failure Modes and Prevention

Spotting these early saves rework, freight and reputation.

• static damage to parts – usually caused by material moisture; prevent it by controlling incoming inspection.
• warpage after washing – usually caused by packing pressure; prevent it by controlling resin drying.
• wear of locating features – usually caused by gate position; prevent it by controlling tool design.
• cracking at low temperature – usually caused by packing pressure; prevent it by controlling tool design.
• loss of stack stiffness – usually caused by cooling rate; prevent it by controlling incoming inspection.

Common Grades and Variants

• Polyethylene Terephthalate based: excellent barrier to CO2 and moisture
• High Density Polyethylene based: high impact strength even at low temperature
• Polypropylene based: lowest density among commodity plastics
• Polycarbonate based: outstanding impact strength (250x glass)

Beyond the base resin, most suppliers offer UV stabilised, food contact, flame retardant, anti-static and recycled content versions of the same product. Ask which additive package is included, because it is often the difference between a part that lasts three years and one that lasts ten.

Processing and Finishing Options

The route below is the one most factories use for this type of part.

• Thick gauge thermoforming
• Cnc trimming
• Welding
• Assembly

Secondary operations such as printing, welding, machining and assembly are often cheaper to do in the same factory, and they reduce the risk of mismatch between components.

How to Specify Industrial dunnage and handling trays Correctly

These are the criteria that actually predict whether the part will perform in service.

1. specify ESD grade if electronics are handled
2. validate washing and drying resistance
3. check stack load and conveyor compatibility
4. design locating features that survive repeated use
5. define the number of returnable trips expected

Send this list to your supplier with the drawing and you will receive comparable quotations from every factory you contact.

Frequently Asked Questions

How do you control colour consistency?

Colour is controlled with a masterbatch reference approved by the customer, and every production lot is checked against the approved sample under standard lighting before shipment.

What tolerance can be achieved?

Standard production tolerance follows the relevant ISO or DIN tolerance class for the process; tighter tolerances are possible after machining or grinding, but they add cost. Define the tolerance only on the functional dimensions.

How long does tooling and sampling take?

A new tool typically takes 25 to 45 days depending on cavity count and complexity, followed by T1 samples within one week. Existing tools can usually start production within 10 to 15 days of order confirmation.

Which certifications can you provide?

We can provide ISO 9001 quality system documentation, material certificates, RoHS and REACH statements, and where applicable food contact, flame retardancy or drinking water approvals. Tell us your target market and we will match the document set.

Can you produce industrial dunnage and handling trays in Polypropylene?

Yes. {mat1} is one of our regular materials for this item, and we can supply virgin, modified and certified grades with full traceability. Material certificates and test reports are issued per batch.

Conclusion

Share your specification and quantity with us and we will recommend the most cost effective material, tooling route and packing method for your market.