Design Guide for PP Industrial Dunnage and Handling Trays in industrial equipment: Draft, Radii and Draw Ratio

Thermoforming rewards designs that respect how a heated sheet stretches. These rules prevent most tooling rework and most thickness complaints.

Use it as a working checklist when you write your next enquiry.

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 gauge 1.5 to 8.0 mm; returnable and reusable designs; stack and nest geometry. Materials most often specified are Polycarbonate, Polyethylene Terephthalate, Polypropylene, Acrylonitrile Butadiene Styrene, 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 equipment covers, protective guards, twin sheet panels.

Key Material Properties

These figures are typical for commercial grades and should be confirmed against the supplier's certificate for your specific lot.

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

Design Rules for Thermoformed Parts

Apply these points before the tool is cut; after that every change costs tooling and time.

• Keep the draw ratio moderate: deep cavities thin the sheet and force you to start with a thicker gauge.
• Leave a flat sealing flange of at least 6 mm when the pack has to be heat sealed or lidded.
• Use a draft angle of at least 3 degrees per side so the part releases without vacuum locks.
• Add ribs, steps or kiss-offs instead of increasing overall gauge to gain stiffness.
• Make corner radii at least equal to the sheet thickness; sharp corners are where holes start.
• Avoid undercuts unless the tool has moving sections, which adds cost to every cycle.

Send these rules to your designer together with the sheet gauge and the target cycle time; most tooling modifications come from ignoring draft and corner radii.

Common Grades and Variants

• Acrylonitrile Butadiene Styrene based: high impact toughness
• Polyethylene Terephthalate based: excellent barrier to CO2 and moisture
• 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

Processing method drives both cost and performance, so it should be fixed early in the design.

• Twin sheet forming
• Thick gauge thermoforming
• Cnc trimming
• Welding

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

Work through these points in order and most specification mistakes disappear.

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

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

Frequently Asked Questions

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.

What is the minimum order quantity for industrial dunnage and handling trays?

For standard sizes and colours the minimum is usually one pallet or one production run; for custom tooling the economic minimum depends on the tooling cost amortised over the expected volume. Send us your annual volume and we will calculate the break even point.

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.

Do you offer samples?

Yes. Standard samples are normally free of charge and shipped within three working days; custom samples are charged at cost and credited against the first production order.

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

If you are planning a new industrial equipment project, send us your drawing, annual volume and target properties, and we will come back with a material proposal, a tooling plan and a budget quotation.