DITAI
Custom thermoformed trays. For the way you handle parts.
Returnable trays, component pockets and handling inserts. Developed around the part, the workstation and the journey between them—from formed and trimmed samples to repeat supply.
Where does the part enter, move and leave?
A tray can fit the CAD and still fail on the line. The engineering brief must include loading direction, contact restrictions, lifting method, stack height, return route and what happens when parts, trays and operators are not perfectly aligned.
A tray that fits on the bench may still be awkward at the workstation.
A part might be loaded by hand, stored in a stack overnight and presented to a robot the next morning. A tight pocket can reduce movement during transport but make removal less predictable. Extra clearance makes loading easier, yet allows the part to settle in more than one position.
Before changing the pocket, establish which requirement is causing the difficulty: movement during transport, the position at pickup, or the force needed to release the part. Those are different problems and may need different features.
Mark surfaces that may support the part and those that must remain untouched. Include seal lips, connectors, finished faces and any surface that will be measured or bonded later. A short loading video is often more useful here than another overall dimension.
Locate the part.
Leave a way to lift it out.
Copying the complete outside surface of a component into a tight pocket can create too many contact points. Small differences in the component, forming or loading angle may then make the part rock, bind or sit high.
Choose the contacts that do useful work.
Identify stable supports, the features that prevent sideways movement and the feature that sets orientation. Relieve the remaining surfaces where contact adds no value. Check the actual component variation, including coatings and fitted clips, rather than only the nominal model.
Decide what keeps the part in place during movement.
A locating wall need not also be a retaining clip. A lid, separate restraint or changed tray orientation may provide retention without squeezing a sensitive surface. An undercut needs its own mould-release and repeated-use review.
Review the complete removal path.
A finger opening is useful only if the operator can grip and lift without tipping into the next component. For automated pickup, provide the gripper envelope and approach direction. Check the first and last pocket, not just an easy central position.
Which surfaces need control?
Do not apply one tight tolerance to every pocket surface. Define what each zone does, what can vary and how it will be inspected in the real loading condition.
If the operator must rotate the part, search for orientation or use two hands to overcome a tight pocket, the handling system—not only the tray—needs review.
The product may sit above the stack stop, deflect the pocket or change how the next tray lands. Approve the real loaded condition, not an empty-stack demonstration.
The polymer name is not the tray specification.
Tray life depends on exact grade, starting gauge, finished-wall distribution, temperature, load, chemicals, cleaning, ESD requirement and the number of handling cycles. A material can be suitable in one route and wrong in another.
Open the thermoforming material guide →
Locate heavy sections on suitable supports and keep sharp edges, chips and residual oil away from protected faces. Review where swarf can collect, whether it can be seen and how it is removed before the next part is loaded.
Define no-contact zones, acceptable contact pressure, protective-film strategy and whether vibration can create rubbing during transport.
First identify whether handling stays inside an ESD protected area or leaves it. Low charging, conductivity and discharge shielding are different functions. A conductive open tray does not, by itself, establish shielding for shipment. Agree the complete packaging arrangement, test methods, conditioning and any relevant grounding provisions with the ESD programme owner.
Separate product protection, cleanliness, biocompatibility, sterilization and packaging-barrier requirements. A polymer datasheet alone does not certify the finished tray or the customer’s process.
Confirm the exact substance authorization, food type, temperature and condition of use. FDA status applies to specific substances and intended uses—not to “PP” or “HDPE” as blanket claims.
Specify the cleaner, concentration, temperature, contact time, rinse and drying method. Check representative trays again for fit, warpage, cracking, residue and label readability after the agreed cleaning cycles. Washing and verified cleanliness are not the same acceptance criterion.
Check the loaded stack.
Then check the empty return.
Returnable trays often need two opposite behaviours: a stable loaded stack and a compact empty return. Those modes need intentional stops, clearances and handling cues.
Keep the stack load off the components
Define the stack stops before checking capacity. The component below should not become the spacer for the next tray. Test the intended load, dwell time and temperature, including a partly filled tray that places more load on one side. A brief empty-stack demonstration does not show long-duration deflection.
Control stack pitch
Agree full and empty stack height, rack clearance and whether mixed tray revisions can safely interlock.
Prevent false seating
Asymmetric keys or orientation features should make an incorrect 180° stack obvious before it becomes unstable.
Release nested trays
Check separation after the intended storage time, not just immediately after forming. Review stop height, air entry and accessible grip points. Nested trays should release without damaging the rim or requiring excessive bending. Record the behaviour over repeated separation cycles.
Keep automation references stable
Locate the tray to the cell, then locate the part to the tray. The gripper must accommodate the combined variation in both interfaces. Agree whether vision correction is available, how orientation is recognised and what happens after a mispick. CNC-cut holes alone do not establish robot pickup accuracy.
Plan for damage
Define inspection points, reject criteria and a visible method to segregate cracked, warped or contaminated trays.
Changing the locating areas.
Keeping the removal path.
Four automotive tray designs had to hold components while allowing automated pickup. The development record follows the work from component layouts and aluminium tooling into sample-fit checks and local revisions.
The changes followed the observed movement.
Workshop checks showed where components could move in their pockets. The team linked those observations to selected locating areas on the tool, rather than tightening the complete pocket. Removal access remained part of the review.
Thin corners needed a different decision.
In another area, abrupt stepped geometry was associated with thin formed corners. The proposed changes used bevelled transitions while retaining the stacking function. That question could not be solved simply by reducing pocket clearance.
The available evidence covers design, tooling and original/revised sample checks. It does not establish customer line acceptance, a validated robot cycle rate or tray service life.
Specify the feature.
Then specify the check.
A single tolerance beside the overall tray size does not explain how the pockets should be inspected or where a robot should expect the part to sit.
Starting sheet is not finished wall thickness.
The sheet stretches during forming. Deep, narrow features and abrupt transitions can leave local areas thinner than the surrounding wall. If a corner or stack stop needs a minimum wall, identify that location and agree how the formed sample will be measured.
The review may involve the starting gauge, radii, draft, pocket spacing and tooling approach together. Adding thickness everywhere is not the only option.
Formed and trimmed dimensions need their own references.
Identify the tool-contact surface, the free surface and the features cut after forming. A hole position depends on how the formed tray is located in the trimming fixture. Drawing dimensions should make that reference clear.
For inspection, agree the support fixture, temperature and whether the tray is empty or loaded. Otherwise two measurements can disagree because they describe different conditions.
Manufacturing background: Spartech thermoforming manual. Supplier guidance informs the review; it is not a statement of DITAI’s guaranteed tolerance.
Compare the cost of using the tray.
The lowest piece price is not always the lowest cost per completed journey. A fair comparison needs the same loading arrangement, protection requirement and expected circulation pattern.
More pockets can reduce the number of trays in circulation, but closer spacing may restrict fingers, grippers or forming geometry. Check the layout against the workstation before choosing capacity.
Include trays in use, awaiting collection, in transit, being washed and held as replacements. Expected reuse should be supported by trials and operating records—not assumed from the resin name.
Separate tooling, samples, production trays, trimming, optional liners or fittings, inspection and packaging. Agree tool ownership, maintenance responsibilities and how future revisions will be priced.
A revised pocket may still fit the old stack, but that does not make the trays interchangeable. Keep a visible revision identifier and define whether old trays may remain in circulation.
What will the sample need to demonstrate?
The approval record should show where the part contacts, how it loads and releases, how the stack carries weight and whether the tray still performs after the environmental and handling conditions it will actually see.
Questions worth settling early.
Send the information you have. If the design is still developing, identify what is fixed and what can change.
Can you work from an existing tray or a physical component?
Yes. A sample and photographs can start the discussion. Identify damage, difficult pickup, unstable stacking or cleaning problems that the replacement must address. Confirm which dimensions can be measured from the sample and which must come from controlled product data. Do not reproduce wear or distortion as if it were the intended design.
Should a returnable tray use a thicker sheet?
Not automatically. First check where the tray is losing stiffness or wearing. A revised support, rim, radius or contact area may be more useful than adding weight everywhere. Specify the load, temperature, handling cycle and locally required finished wall. Compare representative formed samples rather than flat-sheet thickness alone.
Can one tray handle several component versions?
Sometimes. Compare the support surfaces, permitted movement, height and pickup position across all versions. An interchangeable insert may suit a shared carrier, but it adds an interface to inspect and track. If the versions are easy to confuse, identification and error-proofing may matter more than fitting them into one pocket.
How should transport testing be chosen?
Describe the actual route, pallet or carton, restraints, stack and product load. Select a test for that packaged system, not for an empty tray alone. ISTA distinguishes screening from distribution-simulation procedures; a screening result is not proof for every shipping route. Agree damage criteria before testing and review whether material, product or packaging changes require retesting. ISTA test selection reference →
What controls should carry into repeat orders?
Keep the approved CAD and tray revision, exact sheet specification, tool revision, inspection condition and sample references together. Identify changes that need review before shipment, including material substitutions, local tool rework, trimming changes and liners. A tray that looks the same can still locate, nest or clean differently.
When is another manufacturing route worth comparing?
Thermoforming is worth evaluating for open trays and larger sheet-based shapes. If the job depends on dense, intricate features, highly repeatable moulded clips or a very high production volume, compare injection moulding as well. A machined fixture or carrier with replaceable inserts may be more suitable where precise locating features dominate the job. Review tooling cost, geometry, output and inspection together.
Discuss your tray
and its working conditions.
Send the product CAD plus a simple description or video of the handling route. We will review the contact strategy, formed geometry, stack system and the evidence needed before release.
- Part CAD, weight, centre of gravity and allowed / forbidden contact zones
- Manual, robot or conveyor loading direction and pick access
- Full and empty stack requirements, rack/cart and return ratio
- Temperature, chemicals, cleaning, ESD or regulatory conditions
- Prototype and annual quantity, cycle expectation and shipping route
