The Ten PU Caster Technical Questions European Buyers Ask Most

Q1: Why do PU casters delaminate? Is it a bad material?   H3

It is not the material — it is the process. The overwhelming majority of PU casters are two-step bonded: the core is moulded first, then the PU tread is attached with adhesive or mechanical keying, leaving a bond interface you can barely see. When a chair is dragged sideways, or equipment is pushed repeatedly across carpet, shear stress concentrates at the tread edge, and the adhesive layer peels inward. Every delamination case begins at that interface.

Raising the abrasion grade of the PU therefore does not solve delamination — better abrasion resistance extends tread life, not interfacial bond strength. To fix it properly, the interface has to be removed at the process.

Q2: How do I assess delamination risk before buying?   H3

Request a longitudinally sectioned sample. Cut the caster and look at the face: a clear separation line means a bond interface exists; no visible interface means an integrated structure. It takes ten seconds and requires no test equipment.

The second indicator is warranty length. One year is the industry norm; a supplier willing to offer five has generally addressed this risk at the process level. Warranty terms are how a supplier underwrites its own process commercially, and they are more honest than any presentation.

Q3: How does one-time injection differ from ordinary PU over-moulding?   H3

Ordinary PU coverage is usually a secondary operation: core and tread are moulded separately and joined by adhesive or mechanical keying. One-Time Injection completes both within a single process — PU moulded directly over the core to form one integrated body, with no discrete adhesive layer and therefore no peel initiation point. This is Enjoying Go Co., Ltd.'s (Enjoy Caster) patented technology and the basis for our 5-year warranty across the range.

Q4: How do I distinguish abrasion failure from delamination, and why does it matter?   H3

Section the failed sample lengthwise and examine the cut face. Uniform thinning with surface friction marks indicates abrasion — generally a material grade or specification issue, improvable through hardness, diameter, or load distribution. Separation between tread and core with the edge lifting indicates interfacial separation — a process issue, where changing material achieves nothing, and the process itself must change.

This matters because a wrong diagnosis sends the fix in the wrong direction. We have met buyers who spent two years requesting more abrasion-resistant PU while every failed sample showed interfacial separation.

Q5: How should tread hardness be selected?   H3

Hard floors take softer treads; soft floors take harder treads. Tile, concrete, and epoxy call for a softer tread; otherwise you get noise, vibration, and floor indentation. Carpet and carpet tile call for a harder tread with a larger diameter; otherwise the wheel sinks into the pile, and rolling resistance rises sharply. Wood and LVT need a soft tread with verified non-marking performance.

Mixed flooring environments — where one batch of product meets several surfaces — have no single optimum. The practical approach is a compromise hardness with increased diameter, using geometry to reduce dependence on hardness.

Q6: Why does swivel offset matter?   H3

Swivel offset is the horizontal distance between the swivel axis and the wheel axle centre, and it governs self-centring and turning agility. Too little offset gives sluggish steering and directional wander; too much raises initial push resistance and produces noticeable tail swing on turns.

The parameter is omitted from most catalogues, yet its effect is very visible in long-corridor pushing and tight-radius manoeuvring. Ask for the value at RFQ stage and state whether your application involves long straight runs or frequent tight turns.

Q7: Does "non-marking" guarantee no marks at all?   H3

No. Non-marking means the tread will not transfer pigment onto the floor. Excessive load or a hardness mismatch can still cause indentation or friction marks. Non-marking testing should therefore be performed on your specified floor material rather than referenced from generic results — particularly for pale LVT, the surface behind most office complaints.

Q8: Which certifications does the European market require?   H3

The baseline is REACH (chemical registration and SVHC disclosure) and RoHS (hazardous substance restriction), both as third-party reports rather than self-declarations. Third-party test reports from SGS or an equivalent body are generally also required as measured evidence for material and finished product.

In office furniture and mobile equipment, BIFMA test methodology functions as the common durability language and is frequently requested even in Europe, because many brands also sell into North America or serve multinational clients. Where the customer compiles sustainability reporting, PCR post-consumer recycled certification is added.

Q9: Does a custom colour affect durability or warranty?   H3

With two-step bonding it can, because pigment may interfere with adhesion — which is why many suppliers exclude customised items from warranty. With one-time injection, it does not, because pigment is blended uniformly at the PU injection stage and has no bearing on structural strength. Enjoy Caster custom colours therefore carry the same 5-year warranty as standard, with no exclusion.

What buyers should check specifically is how "customised" is defined in the warranty terms. It is the most easily overlooked line, and it determines where risk sits.

Q10: How should caster load capacity be calculated safely?   H3

Catalogue ratings are usually static. In service, momentary impact loads when a cart crosses a threshold or a chair is spun quickly can reach several times the static figure. The conservative method is total equipment weight, including maximum payload, divided by three — because on uneven floors a four-caster configuration typically loads only three wheels at once.

Better still, describe the usage condition in your specification rather than quoting a single number: total load, wheel count, floor level changes, movement speed and frequency. Only then can a supplier recommend a sensible safety factor.

Conclusion & Next Step   H3

These ten questions share one characteristic: none of the answers appear in a catalogue. A datasheet supplies numbers, while what a buyer actually needs to judge is how the component will fail and whether the supplier will stand behind it.

• Request a sectioned sample: ten seconds to confirm whether a bond line exists — the fastest delamination risk assessment available.
• Request test samples: send your application, load and floor material, and we will match specifications and ship.
• Request the full document pack: SGS, BIFMA test methodology basis, RoHS, REACH and PCR in one delivery.
• Send us the question directly: if your situation is not covered by these ten, describe your operating conditions by email, and we will answer from an engineering standpoint, not a sales script.

Enjoy Caster | Enjoying Go Co., Ltd. | www.enjoycaster.com | Patented One-Time Injection technology, with a 5-year warranty across the range including custom colours.