What Is Label Doming? A Complete Guide to the 3D Polyurethane Doming Process

When a domed badge starts lifting at its edges after eighteen months on a machine, the adhesive takes the blame. In many instances, the adhesive was never the problem. The dome shrank, pulled the edges of the label upward and broke the bond from the top down.

That failure has almost nothing to do with the printing and almost everything to do with which resin went on top of it. Label doming is a short process containing a small number of decisions, two or three of which determine whether the badge still looks right in year five. This guide covers how the process works, why polyurethane and epoxy produce different outcomes, and where doming is the wrong choice.

What label doming is

A measured volume of clear two-part resin is dispensed onto a printed, die-cut label. The resin self-levels, flows outward to the cut edge and stops there, held in place by surface tension. Once cured, it forms a clear convex lens permanently bonded to the print beneath it.

You will see the same product called domed labels, resin domed labels, 3D domed labels, gel badges or bubble labels. The terminology varies by sector. The process is essentially the same. Two things happen in that single step. The artwork is lifted optically, so colours appear deeper and text is magnified through the curve. The print is also sealed beneath a hard, flexible skin that takes the abrasion, UV exposure and chemical contact instead of the ink.

The detail worth understanding is that the die-cut edge acts as the mould. No tooling, no cavity or press. The shape you cut is the shape the dome takes, which is why artwork geometry influences the result more than many specifiers expect.

The doming process, step by step

1. Print. Digitally or by screen, onto polyester, polycarbonate, vinyl or over anodised aluminium and etched metal. The ink must be fully cured before resin goes near it. Uncured ink, residual coating or surface oil will cloud the dome edge or stop the resin keying.

2. Die-cut. This creates the boundary the resin will flow to. A clean, consistent cut produces a clean, consistent dome edge. A ragged one produces overflow.

3. Meter, mix and dispense. Production doming uses meter-mix-dispense equipment, which measures the polyol and isocyanate components by volume, mixes them at a fixed ratio and deposits a measured shot onto each label. For irregular shapes or cut lettering, a scripting system moves the dispense head along a programmed path instead of firing one central shot.

4. Cure. The work is held level while the resin crosslinks, which takes several hours at ambient temperature, commonly around twelve. A low-temperature curing oven shortens that and gives tighter control over the finish.

5. Inspect. Check dome height, edge definition, clarity, and colour against the retained reference.

Why doming happens in a temperature and humidity controlled area

Isocyanate reacts with atmospheric moisture. Most bubbles in a finished dome are caused by a reaction with humidity in the room rather than trapped air from mixing. Mixing faults present differently: a bad ratio shows up as foaming, a milky film across the surface, or a dome that never fully hardens. Being able to trace a defect back to its likely cause is an important part of maintaining a controlled doming process.

Polyurethane or epoxy: the decision that sets the lifespan

Both resins produce a clear dome, but they do not give the same long-term result.

Epoxy is cheaper per unit and less sensitive to moisture during production, which makes it easier to work with. Under UV it yellows, hardens and shrinks. The shrinkage can create problems because it places the edges of the label under tension and may eventually lift them from the substrate. A label that has fallen off a machine after two years outdoors is frequently blamed on adhesive specification when the actual cause was the resin above it contracting.

Here is the part that catches procurement teams out. A new epoxy dome and a new polyurethane dome can look almost identical at first. The difference only becomes apparent later, once the product has been exposed to UV and service conditions for some time.

Polyurethane holds its optical clarity outdoors for much longer, remains flexible enough to sit on a curved substrate without cracking, and offers better resistance to UV degradation. It costs more and demands a controlled production environment, which is precisely why some suppliers choose epoxy instead.

Lexicraft uses two-part polyurethane for doming. For applications exposed to daylight, polyurethane is generally the more suitable option, so resin type is worth confirming when comparing specifications or prices.

What the dome actually adds

The print sits beneath the resin rather than on it, so handling, brushing, wiping and pressure washing act on the dome first. Solvents, fuels and industrial cleaning agents meet polyurethane rather than ink, while the dome also helps protect the colour beneath from UV exposure. Its flexibility also makes it suitable for some curved housings and slightly uneven surfaces.

The curved surface adds depth and saturation to the artwork, which is why domed badges are often used on higher-end products where the identification element needs to sit comfortably with the overall finish of the product.

Where doming is the wrong answer

Sustained heat is the main limit. Polyurethane domes are typically rated in the region of minus 40°C to plus 60°C continuous service, depending on formulation. For an exhaust-adjacent location, a furnace enclosure or repeated autoclave cycles, specify chemically etched stainless steel or anodised aluminium.

Large flat areas can also become difficult. A dome over a big surface can sink in the centre. Areas beyond roughly 100 square centimetres are achievable but need deliberate viscosity and dispense control, and some proportions will not hold an even profile.

Sharp internal corners and narrow webs in the artwork create another constraint. Surface tension cannot hold resin against a tight internal angle, so it overflows the cut edge. It is usually easier to address this at artwork stage by allowing a suitable internal radius than to correct it during production.

If the application is not well suited to doming, it is better to identify that at specification stage and choose a material or process that will perform more reliably.

Getting the specification right

A good domed label specification starts with the application. The substrate, whether it is flat or curved, the expected temperature range, UV exposure, chemical contact and cleaning regime all affect the material and dome profile.

Colour references should ideally be supplied as Pantone or RAL values, with artwork showing the die-cut line and any important internal corner radii. If dome height or flexibility is critical, include that too. Quantity and likely repeat schedule also help maintain consistency across future orders.

The resin matters just as much as the artwork. Get the resin, geometry and application details right at specification stage and the badge is far less likely to become a problem later.

Lexicraft uses two-part polyurethane or domed badges and retains approved colour references for repeat work. If doming is suitable for the application, we can advise on the material and dome profile. If another construction would perform better, we will say so.

Request a domed badge sample pack or send us your application brief.