There is a persistent misconception in the surface finishing industry: that metallic coating works best — or only works well — on simple, symmetrical, cylindrical components. Bottles, tubes, standard caps. The assumption is understandable, because these are the formats that dominated early applications of vacuum metallization. But the reality of modern packaging and industrial design has moved well beyond the cylinder, and coating technology has had to follow.
Today, designers working in luxury cosmetic packaging, automotive interiors, pharmaceutical closures and premium beverage containers routinely specify shapes that would have been considered uncoatable a decade ago. Flat-sided compacts, asymmetric jar covers, angular perfume bottles, multi-faceted decorative caps, mascara components with complex profiles — these are not exceptions. They are the norm in any market segment where differentiation through design is a commercial priority.

Where the difficulty actually lies

The challenge of coating non-cylindrical shapes is fundamentally a question of geometry and physics. In a vacuum metallization process, metallic atoms are ejected from a target and travel in relatively straight lines before depositing on the substrate. On a curved surface, this directional deposition can result in uneven layer thickness — thinner on recessed areas, potentially thicker on prominences — if the process is not engineered to compensate.
Surface preparation compounds the challenge. On a cylindrical component, cleaning, pre-treatment and primer application are relatively straightforward because the surface presents a consistent geometry to each processing station. On an irregular shape, shadowing effects, surface tension variations and differential adhesion can all affect the uniformity and durability of the final coating.
This is why 3D sputtering technology matters. Unlike simpler vacuum deposition methods, sputtering produces a more diffuse deposition pattern that can follow the contours of complex geometries more effectively. Combined with careful fixture design and optimised process parameters, it allows metallic finishes to be applied to shapes that other methods cannot handle reliably.

Engineering the process around the shape

Solving the non-cylindrical coating problem is not just about the metallization step. It requires a systems approach that considers every stage of the inline process — from how components are loaded and oriented, to how cleaning and pre-treatment are delivered, to how UV coatings are applied before and after the metallic layer.
Tapematic PST Line II addresses this challenge through a combination of inline 3D sputtering and a modular process architecture that can be configured around the specific requirements of each component family. The tray-based transport system moves pieces through each station in a controlled, repeatable orientation, ensuring that every surface receives consistent treatment regardless of its geometry. The cleaning and pre-treatment module prepares even complex surfaces for optimal coating adhesion, which is the foundation of any durable metallic finish.
Because the system is modular, the sequence and specification of each processing stage can be adapted to the shape being coated. A component with deep recesses may require a different primer formulation or a modified sputtering configuration compared to a shallower, more open form. This flexibility is what allows the PST Line II to handle the full range of shapes that modern packaging design demands.

Compact solutions for complex formats

Tapematic PST Line C brings the same capability for handling non-cylindrical components to a more compact, non-modular format. A common misunderstanding about this system is that it is designed exclusively for cylindrical pieces — in fact, it processes the same variety of shapes as the PST Line II, making it a genuine alternative for manufacturers who need high-quality metallic finishing across diverse product families, without the footprint or investment of a fully modular line.
Both systems support the full decorative process — UV base coat, metallization, UV top coat — and can handle components including jar covers, compacts, mascara tubes, irregular caps and a wide range of closures that share nothing in common geometrically except the need for a flawless metallic finish.

From prototype to production

One of the practical difficulties manufacturers face when introducing a new non-cylindrical format is validating the coating process before committing to full production. Shape variations that look minor on a design drawing can have significant implications for coating uniformity, adhesion and durability — and discovering this at scale is costly.
Tapematic's sampling service, available at the company's headquarters in Ornago, near Milan, allows manufacturers and brands to test specific components on a fully operational line before any production decision is made. This is particularly valuable for complex or irregular shapes, where process validation is not a formality but a genuine technical necessity. Components can be evaluated for finish quality, layer consistency and resistance, giving manufacturers the confidence to move to production with a process that has already been proven on their actual parts.