Reel‑to‑reel (strip) plating is the route to coat functional areas on strip material in a repeatable way – for contacts, solder zones or bond pads. What matters is not only the coating itself, but the technology: selective or full‑surface, track or spot, with or without masking.
ON‑Metall is your full‑service partner for reel‑to‑reel plating and functional coatings. We support you from technical consulting and specification work to selecting the right process route and delivering on time – aligning engineering, purchasing, production and quality.
On this page you’ll find the key technology entry points – from selective to full‑surface, from track to spot – plus practical guidance to clarify transitions, tolerances and evidence/testing early.
If you already have a drawing or a specification, the right technology can often be narrowed down quickly: functional zone(s), required transitions, tolerances and the downstream process (e.g., reflow, crimping, bonding). This overview is designed to support exactly that.
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Send us your drawing, functional zones and target properties – we’ll help structure track/spot, process route and evidence/testing.
Technology overview
In reel‑to‑reel plating, the decision is not only “selective or full‑surface”. What matters is which area is truly functional, how sharp transitions must be and how robust the process needs to be over the full coil length. The entry points below help you structure these decisions quickly.
Understanding Reel-to-Reel Plating & Selectivity
Before choosing a route, it helps to align on the underlying logic. Many later “quality topics” (transitions, tolerances, thickness distribution) are not created during final inspection – they are shaped by the technology decision upstream.Reel‑to‑reel plating: how does it work at its core?
Reel‑to‑reel plating is a continuous coating process where strip material runs as a coil through defined process zones – with the goal of applying functional layers in a repeatable, production‑ready way. Compared to rack or barrel processing, the process is designed for repeatability and throughput. That becomes critical when functional areas must remain stable over long coil lengths or when specifications are tight. For an initial technical assessment, a few inputs are often enough: base material, strip width, strip thickness, functional zones (track/spot) and the downstream process. If you can provide these, the choice between selective technique, full coverage and masking becomes much clearer. Contact us Contact usSelective coating: track or spot – what fits your part?
Selective coating means coating only where the surface later performs a function – either as a continuous track or as a defined spot. This can make the surface not only more economical, but often technically cleaner: fewer unwanted friction zones, more predictable downstream steps and functional layers exactly where they’re needed. At the same time, transition control and repeatability become more important. Quick definitions:- Track: a continuous selective zone along the strip direction (e.g., a contact stripe).
- Spot: a discrete functional area (e.g., pads), often realised via a “window” approach.
Selective techniques: how do you choose depth control, tape, wheel, resist or spot masking?
The selective technique defines how “hard” windows and transitions can be created – and how robust that remains in production. That’s why it’s a real process decision, not a minor detail. In practice, selective zones are implemented differently depending on geometry and target tolerance. Depth‑controlled and continuous routes often fit repeating tracks, while tape or resist approaches can offer more freedom for window shapes. Spot solutions using masking tools come into play when discrete zones are required and the boundary conditions (guiding, tolerances, handling) allow it. If you provide track/spot plus transition tolerance, feasible options can usually be narrowed down quickly. Start a technical request
Full‑surface coating: when is full coverage the better technical choice?
Full‑surface coating makes sense when the entire surface is functional – or when corrosion protection, storage behaviour and downstream steps make continuous coverage safer than selectivity. Full coverage can simplify specifications because transitions no longer matter. In addition, from a pure process perspective it is often the lowest‑cost route: no masking, no window handling and less set‑up and control effort. Whether full coverage is also the most economical solution overall depends on the coating material and the required coated area. With expensive precious metals, selective coating can still be cheaper despite higher process complexity – simply because material is saved where it isn’t needed. More details are available on our page about full‑surface coating.Masking and shutter techniques: when do you need “hard” windows?
Masking means covering areas mechanically or process‑wise so that plating occurs only where intended – especially helpful when windows must be tightly defined. The benefit is better control of transitions and reduced unwanted build‑up on adjacent surfaces. The trade‑off is usually tooling/handling effort and ensuring stability over coil length and throughput. In many projects, the rule of thumb is: the tighter the window and transition tolerance, the earlier masking and selective technique should be evaluated together – not only after first trials.How to choose the right technology
The best technology is not the “most advanced” one – it’s the one that meets your requirements reliably. Four questions help structure the choice and typically save time during specification work.
- Which area is functional? Full coverage, track or spot – the key decision.
- How sharp must the transition be? Define tolerances function‑driven, not only visually.
- What is the downstream process? Reflow, crimping, wire bonding etc. influence surface and layer systems.
- What evidence is required? Thickness, distribution, documentation – plan it early.
If you can answer these points roughly, a suitable route can often be derived quickly. Contact us Contact us
Quality & evidence: proving thickness and distribution
Technology and quality go hand in hand. Especially for selective zones, thickness, distribution and transitions are often the critical point – not because plating is “bad”, but because geometry and process logic shape characteristic effects.
Two common routes for robust evidence are:
- XRF thickness measurement (RFA) – fast, largely non‑destructive, ideal for production checks.
- Cross‑section (Querschliff) – visual evaluation of layer build‑up, edges, transitions and distribution.
When working with selective zones, it can be helpful to consider typical edge build‑up effects (often discussed as “Dog‑Bone”) already during specification and sampling – because it impacts measurement points, tolerances and functional transitions.
Practical knowledge
For further technical perspectives and updates, you may find these sections useful:
🔍 Do you have functional zones (track/spot) and a drawing?
Request technical classificationFAQ
A few questions that come up frequently in reel‑to‑reel and selective plating projects – answered briefly to help you move faster towards a suitable route.
Reel‑to‑reel plating is a continuous coating process for coils, where strip material runs through defined process zones to apply functional layers repeatably.
It is used when production readiness, repeatability and stable specifications matter – for example with contacts, leadframes or stamped strip components.
A track is a continuous selective zone along the strip direction, while a spot is a discrete functional area.
This distinction helps to choose the selective technique, define transition tolerances and plan evidence/testing appropriately from the start.
Selective coating is useful when only certain zones are functional and material/process can be optimised accordingly. Full‑surface coating is useful when the entire surface needs function or protection.
Key drivers are functional areas, transitions, downstream processes and robustness over the full coil length.
Typical routes are XRF measurements for fast production checks and cross‑sections when layer build‑up, edges and transitions must be assessed visually.
Especially with selectivity, it helps to plan measurement points and distribution together with the specification early.
