Panel build & panelisation — V-cut, tab-route and marking.

Who builds the panel?

A production panel groups several individual boards into one manufacturing unit. It is not an edge detail — it determines how fast and how cleanly the SMT line can produce, and therefore the economic unit price. That is why SMTEC follows a clear order of responsibility.

• Priority 1 — SMTEC builds the panel and orders the boards. This is the preferred route, because the panel is then optimally designed for the processes and an economic unit price.
• Priority 2 — the customer builds the panel. In that case the additional requirements (below) are mandatory.

Either way, the panel build happens in consultation with SMTEC, ideally project-specific. That way separation method, component clearances and marking are matched to real manufacturing from the start, instead of being corrected expensively later.

General panel requirements

Regardless of who builds the panel, the same base rules apply for geometry and line handling:

• Panel sizes (length/width) on a 2 mm grid.
• Panel-frame corners rounded, radius 3 mm.
• Panel frame: long side at least 6 mm, short side at least 3 mm.
• Tooling holes ⌀ 3 mm in all corners, one hole offset (poka yoke against wrong insertion).
• Next to each individual board a homogeneous 5 × 5 mm area with solder mask for laser marking.
• Connection by V-cut or "mouse-bite" (perforated tab).
• Preferred: a length-to-width ratio of roughly 16:9.

Panel sizes

How large a panel may sensibly be depends on the material thickness — thinner boards sag and become harder to transport and place. The following are target sizes, the maximum to aim for:

Minimum panel size: 55 × 55 mm · Source: SMTEC Design Guidelines, chapter 8

The minimum panel size is 55 × 55 mm — smaller units can no longer be gripped and transported reliably on the line. Between minimum and maximum you always stay on the 2 mm grid and aim for the 16:9 ratio, so the panel fits well into the machine flow.

When the customer builds the panel

If the customer builds the panel themselves (priority 2), mandatory additional requirements come on top of the general ones. They ensure SMTEC can set up production reproducibly and keep it traceable.

Working files to SMTEC:

• Gerber data of the production panel and paste data after each first order.
• Panel drawing as a dimensioned PDF before production start.

Marking and fiducials:

• "SMTEC / article number" in the panel frame.
• Calendar week + year of production in the panel frame.
• 3 fiducials in an "L" on the short side plus 1 fiducial in the 4th corner, offset (poka yoke).
• All fiducials as far outward as possible, at least 6 mm clearance to the long side — and also entered in the solder-paste data.

Panel connection by thickness:

• For thicknesses above 0.95 mm use a scored routed panel where possible.
• For thicknesses below 0.95 mm or for flex boards connect via holding tabs, if possible with break points (less material for laser separation). The break points must sit on the edge.

V-cut or perforated tab?

The connection decides cost, edge quality and how close components may sit to the edge. Both methods have their place — the choice depends on contour, component clearance and material.

Tab detail dimensions: milling ⌀ 2.0 mm · perforation ⌀ 0.5 mm · tab 1.4 mm

Rule of thumb: for straight standard contours with some edge clearance, the V-cut is the fast, cheap choice. As soon as curved contours, very edge-near components or flex/rigid-flex come into play, there is barely a way around the perforated tab with laser separation — it costs more in setup but delivers the clean, force-free separation these assemblies need.