01The read-rate problem
Every unread barcode on a fast line becomes a manual event: an operator pulls the parcel, finds the label, keys or scans it by hand, and puts the parcel back — at a multiple of the line's per-parcel cost, and usually after the parcel has missed its sort window. Read rate is therefore not a scanner specification; it is the throughput and labour figure of the whole line. Labels land on any face because packers put them where the box gives them a flat surface, and no induction discipline fully changes that.
A scanning tunnel answers with geometry: an arch of cameras and readers over and around the conveyor, covering top, both sides, front, back and — through the belt gap arrangement — the bottom face. The parcel does not need to be oriented. Whatever face carries the label, a reader is looking at it.
02The Goodscan six-sided scanning equipment
The six-sided scanning unit in the Goodscan range is built as a section of a DWS line: it sits over the conveyor where parcels pass in motion, typically paired with the dynamic dimensioning and weighing sections so identity, dimensions and weight are captured in the same pass — the combination the range lists as six-sided scanning equipment for production-line scanning with dynamic DWS. As a tunnel it can also serve a sorting line that already has its measuring point elsewhere, feeding identities to the sorter.
Multiple codes are handled as read: parcels carrying an order label, a carrier label and a returns label present several codes in one pass, and the tunnel captures what it sees for the record and the routing logic to sort out — a better failure mode than a single top reader silently picking whichever code it saw first. Damaged and poorly printed labels remain the honest limit of any reading system; the tunnel's contribution is that orientation stops being a cause of no-reads, so the remaining exceptions are genuinely damaged labels, routed to manual handling with their dimension and weight data already attached.
03Where tunnels are specified
Scanning tunnels earn their place where label discipline cannot be guaranteed: marketplace and 3PL intake with hundreds of packers, returns lines where labels are wherever the customer stuck them, and high-speed sortation where a no-read costs a recirculation or a manual pull. On controlled lines with uniform labelling, a top reader within the dynamic DWS machine is sufficient — the tunnel is the upgrade when the labels stop cooperating. The blog article on read rate works through the economics of the difference.