Digitalisation of Wiring Harness Manufacturing: Two Upgrades Worth Doing First

Wire harness manufacturing has a strange shape. The front end of the process is mostly automated — cutting, stripping, sealing, crimping, twisting all run on special-purpose machines. The back end, where the harness is actually assembled on a board, is still almost entirely done by hand. A 2019 review of the state of the art in automotive harness production put it flatly: at the assembly line, “almost all work steps are executed manually” (Trommnau et al., Procedia CIRP 81, 2019).

The commercial front end has the same shape. Quoting a harness is a manual, expert-dependent exercise in a business where the wire harness is, in the same paper’s words, “one of the most expensive produced parts.”

That is why the two most useful digitalisation upgrades in this industry are not the flashy ones. They are instant quotation and the digital formboard. One digitalises the decision to build; the other digitalises the labour of building. Connected, they make sure the harness you quoted is the harness you build.

Key Takeaways

• Harness pre-production is well automated; the formboard is where the manual labour and the errors live. Digitalising it targets the largest remaining cost centre.
• Boeing’s trials of guided digital instructions for wire harness work reported 25% shorter assembly time and error rates cut roughly in half (Skylight pilot, 2015); a related Boeing/Iowa State study found ~30% faster assembly and ~90% better first-time quality versus desktop PDF instructions.
• Instant quotation fails in two known ways: BOM-only costing that ignores labour, and expert intuition that is fast but inaccurate. Digital quoting only works if the time standards behind it are real.
• The point of connecting the two is data continuity: wire list, BOM, operations, class and revision should flow from quote to board without being re-keyed.
• Digitalisation does not fix bad time standards, incomplete customer drawings, or missing acceptance criteria. It exposes them faster.

Upgrade 1: Instant Quotation

Instant quotation means generating a harness price from structured harness data and predefined costing rules, rather than from a spreadsheet and a senior estimator’s memory.

Why harness quoting is hard

A harness quote is not one number. It is a bill of materials with dozens to hundreds of line items — wire by type, gauge, colour and length; terminals, seals, connectors, cavity plugs, clips, sleeving, tape, labels — plus a labour routing of every operation that touches those parts: cut, strip, seal, crimp, insert, route, tie, tape, mark, test. Each operation carries a time standard. Tooling, margin, and delivery assumptions sit on top.

Research on harness cost estimation identifies two ways this goes wrong. Most published methods, according to a 2017 engineering design conference paper, “calculate the cost by simply considering the Bill of Material and computing the cost of the raw material. The installation cost is not considered.” The alternative — knowledge-based estimation “built on past experiences” — is quick and usable when detail is missing, “however… it lacks of accuracy” (Mandolini et al., ICED17, 2017). The same paper notes that engineers working in mainstream electrical CAD tools “need to adopt manual methods to evaluate costs of components and installation process, employing a long time for the costs estimation phase.”

That is the shape of the problem in most harness shops: either the quote under-counts labour, or it depends on one or two people who can estimate labour from experience and are not always available.

What digital quotation actually does

A digital quoting system takes harness data — ideally straight from the design or the customer’s drawing package — and applies costing rules it can explain. It considers:

• Wire types, colours, gauges and cut lengths
• Connectors, terminals, seals, clips, sleeves, tapes and the small parts that rarely appear on the customer’s drawing
• Assembly operations: cutting, stripping, crimping, insertion, routing, bundling, marking, testing
• Labour time per operation and a complexity factor for the assembly
• Tooling, applicators and fixtures the job needs
• Margin, lot size and delivery assumptions

The benefits the sales side cares about are speed and consistency: faster RFQ response, the same answer regardless of who runs the quote, visible cost-price-margin, fewer missed line items. The benefit the engineering side should care about is that the quote is now structured data rather than a PDF — which is what makes Upgrade 2 possible.

The caveat that matters

Instant quotation is only as good as the time standards underneath it. A system that applies a labour rule it does not have will either default to a guess or leave the field blank. Digitalising the quote does not create time standards; it makes their absence visible. Shops that have documented, measured operation times get accurate instant quotes. Shops that have them in one estimator’s head get fast quotes that are exactly as accurate as that estimator’s memory, now applied at scale.

One more thing a good quote must carry: the workmanship class. Class 2 and Class 3 harnesses under IPC/WHMA-A-620 do not carry the same inspection, rework and documentation content, and a quote that does not record the class is pricing an unknown amount of labour.

Upgrade 2: The Digital Formboard and Guided Work Instructions

A formboard defines the physical layout of a harness during assembly — the routing paths, branch points, breakout lengths, connector positions. The operator routes wires across it, inserts terminals, bundles, tapes, adds clips and labels, and confirms the build. It is the single most labour-intensive step in the process, and it is the last step in the chain still driven by printed drawings and paper work instructions.

The formboard is where augmented reality was invented

This is not a new idea. In 1990, Boeing scientists Tom Caudell and David Mizell were trying to help technicians assembling wire bundles for the new 777 — the first jetliner fully digitally modelled before it was built. Technicians worked on formboards 20 to 30 feet long, constantly referring back to instruction sheets. Caudell and Mizell proposed a see-through headset that would superimpose the wire routes directly onto the board, and Caudell coined a term for it: augmented reality (MIT Technology Review, 2014).

It did not ship. Head tracking could not keep up with a moving worker and wearable computers were too weak. But the problem definition was exactly right, and it has not changed in 35 years. The hardware has.

What a digital formboard does

A digital formboard replaces the paper drawing and the paper instruction packet with an electronic layout and step-by-step guidance delivered at the point of work — on a screen at the board, projected onto the board surface, or through a headset. The operator sees the wire route, the connector location and cavity assignment, the dimension, the sequence step, and the inspection point for the current task, and confirms completion before the next step appears.

Guided instructions can cover:

• Selecting the correct wire, terminal, connector and protection material for the step
• Cutting, stripping and crimping to the specified parameters
• Routing each wire along the correct path with the correct breakout length
• Inserting terminals into the correct connector cavity
• Adding clips, ties, labels, sleeving, tape and protective coverings
• Completing inspection points and confirming each process step
• Recording who did what, when, and with which lot of material

The last item is the one that changes the business. A paper traveller records that a harness was built. A digital formboard records how.

What the evidence shows

The best-documented results come from Boeing, which has been working this exact problem since Caudell’s headset.

In a pilot with Upskill’s Skylight platform on smart glasses, run between March and November 2015 with around 20 wire harness technicians, Boeing reported that assembly time fell by 25% and error rates were “chopped in half.” Before the pilot, technicians had worked from PDF instructions on laptops, consulting complex roadmaps to find attachment points and connector pins in dense bundles (CIO, July 2016).

A controlled study run with Iowa State University compared three instruction modes for an assembly task of over 50 steps and nearly 30 parts: desktop PDF instructions, tablet PDF instructions, and tablet-based guided AR. Boeing’s Paul Davies reported that AR reduced assembly time by around 30% and produced “an almost 90% improvement in first time quality between desktop and Augmented Reality modes,” with the AR group averaging zero errors per person (AREA, August 2015).

Two honest qualifications. The Iowa State study used a mock wing assembly, not a harness, and it measured a laboratory task with student participants. The Skylight pilot was harness-specific but small. Neither is a controlled industrial trial of a projected formboard in a high-mix harness shop. What they do establish is the mechanism: when the instruction is delivered at the point of work, in the operator’s line of sight, in the right sequence, time drops and first-pass errors drop sharply. That mechanism does not depend on the hardware being a headset.

Why guided instructions matter to the operator, and to the company

For the operator, the change is simple. Instead of interpreting a drawing and holding the sequence in memory, they receive clear, visual, revision-controlled guidance for the step in front of them. The company benefits are the mirror image.

Benefit for the operator	Benefit for the company
Clear visual instruction for every assembly step	Fewer assembly errors, defects and rework
Faster learning for new or less-experienced employees	Shorter training and onboarding
Always working from the latest approved revision	Real change control; no obsolete paper on the floor
Easy verification of wire routing and connector cavities	Higher first-pass yield
Less dependence on tribal knowledge or a supervisor	Consistent output across shifts and sites
Digital confirmation of each completed task	Traceability and audit readiness
Confidence on complex builds	More predictable throughput and delivery

The revision-control row deserves emphasis. On a paper-driven floor, an engineering change becomes a race between the new drawing and the old one already clipped to the board. On a digital formboard, the old revision ceases to exist at the point of work the moment the new one is released.

The traceability row is where regulatory and customer pressure is heading. The same review of harness production that documented how manual the board still is also noted that current requirements “will require more documentation, traceability and monitoring of the production process” (Trommnau et al., 2019). A digital formboard generates that record as a by-product of building the harness, rather than as a separate clerical task.

The Connected Digital Journey

Each upgrade is worth doing on its own. The larger value comes from connecting them, because the data that made the quote is the same data the board needs.

In a disconnected shop, the quote is a spreadsheet, the drawing is a PDF, the cut list is another spreadsheet, the formboard is a plotter print, and the work instruction is a Word document. Every handoff is a re-entry, and every re-entry is a chance for the built harness to drift from the quoted one — a different wire length, a substituted terminal, an operation the estimator counted and the floor skipped.

Connected, the wire list, BOM, operations, labour routing, and workmanship class generated at quote flow into engineering release, then into the formboard layout and the guided instruction sequence, then into the quality record. Nothing is retyped. When the customer changes a connector, the change propagates. When the actual build time differs from the quoted time, the variance is visible, and the next quote is better for it.

That last loop is the underrated one. Instant quotation gets more accurate over time only if actual labour data comes back from the floor. A digital formboard is what produces that data.

What Digitalisation Does Not Fix

A note of realism, because vendors in this space rarely offer one.

• It does not create time standards. If your labour data lives in someone’s head, digital quoting will expose the gap, not close it. Measure the operations first.
• It does not complete the customer’s drawing. RFQs arrive with missing cavity plugs, unspecified sleeving and unstated workmanship class. A quoting system can flag gaps; it cannot fill them.
• It does not define acceptable workmanship. Guided instructions tell the operator what to do; a workmanship standard such as IPC/WHMA-A-620 and the terminal manufacturer’s application specification define what “done correctly” means. Both are still required.
• It does not replace process control. Crimp height, pull force and applicator validation are still measured, not displayed.
• It does not survive bad master data. A digital formboard built from a wrong wire list is a very precise way to build the wrong harness.

Digitalisation removes the re-entry, the ambiguity and the paper. It does not remove the engineering.

Conclusion

Harness manufacturing has already automated the parts of the process that were easy to automate. What remains is the quote at the front and the board at the back — the two places where a person still works from paper and memory, and where the errors, the delays and the labour cost concentrate.

Instant quotation makes the commercial decision faster, more consistent and more honest about labour. The digital formboard makes the build clearer, more repeatable and self-documenting. Connecting them means the harness that was quoted is the harness that gets built, and the time it actually took feeds the next quote.

Start there. The rest of the digital factory has something to connect to once those two are in place.

If you run a harness operation: which do you re-key more often today — the data that goes into a quote, or the data that goes onto the board?

Frequently Asked Questions

What is a digital formboard in wire harness manufacturing?

A digital formboard replaces the printed harness layout and paper work instructions with an electronic layout and step-by-step guided instructions delivered at the point of assembly — on a screen, projected onto the board, or through a headset. The operator sees routing, cavity assignments, dimensions and inspection points for the current step, and confirms completion, which creates a build record automatically.

Is there evidence that digital work instructions reduce harness assembly errors?

Yes, though most of it comes from Boeing. A 2015 smart-glasses pilot with about 20 wire harness technicians reported 25% shorter assembly time and error rates roughly halved (CIO, 2016). A Boeing/Iowa State University controlled study found around 30% faster assembly and about 90% better first-time quality with guided AR versus desktop PDF instructions (AREA, 2015). These are pilots and lab studies, not large industrial trials, but the mechanism is consistent.

Why is wire harness quoting so slow?

Because a quote is a full BOM plus a labour routing of every operation, and the labour part usually depends on undocumented time standards held by one or two experienced estimators. Research on harness costing notes that most methods either cost only the raw material and ignore installation labour, or rely on expert judgement that is quick but inaccurate (Mandolini et al., ICED17, 2017).

What data should flow from the quote to the formboard?

The wire list with cut lengths, the bill of materials including small parts, the operation list and labour routing, the applicable workmanship class and revision, and the test specification. If any of these are re-keyed between quote and build, the harness built can drift from the harness quoted.

Does a digital formboard replace IPC/WHMA-A-620?

No. Guided instructions tell the operator what to do and in what order; IPC/WHMA-A-620 and the terminal manufacturer’s application specification define what an acceptable result looks like. Digitalisation makes the standard easier to apply consistently; it does not substitute for it.

Sources

• Trommnau, J., Kühnle, J., Siegert, J., Inderka, R., Bauernhansl, T. — Overview of the State of the Art in the Production Process of Automotive Wire Harnesses, Current Research and Future Trends, Procedia CIRP 81 (2019) 387–392, doi:10.1016/j.procir.2019.03.067 — degree of manual work at the assembly board, documentation and traceability drivers. Open access (CC BY-NC-ND).
• Mandolini, M., Cicconi, P., Castorani, V., Vita, A., Germani, M. — A Design to Cost Method for Electric Cable Harness, Proceedings of ICED17, Vol. 5, Vancouver, August 2017 — failure modes of harness cost estimation.
• Metz, R. — Augmented Reality Gets to Work, MIT Technology Review, 24 February 2014 — Caudell and Mizell, Boeing 777 wire bundle formboards, origin of the term augmented reality.
• Sacco, A. — Google Glass takes flight at Boeing, CIO, 13 July 2016 — Skylight wire harness pilot results.
• AREA — Augmented Reality Can Increase Productivity, 20 August 2015 — Boeing/Iowa State University study as presented by Paul Davies at ARise ‘15.
• Iowa State University VRAC — Augmented reality can increase productivity, 23 September 2015 — university confirmation of the Boeing collaboration.

Study figures above are as reported by the named sources. They are pilot and laboratory results and should be read as evidence of mechanism, not as guaranteed outcomes for any particular harness operation.