Engineering & NPI Process: From Drawing to Volume Ramp
New product introduction is the part of a programme where a drawing becomes a repeatable process. This page
sets out the stages we run, what each stage produces, and what we need from you to keep a programme moving
instead of waiting.
Intervening early is cheaper than correcting late
A dimensional or mating-side problem costs almost nothing to correct on a drawing, a moderate amount to correct at tooling, and a large amount to correct after volume ramps. The purpose of NPI is to move decisions to the cheapest stage at which they can still be made.
That is the whole argument for running a structured introduction. It is not a documentation exercise. Each stage exists to close a specific question before the cost of changing the answer rises: whether the geometry can be formed, whether the mating side closes, whether the tool can hold the tolerance in production, and whether the process repeats at the volume you are planning.
Two things follow from this. First, the review is worth more than the paperwork — a DFM response that arrives before tooling is worth more than a first-article report that arrives after. Second, the fastest way to slow an NPI programme down is to leave one of the early answers open, which is why the intake list later on this page is deliberately specific.
Five stages, four gates
Each stage has a defined input, a defined output, and a gate that must be closed before the next stage starts. A stage that begins with an open gate from the previous one is where programmes lose time.
| Stage | What we do | What we need from you | Output | Gate to close |
|---|---|---|---|---|
| 1. Intake and DFM review | Review drawing, mating-side geometry and assembly method against process capability | Drawing, counterpart geometry, assembly method, target volume and date | DFM response with flagged risks and open questions | Geometry can be formed and the mating side closes |
| 2. Prototype | Produce representative parts to prove form, fit and function before tooling commitment | Confirmation of the DFM response, or the corrected drawing | Physical samples with dimensional data | Fit and function confirmed on your assembly |
| 3. Tooling | Build and qualify tooling; establish the forming and assembly process | Frozen drawing and confirmed volume | Tooling qualification data | Tolerance is held on the tool, not on the drawing |
| 4. First article | Full dimensional and performance verification against the drawing datum | Mating pin or counterpart for force and resistance measurement | First article report, issued before volume ramp | All controlling characteristics verified |
| 5. Volume ramp | Production under the agreed inspection basis, with change control on the drawing | Forecast, packaging and delivery requirements | Production parts with inspection records | Process repeats at the planned volume |
Stages run in this order because the cost of changing an answer rises at every gate.
What to send us to get started
Most delays in the first week are caused by a missing mating-side or assembly detail rather than by the part drawing itself. The list below is what actually unblocks a review.
| Item | Why it is needed | What good looks like |
|---|---|---|
| Part drawing | Defines the geometry we have to form and the characteristics we verify | Controlling dimensions and their tolerances marked, not just nominal |
| Counterpart / mating-side geometry | Part of the stack-up, and not measurable from our side | Mating pin or header drawing with its own position tolerance |
| Assembly method | Determines positional tolerance and the load the joint carries | SMT, THT, wire or harness, and the process used |
| Working stroke and force target | Sets the operating point of the spring, and therefore wear and resistance | A target band, or the mechanical constraint it has to fit |
| Current and environment | Decides whether the contact carries the load and which plating is appropriate | Target current, ambient condition, and duty cycle |
| Volume and target date | Decides the tooling route and the inspection basis | An annual figure and a first-need date |
What the DFM review actually flags
A DFM response is only useful if it says something you did not already know. These are the categories of finding that come out of it, each with the stage at which it is still cheap to fix.
Stack-up that cannot close
The combination of board-side, contact-side and mating-side tolerance leaves no workable band. Cheapest at drawing stage.
Tolerance tighter than the process holds
A dimension that cannot be held in production without a different tooling route. Cheapest at drawing stage.
Feature that will not form cleanly
Geometry that risks tearing, thinning or spring-back in the forming operation. Cheapest before tooling.
Plating or force mismatched to the application
Wear or resistance risk detected from the stroke, force and cycle target rather than from the part number. Cheapest before first article.
Assembly access or fixturing
A position the assembly fixture cannot establish repeatably. Cheapest at prototype stage.
Inspection not defined
A characteristic that matters functionally but has no measurement datum on the drawing. Cheapest before first article.
Each finding is returned with the stage at which it can still be corrected cheaply, because that is the decision the review exists to support.
What the first article report contains
The first article is the point at which the process, not the drawing, is being verified. It is issued before volume ramp so that a deviation is still a tooling or fixture action.
| Deliverable | What it covers | Basis |
|---|---|---|
| Dimensional report | All controlling characteristics, measured against the drawing datum | Vision measuring system |
| Force verification | Insertion and withdrawal force at the specified stroke | Connector force tester, with the intended mating pin |
| Contact resistance | Resistance at the specified current | DC low resistance measurement |
| Plating verification | Gold and nickel thickness against the drawing | Incoming lot measurement |
| Inspection basis for production | Agreed sampling for mechanical and electrical characteristics | AQL 0.65, with dimensions and appearance at 100 % AOI |
Where a characteristic cannot be verified as a pair — force, for instance, which depends on the mating pin — the report states the counterpart used, so the number can be reproduced rather than taken on trust.
Where NPI meets substitution
Most NPI programmes we run are also substitutions: an existing part, or an existing chain of parts, is being replaced under a delivery date. The grade of substitution decides how much of the flow above has to be repeated.
A drop-in substitution still needs the dimensional and force verification above, because the counterpart has changed even though the drawing has not. A pin-to-pin or footprint-compatible substitution adds footprint confirmation and parameter re-verification. A custom part starts at stage 1 with a full DFM review.
Where more than one link of the chain is being replaced — a battery contact and the harness that serves it, for example — the grades have to be assessed together: a drop-in contact feeding a re-qualified harness is not a drop-in assembly. Our cross-reference hub is organised around that problem, and the two technical guides cover the parameters that have to be re-verified: tolerance control and pogo pin selection.
NPI questions engineers ask
How quickly can we get a DFM response?
Send the drawing, the counterpart geometry and the assembly method, and you receive a DFM review and a response within 12 hours.
Do we have to finish tooling before you review the design?
No — and that is the point of running stage 1 first. Most stack-up and formability findings are cheap to correct on the drawing, and expensive to correct after tooling. The review exists to move those decisions earlier.
What if the drawing tolerances cannot be held in production?
We say so at stage 1, with the dimension and the reason. The options are then to change the tooling route, to relax the dimension where function allows, or to specify a precision grade — for example ±0.03 mm where standard production is ±0.05 mm.
Who supplies the mating pin for force verification?
Whoever owns the counterpart design. Force is a property of the pair, so the first article measures our contact against the pin it will actually meet, and the report states which one was used.
Do you handle the harness as well as the contact?
Yes. Custom cable harness assemblies are delivered turnkey, with the contact overmoulded and crimped into a finished harness where that is the practical route. It also means the substitution grades across the chain can be assessed together rather than part by part.
When do we receive the first article report?
Before volume ramp, so that any deviation is still a tooling or fixture action rather than a production problem. It covers dimensions, force, contact resistance and plating.
Send a drawing. Get an NPI response in 12 hours.
DFM review, stack-up comment and the stage at which each finding is still cheap to correct.
