What was the challenge or problem to solve?
A company in the electronics sector needed support with the dimensional verification of PCBs to confirm whether they met a set of dimensions defined in their drawings. The starting point was not to design the board, but to verify that the already-manufactured parts matched exactly what was specified, because small dimensional deviations can compromise assembly, connector fit or the fixing of the board in its housing.
This type of dimensional analysis makes sense when the underlying problem is one of resources, not of criteria: the client did not have the necessary equipment in-house to carry out the check quickly and with the required precision. The challenge was not just to measure, but to do so with enough accuracy for each value to be reliable and traceable against the design.
Dimensional verification of PCBs when measurement resources are lacking
The client worked with several different board references and needed to know, for each one, whether the real dimensions matched those of its drawing. Without adequate metrology equipment on their premises, that check was slow, hardly repeatable and difficult to sustain with guarantees when precision dimensions were involved.
Outsourcing this task to an industrial technical consultant solves two limitations at once: it provides the measuring instruments the client lacks and it also provides the metrological criteria to interpret the results. It is not just about obtaining numbers, but about knowing what is measured, how it is measured and against which reference each value is compared.
INFINITIA’s approach to this type of assignment is consultative before instrumental: first it understands which decision depends on the measurement (validating a batch, accepting a reference, detecting a supplier with deviations) and then it defines the checking plan. That logic steers the whole project toward the data the client really needs in order to decide.
Working on several references in parallel adds an extra demand of order and traceability, since each measured value must be associated with its part and its corresponding drawing. Maintaining that correspondence is what allows the result to be auditable and not a mere list of loose measurements.
External dimensional verification solves two shortfalls at once: it provides the measuring instruments the client does not have and the metrological criteria to interpret each value.
Precision in measuring dimensions: the critical point of the project
The real technical challenge lay in accuracy. A dimension is each measured feature marked on a drawing (a length, a diameter, an angle, a radius or the position of an element), and in electronics those dimensions usually move within very narrow margins, where a deviation of tenths can alter the fit of a component or the seating of the board.
On a PCB, the critical dimensions are not limited to the overall size. The board outline, the diameter and position of the fixing holes, the connector footprints and the distances between elements determine whether the board fits into its casing, whether it screws down where it should and whether its interfaces align with the rest of the assembly. Verifying those dimensions is what separates a board that fits first time from one that forces rework.
Measuring a large number of dimensions with precision, over several references and in a repeatable way, requires a method that does not depend on the operator’s steadiness or introduce error through handling itself. That is why the choice of measuring system conditions the result so much: unsuitable equipment can turn a correct part into a false reject, or the other way round. Properly bounding the scope (which dimensions are checked and to what requirement) avoids over-measuring and concentrates the effort on the dimensions that truly determine the function and assembly of the board.
Drawing tolerances: when a dimension falls out of range
The conformity criterion is set by the drawing. Each dimension comes with a tolerance, the admissible margin above and below the nominal value within which the part is considered correct. When the measured value falls within that margin, the dimension is conforming; when it exceeds it, the dimension is out of tolerance and signals a deviation from the design.
This framework of dimensioning and tolerances is supported, in industrial practice, by standardized systems of dimensional and geometric tolerances, which allows designer, manufacturer and verifier to interpret the drawing in the same way. Comparing the real part against that common reference is what gives value to the measurement and turns a dimensional inspection into a defensible result.
A dimension only makes sense alongside its tolerance: the measured value is not judged on its own, but by whether it falls within the margin the drawing allows.
Working on the client’s files guarantees that the verification is carried out against the same document that defines the product, and not against an approximate interpretation. That alignment between drawing and measurement is the basis of reliable dimensional control.
How was it addressed, or what was the solution?
The Product Development team laid out a path in three linked phases: gathering the documentation and the parts, measuring each dimension with precision optical metrology and pouring the results into a conformity report. Each step prepared the next and reduced the margin of error before issuing a verdict on the boards.
The order responded to a principle of rigor: nothing is measured without first having the drawing that serves as reference and the physical sample that represents the real part. This way of working, typical of a product design and innovation service with an industrial focus, keeps technical criteria as the priority and supports every decision on data and not on assumptions.
Analysis of 2D CAD files and physical samples of each reference
The first task consisted of analyzing the 2D CAD files of each reference together with the corresponding physical samples. The team coordinated with the client to gather both elements, because the project is only viable when the drawing that defines the dimensions and the real part to measure them on are available at the same time.
The 2D CAD files contain the nominal dimensions and the tolerances that act as the reference for the verification. Contrasting each sample against its own drawing avoids confusion between similar references and ensures that each measured value is compared with the correct criterion. This step links naturally with the discipline of 3D modeling and design using CAD and with the practice of clearly defining product requirements and specifications, because a reliable verification starts from a well-defined, unambiguous drawing.
Precision optical metrology: contactless dimensional inspection
The check of each dimension was carried out using precision optical metrology equipment. Optical metrology is a set of contactless measurement techniques that use imaging and vision systems to quantify dimensions, instead of touching the part with a physical instrument. With them, the team checked lengths, diameters, angles, radii and positions quickly and accurately.
The advantage of measuring without contact is especially relevant in electronics: by not touching the board, scratching, deforming or wearing parts that are usually delicate and sensitive to handling is avoided. In addition, optical measurement makes it possible to address fine geometries and small elements with a repeatability difficult to achieve with manual instruments, which makes this technique an ideal route for the dimensional inspection of boards.
Optical metrology measures lengths, diameters, angles, radii and positions without touching the part, which avoids damaging delicate boards and provides fast, repeatable measurements.
This type of check forms part of a dimensional quality control that underpins the reliability of the product, in line with what a rigorous evaluation of the quality of industrial components entails: measuring to confirm that each part meets what its design demands before considering it valid.
Dimensional report with conforming and out-of-tolerance features
With all the dimensions measured, the team collected the values one by one and poured them into a results document. That report gathers, for each part and each dimension, the real value obtained and the indication of whether it meets the drawing or falls outside the specified tolerance.
The value of this deliverable lies in clarity: the client goes from having no means to verify their boards to having a single document where they can see at a glance which dimensions are correct and which show deviation. That information allows them to decide quickly on the acceptance of each reference, detect error patterns and pass on concrete findings to their supplier when appropriate.
The result of the project was clear: the client received a complete dimensional verification of their PCBs, with objective, traceable data against the drawing, without needing to invest in their own metrology equipment.
