Every week a package comes into our Livonia facility: Gerbers, a bill of materials, an assembly drawing; and somewhere in that drawing is a notes block. Often it reads “Build to IPC-A-610.” That is it. No class. No revision.
That is a problem, because IPC-A-610 without a class is like ordering steel without a grade. The class you specify is the single largest quality lever on the job. It changes what our operators accept at the bench, what our inspectors reject under a scope, what we document, and what we charge. Getting it wrong in either direction costs you money.
What the classes actually mean
IPC-A-610 is the acceptability standard for electronic assemblies: the visual criteria that define whether a finished solder joint, component placement, or wire termination passes. The current revision is J, released in April 2024; IPC reported that committee leaders worked through more than 1,350 industry comments in producing it, with expanded guidance on conformal coating inspection and additional visual reference imagery.
The standard sorts product into three classes based on what happens when the assembly fails:
- Class 1: General Electronic Products. Function is the requirement. Cosmetic imperfection is not a concern.
- Class 2: Dedicated Service Electronics. Continued performance and extended life are required. Uninterrupted service is desired but not critical. Most industrial and commercial work lands here.
- Class 3: High Performance / Harsh Environment. Continued performance is critical, downtime cannot be tolerated, and the end-use environment may be harsh. Defense, aerospace, and life-sustaining medical products live here.
The gap between Class 2 and Class 3 shows up in the details. Plated-through-hole fill is the classic example: the two classes hold different vertical fill requirements, and Class 3 tightens what is acceptable for circumferential wetting. Same board, same parts, same operator – a different accept-reject line. Multiply that across a few hundred joints and you have a materially different product.
The thing most buyers do not know
Here is what surprises people: there is no such thing as a “Class 3 certified” contract manufacturer. IPC certifies people, not companies. When a shop tells you it is “IPC Class 3 certified,” that is shorthand at best.
What actually exists is this. Individuals hold IPC certification as Application Specialists, and some hold Certified IPC Trainer status, which allows them to train and certify others. At IPS we hold Certified IPC Trainer and Application Specialist certifications for both IPC-A-610 and IPC/WHMA-A-620, the cable and wire harness standard. That means when we bring an operator onto the floor, we do not ship them out and wait for an open class – we train and certify them here, to the current revision, on the kind of product they will actually be building.
So the useful questions are not “are you Class 3 certified?” They are:
- Who on your floor holds IPC certification, to which standard, and to which revision?
- Can you train and certify in-house, or does coverage lapse while people wait for a class?
- How does the class on my drawing flow into your work instructions and inspection?
How we handle it at IPS
The class is set at quote, not at build. When your package arrives, our review looks for the class call-out before we price labor. If it is missing, we ask. We do not quietly assume Class 2 to make the number look better, and we do not quietly assume Class 3 to be safe – either assumption puts a surprise in front of you later.
Once the class is set, it propagates. It drives the work instructions the operator sees, the thresholds programmed into our 3D solder paste inspection and automated optical inspection, and how much of the build gets documented. Our SPI catches paste volume problems before parts go down. AOI runs after reflow. X-ray covers BGAs and bottom-terminated components where the joint simply is not visible to a camera or a person. Higher-class work gets tighter thresholds and heavier documentation – not just more looking.
On defense work under our CAGE code 9VP58, the class usually arrives with the technical data package and is not negotiable. First article inspection then proves we hit it before a production run starts, and our ISO 9001:2015 and IATF 16949:2016 systems carry the traceability behind it.
What to watch for
- Specifying Class 3 by default. It feels like the safe answer and it is frequently the wrong one. Class 3 raises cost through tighter accept criteria, more rework, more inspection, and more documentation. If the product is a shop-floor controller, you are buying aerospace rigor without getting a reliability benefit that matters to your end user.
- Specifying Class 2 on hardware headed into a harsh environment. The same mistake in the other direction, and the more expensive one – because you find out in the field.
- Mixing classes without saying so. A mostly Class 2 assembly with Class 3 criteria on specific connections is legitimate and common. It just has to be written down, joint by joint, not implied in a phone call.
- Citing no revision. “IPC-A-610” with no letter leaves both sides guessing. Name the class and the revision.
- Assuming the class covers everything. IPC-A-610 is a visual acceptability standard. It does not specify functional test, conformal coating thickness, environmental screening, or cleanliness limits. Those need their own call-outs.
The point of the exercise
Specifying a class is how two parties agree on what “good” looks like before the first board is built. When it is right, the accept-reject conversation happens once, on paper, at quote – instead of six weeks later over a tray of rejected assemblies that both sides believed they had specified correctly.
If you are not sure which class your product should carry, that is a conversation worth having before you release the drawing. We do it with customers most weeks, and it takes about fifteen minutes.
Not sure whether your assembly should be built to Class 2 or Class 3?
Send us your package (drawings, BOM, Gerbers, notes) and we will review the class call-out as part of the quote. Our team returns quote estimates within 24 hours, and if the class is missing or looks mismatched to the application, we will flag it before you commit.
IPS Assembly Corp. | 12077 Merriman Road, Livonia, MI 48150 | (734) 391-0080 | info@ipsassembly.com
