- IPC defines three product classes. The higher the class, the tighter the acceptance criteria.
- You, the customer, choose the class and state it in your procurement documents. The manufacturer builds and inspects to it.
- IPC-A-610 sets acceptance criteria for the finished assembly, J-STD-001 covers soldering processes and materials, and IPC-6012 covers the bare board.
- Rev J is current for both IPC-A-610 and J-STD-001 (released March 2024). Name the revision explicitly.
- Class 3 is for products that can't be allowed to fail, and it usually costs more. Design for it from the start if you'll need it.
The three IPC classes
| Class | IPC name | Intent | Typical products |
|---|---|---|---|
| Class 1 | General electronic products | The main requirement is that the assembly functions | Consumer goods and other products where cosmetic flaws are acceptable |
| Class 2 | Dedicated service electronic products | Continued performance and extended life; uninterrupted service desired but not critical | Communications equipment, business and industrial electronics, instruments |
| Class 3 | High performance / harsh environment electronic products | Continued high performance or performance on demand; downtime can't be tolerated and the environment may be harsh | Aerospace, defense, life-critical medical, and other critical systems |
Who decides the class
The customer (the team that owns the product design) decides the class and states it in the procurement documents: the drawing, the purchase order or both. The manufacturer builds and inspects to that class. A good contract manufacturer will flag design features that make a requested class hard to achieve, but the requirement itself is yours.
The bare board and the assembly are specified separately, so a program can, for example, buy Class 3 bare boards and accept the assembly to Class 2. Make each callout explicit.
How the standards fit together
| Standard | What it covers |
|---|---|
| IPC-A-610 | Acceptability of electronic assemblies: the criteria for judging the finished assembly. It contains no manufacturing process requirements. |
| J-STD-001 | Requirements for soldered electrical and electronic assemblies: materials, methods and acceptance criteria, based on process control. IPC describes it as the industry-consensus standard for soldering processes and materials. |
| IPC-6012 / IPC-A-600 | The bare printed board: qualification and performance (IPC-6012) and visual acceptability (IPC-A-600). IPC-A-610 assumes the bare board already meets these. |
| IPC-7711/7721 | Rework, modification and repair of electronic assemblies. |
| IPC/WHMA-A-620 | Cable and wire harness assemblies. |
IPC-A-610 sets binding acceptance criteria but doesn't prescribe inspection methods or sampling rates. Those are set by the manufacturer's quality system and your contract.
IPC released Revision J of both IPC-A-610 and J-STD-001 together in March 2024; the previous J-STD-001 revision, Rev H, dates from September 2020. A new revision doesn't automatically replace the one in your contract, so the contract decides which applies. Where both standards are invoked, keep their revision letters matched.
What changes in Class 3
Class 3 tightens acceptance criteria across the assembly. Areas engineers most often run into include:
- Solder fill and fillet requirements on through-hole joints
- Allowable component misalignment and overhang on pads
- Solder joint wetting and appearance criteria
- Conditions that are acceptable or only a process indicator at Class 2 but count as defects at Class 3
The exact limits are in IPC-A-610J and J-STD-001J. They're copyrighted, specific to each revision and class, and they change between revisions, so we don't paraphrase them here. During DFM review we'll walk through the criteria that actually matter for your board.
Building to Class 3? Have us check your layout against the Class 3 criteria before the first build.
Schedule a DFM review →Cost, yield and schedule
No standard puts a number on the Class 3 premium; it depends on the design. The drivers are predictable, though: tighter criteria mean more joints and boards fail acceptance and need rework or scrapping, inspection takes longer, and some layouts simply can't meet Class 3 limits without a design change.
The cheapest Class 3 board is the one designed for Class 3 from the start: pads, holes and spacing chosen with the tighter criteria in mind, and the class stated before the first build instead of discovered at inspection.
When you need Class 3
- Your contract or customer requires it. Aerospace, defense and life-critical medical programs commonly do.
- Failure is unacceptable or the environment is harsh: vibration, thermal cycling or long unattended service life.
- Automotive programs that invoke IPC's automotive addendum (J-STD-001JA / IPC-A-610JA). Wherever the addendum doesn't add its own criteria, the Class 3 requirements apply. It applies only when the procurement documents call for it.
If none of these apply, Class 2 is usually the right, more economical choice.
How to call it out
State the standard, the revision and the class in one unambiguous line on the drawing or purchase order. For example:
Assemble and inspect per IPC-A-610, Revision J, Class 3.
- Name the revision. "Latest revision" leaves room for disagreement mid-program.
- Specify the bare board separately (for example, IPC-6012, with its own class).
- Set an order of precedence so it's clear which document wins if the drawing and a standard conflict.
- If your program also invokes J-STD-001, call out the same revision letter for both standards.
Surface Art builds to IPC-A-610 under an ISO 9001:2015 quality system, with ISO 13485 for medical programs and ITAR registration for defense work.
Put your class on the RFQ. Our engineers will flag Class 3 design risks during DFM review, before they turn into rework.
Sources
- IPC, "IPC releases J revisions of two leading standards for electronics assembly" (April 2024). electronics.org
- IPC, J-STD-001JA / IPC-A-610JA Automotive Addendum, table of contents and scope preview. en-standard.eu (PDF)
- Leo Lambert, "IPC specifications and the order of precedence," I-Connect007 (2013). iconnect007.com
- IPC-A-610J, Acceptability of Electronic Assemblies, and J-STD-001J, Requirements for Soldered Electrical and Electronic Assemblies (IPC, 2024). Available from IPC.