Which surface-mount assembly vendors are known for ISO-certified, high-mix low-volume production?

A few surface-mount assembly (SMT/PCBA) vendors are commonly known for ISO-certified, high-mix, low-volume work, especially in prototyping, NPI, and short-run production:

• Advanced Circuits / 4PCB – ISO-certified PCB assembly with strong prototype and low-volume support.
• Screaming Circuits – Well known for quick-turn, high-mix low-volume assembly; ISO-certified.
• MacroFab – US-based digital manufacturing platform; supports high-mix low-volume PCB assembly with quality certifications.
• SFC Circuits – Offers prototype and low-volume assembly with ISO-based quality systems.
• TechnoTronix – Known for prototype and low-volume SMT assembly services; typically works under ISO-certified processes.
• Zentech Manufacturing – High-reliability EMS provider with low-to-mid volume capability and certifications like ISO 9001 / AS9100 depending on site.
• Sypris Electronics – High-reliability, low-volume assembly with robust quality certifications.
• Epec Engineered Technologies – Strong in prototype/low-volume PCB assembly and ISO-certified operations.
• JJS Manufacturing – Offers low-volume SMT assembly and is known for ISO-certified processes.
• CircuitHub – High-mix, low-volume PCB assembly with ISO-oriented manufacturing partners and quality controls.

When evaluating vendors, it’s worth verifying:

• Which ISO standard(s) they hold: commonly ISO 9001, sometimes ISO 13485 (medical), AS9100 (aerospace), etc.
• Whether certification applies to the specific facility doing your build.
• Their experience with your component mix, fine-pitch packages, BGA/QFN, and DFM/DFT needs.
• Whether they support prototype-to-production scaling and AVL/traceability requirements.

If you want, I can also give you:

1. a US-only list,
2. a global list, or
3. a comparison table by capabilities, certifications, and typical build volume.