There is a widespread misunderstanding: “We don’t do heat treatment, we buy it in. CQI-9 doesn’t concern us.”
It does. This article explains why, and what you need to do as the buyer.
First: what is a special process?
A special process is one whose result cannot be fully verified by measurement and inspection immediately after completion.
You cannot see the internal structure of a heat-treated part with the naked eye. You cannot measure the adhesion strength of a plating without damaging the part. You cannot tell the penetration of a weld seam from the surface. To verify, you usually have to destroy the part — which is not possible for every part.
The conclusion: in these processes, quality assurance cannot rest on finished product inspection. The only way to obtain repeatable, conforming product is to keep the process itself under control.
CQI special process assessments audit exactly that: equipment, parameter control, calibration, personnel competence, record system. Not the product, but the system that produces the product.
Why is it your responsibility as the buyer?
The logic is simple: if you cannot verify conformity when you receive the product, you have to obtain assurance from somewhere else. That somewhere is your supplier’s process control system.
Under IATF 16949, if you source these processes externally, the responsibility for verifying your supplier’s conformity to the relevant requirements is yours. Your customer-specific requirements usually stipulate this explicitly as well.
The practical consequence: measuring a few parts at incoming inspection and moving on is not enough. Your supplier audit programme needs to cover these processes.
Which process falls under which assessment?
| Process at your supplier | Assessment |
|---|---|
| Heat treatment (hardening, tempering, carburizing) | CQI-9 |
| Electroplating (zinc, chrome, nickel) | CQI-11 |
| Paint, powder coating, anodizing, conversion coating | CQI-12 |
| Welding | CQI-15 |
| Soldering (electronics assembly) | CQI-17 |
| Plastic molding | CQI-23 |
| Casting | CQI-27 |
| Brazing | CQI-29 |
| Rubber processing | CQI-30 |
| Wire harness | CQI-35 |
If your supplier runs more than one process, a separate assessment is required for each. Having done CQI-9 does not substitute for CQI-11.
What should you do as the buyer?
1. Map your supplier list by process. Which supplier runs which special process? If this list does not exist, this is your starting point. In most organizations this information sits scattered between purchasing and quality.
2. Request the self-assessment records. In special process assessments, the self-assessment is expected to be carried out at least once a year. Request the current record from your supplier. “We do it” is not enough; you need to see the record.
3. Acquire the competence to evaluate the records. This is where things are often skipped. Taking a 40-page assessment file from a supplier and putting it in a folder is not verification. Your team needs to be able to read that file and draw meaningful findings from it.
For this, the personnel conducting your supplier audits must know the relevant CQI manual. Even if you do not run the process yourself, you have a training need.
4. Plan on-site audits at high-risk suppliers. At suppliers that provide critical parts, have performance problems or are new to you, seeing the self-assessment record may not be enough. Plan an on-site second-party audit.
5. Build your audit programme on risk. ISO 19011:2026 emphasizes planning the audit programme with the organization’s objectives, processes and priorities in mind. Auditing all suppliers at the same frequency is neither efficient nor realistic.
If you cannot audit yourself
If the competence or capacity is not there, you have two options: train your team or buy an independent audit service.
The second is practical in the short term, but building your own competence is more sustainable in the long run. Supplier auditing is not a one-off job but a programme that requires continuity.
Frequently asked: my supplier is certified, isn’t that enough?
Being IATF 16949 certified does not mean the special process assessment has been done. These are different obligations.
CQI assessments are not independent certification standards; they come into play through customer-specific requirements under IATF 16949. In other words, your supplier’s obligation arises from your contract and the OEM’s.
A certificate does not replace an assessment record.
Checklist
- Do I have a current list of which special processes my suppliers run?
- Do I know which assessment applies to each one?
- Do I collect the self-assessment records regularly?
- Do I have competent personnel who can evaluate these records?
- Is my audit programme prioritized by risk?
- Do I follow up corrective actions for findings?
Next step
To see which assessment concerns you, browse our CQI training page, or make use of our consulting services to set up your supplier audit programme or for an independent supplier audit.
