In a previous article I described why and how a factory’s quality system can be audited. However, if you want to confirm a factory’s reliability with high certainly, you might have to dig deeper.
A quality audit will only focus on the quality systems. And chances are, the auditor is not familiar with the factory’s production processes, so he won’t look at the process controls that really matter. I wrote about it in this article before.
The key here is to evaluate the maturity of the systems and processes of the factory. This is a bit advanced for most companies that buy from China, but it is relevant for many technical/industrial purchases.
Here are a few elements that are generally skipped during traditional quality audits.
- Is there a system to ensure employees have the right competencies for their jobs?
- Is there a plan to develop competencies? Does it make sense?
- Are the goals & objectives cascaded down to each employee so they know what is important in their job? Do they make sense?
- Are performance evaluations based on those goals & objectives?
New Product Introduction (NPI)
- Is there a formal process for NPI?
- Documents: is a process flow developed? A FMEA? A control plan? Are they real working documents or just “for show”?
- Are critical to quality (CTQ) characteristics of the product highlighted and addressed appropriately?
- Are control methods (including equipment and sampling size) defined?
- Is there a verification that the production equipment is ready to produce the new product (e.g. first sample sign off)?
- Is there a pilot run before the first large production batch? If so, is a process capability study conducted?
- Do the production manager’s targets include “number/proportion of good quality pieces”, or just “number of pieces”?
- Is someone clearly responsible for cost in each workshop?
- Is someone clearly responsible for quality in each workshop?
- Is someone clearly responsible for timing in each workshop?
- Are quality and productivity metrics visible to every one? Can local managers see the right information early enough to take appropriate measures?
Continuous Improvement (CI)
- Is a problem solving methodology defined? Are employees trained in that methodology in an adequate manner?
- Does the whole CI system seem effective (the normal way of doing business), or is it “for show”?
- Are root causes addressed, with a focus on systems and processes?
- Are countermeasures appropriate (e.g. not “retrain operator”) and really validated over time?
- Are the internal defect rate and the customer defect rate tracked, and are they the basis of improvement initiatives?
- A plan guides the maintenance of all tools, production equipment, jigs and fixtures, and test equipment, and it is revised in function of issues found on the shop floor.
- Predictive models guide the re-ordering and the replacement of certain tools.
- Production operators are trained to take care of their equipment.
Process Controls and Mistake Proofing
- Human operations are mistake-proofed as appropriate, with a particular focus on CTQ characteristics.
- Mistake proofing devices/systems are controlled by the maintenance plan.
- Where mistake proofing has been impossible so far, operators are given checklists.
- Special procedures are in place to guide restart of production.
- Process parameters of machinery are documented and a procedure needs to be followed if they are to be modified.
- Process capability (e.g. Cp or Cpk index) is monitored and is adequate (e.g. at least 1.33 for CTQ characteristics).
- Measurement systems are calibrated and validated statistically (e.g. gages R&R).
In addition to the generic checkpoints that apply to virtually every manufacturing facility, an auditor with the right technical experience can check what really matters to the main processes. For example, for rubber molding, our process audit checklist includes the following points:
- Technical capability of making the intended product
- Setup procedures
- Process parameters
- Cycling parameters
- Compression mold process parameters
- Transfer mold process parameters
- Silicone rubber extrusion
- Liquid injection molded silicone (LIM) / liquid silicone rubber (LSR) molding
- Two shot molding (overmolding)
- Material control
- Rubber delivery
- Material processing
- Tool/die storage
- Tool design & manufacturing capabilities
This list is far from exhaustive and you probably need to customize it to your needs. If on-time delivery is quite important, for example, you need to look into supply chain systems (production planning, purchasing, and inventory control).
As I wrote above, this is a bit too advanced for most purchasers. If you buy USB drives that are given away a promotions, this won’t be relevant. If you are in the oil & gas industry, or the medical device industry, you probably need to do some of this. And if you are in an OEM automotive supply chain, you already know this inside out…