How quality engineering on manufactured product in China can help with Root Cause Analysis and solution establishment

Some people have different approach of quality management issue as I explained it in this post here.

I remember a client telling me : “We have tried to solve this problem by contracting with a big inspection company who sent an inspector to solve our quality issue. We got a report from him telling that to solve the problem the supplier has to train better the worker on the line”. When I got appointed by the same client, I went on site and find out the problem was not coming from the manufacturing process but from design. The engineering had been sub-contracted to a company who didn’t perform design and engineering enough well.

I am time to time servicing some importers who face the following problematic “I receive defective products constantly on my Asian production, my supplier tell me he will improve, but I keep receiving defective goods in a random manner. I am tired of constantly performing Defectives Product Sorting on each shipment I do, it cost me a lot of money and still the problem remains unsolved”.

There are some buyers who understand that quality issue can damage their brand image very heavily and reduce their sales drastically. This is particularly true today when information is circulating very quickly and transparently on the Internet. A few bad reviews on Amazon or any other blogs, and your sales may be affected.

Buyers and importers who understand this point are most of time willing to invest time and money to make sure quality issue on their products doesn’t happen again anymore. They want those problems to be solved on the long term. It particularly means, they want their manufacturing process to be reliable, repeatable and under control. They want to eradicate risk of defective by any mean. They want problem to be identified, root cause analyzed, patch solution to those cause to be provided and deployed efficiently so they can sleep better not fearing to receive again and again complaints and claims from customers in a random manner the same way they don’t know when thunder will shock them.

For those customers who want to implement a corrective and preventive approach related to quality issue by performing root cause analysis of their quality problem, a quality engineer having an experience with manufacturing, engineering and design background can be appointed.

What I usually propose them is to act like a good doctor curing a patient:

1. Identify what is the real cause of the problem is by observing and analyzing.
2. Supply a medicine acting as the solution or the patch to make those problems not happening ANYMORE EVER !
3. Make a quick follow up to make sure the patient (the supplier) is cured.

The goal here is not just to check if there are problem or not like what most of inspection companies do, but to really find out what generate those quality problems and to fix them once for all and for the long term.

Quite often, those missions are articulated in a way where a deep work has to be done in cooperation with suppliers themselves. It may happen that some suppliers are reluctant to get a third party to assist them to solve related quality related. There are several reasons for it:

• They may estimate they can solve those problems themselves and it hurt their ego to have someone coming to help them to solve an issue they should be able to solve by themselves
• They don’t want we discover they actually don’t perform the engineering or part of the manufacturing themselves (to perform root cause analysis a clear transparency along all the supply chain is needed: sometimes I need to analyze material specs sheet, electrical schematics, PCB layout, procurement source, plastic press parameters etc…so if no transparency is possible, it would create some complications to understand the cause of related problems)

In any case, the consultant has to be able to use a minimum of diplomacy to make sure the supplier don’t get his ego to be hurt and is willing to open and to be transparent. For this, I have my own techniques which works 99% of the time: show them how they can benefit from this help we bring to them.

To be able to identify properly the causes which generate defectives, it is absolutely necessary to have a very broad and wide view and understanding of the supply, design, manufacturing and logistics chain. Quality issue causes may comes from either one of this phase or from several of them, in some case they may even interact one on the other. Analytics, skills, methodology and cultural knowledge is the key to success on this kind of mission.

A good understanding of technical and engineering standpoint, manufacturing process, local cultural mindset allow to identify root cause, and to propose solutions to solve and patch those root causes. A good common sense is also very important. Regarding methodology and problem approach, a Lean Manufacturing and a Six Sigma approach will help to identify root cause by deploying 5 Whys methodology, Fish Bone Diagram, 7 Basic Quality Tools.

There is a long list of root cause which are usually listed as Man, Machine, Method, Environment, Material, Management. It is good to consider them in a general aspect, yet here is a short list (non exhaustive) of what I see and where most root causes related to quality on physical goods manufacturing may appear in China:

• DESIGN & CONCEPTION ISSUES
  • Wrong material choice for parts (e.g not capable to handle temperature, stress etc…)
  • Wrong choice of mechanical assembly or wrong placement in a design (e.g tolerances ignorance…)
  • Wrong understanding of certifications constraints (e.g misinterpreting a standard requirement involving wrong design…)
  • Wrong choice in system architecture (e.g not allowing maintenance…)
  • Not enough simulations performed to test reliability of systems

• PROCUREMENT ISSUES
  • Cost killing by swapping material or component to save cost (e.g sometimes the real cause is that the sub supplier has to pay an envelope to the buyer of the assembler to get the deal, hence its margin his reduce so he has to substitute material in order to still stay afloat on his order)
  • Lack of control on the supply chain to verify what sub suppliers make on their production (e.g lack of curiosity to understand how the sub supplier perform its own quality assurance process..)

• MANUFACTURING ISSUES
  • Wrong assembly process (e.g assembly not being made in the proper order generating defects…)
  • Lack or wrong of training on the workers (e.g no standardized process for training + high turn over making that workers are not trained…)
  • Lack of common sense or organization (e.g no fixture used to make a process to be repeatable and reliable…)
  • Lack of documentation or improperly used (e.g documentation unreadable, not visible on site, …)
  • Lack of process control (e.g no procedure being implemented to control a critical process, no qc checklist, no performance record)
  • Lack of maintenance on equipments

• LOGISTIC ISSUES
  • Packaging issue (e.g packaging design is not adapted to transportation constraints)
  • Loading issue (e.g container improperly loaded generating defects)

This is a very short and partial list, but it covers a wide range of problems generating root cause quality issue.

Have you experienced any quality issue which you didn’t success to solve or which constantly come back on your productions? If yes, please share them, I am curious.

This article was written by Christopher Oliva, Msc Electrical Engineering & Ms Business Administration, ISO 9001 Lead Auditor, Certified Quality Engineer (CQE) and Six Sigma Green Belet living between France and China (Shenzhen) since 2008 involved in product development and manafacturing of hardware products.

Christopher act as a consultant for a quality inspection company and a product development & supply chain management company. He regularly shares his experience of product development, manufacturing and procurement in China on his blog : https://quality-manufacturing.org