Acceptance sampling isn’t scary

As it turns out, a significant number of people find the Pro QC site searching for sampling and sampling related terms such as ANSI Z1.4 or MIL-STD-105E  (no longer in use).  In speaking with organizations, I’ve also detected a certain level of fear regarding how to approach an acceptance sampling strategy.

Fear is unnecessary… In fact, sampling here is nothing more than a tool you’re going to use to provide a realistic (of course statistically relevant) assessment of quality and be able to ultimately determine whether or not product is meeting expectations without having to spend the time and money involved with a 100% inspection.  This is a good thing.

Some advice…

Get your specs straight – Before you even start to think about AQLs and defect classifications, go back and make sure you’ve really evaluated your product and have created detailed product specifications.  Once you have this information, go through each item and determine how you want to classify nonconformance (major, minor or critical).  At Pro QC, we use the following general guideline for defect classifications:

  • Critical – Any condition found which poses the possibility of causing injury or harm to, or otherwise endangering the life or safety of, the end user of the product or others in the immediate vicinity of its use.
  • Major – Any condition found adversely affecting the product’s marketability and sale-ability or adversely affecting its required form, fit or function and which is likely to result in the end user returning it to the source from which is was purchased for refund or replacement.
  • Minor – Any condition found which while possibly less than desirable to the end user of the product, does not adversely affect its marketability, sale-ability, form, fit or function and is unlikely to result in its return to the source from which is was purchased.

Special or General? – The ANSI Z1.4 tables show various sample sizes based on lot (batch)  sizes in relation to Special and General levels. Here, you’ll want to go through your spec and determine what would require higher levels (general) of sampling or lower (special).  For example, if you have an electronic product that requires functional testing (need to make sure it turns on maybe), special levels of testing makes sense because it may be considered destructive.  The same goes for drop-testing to determine the packaging integrity.  Time is an obvious important consideration, as it relates to not only cost but to shipment schedules as well.  An example might look like this:

  • Visual (cosmetic/workmanship) inspection – General Level 1
  • Drop-testing (Package integrity ISTA testing) – Special Level 3
  • Functional Testing – Special Level 1

Single or Double? – Pro QC uses ANSI Z1.4 single normal sampling as a standard, but we have had clients request double.  If you look at the tables, you’ll note the difference is simply the number you look at.  So, it goes back to time and cost, but you’re also considering your level of assurance with the supplier in general.  You can look at less with double if the product meets expectations, but you’ll be taking a 2nd full sample set if not.

Know your AQLs – Acceptable Quality Limits are simply “the worst tolerable process average in percentage or ratio, that is still considered acceptable: that is, it is at an acceptable quality level.” To figure out what works best, play around with the numbers… Plug in your average lot sizes and levels and go through the row of scenarios.  What are you comfortable with?  An example might look like this:

  • Major Defects 1.5
  • Minor Defects, 4.0
  • Critical Defects 0.10

Tweak it – Sampling strategy is something that can grow and evolve with your product. As you develop supplier relationships and analyze inspection feedback, you’ll be able to make adjustments as necessary.

Utilize the experts – Of course, a 3rd party quality assurance provider such as Pro QC, can provide you with expert advice and guidance or even evaluate your product and develop the specs/sampling for you.  That both relieves apprehension and leverages expertise.

Note: International and national equivalents of the ANSI Z1.4 2003 standard exist as ISO 2859, NF06-022, BS 6001 and DIN 40080.

Supply chain management basics

I recently stumbled on a series of videos produced by Arizona State University and the W.P Carey School of Business‘ Department of Supply Chain Management (ASU-WPC-SCM) relating to the basics of SCM.  While basic in nature, the series is well organized and appears to piece together SCM quite well.  As a refresher, I think these videos are excellent idea generators.

There are twelve modules, with topics ranging from social responsibility, manufacturing & operations, logistics and metrics.  Module eleven relates to quality management and is quite succinct.

 

Aerosonic’s journey to all things lean…

An open invitation recently went out via the ASQ Tampa-St. Petersburg LinkedIn Group regarding an upcoming APICS meeting that would include a plant tour of Aerosonic Corporation.  I grew up with Aerosonic right around the corner, so I couldn’t resist the opportunity to poke around and learn more about they do.

It turns out that Aerosonic Corporation has been making “gizmos for airplanes” for over fifty years.  More specifically, their product lines include integrated cockpit displays, sensors, probes, digital and mechanical standby displays. “With its well-established industry presence, Aerosonic maintains long-standing relationships with nearly every major aircraft manufacturer worldwide.” Personally, I was impressed that one of their products, an altimeter, had over 400 parts.  I can’t even imagine how you would organize production on a custom build piece of equipment like that or what a MRP nightmare it would be!  Unlike most of the production I’ve seen, Aerosonic’s products require a great deal of customization and hands-on craftsmanship.

A few years ago, a fire left the company inoperable for about nine months.  The fire not only destroyed the facility, but it ignited a need for change… and so their lean journey began.  They got serious about making real changes and they started by focusing on what they referred to in the presentation before the tour as “wetware.”  I also learned a little about Training Within Industry (TWI) as they attributed this system with their ability to now tie goals with performance.

During the tour, you could sense that the situation before their lean aspirations was bleak.  They described an organization not unlike many small business that were started with the best of intentions but later experienced difficulties adapting to a more “corporate like” environment.  Change management would prove once again to be the most difficult component of transition.  While top management support certainly came through during the presentation and tour, employee resistance was noted as the most challenging component.

It was interesting to see an organization going through this process of change.  It’s a reminder that although being lean may be an arduous process, the results speak for themselves.  By moving to a cellular layout, communication and overall productivity has improved significantly at Aerosonic. Improving inventory management and incorporating employee ideas and suggestions for productivity improvement has contributed significant gains as well.

I want to thank the local APICS chapter for extending this invitation and Aerosonic for opening their doors and providing an honest and realistic portrayal of the lean journey in action.  They are very fortunate to have such a passionate group of individuals in top management to lead the way!

Remembering ASQ’s World Conference on Quality & Improvement

The American Society for Quality posted this to Facebook today, and I couldn’t help but reminisce my own experience at the show earlier this year.  More information from my time at the conference is noted in my blog.  The passion ASQ members have for their industries and quality in general was inspiring, and it makes me very proud to participate as a global voice for quality.  I’m hoping to see everyone again in Anaheim next year!

 

How do you select the right suppliers?

Selecting suppliers is undoubtedly one of the most challenging tasks organizations contend with.  Between finding, evaluating and selecting suppliers that will meet existing needs with room to grow doesn’t have to be an arduous process.  While requirements do vary greatly depending on industry, company size, demand, etc., the process of supplier selection can be simplified using a general road map that reduces much of the risks and cost.

So, how do you select the right suppliers?

Evaluate your needs– Where supplier selection and most other things are concerned, planning is key.  Organizations need to carefully evaluate the internal and external factors that affect the kind of supplier they need.  Not only is it a good idea for organizational strategy purposes, but potential suppliers will likely find this information useful for quoting purposes as well.  I’ve found that feedback relating to poor choices in supplier selection is mainly attributed to poor communication.  In other words, failure to meet expectations usually happens when expectations are not well defined and/or communicated to all.

Find potential suppliers using a concentrated checklist– Once you’ve figured out what you need, imagine the ideal supplier.  In fact, brainstorm all of the characteristics that this perfect supplier would have.  Then, take that list of wants and needs and concentrate it down to a handful of attributes.  If you find it difficult to narrow down, see if any of the items can be characterized into a broader category and then assign weighted values.  It’s a good idea to incorporate values regardless so analyzing the options becomes easier.  Scouting often starts with online searches using marketplaces such as Alibaba.com.  Follow-up interviews using the checklist as a guideline keeps everything in perspective.

Analyze the options– Go back and review the serious prospects.  Pick a handful that outshines the rest based on the checklists.  A grid analysis is an excellent tool for organizing information like this.  It forces you to look at the bigger picture, yet it retains the ability to see each option separate or broken down by characteristic.  At this point, a proactive approach we suggest is conducting supplier audits for the two or three choices that stand out as the best potential fit.  “An on-site audit of the facility includes an evaluation of general operations, quality systems, qualifications and capabilities of the supplier as a viable source.”   During an audit, checklist information can be verified on-site through various interviews and documentation review.

Make a decision—  When selecting suppliers, make sure you maintain perspective regarding your requirements and weights of various attributes as noted during the information gathering process.  It’s very easy to look at the bottom line and compromise on salient issues.  Trust your information.  And, be sure to follow-up with any potential prospects you didn’t select.

Develop a relationship– Developing a relationship with suppliers is critical to long-term success.  It’s difficult to find a company that disagrees with this, but much easier to find one that truly dedicates the time and resources towards accomplishing it. Documented expectations and open communication reduce the headaches associated with poor quality, missed shipments or ultimately the process of switching suppliers.  Regular follow-up is an invaluable and cost-effective way to identify potential issues early on.

Monitor performance– Ongoing evaluation of suppliers is necessary for continuous improvement.  Gathering and analyzing performance data (inspection defect information, return rates, etc.) on a regular basis, in addition to intermittent on-site audits, identifies areas of improvement and insures expectations are being met. Where necessary, corrective action can be incorporated to resolve issues prior to customer impact and possibly even before they start.

Note that as a 3rd party quality assurance provider with resources in over 30 countries, Pro QC assists clients with Vendor Identification services that includes checklist development and scouting. In addition, Pro QC’s team of quality professionals offer expertise and local knowledge you can put to use on-site, providing unbiased assessments while reducing the time and cost associated with travel and evaluation. Product InspectionsCorrective Action and Supplier Development services also complement the supplier selection process as noted in this article.