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MSA Location Variation

Gage R&R, Torque Wrence

Question

Is it acceptable to use traceable standards (VLSI, NIST, etc.) to complete stability, bias and linearity studies if these standards cover the operating range of the gage? For stability and bias, the AIAG MSA 4th edition (p. 85, p. 87) states, “Obtain a sample and establish its reference value(s) relative to a traceable standard…” For linearity, the AIAG MSA 4th edition (p. 96) states, “select g>= 5 parts whose measurements, due to process variation, cover the operating range of the gage.” Specifically for designating a master sample (from production) to assess stability, we have an issue with degredation or oxide growth on the master sample that introduces known variation in thickness measurements. In this case, would it be justifiable to use VLSI standards to assess stability over time? Thanks for your help and guidance!

Answer

The quick answer is “that depends”.

The purpose of measurement systems studies is to evaluate the entire measurement system which includes the equipment, method, appraiser and the within part variability. The problem with using standards is that they are too good in that their reference value will usually be on an incremental value / discrimination point and not between points which require either truncation or rounding. Using standards can end up with average ranges of zero which is interpreted that the measurement system does not sufficient discrimination for the task.

Consequently I am disinclined to support the use of standards in measurement system studies.

However, it appears that this question is motivated by the need to look at the stability of the measurement system and actual parts will degrade over time. In this case we are not interested in the common cause variation but the existence / occurrence of a special cause. If the measurement system shows itself to be acceptable using normal parts then the stability of the system can be monitored using standards (at least 2 at the limits, preferably 3 with one in the middle).

If a bias studies on the standards have the overall range of 0 then ANY reading in a stability study using these standards other than the reference value indicates that the measurement system has changed.

If a bias studies on the standards does not have zero variability then things get a little tricky. Statistical control limits will probably not work unless this variability is not small (then the question become understanding why). You may have to resort to using the “precision” limits provided by the equipment manufacturer. Remember the objective is to be able to identify whether something changed (a special cause is affecting) the measurement system.

Greg

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AS9100C

Airplane, aerospace, AS9100

Question:

Question: AS9100C, which is an expansion of the ISO 9001:2008, states that a “process” based system is being promoted as is shown in 0.2 of the Introduction. Why are 3rd party auditors being required to use the AS9101 Quality Management Systems Audit Requirements for Aviation, Space and Defense Organizations checklists for their audits? These check lists are not “process” based and go back to the old procedure systems of the 1994 standard.

Each of our core processes consists of a flow chart of the process, process turtle and PEAR. If you were doing a true process audit you would take these documents and perform the audit and not limit the auditor to being “boxed in” by a check list. If the QMS has been developed correctly the process approach audit will allow you to cross other processes when being performed.

Response:

Thanks for the question. The IAQG AS9101 team does firmly believe in promoting the process approach which you will see reflected with the next AS9101 revision. I agree that auditors should follow the process while performing all auditing (including 3rd party audits), yet it is also important to ensure that all the AS9100 requirements are satisfied. That is why AS9100 auditors are trained to audit the process and then complete the Objective Evidence Record to ensure all AS9100 requirements are fulfilled.

Thanks,
Buddy Cressionnie
Americas 9100 Lead

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Using A3: Toyota’s Process Improvement Tool

Q: I’m interested in obtaining more information about A3, a process improvement tool created by Toyota. Do you have any resources that explain the ways to use A3 or offer a template?

A: Thank you for contacting ASQ. The Learn About Quality portion of ASQ’s website hosts a helpful A3 Report page, which will certainly be helpful to you.

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ASQ’s Research Librarian

QMS Documentation Management

About ASQ's Ask the Standards Expert program and blog

Q: I was wondering if ASQ has any good information on managing QMS documentation. My company is working right now on finding a solution for a better way to manage QMS documentation. We have previewed some QMS document management software but think we can do all of the programming in house with Microsoft SharePoint. If you have any suggestions I would love to hear them.

A: Thank you for contacting ASQ. According to The Quality Improvement Glossary by Donald L. Siebels, a quality management system is “a formalized system that documents the structure, responsibilities, and procedures required to achieve effective customer satisfaction levels”.

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Six Sigma Standard

DMAIC process

Q: How are the new ISO 13053-1:2011 Quantitative methods in process improvement – Six Sigma – Part 1: DMAIC methodology, and ISO 13053-2:2011 Quantitative methods in process improvement – Six Sigma – Part 2: Tools and techniques standards to be used?

Is it for certifying Green and Black Belts, or what? Are there plans for “registering companies” to the standard? Thanks in advance for your response.

A: The scope of ISO 13053-1:2011 is to “recommend the preferred or best practice for each of the stages of the DMAIC methodology used during the execution of a Six Sigma project. It also recommends how Six Sigma projects should be managed and the roles of personnel involved in such projects. It is applicable to organizations using manufacturing processes as well as service and transactional processes.”

Similarly, the scope of ISO 13053-2:2011 is to “describe the tools and techniques to be used at each phase in the DMAIC approach illustrating them through fact sheets.”

There is no plan at this point to develop documents that have for intent, or scope, to certify Six Sigma Belts or to register companies to the standard.

Michele Boulanger
U.S. TAG to ISO/TC 69 Chair, SC7 Expert

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Delta Triangle

Manufacturing, inspection, exclusions

Question

When revising drawings to include the delta triangle in the title block, does the drawing index sheet also contain the triangle in the title block?

Answer

The term “delta” refers to a triangle placed on the drawing for reference. The triangle is commonly placed next to a dimension, such as 2.65, 5, or other locations where it applies to a feature or item. This is used to refer the reader to a general note that relates to this item.

So if the delta triangle is used as a reference in your main title block, then I would say yes, add it to the index sheet if it makes the reference more clear.

In addition to drawing a reader’s attention to notes, the delta triangle is also quite often used with print revisions. For example, if a drawing was a revision 2, and then a new revision is generated. It might say something simple like, Rev. 3- 2.235 dimension changed to 2.240. Then a delta triangle with the number 3 in it would be next to the 2.240 dimension referring to the revision.

Bud Salsbury
ASQ Senior Member, CQT, CQI

ANSI/ASQC C1-1996 Supplier Testing

Schedule, calendar, timeline

Q: I need clarification on the following, please:

ANSI/ASQC C1-1996 — Specification of General Requirements for a Quality Program — has been included in the required specifications from a prospective customer. Section 3.3.4 states (in the last sentence) “Furthermore, the validity of certifications shall be periodically verified by the buyer through independent testing.”

What criteria (time-frame, suppliers, mills, etc.) should be used to comply with “periodically?”

What testing is to be performed for the required independent testing? Is it to be only a chemical analysis, or are mechanical tests to be performed as well?

Does this standard require independent testing of materials in purchased components such as gaskets, glass, bolts and fittings, or is “raw materials” only meant to be the base materials such as plate and sheet steel that we purchase?

A: To begin with, most establishments, including your customer, already know that materials most often come with material test certificates. For example, when you order a sheet of steel from EMJ Metals or another supplier, they will supply a test certificate along with it.

The certificates include that data which would be most important to your customer such as chemical analysis, mechanical properties, ASTM specifications, etc. You are probably already aware of all this.

As for “periodic” and “independent” testing, here is my opinion:

If you have, in writing, a document stating that all purchased materials will be subject to receiving inspection and such inspections will verify that customer requirements have been met, that will be step 1.

For step 2, if you go to the web site of almost any materials supplier, they will have documentation (quality manual, ISO certification, etc.) which you can use as evidence they are a qualified supplier.

You can then contact that supplier and ask if they will verify, in writing, that they also test the material they are sending. Steel suppliers, like most material suppliers, sell what they receive from the original mills. The material certs they provide to you are made of tests the mills run. A company such as EMJ, which I mentioned earlier, uses what is called a Niton tester to verify chemical make up of the product which they buy and in turn sell to their customers.

Finally, step 3: as with any quality management system, you must “do what you say you do.” So, if you say that part of your receiving inspection includes hardness testing, be ready to provide evidence of that (incoming inspection reports).

In closing, I feel confident that if you prepare the steps noted above, or something similar and communicate this to your potential customer, they will be doubly satisfied with your company. Doubly because all of this would display evidence of an organization with a mature QMS.

Bud Salsbury,
ASQ Senior Member, CQT,CQI

For more on this topic, please visit ASQ’s website.