Book promotion

Document control

Product Identification and Traceability

Process control

Inspection, Testing, Calibration, and Control

Control of nonconforming product

Storage, Packaging, Handling and Delivery

Major problem areas (primary sources of ISO 9000 nonconformances)

Related pages

Statistical hypothesis testing

Gage capability

Manufacturing worker's role in quality

Concept of variation in quality and SPC

ISO 9000

excerpt from SPC Essentials and Productivity Improvement: A Manufacturing Approach
All material (C) 1996, Intersil Corporation (formerly Harris Semiconductor) or ASQC Quality Press
May not be reproduced in any form without prior permission, except as defined under "fair use"

The book includes a section on the ISO 9000 standard for quality systems. It describes ISO 9000 and some of its provisions, and explains why it is important. The goal is to promote awareness of ISO 9000 at all organizational levels, especially among frontline workers. The people who do the job every day are often in the best position to notice things that do not conform to ISO 9000. If your company is seeking or maintaining ISO 9000 registration, this section should answer your production workers' questions about the program.

ISO 9000

Anything that can go wrong, will.

-Murphy's Law 

ISO 9000 is a system for making sure that everything will go right. 

ISO 9000 is a set of international standards for quality management systems. It applies to management and process controls for assuring quality. Companies that meet these standards can receive ISO 9000 registration from accredited registrars. Many industrial customers are starting to require their suppliers to achieve ISO 9000 certification. The standards include ISO 9002, which is for production, installation, and servicing. ISO 9001 includes all the elements of ISO 9001, and adds standards for product design.

The automotive QS-9000 quality standards are extensions of the ISO 9000 standards. An organization that qualifies for QS-9000 certification also meets ISO 9000 standards. Meeting ISO 9000 standards, however, is not sufficient for QS-9000 certification.

How does ISO 9000 help us do our jobs? How does it help us deliver quality products and services consistently? ISO 9000 systematically guides an assessment of our quality management system and process controls. It helps us look at how we make the product or deliver the service. It makes us ask, "What can go wrong, and how can we change the system to prevent it from doing so?"

Some companies' goal is to "get the ISO 9000 certificate so we can do business in Europe." They view the certification process as a costly annoyance. This is an error. The systematic assessment of the quality management system can improve productivity and quality, and help the company make money (Scotto, 1996).

This section will not discuss the details of ISO 9000, but will give examples of its applications.

Documentation Control

Primitive tribes transmitted their lore orally, since no one could read or write. The "oral tradition" may have been the origin of poetry. The rhyming verses helped the storyteller or speaker remember what to say. This is not, however, how we want to run a manufacturing process. There must be written instructions and specifications to make sure that everyone does the job the same way.

Document changes are a common trouble source. Suppose that an operating instruction says to set a furnace temperature to 350 [degrees] C. A change in materials requires operation at 370 C, so the process engineer revises the operating instruction. What happens if he or she delivers the revision to the manufacturing area, but an old copy remains there? Someone may pick up the old instruction and set the oven to the wrong temperature.

ANSI/ASQC Q9002-1994's section 4.5, "Document and Data Control," requires procedures to prevent this from happening. It specifically calls for controls to "…preclude the use of invalid and/or obsolete documents" (ASQC, 1994).

  1. There must be procedures for removing obsolete documents from manufacturing areas.
    • A specific person may be responsible for replacing obsolete documents with new ones.
    • Electronic databases can assure that only the current instructions are available.
      • However, there must be a computer monitor near each workstation.
  2. Everyone who performs a job must know when the instructions change.
    • Harris Semiconductor uses a revision signoff log. After reading the new instruction, each operator signs the revision log. Other companies may have different procedures.
Product Identification and Traceability

Chapter 3 will discuss why archery was inherently superior to gunnery until the 19th century. Armies of the 15th and 16th centuries did not adopt guns because they were superior to bows, but because they were easy to use. Bows were better weapons, but it took years of training and practice to make a good archer. The 19th century saw the invention of breechloading rifles, which are easy to use and are more effective than bows.

One of the bow's advantages was traceability. The archer could watch his arrows in flight, and change his aim accordingly. If something was wrong with his bow, he would know it immediately. The archer's product- his shot- was traceable. He knew which arrows were coming from his bow, and which were coming from his neighbors'. The firearms of that era, like matchlock muskets, offered no such advantage. The bullet was invisible in flight, and provided no feedback to the gunner.

If our process is making defective product, we need to know where it is coming from. Do all the bad parts come from one workstation, or one material lot? Traceability is also a requirement for effective statistical process control (SPC). For example, each workstation should have its own control chart. To put a measurement on the right chart, we must know which workstation produced it. (This assumes that measurement or inspection happens after the part leaves the workstation.)

Process Control

Process control includes the following.

  1. Control of the working environment
    • Temperature
      • Temperature affects spin coating processes (semiconductor industry), painting, and other coating operations.
    • Humidity
    • Particulate contamination (semiconductor industry)
    • Noise and vibration
    • Electrostatic discharge (semiconductor industry)
    • Bacterial contamination (food processing, pharmaceutical industries)
  2. Control of the manufacturing process
    • Statistical process control (SPC)
    • Automatic feedback process control
  3. Preventive maintenance
    • Total Productive Maintenance (TPM) is a way to achieve this.
Inspection, Testing, Calibration, and Control

Sections 4.10 and 4.11 of ANSI/ASQC Q9002-1994 govern inspection, testing, and control of inspection and testing equipment. Section 4.12 covers the product's inspection and test status. These sections' principal goal is to make sure of the following.

  1. Products that require inspection or testing actually receive them.
    • This applies to incoming materials and outgoing product.
    • Lot travelers, lot tickets, or routings show the inspection or test status.
  2. Gages (measuring equipment) receive the necessary calibration.
    • Calibration means comparing the gage's measurement to a standard. If the measurement does not match the standard, we must adjust the gage until it does. "Reconditioning" is another word for calibration.
    • Suppose that we discover that a gage is out of calibration on April 1. It was in calibration on March 1. There is a quality exposure on every part that went through that gage between March 1 and April 1. (We don't know when the gage went out of calibration.)
    • Each gage should have a sticker that shows the date of its last calibration, and the due date for the next one.
    • Gages that do not require calibration should have stickers saying, "No calibration required." This shows that the manufacturing team is aware of the gage, and has judged that it does not need calibration.
      • This consideration applies to gages that measure product, or whose performance affects product quality. Room clocks, for example, do not require stickers.
      • Uncalibrated gages should not be present in the manufacturing area if someone could use them to measure product. It does not matter that no one plans to use these gages on product.
Calibration is similar to what police and detectives call chain of custody. Suppose a gage is in calibration on March 1, but is out of calibration on April 1. Everything that went through it between those dates is suspect. We know that it went out of calibration somewhere between those dates, but not exactly when.

Suppose that a vehicle may contain crime evidence. The police have it in their custody, but someone manages to break into it. This compromises the reliability of any evidence the police may collect from it afterward. Similarly, we cannot rely on the quality of product that went through a gage whose calibration is questionable. A lawyer does not want to give questionable evidence to a jury, and we don't want to give questionable product to a customer.

Control of Nonconforming Product

In one of C.S. Forester's Horatio Hornblower stories, an English warship receives barrels of spoiled meat. Hornblower decides to exchange the barrels for good ones, but he suspects that the supplier may sell the bad ones to another ship. If the other ship's captain is in a hurry to sail, he won't find out until it is too late. Hornblower therefore orders two midshipmen to write "CONDEMNED" on each barrel with a hot iron. This is an example of segregation of nonconforming product.

Today, few people want to use or sell nonconforming material. (The unscrupulous ones who do usually don't stay in business very long.) There is, however, a chance of doing it accidentally. Suppose our incoming inspection department discovers a problem with a batch of incoming material. They put it aside instead of releasing it to the factory, but don't mark it. Someone from the factory needs this material, and sees the package in the inspection room. They may pick it up and take it into the factory. In the production area, someone may take rejects out of a box and put them aside. If they don't mark them as rejects, someone else may pick them up and use them.

Section 4.13 of the ISO 9002 standard requires suppliers to prevent accidental use of nonconforming materials. Methods for doing this include:

  1. Rework
  2. Acceptance by the customer, perhaps at a lower price
    • Clothing manufacturers sell nonconforming garments as "seconds."
  3. Downgrading
  4. Scrap
The manufacturer must identify and segregate nonconforming items to prevent their accidental use. A bright orange "REJECTED" sticker can identify nonconforming materials or parts. A reject rack, or lockable reject cage, can hold nonconforming pieces.

Here is an example of how an electrical tester prevents bad pieces from mixing with good ones. The tester sorts the parts into bins according to the parts' electrical characteristics. Rejects go into the reject bin (Figure 2-20).

Figure 2-20. Sorting of Parts by Electrical Tester

  1. The arm's idle position is over the reject bin. If the arm stops working, it will not put everything into a bin for shippable product.
  2. The tester counts the nonconforming pieces. This count must match the quantity in the reject bin. If it doesn't, we must suspect that bad ones went into the wrong bins.
Storage, Packaging, Handling and Delivery

Readers of Tom Clancy's Red Storm Rising and Debt of Honor will be familiar with this issue. In Red Storm Rising, the Soviets transport antiaircraft missiles by ship to Iceland. Seawater (or salt spray) damages some missiles. While the Russians designed their naval missiles to resist salt water, they didn't do this for their Army missiles. In Debt of Honor, sea water damages some automobile gasoline tanks from Japan. Section 4.15 of the ISO 9002 standard would have been helpful in these situations.

Is the product perishable? Does it have a shelf life? Is it vulnerable to damage by heat, shock, or electrostatic discharge? Here are some practices for addressing these issues.

  • Semiconductor and microelectronic products require special packaging to protect them from electrostatic discharge (ESD).
  • The factory must use materials before their expiration dates.
    • Foods in supermarkets often have "sell by" dates.
    • Recall the option of selling nonconforming pieces at a lower price. Supermarkets often drop the price of fish on the expiration date.
    • Nonprescription drugs also have expiration dates.
  • Some chemicals require refrigeration, or must not exceed certain temperatures.
    • There are temperature-sensitive stickers for application to packages. The sticker undergoes a permanent color change if the temperature exceeds the specification.
    • Does the supermarket's refrigerator shelf keep the items in front as cold as the items in back? One of the authors usually selects items from behind the front row.
  • Is the product sensitive to shock? Will violating the "this side up" instruction damage it?
    • There are tipping indicators that show whether a package has been mishandled.
Other Provisions

Other sections of the ISO 9002 standard include the following.

  1. Management responsibility (Section 4.1)
    • Management is responsible for developing and implementing a quality policy.
  2. Quality system (Section 4.2)
    • The factory's quality manual provides the basic requirements for the quality system.
    • All work instructions and specifications must support, or conform to, the quality manual.
  3. Review of contracts, e.g. with suppliers or subcontractors (Section 4.3)
  4. Control of product design (ANSI/ASQC Q9001-1994, Section 4.4)
    • This is part of ISO 9001, but not ISO 9002. Manufacturers that do not design products don't have to worry about this section.
  5. Assurance that purchases from suppliers meet specifications (Section 4.6)
  6. Control of products supplied by the customer (Section 4.7)
  7. Control and retention of quality records (Section 4.16)
  8. Internal quality audits (Section 4.17)
    • The organization audits its own activities to make sure they follow ISO 9000 requirements.
  9. Training (Section 4.18)
    • The organization makes sure that people have the right training for their jobs.
    • Some occupations, like driving a truck or forklift, or doing electrical work, require licenses.
  10. Servicing (4.19)
  11. Statistical techniques (4.20)
Major Problem Areas

The Pareto principle applies to ISO 9000. A few program elements are the source of most of the problems. Robert M. Bakker of Entala, Inc. (Grand Rapids, MI) said that many companies that are seeking QS-9000 registration run into trouble with the following elements (Manufacturing Engineering, May 1996). (Remember that QS-9000 includes all the elements of ISO 9000.)

  1. Documentation control (element 4.5)
    • "…little yellow sticky notes with work instructions stuck to documents or machinery won't cut it."
  2. Inspection and testing (element 4.10)
  3. Control of Inspection, Measuring, and Test Equipment (element 4.11)
    • "…there's often at least one gage with no record of calibration."

The chapter's problem set includes six simple examples of factory procedures, and asks readers to decide whether they're acceptable under ISO 9000. (The material in this section equips readers to answer these questions.)

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