Communication between suppliers or vendors and their customers often entails a mix of specifications and requirements. Customers set requirements and suppliers offer specifications. When they match, or when a supplier component specifications meet the customer’s requirements, we have the potential for a transaction.

Most products on the market include materials, components, or subassemblies from other organizations. The product development team conceives of a product concept then organizes the necessary elements to create a product. Many of those elements are purchased.

Elements may be standard items, like bolts or capacitors, essentially bought off the shelf. Some elements are custom-made. Custom elements may include drawings and extensive documented requirements. Examples of custom elements of a product include printed circuit boards and molded enclosure parts.

RELIABILITY REQUIREMENTS

The reliability requirements are the goal statement for the element. If a cell phone has a system goal of 95% reliable over 5 years, then the main circuit board within the phone may have a reliability goal of 99% reliable over 5 years. The development team may refine the environmental and use conditions specific for the element, in this case a circuit board, to fully describe the reliability requirements.

Just as when setting a reliability goal the apportioned goal for purchased elements requires four elements: function, environment, duration, and probability.

• Function is often detailed in a requirements document.
• Environment involves use conditions and profile details.
• Duration is the length of time or number of cycles.
• Probability specifies the likelihood of successfully functioning over the duration.

Specific requirements for purchased elements of a product provide the supplier with the necessary information to provide or craft an element of the product that enables the system to meet reliability goals. If the supplier does not know the reliability requirements, it will attempt to provide a part that meets the stated requirements only. In such cases, the reliability performance will be uncertain.

Generally, suppliers desire to provide components that last longer than the product’s expected duration of use. Suppliers do not want to field customer complaints that their element of a product is causing premature or early failures. The more information the supplier has about the product and reliability goals, the more likely the supplier can provide a solution.

Bio:

Fred Schenkelberg is an experienced reliability engineering and management consultant with his firm FMS Reliability. His passion is working with teams to create cost-effective reliability programs that solve problems, create durable and reliable products, increase customer satisfaction, and reduce warranty costs. If you enjoyed this articles consider subscribing to the ongoing series at Accendo Reliability.