Reducing Errors in Manufacturing

The current economic downturn may have reduced a company’s business, but it has not reduced the requirements associated with doing business. This is particularly true for the numerous activities associated with technical data interpretation and application. For example, although the quantity of parts to be produced may be significantly less than last year, everything associated with the technical data package must still be addressed. This includes reviewing the constituent documents to determine accuracy and completeness, setting up first article inspections, generating manufacturing process plans, and so on.

In this period of reduced resources, there is even less margin for error. This means that those companies that get it right the first time have a distinct competitive advantage over those that can’t. The former are more productive, more cost-efficient, better able to meet schedules, and more valuable to their customers who are being whipsawed by rapidly changing economic conditions.

Fortunately, there are a variety of reasonably priced software tools available to greatly reduce the occurrence of errors. These tools enable the user to dramatically enhance accuracy and productivity when working with a customer’s technical requirements. These tools help to identify a part’s detailed characteristics, derive specific process requirements, generate process plans, and automate the creation of inspection plans.

Scoping the challenge

For many small and medium-sized enterprises, business starts when the customer shares the technical data package--typically comprised of CAD models, material and process specifications, and related documents--that defines the detailed requirements for its specific product The manufacturing supplier must convert the customer technical data package (TDP) into the necessary internal documentation. For example, manufacturing and quality engineers create process and inspection plans from the TDP that must address the requirements for initial production and downstream process control.

The current approach for most companies generally involves making hard copies of drawings and specifications and providing a copy to those concerned in each functional discipline. It’s not only a redundant and laborious process, it’s also a breeding ground for errors and omissions. In industries such as aerospace, automotive, and health care, overlooking product requirements has always had the potential for the devastating consequences associated with quality escapes. This issue has not gone away, but is actually amplified by the challenge of ensuring that all requirements are met during this period of limited resources. In short, if the luxury of a “do over” or extra resources to find and correct mistakes ever did exist, it is no longer with us.

Establishing a foundation

A TDP is the collection of product images and narrative documents that enable a production source to take an abstract design and convert it into a tangible product that meets performance, cost, and schedule requirements. The expanded dependence on the supply chain has driven the importance of the TDP. This has increased the need for tools to assist in the organization, interpretation, and documentation of information within the TDP.

Recognition of the importance of the TDP has grown substantially across many industries, but it has received a special focus in the aerospace industry. In November 2008, the aerospace industry published National Aerospace Standard NAS 3500--”Technical Data Package--Composition, communication, and application.” Its purpose is to “facilitate better composition, communication, and application of technical data at every level of the supply chain. For aerospace industry primes, this means less expensive deliverables… for suppliers it means enhanced efficiency and responsiveness to their customers’ requirements.”

A software tool that has emerged for TDP management is DISCUS ( www.discussoftware.com [1]), which electronically organizes and integrates all elements of the TDP, including product images (drawings and CAD models), specifications, and related narrative documents. As shown in figure 1, above, DISCUS enables the user to identify--or balloon--all responding characteristics. The software organizes requirements into a systematic bill of characteristics and shares the information using a variety of digital applications.

By bringing the entire TDP together into an easily navigable electronic format, a supplier and customer can collaboratively validate that they have a shared understanding of the design intent. This is essential in establishing an error-proof environment for getting it right the first time. A shared understanding of the customer’s expectation in relation to the supplier’s interpretation of that expectation helps to ensure product integrity, and enables efficiency at both ends of the supply chain. A TDP captured with software allows a user at any level of the supply chain to further reduce the likelihood for errors, as well as to optimize productivity throughout operations.

The bill of characteristics is one of the key components of a TDP. It is a complete list of requirements for the final product. As depicted in figure 2, below, there are a variety of downstream applications that are dependent on the TDP. By first building a structured, organized TDP, manufacturing companies can eliminate the manual, redundant transcription of information. This move is a crucial step toward error reduction.

A time-consuming, error-prone activity that is contingent on the TDP is the first article inspection (FAI) process. The FAI involves the detailed verification of 100 percent of the part characteristics on the initial production part. An Air Force- sponsored analysis of the labor efforts within the aerospace supply chain revealed that it’s not unusual for suppliers to perform 100 or more FAIs annually and devote the equivalent of one or two full-time engineers to the manual creation of FAI reports.

DISCUS for FAI seamlessly takes the characteristic-level information from the TDP to a variety of FAI formats, ranging from customer-specific formats to forms compliant to the standard AS9102--”Aerospace first article inspection requirement.” Another widely-used destination for TDP information is Net-Inspect ( www.net-inspect.com [2] ), a web-based software toolset that offers multiple ways to manage data at the characteristic level. Net-Inspect is used in the aerospace industry to provide statistical process control (SPC) insight at all levels of the supply chain. These tools have consistently increased FAI and SPC productivity by a minimum of 50 percent, and in some instances as much as 80 percent.

The magnitude of a well-defined TDP is apparent during the creation of the manufacturing process plans. Process planning is typically defined as the effort involved in generating the comprehensive set of manufacturing instructions necessary for realizing the designed product. The result of process planning is the creation of the manufacturing planning documentation. Process planning has long been recognized as a weak link in the product realization process and is a major source of inefficiency, duplicative steps, and errors. In fact, it is not unusual for manufacturing and quality engineers to spend days preparing the manufacturing planning for just one part.

There is an emerging software application to support this process that uses the information from the TDP. The primary output from DISCUS Planner is a structured and fully completed set of manufacturing planning documentation. This includes a summary routing, and the work instructions, inspection sheets, and process illustrations for each operation. In addition to these primary features, it automatically generates an operations analysis for the user to indicate a characteristic’s where-used and delta values by operation. This helps to reduce errors by ensuring that all characteristics are addressed during the specific manufacturing steps.

Within the supply chain, a study of small and medium enterprises in the aerospace and automotive industries indicated that more than 70 percent of the companies use a formalized enterprise resource planning system. A typical scenario for process planning begins when an engineer uses a complex and expensive CAD tool to analyze a part and extract pertinent details. The engineer then types notes and calculations in Excel and Word, and later uses standard desktop software tools such as PowerPoint or Paint to create manufacturing documentation. Finally, the engineer enters the necessary salient data (operations, work centers, durations, etc.) into the enterprise resource planning system.

This process, like the creation of FAIs, is resource- intensive with a high likelihood of errors and omissions. Ensuring that every characteristic from the TDP is subsequently “consumed” and validated during production is an important objective of process planning--but it has remained an elusive one.

CMM programming

The CMM program is an essential complement to first article inspection and process planning. It closes the loop in measuring the actual results for the specific part characteristics. In most companies, CMM programmers typically review hard copies of the drawing and manually enter codes for probing the part. For a complex part, the labor effort can take days, and the manual setup of the CMM program is susceptible to errors.

The time and labor to set up a CMM can be reduced as much as 80 percent using PAS CMM software from PAS Technology ( www.pastechnology.com [3] ). PAS CMM uses a combination of sophisticated 3-D model feature recognition and probe control to almost completely automate the generation of the code to control the CMM.

Staying competitive

The productivity gains from the various software tools are impressive, but the results from error reduction are arguably even greater. Joseph Murphy, chairman of aerospace industry supplier Ferco Tech, reinforces this distinction. “These tools provide a two-fold benefit,” says Murphy. “First, they greatly enhance the productivity of our quality engineers. But the real savings is in their error-proofing capabilities. If something escapes, it’s hard to calculate the cost. But the software gives you more assurance that products will be built right the first time, saving more than what we would ever pay for the service.”

Error-proofing is about product integrity and productivity, which are complementary necessities in a very demanding and highly competitive marketplace. Attempting to ensure product integrity without the intelligent application of software tools can be costly and resource intensive.

Companies that succeed in today’s environment recognize that they must get it right the first time and continue to get it right over the entire product life cycle. These companies also recognize that they can achieve their product integrity and productivity objectives even in the face of reduced resources and a shifting business base. They are the ones taking advantage of the breakthrough software tools that make this possible.