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Flow Down Impact on Nadcap Testing of Forged Parts
By: Admin on April 4, 2013

Flow down is the term applied to the process by which product specifications agreed to by a supplier are communicated to any and all additional subcontractors used in manufacturing, treating or testing a product or component. More than just a phrase or concept, flow down is a tool that helps forge shops ensure they receive maximum value from their testing partner.

What is the cost of a late laboratory report?

If you depend on a laboratory to deliver test reports in order for you to ship product to your customer, here’s some helmetallurgical testingpful news. Aerospace forging manufacturers can greatly impact the desired gains they receive when they require independent testing in accordance with Nadcap requirements. The most obvious gains in value manufacturers seek are quality, speed, reliability, ease of doing business and cost-effectiveness.

Forge shops are often dependent on their testing-laboratory partner for mission-critical data that could ultimately enable or delay shipment of product. Therefore, forgers need fast and accurate results from their testing-lab partner. Fortunately, building a collaborative relationship with a laboratory is mutually beneficial for all involved. To understand how the manufacturer can positively impact the value received from the laboratory, some background on how laboratory costs are generated is helpful.

About Flow Down

Definitive of theflow down process is the fact that, throughout the supply chain, contractors will provide specific details for subcontractors, such as third-party laboratories, to fulfill their purchase orders. Flowed-down information will include such requirements as material specifications and revision level, test methods, special process requirements, part marking, certifications, etc. Subcontractors will review the information and obtain required data or clarification from the contractor if the requirements are incomplete or unclear.

Test labs live in a world of data where highly educated and skilled scientists and engineers are responsible for conducting tests and supplying results. The costs incurred include the costs of the sophisticated instruments they use coupled with the time spent by lab personnel in the process of obtaining results.

The bulk of the time and cost generated is often incurred during sample log-in and technical review of the incoming sample and accompanying instructions. At this step, technicians and engineers define what preparation and testing is to be completed. This process includes purchase-order and specification review as well as understanding the condition of the as-received sample in order to pass on accurate instructions to the laboratory work centers. All of these are directly affected by the completeness and accuracy of the requirements flowed down through the supply chain. The next step is sample preparation, which may include sectioning, machining, grinding, mounting, polishing or digestion of the sample. Conducting the test and report preparation are the last and often the most rapid operations performed. 

This cursory look at testing-cost generators reveals that the greatest variables in speed, quality and cost of results are the tasks associated with log-in and technical review processes. These tasks can be positively impacted through concise and accurate flow down of information. Important flow down requirements include specifications, revision-level numbers and dates, special end-user requirements and ITAR (International Traffic in Arms Regulations) restrictions. This key information assures the speed and accuracy you require and is critical to a successful and efficient relationship with your lab.

How Frequent Are Flow Down Problems?

At a meeting last year, the Nadcap Supplier Support Committee reported that in regard to flow down issues concerning specifications, revisions and other requirements from sub-tiers, 41% of respondents reported that they rarely or never have problems with flow down. That, of course, means that 59% of respondents did have problems receiving the proper information enabling them to quickly and accurately respond to the incoming purchase order.

The critical nature of accurate flow down is deemed to be so important to suppliers and subscribers that the Nadcap Supplier Support Committee (SSC) has established a flow down sub-team to help the industry deal with concerns regarding inaccurate and missing critical information through the supply chain. The Nadcap SSC Flow Down sub-team objective is: “Prevent product non-compliances and production delays through effective customer requirements flow down.” 

A consensus of surveyed suppliers indicated that critical information is often missing on purchase orders, especially at the lower supply-chain tiers. Also, having to pull complete information from the customer is more prevalent than flowing down the information. 

A Case in Point

Consider this recent situation involving an aerospace manufacturer. A forging manufacturer submitted samples to their lab and asked the lab to “use the current revision” of a specification. The lab proceeded with testing and reported results to the current revision level of the specification on file at the lab. The customer received the report and noticed a discrepancy between the revision level used by the laboratory and the revision level used in manufacturing the part. In this instance, the new revision of the specification included changes to the test method. The lab had to re-process the order according to the new revision of the specification, costing all parties more time and money. It is important to remember that, in most cases, the company working directly with the end user is the only part of the supply chain that has access to specifications and revision-level history.

Flow Down Checklist

Jennifer Tret, vice president of materials testing at Sherry Laboratories and Nadcap Flow Down sub-team chair, offers the following checklist of essential items to be included by forging manufacturers when submitting orders to their test lab. 

  • Identify the technical contact to answer contract-review questions.
  • Provide sample identification to be included on the analytical report.
  • Show the material grade.
  • Specify the condition of the forging as-received by the lab.
  • Define specimen conditioning that the lab must perform (e.g., heat-treat time and temperature).
  • A copy of the current specification, drawing or list of purchase-order requirements.
  • Specify the part location from which to extract specimens – a drawing or sketch is preferred or simply write on the sample.
    • Specify direction (e.g., longitudinal, radial, etc.)
    • Specify depth (e.g., surface, mid-radius, etc.)
  • List tests to perform.
  • Identify test methods to use, including the current revision (e.g., ASTM E8-11 or EN ISO 6892-2:2011 with revision number and date).
  • End user of the part is to ensure that proper accreditations are held by the lab and that specific requirements of that aerospace OEM are followed; list ITAR restrictions.
  • Identify whom to promptly notify regarding nonconforming test results, and provide instructions for immediate retesting.
  • Define remnant and specimen-retention policy and requirements (return or store remnants and test specimens).

The omission of any one of the above items can have a pronounced negative effect on the speed and accuracy of a testing and reporting event. At best, the omission will require a phone call from the lab to the purchaser to clarify requirements. Even if contact is made on the first attempt, it means an extra step in communication by both parties before the order can proceed. In today’s busy world, a more likely scenario is multiple calls or e-mails and up to several days of delay. Extra steps mean delays and extra cost, which is detrimental to both parties. 

Nadcap labs will keep your order on hold until all questions are clarified. It is not feasible to proceed with the initial sample preparation until all missing information is received because virtually every phase of the preparation and testing process is intertwined into a precise sequence of events that requires the information listed above. 

Utilizing the flow down checklist on each order submitted will quickly become second nature and yield real dividends in speed, efficiency, cost savings and first-pass quality. A typical Nadcap test compliance event may be scheduled to take three days from the sample receipt at the test lab.

Let’s assume a checklist item is missing from the order, and it takes a day to get the required information. A three-day event is now a four-day event, increasing the turn time by 33%. The obvious questions are:

  • What is the cost of a one-day delay in receiving test results?
  • How detrimental is its effect on your ability to ship approved product to your customer? 

Conclusion

When Nadcap testing of forged parts is required, “flow down” is not just a coined, popular phrase but a real tool enabling manufacturers to ensure they receive maximum value from their testing partner.

Another desirable side effect of ordering with a checklist is that this is a big first step toward turning the traditional buyer/seller relationship into a true partnering relationship with your test lab. Both partners can achieve desirable gains in speed, efficiency, quality and ease of doing business.

Sherry Laboratories' materials testing division provides metallurgical testing services as well as failure analysis and reverse engineering for clients in a variety of industries, including aerospace, defense, medical device, automotive and power generation.

We welcome the opportunity to provide you a quote for our services or discuss how we can help.

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