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Publication Date: 05/1/2012
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PCBA Bonepiles: The Neglected Green Revenue Stream Rehabilitated
Complex bonepile PCB being tested.

Bonepiles. Everybody's got them. They're collections of PCB assemblies that are defective and can't be rescued. In today's fast-paced, production-oriented, revenue-driven environment, when an assembled board is deemed unrepairable, it frequently is written off and placed into a "bonepile," industry vernacular for an accumulation of defective printed circuit board assemblies. This happens most frequently at OEM facilities; however, it is not uncommon for electronics manufacturing service companies to also have accumulated piles of these boards. Often, companies exhaust their troubleshooting budget and even write such failures off their books. In spite of this, written-off boards frequently continue to reside in warehouses, hence the term "bonepile".

Bonepiles have existed for as long as electronic products have been built. They're unpopular because, obviously, they represent "dead money," specifically forgone revenue. They are viewed unfavorably because they burn a figurative, if not literal, hole in the finances of electronics producers. Typically, the bigger the company, the bigger the bonepile. Every company has one. Getting them to admit it and expend the effort and resources to recover these is another matter altogether. Bonepiles are not sexy compared to flashy new products; nevertheless, they represent a hidden manufacturing cost that needs to be recovered, especially in these frugal times. What, then, can be done to solve, or at least reduce, this vexing industry problem? And what about environmental considerations? Enter test-centered bonepile rehabilitation, a.k.a. Bone Pile Repair — more specifically, bonepile rehabilitation at the board level, and in volume. In the United States, Datest, leveraging 28 years of experience in PCBA production testing and test engineering, is busily innovating bonepile recovery. This involves recovery, rehabilitation and analysis of failed PCBAs, and the process can produce key results, and recovered money to the industry. In some cases what was once pure waste (scrap) has become the nucleus of a new profit center.

Rehabilitating Bonepiles
While there are numerous upsides to bonepile rehabilitation, the three most compelling to today's OEMs and their contract manufacturers include:

Financial benefits. Bonepile rehabilitation brings significant cost savings and revenue recovery. Think of it as "found money." The folks in the corner offices generally are quite pleased when this money is found. These cost savings are continuous because companies that implement the bonepile rehabilitation process will no longer accumulate failed boards, or at least warehouse fewer failed units deemed beyond hope of recovery. Nor will an OEM need to initiate costly one-off production runs to replace scrapped boards.

Green appeal. Today, scrapping boards is the accepted method of dealing with bonepile boards after they have been written off. However, using Datest's expertise, the previously failed products get recycled, rehabilitated, and returned to productive use. Fewer resources are expended replacing failed units by building new units from scratch. Less e-waste means fewer landfills, with more metals and other materials returned to productive use rather than to the ground.

Process Feedback. Bonepile rehabilitation generates valuable Pareto data that can feed back and be used to improve control over the manufacturing process, thereby driving longer term, additional cost and resource savings. Done properly, lessons can be learned for future applicability and long-term reduction and even elimination of systemic failures.

It all adds up. You just need the test and inspection tools — and the knowledge and experience to implement a cost-effective rehabilitation program.

Process Development
The concept is straightforward but seldom implemented: customers bring data, documentation and previously written-off test failures. Datest then uses its test engineering resources and decades of troubleshooting knowledge and multiple ATE test platforms and inspection systems to bring the boards "back to life." It makes full use of its suite of integrated testing and inspection resources to troubleshoot, rework and restore assemblies to operational status that previously failed a customer's functional or system test. Datest will directly rework the boards or show customers where to rework if they prefer to do it themselves. Like all other facets of manufacturing, communication is key. Therefore, the company works closely with customers to define what constitutes a "good" board after it is reworked. The rehabilitation service is offered at a fraction of the original manufactured cost and is suitable for reverse logistics, warranty repair and returns management programs.

Datest mobilizes the same hardware and software resources utilized in production board testing to aid in troubleshooting, fault diagnosis, repair and recovery. Testing using the flying probe system, Boundary Scan/JTAG testing and X-ray inspection are all highly effective, and frequently used for this task. In extremely high-volume applications, in-circuit testing (ICT) also may be used. The objective is to arrive at an efficient test solution that is both cost-effective and delivers significant value with a high recovery rate at zero-risk to customers.

Datest's rehabilitation team plays a role in the process that is as important as the hardware and software resources that are used. Each member brings decades of analysis, troubleshooting and debug experience to each project with the purpose of providing customers with the best solution possible. The customer is provided with regular status reports as well as failure disposition data and trend analysis, and also is given the opportunity to review each program for cost-effectiveness and derived value at regular intervals. Nothing in the process is unique other than the execution and, of course, the results.
One of many costly PCBs rescued from the bonepile by comprehensive testing.

Using state-of-the-art 100 percent solder joint automatic X-ray inspection machines and engineering's expertise in X-ray inspection, X-ray image analysis, Datest identified solder joint defects normally hidden or undetected due to design. X-ray is augmented, where necessary, by flying probe, boundary scan, and in-circuit testing.

Case Studies
A designer/manufacturer of custom digital flat-panel displays enlisted Datest's assistance in troubleshooting 25 high-end video processor cards. Fully burdened cost of the assembled boards was approximately $2100 per piece. Datest used Agilent 5DX X-ray technology to pinpoint missing components, misplaced components, solder bridging and insufficient solder conditions. Boards were returned to the customer with defects that the X-ray inspection had identified. The customer performed its own repairs, following instructions provided by Datest, and was able to successfully rehabilitate and return to service 18 of the 25 boards — a restored value of nearly $40K . Cost of X-ray program and inspection: $6K.

Security Systems on the Pile
As part of a major green initiative, a leading manufacturer of security systems hired Datest to assume responsibility for rehabilitating field returns of a major product line. Prior to engaging with Datest, the customer was discarding field failures of this product as scrap and e-waste. Now Datest is taking regular returns from this customer, processing them through flying probe, in-circuit and X-ray test technology. It also identifies failed parts and replaces them, and retests them using the customer's functional test apparatus. Following passage of all of these steps, good boards are returned to the customer's inventory as working units for possible replacement into future field returns. In addition to the obvious green benefits, adoption of this initiative has reduced OEM costs by eliminating the need for a production line to manufacture replacement boards, thereby freeing internal assembly capacity for higher-priority products. Meanwhile, the field service operation has evolved from a cost center into a profit center. The customer expects to save several hundred thousand dollars annually over the life of this initiative, which is expected to last at least two years and possibly as long as four years.

Failed Analytical Instruments
A manufacturer of analytical instruments, working with multiple contract manufacturers over a period of several years, had accumulated a significant bonepile valued conservatively at $300K. The majority of this value had already been written off the client's books. Initially, Datest was hired to provide X-ray services for a control group of failed PCBAs selected from this bonepile. Using X-ray inspection, Datest was able to identify root causes of failures of the majority of the boards in this control group. Encouraged by this initial success, Datest, in consultation with the client, added more resources — specifically, flying probe, boundary scan and in-circuit testing — to augment X-ray and to attack other portions of the client's bonepile. In an 18-month period, Datest was able to successfully rehabilitate 80 percent of the customer's failed PCBAs. This was "found money" for a very happy customer. Datest has applied its proven and longstanding expertise in the board testing and inspection realm to establish a systematic solution to this problem, deliver enduring value and contribute to a better environment. By analyzing the failures and using its full range of testing solutions, platforms, and engineering know-how, Datest can rehabilitate many of the bad boards, restore "lost" revenue and contribute to a greener world. This is an economical and intuitive answer to a perennial issue that delivers significant monetary and environmental benefits in a world where diminished resources have become a fact of life.

Contact: Datest's, 47810 Westinghouse Dr., Fremont, CA 94539 510-490-4600 fax: 510-490-4111 E-mail: rboguski@datest.com Web:

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