PCBA Bonepiles: The Neglected Green Revenue Stream Rehabilitated

By Robert A. Boguski, Jr.

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," which is electronics industry vernacular for an accumulation of defective printed circuit board assemblies (PCBAs). This happens most frequently at OEMs' facilities; however, it is not uncommon for electronics manufacturing services (EMS) 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 the companies' warehouses; hence the term bonepile.

Bonepiles have existed for as long as electronic products have been built. They are 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 recovering these is another matter altogether. Bonepiles are not sexy compared to flashy new products; nevertheless, they represent a hidden manufacturing cost in need of recovering, especially in these frugal times.

What, then, can be done to solve, or at least reduce, this vexing industry-old 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 production PCBA testing and test engineering, is innovating bonepile recovery, rehabilitation and analysis of failed PCBAs to deliver 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.

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

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

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 in-house. 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 ideal 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 (i.e., has 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.

Case Studies
Datest, 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, 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. The following three case studies illustrate the advantages and demonstrated success of Datest's bonepile rehabilitation efforts.

Case Study #1
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 boards — a nearly $40K restored value. Cost of X-ray program and inspection: $6K.

Case Study #2
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.

Case Study #3
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 additional 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.

Summary
PCBAs that are perceived to be unrepairable represent a significant challenge, and revenue loss, to the industry — and have since electronic products have first been built. Not knowing what else to do with them, OEMs and EMS providers take a loss on them and set them off to the side in a bonepile. 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.

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For more information, contact Datest's President Robert A. Boguski, Jr. at 47810 Westinghouse Dr., Fremont, CA 94539; 510-490-4600; Fax: 510-490-4111; E-mail: rboguski@datest.com; Web Site: www.datest.com.