The Dunlee division of Philips Healthcare has been manufacturing X-ray tubes since 1946. Acquired by Philips in 2001, the company’s Aurora, IL, manufacturing facility occupies 140,000 square feet, with more than 250 employees. Philips is engaged in the manufacture and sale of X-ray tubes and housing assemblies for medical diagnostic imaging devices.

The Aurora facility is relatively new, completed in 1994. It is bright and clean, with a well organized manufacturing operation and a comfortable office environment. A display case in a main hallway near the lobby charts the long history of the company, housing relics of X-ray past and specimens of X-ray present. A mural at the end of this hall depicts the history of X-ray technology, tracking its evolution from inception to today’s sophisticated applications.

The Aurora facility supports computed tomography (CT) and general X-ray systems manufactured by Philips as well as third-party OEMs; the company also supplies to independent service organizations. Within Philips Healthcare’s Imaging Systems group, the facility is part of a business unit called Generators, Tubes and Third-Party Business (GTT). The company typically retains the Dunlee brand name when selling product to third-party OEMs or independent service groups; however, some products are proprietary to Philips.

Philips is compliant to the FDA’s 21 CFR 820, certified to ISO 13485: 2003, ISO 13485 CMDCAS-meeting Canada’s requirements for the standard-and Ordinance 169 under PAL, the ordinance related to quality systems under Japan’s Pharmaceutical Affairs Law (PAL).

An employee crafts an X-ray tube out of molten glass. This structure envelopes the anode and cathode assemblies. Source: Philips Healthcare

A Culture of Quality and Improvement

Thomas Muchowicz, director of quality and regulatory, is head of the quality staff at Philips. Muchowicz reports directly to the president of the facility, is part of the local management team and serves as the facility’s representative for ISO compliance.

“My group is relatively small,” says Muchowicz, “so I have a number of people who have expertise in one area.”

Muchowicz has an employee who specializes in product regulatory compliance and product licensing, for example. Another individual is responsible for environmental health and safety. The facility has two quality specialists. One of the quality specialists focuses on systems, such as the training system and the corrective and preventative action (CAPA) system, while the other focuses on product quality and analysis.

In addition, product champions serve as an interface between the customers and the facility. For example, if there are performance problems such as early-life product failures, the product champions are the first to be notified, and it is their responsibility to drive the corrections or improvements into the product.

Muchowicz and his small quality staff serve as the facility’s knowledge base and assist the rest of the organization in meeting customer requirements and maintaining compliance.

“Everybody’s responsible for quality,” says Muchowicz. “We have a number of teams that are put in place to improve product quality, whether we’re seeing a measuring trend in the wrong direction or it’s a company objective to improve our yield or field performance.” Indeed, walking from department to department at the Philips facility, one will notice that each department posts its quality trend and improvement initiative information for all to see.

The teams, led by any qualified employee such as a product champion, Green Belt, Black Belt, engineer, manager or supervisor, will define a problem and work through it to determine a solution. Changes are put in place and results monitored. The teams enter their improvement projects in a Philips-wide initiative called the quality improvement competition.

The teams determine a process or product that needs improvement and then use quality tools, such as Six Sigma or MEDIC-a Philips methodology for process improvement similar to Six Sigma-to develop and test a solution. The teams first have a series of competitions at a local level to determine how well they have achieved their goals. The winner at the local level competes in a regional competition, and the winner of that goes on to compete in a final worldwide competition, where regional winners from all divisions of Philips compete.

“The whole intent is that it is a way of having people use the quality tools, make improvements, gain results and have some fun doing it,” says Muchowicz. “And in the process, if you have a good team you get to go see other places and meet some people at other plant locations. It’s an opportunity to share ideas and best practices as well as meet the Philips executive team. So it’s a fun thing and it works really well.”

Muchowicz says that in 2007 the Aurora facility had a team that made it to the world finals, which was held in Cancun, Mexico. The team had identified shipping problems that arose from the facility’s packaging practices and implemented an initiative to correct this. Although the team did not win, it met its objectives and drove improvement at the Aurora site. “The bottom line is that they came up with a new packaging scheme that not only met their objectives but decreased our environmental impact by providing a packaging platform that was lighter weight, reusable, fully recyclable and more reliable,” says Muchowicz.

The Dunlee division of Philips Healthcare manufactures both glass and metal X-ray tubes for use in medical diagnostic imaging devices. Source: Philips Healthcare

Ensuring a High-Quality Product

As one would expect, the manufacture of X-ray tubes involves a great deal of quality assurance. Low-tolerance parts are brought in from outside suppliers and measured by the incoming quality assurance department. High-tolerance parts are machined in house and measured in process.

What is impressive to an outside observer, though not surprising, is the scrutiny an X-ray tube must endure during its manufacture. First the metal components are cleaned, degassed and stored in nitrogen cabinets. The anode and cathode assemblies are then made, a painstaking process requiring a high level of in-process quality control.

After the anode and cathode assemblies are complete, they are incorporated in either a glass or metal X-ray tube, depending on the type of machine the tube will be installed in. After the anode and cathode assemblies are housed within the tube, they undergo helium leak testing. A vacuum is created inside of the tube, and helium is sprayed on the outside to detect any leaks.

Next the tube undergoes more degassing. The tube is put into a vacuum and heated to nearly 1,200 C. After this an electrical test is performed. The tube is first submerged in mineral oil, which insulates against high voltage and assists with heat transfer, and then operated at high voltage levels to simulate use. The product also is subjected to over-voltage electrical conditions to ensure stability in use.

After the X-ray tube has shown structural and operational integrity, it is put into its metal housing and a cooling unit is added. The space between the tube and its protective housing is filled with mineral oil. At this point a second electrical test is performed, along with a radiation leak test. Again, the tube is tested at over-voltage levels.

A third and final test in which the unit is installed in a functional CT machine is performed. The CT machine is operated at normal conditions, producing scans both while rotating and stationary during the three- to four-hour test. After the completion of this test, the unit undergoes a final inspection. Here the unit’s device history record is reviewed to ensure that is has passed all tests, after which it is cleaned and labeled.

As a quality assurance step, the finished X-ray unit is installed in a CT machine, which is operated at normal conditions, producing scans during a three- to four-hour test. Source: Philips Healthcare

Initiatives and Methodology

The facility is subject to a Philips initiative called business excellence (BE) and a proprietary methodology called process survey tools (PST). BE aims to improve how the company works and does business and PST is the methodology used to achieve those improvements. With BE/PST, the facility ranks itself, benchmarks against other Philips locations and sets targets and goals to improve business performance.

While improvement initiatives use MEDIC, the facility also uses Design for Six Sigma (DFSS), 5S and lean methodology, with a Black Belt, Green Belt and two Green-Belts-in-training on staff. The staff applied 5S throughout the entire facility. Muchowicz says that this was the first step in moving to a lean process. Now more emphasis is being put on elimination of wait time and nonvalue-added activity.

Related to a high-quality product is the use of DFSS, methodology that standardizes product development. Also, the facility adheres to Philips’ product creation process (PCP), which follows the stages of product development, mandating phase reviews after the completion of each stage.

In terms of overall improvements, Philips is focused on improving internal yields and product life. “Our product yields have always been good, but we’re really pushing the envelope now to get those first-pass yields very high,” says Muchowicz. “X-ray tubes are expendable devices, but they’re also expensive devices so we’ve gone through a lot of improvements to make sure the product lasts longer and longer in the field."

Finished units-X-ray tube, housing and cooling unit-await the second electrical testing, or “seasoning,” which will test the unit at overvoltage and check for radiation leakage. Source: Quality Magazine

Training and Tracking Quality

As one would expect, employee training is very important at Philips. All employees receive training regarding safety and the company’s quality system, and each employee undergoes a training plan specific to task or career path. The training and employee development system (TEDS) is a database that serves to track employee status on training requirements and notify employees of unmet training requirements. If, for example, there is a revision to a management system document, affected employees will be notified automatically and told what training to complete.

At least annually, employees have a review with their manager, and part of that entails looking at the employee’s prospective career path. Philips also offers outside and inside training to employees, classes related to career growth.

Supplier quality is fastidiously measured at Philips. A supplier management steering committee provides direction to the company regarding the use of suppliers. The committee is a cross-functional team comprised of representatives from the materials group, quality, engineering and production support. The committee meets on a monthly basis, to review supplier performance in terms of part quality and on-time delivery. Preferred suppliers are rated on a quarterly basis and are subjected to a risk assessment annually.

As with supplier quality, Philips keeps an acute focus on its own quality levels. Monthly, a product quality meeting is held, at which internal and external issues affecting the company are discussed. Teams report on the status of specific improvement projects, and data is presented regarding performance of infield product, internal yields and improvement initiatives.

Muchowicz prefers to use survival plots to track infield product quality. This is because X-ray tubes have either long or short lives, he says. After an X-ray tube has survived the initial early-failure window, it has a much greater chance of a long life.

Philips also performs quarterly business reviews, in which companywide issues are examined, such as those pertaining to regulatory, employee, health and safely, sales and new product development. Finally, the management system is reviewed annually.

Because of the stringent requirements medical devices are subject to, the mantra that quality is everyone’s responsibility must have a particular resonance with individuals who manufacturer such products. And at Philips, it is easy to see the care with which products are crafted; furthermore, improvement in all areas of business, quality or otherwise, is a constant.Q

For more information

The Dunlee division of Philips Healthcare

  • Founded in 1946
  • Moved to current Aurora, IL, facility in 1994
  • Acquired by Philips Healthcare in 2001
  • Employs more than 250 at Aurora, IL, facility
  • Part of Philips Healthcare’s Generators, Tubes and Third-Party Business (GTT) business unit
  • Supplies X-ray tubes and housing assemblies to Philips, third-party OEMs and independent service organizations
  • Has subsidiaries in Dallas; Richmond, VA; and Brazil

  • Disciplines and Products

    Technology disciplines of Aurora facility:
    • Glass
    • Vacuum
    • High-Voltage Electrical
    • Metallurgical
    • Mechanical G-Force
    Products manufactured at Aurora facility:
    • Philips CT Tubes
    • Philips Neusoft CT Tubes
    • Picker-Marconi CT Tubes
    • Philips-Dunlee CT Products