When it was time to replace the factory cleaning the spiral groove bearing assembly, Philips Medical Systems turned to Ecoclean again.
Shortly after the discovery of X-rays by Wilhelm Conrad Röntgen in 1895, Philips Medical Systems DMC GmbH began to develop and manufacture X-ray tubes together with Carl Heinrich Florenz Müller, a glassblower born in Thuringia, Germany.By March 1896, he had built the first X-ray tube in his workshop, and three years later patented the first water-cooled anti-cathode model.The speed of tube development and the success of X-ray tube technology spurred global demand, turning artisan workshops into X-ray tube specialist factories.In 1927, Philips, the sole shareholder at the time, took over the factory and has continued to shape X-ray technology with innovative solutions and continuous improvement.
Products used in Philips healthcare systems and sold under the Dunlee brand have contributed significantly to advances in diagnostic imaging, computed tomography (CT) and interventional radiology.
“In addition to modern manufacturing techniques, high precision and continuous process optimization, component cleanliness plays an important role in ensuring the functional reliability and longevity of our products,” says André Hatje, Senior Engineer Process Development, X-ray Tubes Division.Residual particle contamination specifications—two or fewer 5µm particles and one or less 10µm size—must be met when cleaning various X-ray tube components—emphasizing the cleanliness required in the process.
When it comes time to replace the Philips spiral groove bearing component cleaning equipment, the company makes meeting high cleanliness requirements as its main criterion.The molybdenum bearing is the core of the high-tech X-ray tube, after the laser application of the groove structure, a dry grinding step is carried out.A cleaning follows, during which grinding dust and smoke traces must be removed from the grooves left by the laser process.To simplify process validation, compact standard machines are used for cleaning.Against this background, a process developer contacted several manufacturers of cleaning equipment, including Ecoclean GmbH in Filderstadt.
After cleaning tests with several manufacturers, the researchers determined that the required cleanliness of the helical groove bearing components could only be achieved with Ecoclean’s EcoCwave.
This machine for the immersion and spray process operates with the same acidic cleaning media previously used at Philips and covers an area of ​​6.9 square meters.Equipped with three overflow tanks, one for washing and two for rinsing, the flow-optimized cylindrical design and upright position prevent dirt build-up.Each tank has a separate media circuit with full flow filtration, so cleaning and flushing fluids are filtered during filling and emptying and in bypass.Deionized water for final rinse is processed in the integrated Aquaclean system.
Frequency-controlled pumps allow flow to be adjusted according to parts during filling and emptying.This allows the studio to be filled to different levels for denser media exchange in key areas of the assembly.The parts are then dried by hot air and vacuum.
“We were very pleased with the cleaning results. All the parts came out of the factory so clean that we could transfer them directly to the clean room for further processing,” Hatje said, noting that the next steps involved annealing the parts and coating them with liquid Metal.
Philips uses an 18-year-old multi-stage ultrasonic machine from UCM AG to clean parts ranging from small screws and anode plates to 225mm diameter cathode sleeves and casing pans.The metals from which these parts are made are equally diverse – nickel-iron materials, stainless steel, molybdenum, copper, tungsten and titanium.
“Parts are cleaned after different processing steps, such as grinding and electroplating, and before annealing or brazing. As a result, this is the most frequently used machine in our material supply system and it continues to provide satisfactory cleaning results,” Hatje Say.
However, the company reached its capacity limit and decided to purchase a second machine from UCM, a division of the SBS Ecoclean Group specializing in precision and ultra-fine cleaning.While existing machines could handle the process, the number of cleaning and rinsing steps, and the drying process, Philips wanted a new cleaning system that was faster, more versatile and provided better results.
Some components were not optimally cleaned with their current system during the intermediate cleaning phase, which did not affect subsequent processes.
Including loading and unloading, the fully enclosed ultrasonic cleaning system has 12 stations and two transfer units.They can be freely programmed, as are process parameters in various tanks.
“In order to meet the different cleanliness requirements of different components and downstream processes, we use about 30 different cleaning programs in the system, which are automatically selected by the integrated barcode system,” Hatje explains.
The system’s transport racks are equipped with different grippers that pick up cleaning containers and perform functions such as lifting, lowering and rotating at the processing station.According to the plan, a feasible throughput is 12 to 15 baskets per hour operating in three shifts, 6 days a week.
After loading, the first four tanks are designed for a cleaning process with an intermediate rinse step.For better and faster results, the cleaning tank is equipped with multi-frequency ultrasonic waves (25kHz and 75kHz) on the bottom and sides.The plate sensor flange is mounted in a water tank without components to collect dirt.In addition, the wash tank has a bottom filter system and overflows on both sides for the discharge of suspended and floating particles.This ensures that any removed impurities that accumulate at the bottom are separated by the flush nozzle and sucked up at the lowest point of the tank.Fluids from the surface and bottom filter systems are processed through separate filter circuits.The cleaning tank is also equipped with an electrolytic degreasing device.
“We have developed this feature with UCM for older machines because it also allows us to clean parts with dry polishing paste,” Hatje said.
However, the newly added cleaning is noticeably better.A spray rinse with deionized water is integrated in the fifth treatment station to remove very fine dust still adhering to the surface after cleaning and the first soak rinse.
The spray rinse is followed by three immersion rinse stations.For parts made of ferrous materials, a corrosion inhibitor is added to the deionized water used in the last rinse cycle.All four rinsing stations have individual lifting equipment for removing the baskets after a defined dwell time and agitating the parts while rinsing.The next two partial drying stations are equipped with combined infrared vacuum dryers.At the unloading station, the housing with integrated laminar flow box prevents recontamination of the components.
“The new cleaning system gives us more cleaning options, allowing us to achieve better cleaning results with shorter cycle times. That’s why we plan to have UCM properly modernize our older machines,” Hatje concluded.