Photo Review Visits Sony’s Kohda TEC Factory

Photo Review was represented in a group of approximately 40 journalists from the Asia-Pacific region who visited Sony’s Kohda TEC factory, where Cyber-shot digicams, camcorders, camera modules, printers and Memory Sticks are assembled. The factory is located in the Aichi prefecture, a little over an hour by bus from Nagoya city, which has the fourth largest urban population in Japan. The area, which is one of the three largest industrial centres in Honshu (Japan’s largest island), is home to well-known brand names like Toyota, Toshiba, Hitachi, Suzuki and Brother (see map).

The above map shows the location of Sony’s Kohda TEC factory (marked by a magenta star), among the many factories in the Aichi prefecture.

Sony built its first factory at Kohda in 1972 but the current facility dates from April 2001 and it one of Sony’s most technologically sophisticated plants. The facility is one of 13 Sony factories in Japan and covers roughly 200,000 square metres of land, of which 80,000 square metres is occupied by buildings.

An aerial view of the Kohda TEC factory showing the main manufacturing and administrative building.

The Kohda TEC factory employs approximately 1500 permanent staff, with the main ethnic groups being Japanese and Brazilian. Dual-language signs are found throughout the facility. The factory area we visited occupied two floors. On the lower one were lines of large, highly-automated chip mounting machines that positioned the silicon chips used as image sensors or microprocessors, along with other miniaturised components, on printed circuit boards.

Most of the chips come from dedicated foundries in the area around Nagasaki in Kyusu and Shiroishi towards the north of the island. They are shipped to Kohda TEC on tapes of varying width and length, ready to be fed into the automatic placing machines. Other parts – and image processing technologies – are produced in other Sony factories before being sent to Kohda TEC.

The highly-automated Surface Mount Assembly Line consists of three main types of machinery, all of which mount electronic components on printed circuit boards: a multi-functional placer, which handles the larger chips and takes an average of 0.32 seconds for each chip placement; a medium-speed placer which handles the smallest chips (each measuring 0.6 x 0.3 mm) at a rate of 0.2 seconds per chip and a high-speed placer which takes only 0.066 seconds per chip and handles varied component sizes, all of them square.

Once the chips are mounted, the circuit boards pas through the Air Reflow Oven for soldering. This machine maintains a constant airflow at between 220 and 240 degrees Celsius and uses lead-free soldering. It takes an average of three minutes per board to complete the soldering process. The finished circuit boards then pass to the relevant assembly line.

Sony pioneered the “tray cell” system that is used to assemble digital cameras and camcorders in the Kohda TEC plant. The system was initiated 12 years ago and has been refined over time to the point where many other manufacturers have adopted it. Each “cell” handles the entire assembly process, from collecting components to delivering the finished product, packed and ready for shipment.

Assembly of cameras takes place in modular “tray cell” workstations.

The camera cell we observed was assembling DSC-T30 Cyber-shots and consisted of 18 operators. Most were employed in fitting the various components into the camera case. The components were delivered on small trays and similar trays were used to pass each partially completed module on to the next work station. Several clean air cabinets (compliant with Class 5000 standard) were used to ensure no dust entered the camera at critical stages.

At certain points in the assembly process, each module was tested to ensure the camera controls, LCD, flash and anti-shake mechanism performed to specifications. Completed cameras were then packed in boxes with the appropriate documentation and software disks and then into shipping cartons ready for despatch. The production cell was turning out one completed camera every 30 minutes on average; a total of 600 cameras in an eight-hour day.

Components are inserted by hand and tested at regular intervals.

Right next door was a similar “cell’ working on DSC-W70 cameras, while further on, two employees were assembling a new cell for yet another camera model. The system’s success is largely due to the fact that hand-assembly is more accurate and cost-effective than machine assembly so there is much less wastage. It is also far more versatile as new modules can be configured in less than a day to meet increased demand for popular cameras or when new camera models are introduced.

The camcorder line was similarly configured and the “cell” we were shown was making DCR-DVD105 Handycams, coincidentally for the Australian market. Each “cell” contained 26 operators, eight of whom were involved in actual assembly, six in testing and two specialising in lens and EVF (electronic viewfinder) integration. The camera consisted of 126 separate components and it took an average of 50 minutes and 31 seconds from start to completion of packaging for shipping.

Staff in the factory begin work at 8.15 am and end at 5.15 pm, with a five-minute break at 10 am, 45 minutes for lunch and a 10-minute break mid-afternoon. Kohda TEC is involved in a facility-wide effort to increase innovation in order to keep production within Japan and provide on-going employment for its staff. Consequently, it must ensure a high level of quality in the products it produces, effective cost control and efficient delivery of products from the factory. Evidence of all three could be found in the Kohda plant.