Green Production Line

The Yokogawa Group established the Green Production Line Improvement Guidelines in 2002 and promotes improvements to reduce the environmental burden at each production line. Yokogawa is also making efforts to conserve the environment by reducing contaminants in the air, water, and soil, as well reducing CO2 emissions generated by the use of electricity, while at the same time reducing costs.

Yokogawa Manufacturing Kofu Factory has reduced the oil usage in water-soluble cutting fluid as a part of environmental conservation activities in fiscal year of 2008 on its metal cutting production line.

The cutting fluid used for metal cutting is a combination of oil and water. The density of the cutting fluid can be controlled by adjusting the quantity of tap water added to the fluid.

When the density of the cutting fluid was too high infrequently, the oil emulsion generated large amounts of foam and the cutting fluid leaked from the machine tools. We tested various densities of cutting fluid based on the vendor recommended density and decided the proper density for each machine tool. We carried out the density control on a daily basis by using a refractometer. Combined with training for the personnel responsible for various machine tools, the proper density of cutting fluid for each machine tool was obtained and applied. As a result of this activity to maintain the proper density of the water soluble cutting fluid used at Kofu Factory, the average monthly oil usage was reduced by 898L compared to the previous average monthly usage.

Moreover, originally, the cutting fluid that flowed out with metal crumbs was disposed with metal cutting waste. Now, before disposing the metal crumbs, a pump is used to suck the mixed cutting fluid and put back to the tank for reutilization.

In the future, we will test cutting fluids of different types to find more environmentally friendly water soluble cutting fluid, and aim further oil reduction.

Yokogawa Manufacturing Kofu Factory has changed the capsule body thickness as a part of environmental conservation activities on its differential pressure transmitter production line. This activity was carried out based on the Material Flow Cost Accounting* method.

When manufacturing a differential pressure transmitter product, a semi-product forged or casted roughly in the designed shape of the capsule body needs to be purchased from the iron and steel product maker. After cutting and scraping the semi product, the workpiece of the differential pressure transmitter capsule can be completed. Our activity for reducing the material waste targeted the scraped materials in this process. According to the research result of our research and development department, the scraped part can be reduced by reducing the surface unevenness. Thus, the weight of the capsule body semi product is changed from 1,400g to 1,250g. With this change alone, the scraped materials and waste materials are reduced by 600kg per month on average. Based on the "3R” concept (Reduce, Reuse and Recycle), zero-waste design and engineering processes should be considered. Our activity is an actual practice of Reducing, as one of various activities.

• * Material Flow Cost Accounting: Material Flow Cost Accounting is an environmental management accounting method aimed at reducing waste in the manufacturing processes. This accounting method aims to measure both a material loss and s a monetary loss by classifying the loss into material cost, system cost, energy cost and waste cost in the accounting system.

Yokogawa Manufacturing Ome Factory has taken a proactive step to save water in the printed circuit board cleaning process.

Originally, in Ōme Factory, about 400t of pure water was required each day for the surface cleaning processes of the printed circuit board production line. The water was mainly drawn from the water well. In recent years, no more than 300t of water can be drawn from the water well per day. The production line was even stopped occasionally due to the water shortage in the water well.

On the other hand, another Yokogawa group company, Yokogawa Denshikiki,owns a patent for "Direct Cleaning Method" which is already implemented in dish washing machine products. Compared to the similar products of other manufacturers, this direct cleaning method uses water spray for cleaning and the water consumption is very small. Therefore, the two group companies took a joint test to figure out a way to apply the cleaning power and water saving features of the dish washing machine to the printed circuit board cleaning process. This resulted in successful development of the Water Saving PCB Cleaning Machine. Using this Water Saving PCB Cleaning Machine on the copper gilding production line yielded a very good water saving performance, the daily water consumption was reduced from 13t to 1.8 t, which is an 82% saving. Now, this success is being widely introduced to other production lines. When this cleaning method is applied to all the planned production lines in Ome Factory, the pure water consumption of the entire Ome Factory can be reduced by 25%, at the same time, the water sewerage is accordingly reduced as well. With this success, Yokogawa Denshikiki is considering to add this technology to its business lineup.