Fundamental Study on the Possibility of Biomachining

研究了在实际加工技术中不存在的生物加工的可能性。利用一种能吞噬金属的特殊细菌，进行了金属的精细加工实验。首先，开发了一种营养化石菌的氧化亚铁硫杆菌的培养方法。基础实验表明，金属的加工基本上是可能的。我们将这种技术命名为“生物机械加工”。为了确定加工区域，采用光刻方法在被加工件上形成光刻胶。在培养液中振荡时，去除深度随加工时间的延长而增加。对纯铁、纯铜和黄铜的去除速率分别为14微米/小时、20微米/小时和18微米/小时。其次，研究了电场或磁场的影响。当施加适当的电场时，去除速率增加，而磁场对去除速率没有影响。我们将这项技术命名为“电场辅助生物加工”。在电场辅助生物机械加工中，我们可以通过电场条件来控制去除深度，这在实际应用中是非常有用的。此外，当使用适当的工具电极时，可以加工指定区域。上述实验结果表明，细菌对金属的生物浸出基本是可能的。当未来对细菌进行遗传解释时，这些细菌可能是微加工领域的自主控制的微型机器人。对本研究的进一步发展进行了展望。

The possibility of biological machining that doesn't exist in practical machining techniques is investigated in this study. The experiment of fine and precision machining of metals was done with peculiar bacteria that eat metal. First, the culture of tiobacillus ferrooxidans that is one of chemolithotrophic bacteria was developed. The basic experiment showed that the machining of metals was fundamentally possible. We named this technique "biomachining". In order to define the machining area, the photo-resist was formed on the workpiece using photolithography method. The removal depth increased with the machining time when the workpiece was shaked in the cultured fluid. The removal rate for pure iron, pure copper and brass were 14mum/hr, 20mum/hr and 18mum/hr respectively. Next the effects of electric field or magnetic field were investigated. When the proper electric field was given, the removal rate increased, while the magnetic field had no effect on the removal rate. We named this technique "electric field assisted biomachining". In the electric field assisted biomachining, we can control the removal depth by the electrical condition, which is very useful in practical use. Moreover, it is possible to machine the designated area when the proper tool electrode was used. The above experimental results made clear that the biomachining of metals by bacteria was basically possible. When the genetic explication of the bacteria will be done in future, these bacteria might be self-controlled micro robots in the field of micromachining. Further development of this research is expected.