Electro discharge machining (EDM) has been employed in micro mold making field. Material forming technology using a mold is well known as short cycle time process for cost effective mass production of micro products. However, machine tools for a small mold machining are usually very large. If small molds can be made by smaller machine tools, it contributes to saving energy and to reducing environmental load. This study aims to manufacture a hybrid micro machine tool. It is a tabletop size machine tool. Downsizing of the machine tool saves energy, floor space, and material resources of machine tool, and also reduces environmental load. Furthermore, the machine tool has five changeable machining units. These units eliminate setting error of work material by carrying out several machining methods from rough machining to finishing on the same machine.
The concept of hybrid micro machine tool
In small mold machining, various machine tools, such as a machining center, a grinding machine, a polishing machine, an EDM machine, and an ECM machine are used. This equipment is very large compared with the machined mold, though. If a small machine tool is used in a small mold machining, it could save material resources, processing energy, and constructing energy of the machine tool. Furthermore, the small machine tool has following characteristics.
Fine positioning accuracy and smooth movement of a work piece and a tool.
High flexibility of the design of the machine tool.
Easy layout of machine tools.
While a table top size milling machine has already put on the market, such a tool does not have enough rigidity for micro milling because the machine tool is designed to cut wax. Masuzawa et al. developed an EDM machine for small size material machining. It can be only used for EDM.
A precise mold machining needs several machines from rough machining to finishing. In such case, it is much tough to keep the proper clearance between the tool (electrode) and the work piece, because the work piece has to be set up at each machine tool in each process. If mechanical machining, non conventional machining, and complex machining which is used in combination with both machining process are available on the same machine tool, work setting error is eliminated. In addition to this, complex machining has possibility that one machining method makes up for other machining method's shortcoming. Complex machining with a small machine tool has two merits. The first is that it is very easy to change machining method. The second is that environmental load for replacing and wasting of electrolyte, dielectric, coolant, and abrasive oil is little. There has been, however, no study about complex machining by using small machine tool. So, a machine tool, which enables to mechanical machining, non conventional machining, and complex ...