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Ch33-I044963.fm Page 157 Tuesday, August 1, 2006 3:12 PM
1, 2006
Tuesday, August
Page 157
Ch33-I044963.fm
3:12 PM
157
157
DEVELOPMENT OF CURVED HOLE
MACHINING METHOD
- SIZE REDUCTION OF HOLE DIAMETER -

1
1
2
1
T. Nakajima , T. Ishida , M. Kita , K. Teramoto and Y. Takeuchi 1
1
Dept. of Mechanical Eng., Graduate School ofEng., Osaka University
Yamadaoka2-1, Suita, Osaka 565-0871 JAPAN
2
Dept. of Machinery System Production Technolgy, Kinki Polytechnic College
Inabatyou 1778, Kishiwada, Osaka 596-0103 JAPAN

ABSTRACT

This study deals with a diameter reduction of curved holes that can be machined by the method developed by the
authors. In order to improve the productivity of molding, it is necessary to increase the efficiency of the cooling
stage in a molding cycle. It depends on the shape and the arrangement of water channels, i.e., pipelines built in
molds. However, water channels consist of a series of straight holes due to the fabrication by drilling. Accord-
ingly, it is strongly required to develop a machining method of curved holes since curved water channels are
desirable. To meet the requirement, the device has been developed, which can make an electrode move along a
curved trajectory with electrical discharge machining. The device can fabricate curved holes. However, the
fabricated curved holes have a problem that their diameter is too large to employ them as a water channel. In the
study, thus, the size reduction of the curved holes is tried by improving the electrode and its peripheral parts.

KEYWORDS

curved hole, electrical discharge machining, size reduction, helical compression spring, servomotor, water chan-
nel, wire feeding

INTRODUCTION

Injection molding is one of very important manufacturing methods and is employed to create various products in
a variety of industries. Therefore, an innovation in an inj ection molding technologies has a very strong impact on
our society, hi general, injectionmolding has the cycle which is composed of melting material, injecting the melted
material to a mold, solidifying the material and taking out a desired-shaped material from the mold. Accordingly,