Single Point Micro Incremental Forming of Miniature Shell Structures

Abstract

This study focuses on single point micro incremental forming (SPMIF) applied to the forming of miniature shell products in meso-scale. For this study, a desk-top type of CNC forming machine was newly constructed as an experimental apparatus. A thin aluminum foil with a thickness of 12 μm and a thin round-tip bar with a radius of 100 μm were utilized as a blank and a forming tool, respectively. Some fundamental and complex shell structures were formed for investigating the characteristics of the SPMIF process without using any die and backing plate. The analysis of contact region in forming polygonal pyramids confirmed that fracture on an edge of a polygonal pyramid, which determined the forming limit of SPMIF, was strongly affected by the size of re-contact area. Through the SPMIF process established in this study, complex shell structures were accomplished with elaborate tool paths.

Single-Point Incremental Micro-Forming of Thin Shell Products Utilizing High Formability

“…2. This holder is called HT type a little different from another called ST1 type (6) . The forming limit of a blank could decrease with increasing tension applied to the blank.…”

“…By contrast, HT type blank holder could apply a slight and appropriate size of tension to a blank by adjusting the clearance between a tensioner and O-ring. As described above, the authors and colleagues have developed a method of incremental micro-forming without using a backing plate supporting a blank (5) (6) , which has been always used in incremental forming (3) (4) . Because miniaturization of a backing plate also can be a bottleneck of incremental micro-forming, no backing plate was used in this study.…”

“…The authors and colleagues applied this method to forming of various miniature shell products of aluminum foil without using any die, mould and backing plate (5) (6) . The miniature products formed in reference (5) were pyramids with base sizes of 1 mm and 10 mm, 1 mm-long car body, dots 0.1 mm in diameter and six letters of 2.83 points (1 mm), while those in reference (6) were pyramids with trigonal, pentagonal and nonagonal bases, a combined shell structure of two quarter cones and two quarter pyramids, a bulged spade on a truncated cone and a twisted pentagonal pyramid.…”

“…The miniature products formed in reference (5) were pyramids with base sizes of 1 mm and 10 mm, 1 mm-long car body, dots 0.1 mm in diameter and six letters of 2.83 points (1 mm), while those in reference (6) were pyramids with trigonal, pentagonal and nonagonal bases, a combined shell structure of two quarter cones and two quarter pyramids, a bulged spade on a truncated cone and a twisted pentagonal pyramid. All the bases of miniature products in reference (6) were inscribed in a circle 1 mm in diameter. From the experimental results, it was found that pure water worked effectively as lubricant to reduce the forming forces between a single point tool and aluminum foil (5) .…”

Comparison of Sequential Light, Scanning Electron and Atomic Force Examine Methods for Electron Beam Lithography Generated Patterns

“…Microfabrication and nanofabrication are revolutionary milestones in fabrication technologies, many enlightening methods have been introduced e.g., micro-EDM [1] , micro incremental forming [2] , microlithography [3] , nano-imprinting [4] etc. Microfabrication is also been recognized as micromanufacturing in term of describing the process for fabricating miniature structures.…”