Kensuke Tsuchiya

Micro Handling with Rotational Needle-type Tools under Real Time Observation

Abstract This paper analyzes human operation of an arbitrary single micro object under 1mm while observing the object and systematically studies the design of a micro handling system to perform such operations. This system features the following mechanical elements; (1) a needle-type tool with a tip as small as the micro object to handle; (2) a palette engraved with micro structures to hold the micro object; (3) a driving mechanism not only to translate the tool but also to rotate it; (4) a microscope to observe the tool operation in real time. As the microscope occupies a large volume, the system sets the mechanism elements in a centralized arrangement so the micro object, tool tip, center of tool rotation, microscope focus intersect at one point and the remaining elements are radially arranged around it. We used this system to conduct several operations including a SEM monitored micro house construction by assembling and bonding walls and roof, an optical microscope monitored microscopic insemination by inserting a sperm into an ovum, and a fluorescent microscope monitored DNA surgery cutting out an arbitrary gene from a chromosome. These operations verified the effect of the above design guideline, that is the group of mechanism elements and their construction.

A rotating cutting tool to remove hard cemented deposits in heart blood vessels without damaging soft vessel walls

Abstract A rotating cutting tool was developed to remove hard cemented deposits in the heart blood vessels without damaging the soft vessel walls. The new tool has a “grater-like” configuration which is made of anodized aluminum with 20|im high micro-blades on a 2mm diameter tip, and it rotates at 200,000 rpm underwater. An evaluation test demonstrated the feasibility of the new tool by cutting the hard shell, and not the soft white, of a hardboiled egg. The water pressure forms a hydrodynamic film around the tool tip to press down the soft tissue, protecting it from any unwanted cuts.

Iterative imprint for multilayered nanostructures by feeding, vacuum forming, and bonding of sheets

The authors proposed an iterative imprint method for multilayered nanostructures. A thermoplastic sheet is fed onto a nanostructured mold and thermally imprinted by vacuum pumping between the mold and the sheet. Next, the imprinted sheet is thermally bonded onto a sheet that had been formed in the preprocess and that is held by an upper punch at the position opposite to the mold, and then the upper punch picks the sheet up from the mold. Repeating these processes realizes precision multilayered structures while maintaining horizontal positions of the upper punch and the vacuum-forming mold. This method will lead to the low-cost, high-accuracy fabrication of three-dimensional photonic devices. The authors formed 400×400×270 nm3 square hollows with an 800 nm pitch on the surface of a polymethyl methacrylate sheet of 1 μm thickness. The decrease in the light intensity diffracted by the mold surface as a result of the filling of the sheet was monitored in real time during the forming. The authors also success...

Single-pass forming for three-dimensional microstructures by high-speed shearing of multilayer thin films

The authors propose a single-pass forming technique for three-dimensional microstructures by shearing multilayer thin films. At a high strain rate, when strain is applied to a material at a speed higher than that of plastic wave propagation, the material is generally fractured without plastic deformation. In their experiment, a punch freely falling onto the back of a microfabricated mold allowed a high strain rate to be applied to the substrate. Multilayer thin films of eight evaporated layers of 250-nm-thick Si and SiO were successfully deformed to the bottom layer when the strain rate was over 1000–1500 s−1.

Cell Culture in a Closed Nano-Space

The minimum size of a closed nano-space in which cells can survive was determined using 4-nl nanowells. One or two cells could divide in the nanowell. Our results suggest that the cell division activity in the nano-space is determined by the conflict between intercellular effects and consumption of substrates.

Development of micro-scale tensile fatigue test system

We developed a micro-scale tensile fatigue test system, which can test specimens fabricated from bulk materials. In this system, a probe is attached to a micro-manipulator and the micro-manipulator enables accurate initial positioning and applying tensile stress. In this paper, we present the system and the result of tensile tests and tensile fatigue tests on the specimens which are made of coarse-grained magnesium alloy, AZ31. The tensile tests suggests that the system can apply accurate tensile stress to the micro-scale specimens and the tensile strength of micro-scale structures is much stronger than that of bulk materials. And the tensile fatigue test indicates that the system can apply intended cyclic tensile stress.

Measuring mechanical properties of micro structures using micro manipulator with low rigidity

The authors propose a method for measuring a micro force using a micro manipulator with low rigidity. In order to understand micro scale phenomena and design better micro devices, we have to do much more strength tests or destructive tests on micro objects, such as to apply some force and detect its behavior, response or deflection. We developed a system to move a probe along 3 axes. The tip end of the manipulator could be shaped into a suitable shape for a target. Using the system, we carried out three strength tests of micro objects, such as measuring mechanical properties of nanowire, shear strength of fixed abrasive grains and mechanical strength of chromosomes. Through these demonstrations, we confirmed the validity of our proposal.

Preventing Misuse of Consumer Products

Accidents with consumer products originate from either product defects or misuse. These two explicit causes result from aging degradation, coupled design, or in some cases from causes that are unknown. We analyzed over 600 cases of past accidents with consumer products in the Japanese market. Of the 309 cases of product defects, 51% were caused by aging degradation, and coupled design was responsible for 66% of the 296 cases of misuse. Evaluation, from the viewpoint of axiomatic design, of these coupled design caused misuse cases revealed that over half of them had coupling of the operational functional requirement in the design stage. These cases consist about 38% of the 296 misuse cases. Instead of blaming the user for misuse, if the designer carefully removes such coupling in the design stage, such accidents can be avoided. In the actual design work, changing part configurations, or adding sensors or interlocks can decouple operational functional requirements.Copyright

Sub-wavelength Pitched Cubic Mosaic Multi-layer Precisely Pressed by Nano-features Mold for Multi-functional Optical Elements

The new manufacturing process for the sub-wavelength, 200–400 nm pitched cubic mosaic multi-layer structure was designed. The two materials with the high/low refractive index form the mosaic structure for multi-functional optical elements such as polarizers or color separators. The structure could be precisely pressed by a nano-features mold with the convex mosaic pattern. This paper proposed two processes even at early development stage: an all-at-once press of the mold on the multi-layered sheet at several meters per second, and a repetitious press on the about 1 µm thick one-layered sheets, providing the other material sheet alternately.

Development of a Dicing Blade with Combined Structure Utilizing Photocurable Resins

工作物を高能率で切断するため,スロット付きセグメン トタイプのダイヤモンドカッタが広く用いられている.ス ロットの存在が切り屑の逃げ場を提供し,自生発刃作用を 活性化させ,加工液の加工点への浸透を高めるなどの理由 で,切断抵抗や切断温度の低下に効果があることがよく知 られている.また,切断抵抗の抑制は工具の寿命を長くし ている. ダイヤモンド切断砥石には,ダイヤモンドカッタとダイ シングブレードがある.アスファルト道路の切断などに用 いられるダイヤモンドカッタはスロットのある剛性の高い 台金の外周に砥粒層のセグメントが取り付けられている. 現在,外周径が 0.1 mから 3.5 mまでのものが製作されて いる.大口径になるほど台金の高速回転によるアンバラン ス等による横揺れが起こり易く,剛性の低い厚さ 1 mm以 下のカッタの利用は困難とされている.一方,半導体部品 に使用されるシリコンウェーハやセラミックス,水晶など の硬脆材料の切断に利用されているダイシングブレード は,外径が 50 mmから 150 mm程度のもので,カーフロス を低減させるため厚さが 0.2 mm以下の薄いものが一般的 に使用されている.そのため,通常刃物全体が砥粒層で構 成された一体構造をしていて,オールブレードタイプある いはコンティニュアスタイプと呼ばれている.しかし,従 来の熱硬化性樹脂からなるダイシングブレードは,高温の 熱を加える工程において熱収縮と反りが生じ,薄形のスロ ット付きブレードの製造はできないと考えられてきた.こ れに対し,著者らはブレードの結合剤に光硬化性樹脂を用 いることでこの問題を解決し,極薄ブレード(1)および 三層ブレード(2)の開発を行った. 本論文では,光硬化性樹脂を用いたブレードの高性能化 を果たすために,光透過の制御ができるマスクを活用して, スロット付きブレードの製作を検討する.さらにスロット 付きブレードの切断品質を高めるようなブレードの開発を 行った.これら三層ブレードやスロット付きブレードは, 厚み方向や円周方向に所定の構造を有することから,構造 制御型ブレードと称している.