Tiny Parts Research Articles

Effects of Metal Powder Characteristics on the Compactibility and Sinterability in Micro Metal Injection Molding Process

Metal injection molding for tiny parts is called micro metal injection molding, “μ-MIM” which is considered to be one of promising process to manufacture the micro parts for various applications. In μ-MIM, the feedstock properties, particularly particle size and shape of metal powder are significantly important for the quality of micro parts. The purpose of this study is to investigate the effect of metal powder characteristics on the compactibility and sinterability. The three types of powders (3μm and 9μm water-atomized powders and 3μm gas atomized powder) were used for the comparison. The melt viscosity of the feedstock was utilized as an index for evaluation of compactibility by injection molding. Then the spring shape of green compact specimen was produced by the micro injection molding machine. The green density was also evaluated for compactibility of the feedstock. The density and grain size of sintered specimens were investigated by changing sintering temperature and time.

ハンドピッキングを用いたコークスおよびセミコークスの局所構造解析

Coal is a complicated mixture, which consists of inorganic matters and organic matters. Therefore, coke formed through pyrolysis of coal is also a complicated mixture. On the other hand, there are many reports for the relation between carbon structure of coke and the strength, and the carbon structure of bulk coke is used experientially as one of index for evaluation of coke quality. It is important for an essential understanding to get information based on the each microstructure because of complexity of coke. In this study, the technique of sampling arbitrary tiny parts was developed, and the carbon structure of the tiny coke partial was analyzed. Consequently, it was revealed that high quality coke had uniform carbon structure, but the structures of inferior coke were heterogeneous. It was recognized that crystallinity of coke is influenced by the kind of mineral matter and its distribution in addition to the type of organic matter such as soft carbon and hard carbon.

Victor Ambros

Victor Ambros

A lightweight linear actuator with concentratedly placed stationary coils

This paper presents a novel lightweight linear actuator using permanent magnets and having its coils on the stator concentratedly. The rated force is 6 N, the stroke is 30 mm, and the weight is below 300 g owing to its unique structure. The machine is to be applied to, e.g., a pick-and-place actuator of tiny electronic parts, and the performance for the application is confirmed through experiments with a prototype. © 2005 Wiley Periodicals, Inc. Electr Eng Jpn, 153(4): 59–67, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20158

2201 マイクロ金属粉末射出成形品の寸法精度向上のための製造技術(S28-1 粉末成形とその評価(1),S28 粉末成形とその評価)

This study aims to develop processing techniques to improve dimensional accuracy of tiny parts produced by micro metal injection molding (μ-MIM). Micro dumbbell specimens were molded by a micro injection molding machine, which can be monitored with the mold pressure in injection process measured at the both side chucking portions. The effects of particle size distribution of stainless steel powders on the mold pressure and dimension in green compacts and sintered bodies were investigated. The reduction of the difference in dimension of chucking parts of micro dumbbell specimens to 5μm was achieved by using the powder undercut below 5μm in particle diameter.

Camino al hogar inteligente

Today there are many projects related to intelligent houses such as Casa Internet, Madrid 2001 or its british equivalent in Watford, and most recently the Solar Decathlon´s project. Thanks to these proposals the domotic market gently opens to one day become what we could call as the intelligent “home”. Thought out the last few years, huge technological improvements have provided the buildings with brand new senses. However ,the idea of a comfortable home where the coffee maker would notice our awakening or the entrance door would suggest it’s closure after we leave, is still far away. A new path is opening in front of us, one that won’t end until all the necessary steps will be taken in the same direction, the merging of interfaces in the field of domotics. There are many domotic tendencies and possibilities discussed in this article, many options for one very same goal, control. Or even better, the capability of decision of tiny parts or hour home or office for a better and richer living experience.

マイクロ金属粉末射出成形品の寸法精度向上のための成形条件の最適化(S18-1 粉末成形とその評価(1),S18 粉末成形とその評価)

Micro Metal injection molding (μ-MIM) is one of premising processes to manufacture tiny metal parts. Micro dumbbell specimens were molded by a micro injection molding machine, the mold pressure in injection process was measured at the both side chucking portions, and the effects of injection volume on the mold pressure and dimension in green compacts and sintered bodies were investigated. Dimension of molded parts and sintered ones were correlated by injection volume and then the possibility for dimensional control by the mold pressure was shown. It was also confirmed that the micro injection machine has some advantages for producing μ-MIM products.

Lightweight Linear Actuator with Concentratedly-placed Stationary Coils

This paper presents a novel lightweight linear actuator using permanent magnets and having its coils on the stator concentratedly. The rated force is 6N, the stroke is 30mm, and the weight is below 300g owing to its unique structure. The machine is to be applied to e.g. a pick-and-place actuator of tiny electronic parts, and the performance for the application is confirmed through experiments with a prototype.

Anomalous diffusion on dynamical networks: a model for interacting epithelial cell migration

We propose a model for cell migration where epithelial cells are able to detect trajectories of other cells and try to follow them. As cells move along in 2D cell culture, they mark their paths by loosing tiny parts of cytoplasm. Any cell moving on a surface where other cells have moved before faces a network of cell trajectories, which it tries to restrict its motion onto. With the Tsallis modification of classical thermodynamics one can solve the relevant Fokker–Planck like equation and obtain experimentally testable distribution functions. We compare the model to experimental data of normal mammary epithelial cells and cells which have been genetically manipulated to change their cell–cell interaction.

Non-adhesive direct bonding of tiny parts by means of ultraprecision trapezoid microgrooves

The study proposes a new method of bonding two small parts without the use of any adhesive by making use of ultraprecision trapezoid microgrooves on the surfaces of each part. These trapezoid microgrooves allow small parts to be bonded together with high positioning accuracy due to a wedge effect and an adhesion phenomenon between the mating surfaces. Ultraprecision trapezoid microgrooves are created by using an ultraprecision machining center having 1 nm positioning resolution and a diamond milling cutter. From experimental and simulated results, it is found that the bonding strength in general increases with decreasing wedge angle. The effect of the wedge length on bonding strength varies with the wedge angle where the strength increases with increasing length for wedge angles greater than 8° but increases with decreasing length for wedge angles less than 8°.

Manufacture of diffraction grating on tiny parts by means of ultraprecision milling

The study deals with the manufacture of diffraction grating by applying the ultraprecision microgrooving technology. Microgrooving is performed by the use of a lathe-type ultraprecision milling machine having 1 nm positioning accuracy, together with a rotating diamond cutter. As an example of microgroove, a diffraction grating with 32 768 V-shaped grooves is fabricated in a pitch of 1 μm and a depth of 0.5 μm around the circumference of copper disk of 12 mm in diameter. The high-speed rotating cutter allows the microgrooves to be sharply machined without burrs and accumulative pitch errors, taking account of cutting order. The surface roughness of machined grooves is 1 nm (Ra), which experimentally shows good optical properties.

Manufacture of Micropropellers by Means of Ultraprecision Milling Machine

The requirement for producing metallic microparts for use in micromachines and/or micromechanisms will continue to increase. This study deals with the manufacturing of tiny parts, of mm-size, using micromachining technology and an ultraprecision milling machine, which consists of a z-motion table, a positionable spindle on it as the c-rotational axis, and an x-motion table. The spindle, which has a pseudo ball end mill composed of a single crystal diamond, is mounted on the x-table. A new manufacturing procedure is devised in order to create a propeller, 3 mm in diameter, as a representative micropart, based on the CAD data of the propeller. As a result, it was found that a functional machined propeller, with a surface roughness of 0.1 μm, can be mounted onto a micromotor shaft, 0.7 mm in diameter.

Homing in on vertebrates

Imagine being set adrift in a canoe in the middle of an ocean. Which way would you paddle? Most humans would be as lost as lost can be, but creatures such as pigeons, turtles and whales have no difficulty navigating in such circumstances. How they do so remains one of the biggest mysteries in the behavioural sciences, at the centre of which is the question of how organisms might sense the Earth's magnetic field and use it for navigation and homing (a topic with a chequered history — see box, overleaf). The mystery, however, is gradually being solved, and the latest instalment in the story comes in Walker and colleagues' study of rainbow trout (page 371 of this issue). All known sensory systems have specialized receptor cells designed to respond to the external stimulus, and these are always coupled to neurons to bring this information to the brain. In modern times the main objection to claims that magnetoreception is genuine was biophysical — that there was no evidence of appropriate receptors. The first clue towards meeting this objection came in an obscure place, the teeth of small molluscs. The late Heinz A. Lowenstam discovered that the major lateral teeth of the chitons are capped by massive amounts of a hardening agent, the permanently magnetic mineral magnetite (Fe_(3)O_4) (Fig. 1). Later, with the development of ultrasensitive superconducting moment magnetometers, came the recognition that tiny (parts per billion) levels of biogenic magnetite are naturally present in animals as diverse as insects, birds, fish and even humans. The final crack in the biophysical arguments against magnetoreception came with the discovery of the magnetotactic bacteria and protists (Fig. 2), which possess linear chains of either single-domain magnetite or greigite (Fe_(3)S_4). They provide unequivocal examples of biological activity being influenced by the geomagnetic field.

Computational methods for design and control of MEMS micromanipulator arrays

As improvements in fabrication technology for microelectromechanical systems, or MEMS, increase the availability and diversity of these micromachines, engineers are defining a growing number of tasks to which they can be put. The idea of carrying out tasks using large coordinated groups of MEMS units motivates the development of automated, algorithmic methods for designing and controlling these groups of devices. We report on progress towards computational MEMS, taking on the challenge of design and control of massively parallel arrays of microactuators. Arrays of MEMS devices can move and position tiny parts, such as integrated circuit chips, in flexible and predictable ways by oscillatory or ciliary action. The theory of programmable force fields can model this action, leading to algorithms for various types of micromanipulation that require no sensing of where the part is. Experiments support the theory.

Advanced Three-Dimensional Micromachining by Means of Ultraprecision Milling. 2nd Report. High-Precision Tool Chuch System.

This study deals with the improvement of ultraprecision micromachining technology by devising a tool chucking mechanism. A lathe-type ultraprecision milling machine equipped with an improved pseudo ball end mill as a cutting tool was designed to create tiny parts with nm-order surface roughness. The dimensional accuracy and surface roughness are significantly influenced by the rotational accuracy of the pseudo ball end mills, which are mounted on the spindle using a chucking mechanism. To meet the requirement, a new chucking mechanism was devised as a substitute of a three-jaw-type chuck to improve the setting repeatability of the tool. The new chucking mechanism enables the tool to be rightly positioned within the range of 0.2 μm. As a result, the ultraprecision milling machine equipped with the chucking mechanism and the tool was able to produce a traditional Noh mask on a copper surface of 1 mm in diameter with a surface roughness of 58 nm (p-v). In addition, it was found that the contour line pattern observed on the mask surface was due to a three dimensional cutter mark.

超精密フライス加工機による微小部品加工の試み

The requirement of producing metallic micro-parts for micro-machine and/or micro-mechanism will be increased. The study deals with manufacturing of tiny parts in mm-size by use of micro-machining technique of an ultra-precision milling machine. The ultra-precision milling machine, consisting of Z-motion table, positional spindle on it as C-rotational axis, X-motion table, is equipped with a pseudo-ballend mill composed of a single crystal diamond tool mounted at the top of high speed air spindle on X-motion table. A new manufacturing procedure is devised to manufacture a propeller of 3 mm in diameter as an example of micro-parts by use of ultra-precision milling machine. On the basis of CAD data of a propeller, two kinds of NC data, for front face and back one, are generated to machine the whole shape together with preparation of jig. It is found that the machined propeller mounted to the micro motor shaft works.

Selwyn On Winged Feet

SELWYN ON WINGED FEET / Barbara Phillips February 29 I tried to teU MUdred about the cemetery today, but as soon as I started on the business at Father's grave—I hadn't even gotten to what happened at Walter's—she put me off: "Oh, please." "But let me teU you about WaI-" "Stop it!" She clapped her hands to her ears. "You and your relentless imagination! It's driving me crazy!" Well, I'm sorry for that, but it's keeping me sane. Step by step, then. I intended just to nod to Father on my way to Walter, but those same sounds—the dry cluttering, the Uttle burps and farts—made me stop. And a good thing I did. There is even less of the old miser to see than last month. That beaky curve to the nose and the long cleft above the upper Up are gone, aU fuzzed out. Bony shoulders blurred. Things are getting eaten away. But neatly! No rags of flesh hanging off the cheeks. The worms nibble and digest, nibble and digest, tucking the debris inside their tiny lower parts, processing it. Depositing neat Uttle BBs of hard shit around the perimeter of Father's dwindling corpse. A tidy goodbye. At least to part of him. Two months dead and stiU I can't make out what's happening below the waist. Father wouldn't stand for it. "Stop fingering your lower decorations, boy!" Yes, sir! Then to Walter's gravestone, and at first it was the usual circus, the numbers flashing and screaming Uke some vulgar neon sign: 1976—1992! As if the arithmetic wasn't already burned into my brain. Six from twelve leaves six. He wUl never be more than sixteen. Steadied myself for the tears to begin, but then I saw it— a diploma!—roUed up and tied, resting like a flower on his chest, in the V between his crossed wrists. I drove home writing my boy a fine epitaph. Magna cum laude; Classical Ut, Ancient Greek. Here at Berkeley, or Stanford—more than affordable, what with Father's estate. Harvard doctorate. Professorship at Yale. Endowed chair. But then the old questions came: Would he have wanted to go to college at aU? Did he say? Did I listen? These uncertainties about Walter wiU break my heart. Can't even recaU his face, not clearly. AU I get are memories of ancient snapshots. Walter propped in his infant seat, teething on The Missouri Review · 193 the leg of Louise's Barbie doU. Walter in baby pajamas, straddUng MUdred's hip, tugging at that daffodiUy nightgown she used to wear. "Don't take a picture of me now," she laughed, but I wanted to capture her in that nightgown. Then I waited for her to calm hurt and come back to bed. Got home from the graves to find her at the maUbox, head bent over a page from an opened envelope. It wasn't till the car door slammed behind me that she looked up. Her eyes were relaxed into their long-ago, placid, pale-lashed softness. But of course. It was a letter from Louise. "She's taken that job," Mildred said, and went back to her reading. A while later she was still mild-eyed, so I tried: "Did he ever talk to you about music?" I seemed to remember Walter diddling with an electric guitar. "Or Uterature? Just imagine, if he had become a writer." Her mouth tightened, pulling the skin at the corners into pouchy furrows. I shouldn't have barreled on about the graves. February 29, p.m. Depressed, and thought a jog would help. Ran the steep trail to the crest (behind that same woman for a whUe—magnificent haunches!) and for a short time did feel better: muscles pushing, lungs pulling, aU that mattered was the climb. But at the stretch where the path levels out, the trapped fog and the sharp, woody smeU of eucalyptus threw me back a year. Accident, the poUcemen said when they came to the door. Your son. I couldn't teU if the wet on my cheek was mist or tears. God, those first...

The Antarctic Treaty System: Environmental protection, conservation, and the question of competing use

The Antarctic Treaty System consists of the Treaty itself, over 130 recommendations made under it, the Agreed Measures for the Conservation of Antarctic Fauna and Flora, the Convention for the Conservation of Antarctic Seals, and the Convention for the Conservation of Antarctic Marine Living Resources. Consultations have been held among parties to the Antarctic Treaty to elaborate an Antarctic minerals regime. It has become clear that how to deal with issues of competing use has begun to emerge as an important political question. In such a context the development of an Antarctic conservation strategy is a potentially helpful step. Competition of use, when it occurs, will be localised and different in different areas. In only tiny parts will it be severe, but these parts may be the biologically richest coastal areas. Various activities and their possible interactions are considered. It is concluded that any arrangement of Antarctic activities which given an automatic priority of one over others is wrong. Similarly, no activity should be subservient to all others. An Antarctic conservation strategy needs to be developed and in its operation the concept of adaptive environmental assessment and management needs to be applied. Within the Antarctic Treaty System there are moves towards assessment. What is needed now is a framework within which such concepts can operate; that is, a conservation and environmental strategy.

Re-Reading English and the Uncommitted Reader

Full speed ahead with transactions and down with behavioral objectives! Henry decries the age of behavioral objectives and considers them to be a major force in confusing us and, by innuendo, holding up the wheels of progress. I couldn't agree more. It's about time state departments of education and local school leaders really took a look at the whole complex learner in the whole complex setting and realized that fragmented bits do not an educated citizen make. It's about time leaders in English Education as well as those in the other disciplines accept the fact that learners learn best when they deal with problems of significance to them. Drill books focused on fragments of language and assessments which break up a discipline into tiny parts should be banned.