A cell fusion technique using micromechanical silicon devices has been developed. It permits a number of one-to-one cell fusion operations between two different biological cell groups to be carried out simultaneously, instead of the conventional collective fusion operation. A matrix array of 1584 microchambers, each containing a single pair of cells, have been fabricated on a 3-inch silicon wafer. Fusion of the paired cells is induced by electric pulses applied between electrodes embedded in the microchambers. In order to feed a pair of cells from two different cell groups to every microchamber, a cell carrier made of a silicon wafer has been developed. A single cell particle is absorbed to and released from the port of the carrier plate. The carrier plate is transferred over the microchamber plate and simultaneously releases cells into the microchambers. Repeating this operation independently for the cell groups A and B, a single pair of AB is formed in every microchamber. It is observed that pairs of lettuce cells are successfully fused in the microchambers.
The experimental modal analysis is widely utilized in dynamic design of machines to meet the requirement for less vibration and noise, and further the sensitivity analysis is newly adopted to find the appropriate points to reduce the vibration due to structural modification for better dynamics. On the contrary, concerning about the noise induced by the vibration, the present analysis consists of two steps: after the vibrational sensitivity analysis, the noise may be predicted through coefficient of sound radiation, for instance, which yields rather time consuming and inaccuracy. This paper describes the development of a new acoustic sensitivity analysis, which is directly based on the result of acoustic modal analysis when measuring the sound with a microphone against the excitation force. This analysis can provide very useful informations on which parts of the structure should be modified in order to reduce the noise with easy-use and enough accuracy. A simple plate structure and a complex automobile engine are used to confirm the effectiveness of the acoustic sensitivity analysis developed.
Although a mold is one of the most powerful tools in the production activity, mold designers depend on their experience and intuition to determine mold configurations. Mold CAD systems, in these days, can assist mold designers from initial mold design to performance analysis. But mold designers are forced to control the whole design process and to make no mistakes. Basically, a mold shape is generated by (1) reversing a product shape in a blank shape and (2) dividing it into two or more parts, named a cavity, core and side-core, respectively, along with parting lines. In this mold generating process, designer must at least determine the parting direction and parting lines in order to be able to eject products from the mold, and not allowing mistakes. It would be ideal if the system automatically generates the mold shape model from the given product model without any assist from the designer. As the first step to construct the ideal mold CAD system, this paper presents the algorithm which determines the ejectability of products from a mold in the given parting direction, including automatic generation of parting lines, applied to CSG·B-Reps dual solid product model.
In this paper, two types of bolted joint with plastics bolt, Type 1 and Type 2, are examined for the purpose of absorbing the energy in the joints. The bolt is made of polycarbonate(PC) and its size is M 12. The clamped members of the both joint types are composed of a cylinder and a steel crosshead. The cylinders of Type 1 and Type 2 are made of PC and steel respectively and for Type 2, O-ring is attached to the crosshead. The relations between the allowable energy and the corresponding tightening force in the both joint types are derived and compared with the experimental results. As the result, obtained conclusions are summarized as follows: (1) When the residual pressure required on the bearing surfaces in a joint is relatively low, Type 2 is superior in energy absorption to Type 1. (2) When the residual pressure required exceeds a certain value, energy absorptivity between these two types is reversed. (3) Maximum allowable energy and the corresponding optimum tightening force could be predicted fairly well by use of simple calculation method proposed in this article.
Electrolytic single diamond cutting are performed to make clear the grinding mechanism of the electromechanical grinding at high work feed rate. Single diamond tools with any wear flat area are used to simulate the wear of abrasive grains on peripheral surface area of the grinding wheel. Effects of electrolytic action on frictional components in single diamond cutting forces are investigated with reference to proposed empirical cutting force equations. Summary of results are shown below. (1) Cutting forces in a single diamond cutting with any wear flat area are confirmed experimentally to consist of three components: cutting force, ploughing force and frictional or sliding force. Frictional components contains three important factors, namely compressive yield stress Kn, friction coefficient μ and wear flat area. (2) Frictional components decrease by electrolytic action, which are mainly induced by the reduction of compressive yield stress. Friction coefficient are held constant even by the applied electrolytic action. (3) Sudden stop equipment shows the preferential dissolution of hardened second phase particles in Al-Si-Cu alloy and alloy tool steel SKD11. Preferential dissolution may cause the reduction of the compressive yield stress of workpiece and/or contact pressure between workpiece and grinding wheel.
It is important to make clear how the shape of tooth profile error affect to the rotational vibration of a pair of spur gears. The effect of the amplitude and the shape of tooth profile error to the amplitude of the vibration is discussed in this paper. The vibration system which is discussed here is consist of the spring action of meshing teeth and the moment of inertia of the gear blanks of a pair of gears and the tooth profile errors. The amplitude-rotational speed characteristics of vibration system are numerically obtained with the finite difference method. The vibration waveform of each test gear is measured by the gears meshing tester which is specially made for this purpose. It is found that the vibration bahavior of gears obtained by the numerical calculation agrees with experimental results. The formulas which express the relations between the main resonance component of the amplitude-rotationl speed characteristics and the each component of harmonic analysis of tooth profile errors are induced.
The study deals with the method of the automatic measurement of workpiece dimensions being arbitrarily set on the table of a 3-dimensional coordinate measuring machine. The measuring path is in advance generated on the basis of a personal CAD/CAM system employing the solid modeling technique. The coordinates of workpieces defined by CAD are different from those of the actual workpieces on the table. To know the position and attitude of workpieces, the image data taken by an ITV camera is compared with CAD data. Based on the information, the measuring path is altered, that makes it possible to actually measure workpieces. The method is experimentally found to be valid.
Following the precision machining method with a control system ( Workpiece-Referred Form Accuracy Control: WORFAC ) proposed in the previous report, in this report the system and an experiment with an in-process measurement sensor, K-HIPOSS, and a parallel leaf-spring micro-tool servo are described. Comparing to the standard HIPOSS model, K-HIPOSS features a long working distance and a wide dynamic range of about 6μm, so that it is more suitable for in-process measurement. A parallel leaf-spring micro-tool servo uses a piezoelectric actuater to drive the diamond tool, of which displacement is detected by the strain-gauges on the leaf-springs. This strain signal is used for compensating the hysteresis of a piezo electric stack and improving the motion performance of a feedback loop. The WORFAC experiment was applied to a simple plane-mirror turning and the result demonstrated its perfect compensation for disturbances.
A novel optical profiling method is proposed, which is nearly insensitive to vertical vibrations and able to measure the roughness of supersmooth surfaces on a long track. This method makes simultaneous height measurements of both a measurement position and its surroundings and perform subsequent digital subtraction of the latter from the former to obtain the roughness data. An instrument incorporated with this method is shown to have a height sensitivity of 0.1 nm under normal vibrational circumstance (0.4 cm/S2). Data obtained from measurements of a disk substrate, a mirror, an optical flat and a silicon wafer are included.
The study deals with the friction drive as a precise linear feed mechanism and the application to feed component of an ultra precision lathe. An experimental setup of the friction drive is subjected to investigation to make clear inherent physical phenomena of a friction drive such as the relationship between slip and load under the feed speed of 0.1-10 mm/s. The practical precise linear feed mechanism for the ultra lathe is designed, combining the friction drive with an air slider in reference to the experimental results. It is experimentally confirmed that the feed mechanism having a linear encoder with a resolution of 0.2 μm provides the rapid step response and the positioning accuracy of ± 0.4 μm over a travel of 50 mm.
This paper presents a non-contact measuring system for pitch errors of a gear. The system has two laser beams which are equivalent respectively to a fixed probe and a measuring probe in a contact measuring system. One of the beam is used to making a trigger signal at each passing of a tooth. The other beam is used to detect displacement of a tooth flank from an origin. At every time when a tooth surface crosses the laser beam for a trigger, a displacement of another tooth flank is sensed by the other beam. The pitch errors are obtained from the sampled set of displacements. There is no mechanical interference between probes and a test gear in this system, therefore, high speed measurement is to be possible. In this measuring system 3-4 s was needed to measure pitch errors of a spur gear with 48 teeth. In the measurement, the maximum deviation was estimated to be 1.0 μm. In order to obtain more accurate pitch errors by averaging ten values of repeated measurement, it took about 60-90 s for sampling. In this case, the maximum deviation was estimated to be 0.2-0.3 μm.
Property of the working surface of dressed grinding wheel is evaluated in term of the shape distribution of grain edges. The distribution, which is obtained by optical measurement of grain edge shapes, is greatly affected by grain material and dressing conditions; feedrate as well as dresser infeed can adjust it when the sharp dresser is used, while feed rate hardly change the dullness of grain edges when the worn dresser is used for fine dressing of GC wheel. Next, shape transition of grain edge due to collision with dresser is analyzed as a Markov process. The transition probabilities among the edge models is calculated and the effect of feed rate on the distribution is examined quantitatively.
Several studies on wandering motion of drill have been conducted so far. However, the drilling operations in these earlier reports were carried out in the fixed workpiece, which wandering motion is under restricted condition, consequently there was a large difference between the actual wandering phenomenon and the measured result. Therefore, in this report, a new apparatus was designed to measure the wandering motion of drill. By using this apparatus, workpiece could be moved freely in a plane of right angle to drill by wandering motion of drill. Detecting the displacement of workpiece, the relationship between wandering behavior and point shape of drills were examined. From the experimental results, relationship between point shape of drill and wandering motion was clear, and it is confirmed that the apparatus developed here is available to detect the wandering behavior of drill at the beginning of cutting. Moreover, this apparatus is also useful to investigate the accuracy of drill.
Cutting performance of SiC-whisker (SiCw) reinforced ceramic tools on the machining of gray cast iron was investigated. In continuous dry cutting, the toughened Al2O3 + SiCw tool exhibited a stable and prolonged tool life compared to the Al2O3 + TiC tool. The life of the Al2O3 + SiCw tool was about twice as long as the Al2O3 +TiC tool at the optimum cutting condition. Since groove wear was inhibited by the whiskers incorporation, the surface roughness of the workpiece after cutting was improved, resulting in the possibility of using the tool for finishing operation. Nevertheless, SiCw reinforced ceramic tool can not be applicable for cutting of the cast iron containing a large amount of ferrite phase. In the interrupted cutting, a significant improvement of the tool life due to whisker reinforcement was observed in the alumina based tools compared to silicon nitride based tools. However, the SiC-whisker incorporation was effective for inhibiting the groove wear for both alumina and silicon nitride based tools.