Results of experimental examinations are reported on the surface roughness measurement of replicas, using a new surface tester. The touching force of the stylus of this tester is only 4 mg. The force of 4 mg is equal to the opening force of a break switch used as a sensor of a servomechanism in the tester. The opening force presumably contains some adhesion force. The results of measurement show that the adhesion force is about 10% of the touching force. Now, surface roughness of a sample piece and its replicas are measured by this tester. For replica materials, two kinds of plastics are used; one is a new dental impression plastics, and the other, a laminated plastic plate composed of three layers. Both of them are presumed to be superior to conventional replica materials in copying accuracy. The sample piece has a roughness about 3 μm of peak-to-peak value. Roughness values of it and its replicas measured by this tester, are well agreed with the results measured by light interference photomicrographs.
To study the dynamic behavior of the Bourdon tube for bending is an important subject for making a better accuracy one, and also for the design of the good bender. In this paper, the plastic bending of flat-tube with thin thickness and flat-oval cross section are analyzed. For calculations of the stress and the strain, the Bourdon tube with idealized cross section is assumed, and to obtain the solutions, this idealized cross section is separated into two parallel parts. Considering boundary conditions, the solutions about the stress and the strain in plastic bending of the Bourdon tube are decided. For the calculations of the bending moment of it, the material with property of linear-incleasing work-hardening type is assumed, and the solutions by using plane strain theory are obtained. For n=1 (n, work-hardening coefficient), the numerical graphs using these solutions are drawn up. Next, the experimental values of the bending moments are compared with these graphs. From these results, the authors obtain the conclusions that representation of bending moment for idealized cross section can be applied sufficiently to the Bourdon tube with flat-oval cross section.
In gun drilling, the motion and attitude of the drill tip in a hole are indispensable to know the fundamental phenomenon and the accuracy of the hole is dominated by them. They can be obtained from the oil film thickness between the wear surface of drill and the hole wall. In our study, the variation of oil film thickness is transformed into the variation of the effective resistance, by means of inductance type of four small pickups and universal type of strain meter. As the output obtained shows the reciprocal of oil film thickness, linearizing circuit is designed by operational amplifier divider. Within the measuring range of 100 μm, the linearized output is 0.03 V/μm and the maximum noise is 30 mVp-p. The error of linearity is within ± 0.7 μm. The measuring error of pickup due to temperature depends on a conductivity change of the coil wire. By balancing the DC activated bridge circuit, the errors can be reduced within 1.0, 2.0 and 3.9 μm respectively at oil film thickness of 10, 50 and 100 μm. An example of practical measurements is shown.
The present paper deals with an experimental study of the effects of land shapes and clearance angles on dyamics of the metal cutting process from the view point of chatter control. The dynamics of the metal cutting process is expressed by a stiffness vector of the process, which can be obtained by subtracting the stiffness vector of the structure measured when out of cutting from that measured during cutting. In order to measure those vectors a transfer function analyser and an electromagnetic exciter are used. The measurement of the stiffness vectors during cutting are executed on condition that the tool is excited harmonically in the direction of the thrust force during orthogonally cutting and the regenerative and mode coupling effects are excluded. Chatter control effects are evaluated by the amount of energy expended at the cutting process in a cycle of vibration. Experimental results show that chatter control effects of lands are very large comparing with those of small clearance angles. It is found also that degree of the effects of land shapes solely depend upon the length of the land projected onto the mean cutting direction when the other conditions are retained.
The automatic adjustment system of machine level is studied by the model experiment. Three kinds of the methods are proposed for automatic adjustment operation; the feedback control method, the fixed model method, and the parameter identification method. It is shown that the feedback control method is efficient for the rough adjustment and that the fixed model method and the parameter identification method, on the other hand, prove useful for the precise adjustment. By the fixed model method, the rapid convergence in adjustment is obtained only if the system characteristics are not so far from those assumed on the model. However in the parameter identification method, the rate of convergence in adjustment does not depend on the system characteristics.
Theoretical analyses for grinding mechanism have been performed almost in grinding process with constant depth of cut and not so in grinding process with constant load. In this paper, theoretical considerations for grinding mechanism in grinding process with constant load are performed by statistical method. Namely, the rate of effective cutting edges, the distribution of grain depth of cut, grain cutting half width, grain cutting area and load assigned area of grain, and the roughness of ground surface in grinding process with constant load are analyzed theoretically. Further, the results of analyses obtained in this paper are available for honing, superfinishing and belt grinding process successfully.
The magnetized ball was included in the linear ball bearing and the measuring coil was set up also in the shaft so as to study three dimensional motion of the ball during operation, and an electric current of the coil circuit caused by the magnetic flux change owing to the motion of magnetized ball was recorded. Moreover, the theoretical analysis concerning such measuring method was performed and that was signified experimentally. The behaviours of ball about various bearing speeds, loads and lubrication conditions applying above mentioned method were measured. As this result, it was ascertained as follows. (1) The ball of linear ball bearing generates 6-19% rotational slip on the contact portion between ball and shaft. (2) The rotation axis of ball also changes about 10-30 degree on that contact portion. (3) The ball in the pocket portion of bearing retainer does hardly rotate and slides on that place pushing one another.