Grinding Load Research Articles

Processing Characteristics of Structured Lapping Films under Grinding Load Control

Pyramidal structured lapping film, which has minute pyramidal structures formed by abrasive grains and adhesives on polyester films, is newly developed finishing tool[1,2]. It is said that the tool has eminent grinding characteristics, mainly, good finished surface quality because chips generated during grinding process can escape into spaces between pyramidal structures, and high grinding efficiency because new abrasive grains come out from inside of the pyramidal structures during grinding process. However, finishing characteristics of this grinding tool have not yet been fully explained. In this research, the grinding experiments were conducted, focusing on the efficiency of grinding. The grinding forces were measured to examine the state of the surface of the tool. In addition, to improve the grinding efficiency using this tool, a method for changing the grinding load continuously while processing was used. This method was intended to enhance the effective chip generation and new abrasive grain emergence. As a result, stock removal of the workpiece was increased more than when the grinding load was kept constant. Moreover, using scanning electron microscope, this new grinding tool surface was observed, and its effectiveness was examined.

Strength and Power Determinants of Grinding Performance in America's Cup Sailors

The purpose grinding is a physically demanding component of America's Cup sailing that is important to overall team performance, but little research is available on the determinants of grinding performance. We examined the relationship between various measures of muscular performance and the performance of upper-body grinding. Eleven elite male America's Cup sailors (33.9 +/- 5.5 yr, 97.8 +/- 12.5 kg, 186.0 +/- 7.1 cm) who performed grinding as part of their on-board role with extensive strength training experience participated in this study. Muscular performance testing examined the force, velocity, and power capabilities of the upper-body musculature, with upper-body push (bench press) and pull (bench pull) movements performed across loads of 10-100% of 1 repetition maximum (1RM). Functional grinding performance was examined for both forward and backward grinding and at 2 different resistances (moderate = 48 N x m, heavy = 68 N x m) using a land-based ergometer. Bench press 1RM and maximum force capability were the measures demonstrating the strongest correlation with forward grinding performance (r = 0.88-0.99 and 0.87-0.99, respectively), with the relationship increasing with grinding load. For backward grinding, there was a very strong relationship with bench pull maximum power (r = 0.85-0.98) in addition to 1RM (r = 0.90-0.95) and maximum force (r = 0.87-0.95). It appears that although maximal strength is a crucial muscular performance characteristic for grinding performance in all conditions, for backward grinding, there is the additional need to focus on the development of speed strength/power to maximize performance gains. This information was used by the Emirates Team New Zealand physical conditioner to develop a conditioning intervention to help improve grinding performance.

簡易粉砕機における高灰分炭の単体分離特性と灰分性状の影響

Three types of mill, such as a roll mill, a jaw crusher and a hammer mill, are used as coarse pulverizing devices to find suitable pulverizing conditions for mineral liberation of two kinds of high-ash coals. High-ash coal A, containing a large amount of quartz, and coal B, containing clay, were used as test samples. It was found that the roll mill was the most efficient device, and its characteristic of mineral liberation is suitable to implement an efficient mineral removal method. A grinding load above 1.0 kN in the roll mill for coal A had little effect on mineral liberation, however, the characteristic of mineral liberation and grindability were improved with increasing the roll rotational speed. On the contrary, the mineral liberation for coal B tends to improve at lower roll rotational speeds. Consequently, combustible recovery of 80% and mineral removal ratio of 60% were obtained in the mineral removal test of these coals. Furthermore, it is possible to reduce mineral matters in high-ash coal, such as low-grade coal, to 20 mass% by choosing suitable conditions for coarse grinding mills.

Development of Robot Control and Measurement for Unknown Geometric Surface Grinding

This paper introduces the control and measurement of a double parallel robot manipulator applied for unknown geometric surface grinding. A measurement system is developed to recognize a grinding path by a vision camera and to observe a grinding load by a current sensor. With the measured fusion information, an intelligent controller identifies the unknown geometric surface and moves the robot along the grinding path with a constant grinding load.

Effects of Supporting Stiffness of a Float and Grinding Load on Fundamental Grinding Characteristics of Ceramic Balls in Magnetic Fluid Grinding.

Magnetic fluid grinding has been developed as a new process which can remove materials in the finishing of ceramic balls some fifty to one hundred times more rapidly than the conventionally used lapping process. However sufficient data for the optimum design of the magnetic field have not been obtained. This paper presents experimentally the effects of supporting stiffness of a float and grinding load on removal rate and sphericity. The supporting stiffness of a float is defined as the derivative of magnetic buoyant force Fb of a float with respect to the distance h of a float from magnet. The lower supporting stiffness of a float provides smaller minimum sphericity, and the higher supporting stiffness of a float provides higher removal rate and rapidly decreasing rate of sphericity. Lower grinding load provides smaller minimum sphericity. From these results, the importance of the design of supporting system of a float can be realized in magnetic fluid grinding.

Magnetic Fluid Grinding for Innersurface of Pipe of Which Cross-sectional Shape is Hexagonal Circle.

In magetic fluid grinding for innersurface of pipe of which cross-sectional shape was hexagonal circle, a ratio of ground area to whole innersurface area of pipe and distribution of ground depth were studied experimentally and theoretically. Whole innersurface of pipe was ground under revolution speed of 125 rpm. But, over its speed, ground area decreased with the increase of revolution speed. The distribution of ground depth in innersurface of pipe wad changed by the change of revolution speed. Such both properties were explained by the change of grinding load which was the sum of magnetic buoyant force Fm of a float, a force Fs due to squeeze effect and a force Fd due to viscous damping effect. Therefore, if optimum grinding load was designed, the whole innersurface of pipe of which cross-sectional shape was hexagonal circle is ground sufficiently.

Magnetic fluid grinding. (2nd report. Grinding properties of a cylinder end with a float).

The grinding properties of an aluminum alloy cylinder end with a float were experimentally studied. Only the contact interface between the cylinder end and the float was ground, and a flat ground surface and sharp edge at the cylinder end were obtained. The removal rate with the float was 360 times larger than the removal rate without the float. The maximum removal rate was 3.38×10-3 mm3/m. The removal rate was observed as a function of the initial grinding load, revolution speed, abrasive grain concentration and abrasive grain size. It was concluded that the end of an aluminum cylinder could be ground effectively and accurately shape wise by magnetic fluid grinding with a float.

A study on magnetic fluid grinding. (1st Report, The effect of the floating pad on removal rate of Si3N4 balls).

A new grinding method using magnetic fluid containing abrasive grains was studied. This method was named magnetic fluid grinding. The magnetic buoyant force of abrasive grains produced by a magnetic field was generally too small to produce an effective grinding load. In order to obtain a larger grinding load, a new grinding tool, which was called the floating pad, was introduced. The floating pad in the magnetic fluid was very effective in increasing the removal rate in grinding. The floating pad was also effective for producing smooth surface and better sphericity of ball specimen. Therefore, it was concluded that the floating pad was and essential tool for practical magnetic fluid grinding.

支台歯形成時の切削圧の測定

When a vital tooth is cut or ground with air turbine handpiece, the load applied on the tooth should be controlled to be moderate, because too high a grinding load may cause pain or pulpal damage of the patient. In this study, the applied revolution and load in tooth-grinding were measured with use of a testing apparatus designed for giving instruction to dental students in proper grinding technique. The data were compared between the dentists in our department (skilled group) and the students (unskilled group). The results were summarized as follows : 1. Recorded load in tooth-grinding 1) The maximum vertical load detected was less than 100 g in the skilled group. 2) The unskilled group showed higher load than the skilled group. 3) In the unskilled group, the load was lower in woman group than in man group. 4) In the skilled grrup, there was no significant difference in the load for grinding between the dentists having 1 to 4 years' experience and those over 7 years'. 2. Recorded revolution in tooth-grinding 1) There was no significant difference in the average revolution of the air turbine between the unskilled and skilled groups. 2) In the unskilled group, the revolution was higher in woman group than in man group. 3) In the skilled group, there was no significant difference in the revolution between the dentists having 1 to 4 yearas' experience and those over 7 year'. 3. Correlation between recorded load and revolution in tooth-grinding 1) In all the groups, the load for grinding was negatively correlated with the revolution detected. 2) The skilled group showed a common tendency to increase the load for grinding more than the unskilled group as the revolution was decreased.

Development of an Experimental Setup for the Investigation of Grinding of Wood and a Proposal for a Pulsed Loading Technique

The study of the fiberizing mechanism in the grinding of wood requires specialized laboratory equipment to allow process alteration and data collection. The design and development of a unique grinding setup and the control device and instrumentation needed for wood grinding research are outlined. A pulsed loading technique for increasing the effectiveness of the fiberizing mechanism is proposed and this technique is tested in a series of experiments conducted with the grinding operations. Significant energy saving and pulp quality improvement for wood ground at 72 F (22.2 C) are achieved using a variable frequency and amplitude load pulsation superimposed over the constant grinding load. The pulsed loading technique can be used as a control device to minimize the effect of grinder input variation such as wood properties or stone surface conditions by altering the process during grinding to optimize the effect of the fiberizing mechanism.

ホーニング仕上過程における目づまりのインプロセス測定

In honing works, the loading of abrasive sticks is thought to play an important role in its finishing process, for example, the creation of smooth surfaces and high dimensional accuracies is generally said to be accompanied with the development of the loading. But there has been no appropriate method for mesuring this loading, so its growing process and influences still have not been fully investigated.In this study, a method of magnetical in-process measurement of this loading is developed with the object of the application to the experimental analysis of honing mechanisms, and its characteristics and applicability are investigated in the cast-iron honing experiment. The main results are as follows;(1) For the measurement of the loading in such cases as honing works in which the abrasive tools move slowly, the utilization of the magnetic resistance change accompanied with the loading is available, differing from the case of the grinding loading reported in the previous paper.(2) In the application experiment, the developed apparatus has well operated and some aspect of the loading in the cast-iron honing, for example, its growing process and its relations with the metal removals and the surface finish, has been definitely shown.