Measuring Feed Force in Machining Using a Strain Gage

Measuring the forces that work during machining has been being concerned by researchers for years. There are three main forces that work in turning: thrust force, axial force, and radial force. Thus, feeding force measurement is needed in machine manufacturing. This research attempts to develop measurement method through feeding force, using strain gauge sensor. The aim of measurement of feeding force in this research is to find out the influence parameter of machine towards feeding force. The research used experimental method with design experiment Taguchi to know the influence of machine parameters to feeding force in turning process. The measurement tool is strain gauge sensor connected to cutting tool. The workspace is alluminium 6061 with 15 mm in diameter and 150 mm in length. The parameters for this research are speed rate (140 rpm, 215 rpm, and 330 rpm), feed rate (0,043 mm/r , 0,065 mm/r , and 0,081 mm/r), and depth of cut (0,2 mm, 0,4 mm, and 0,6 mm). The result showed that speed rate is the most significant parameter, with the contribution percentage is 92 %. Speed rate and feed rate parameter have insignificant influence. The contribution percentage of speed rate is 2% while the feed rate has % contribution percentage. The conclusion of the research is that the bigger number of speed rate, the bigger feeding force it will have.

The Influence of Blade Type and Feeding Force during Resin Bonded Dentin Specimen Preparation on the Microtensile Bond Strength Test

This paper presents the effect of blade type and feeding force during resin-bonded dentin specimen preparation on the microtensile bond strength (μTBS) test. Forty resin-bonded flat middle dentin specimens were divided into four groups. The specimens of each group were sectioned according to type of blade and feeding force as follows: fine grit/20 N, fine grit/40 N, medium grit/20 N, and medium grit/40 N to obtain resin-dentin sticks with a cross-sectional area of 1.0 mm2. Four sticks from the center of each tooth were subjected to the μTBS test. Five remaining sticks of each group were selected for surface topography observation under a scanning electron microscope (SEM). As a result, the bond strength of the medium-grit group was higher than that of the fine-grit group (p < 0.001), whereas the feeding force had no influence on bond strength values (p = 0.648). From the SEM, sticks prepared with the fine-grit blade showed a smoother surface integrity and fewer defects on the specimen edges in comparison with the sticks prepared with the medium-grit blade. The grit type of the blade is one of the considerable factors that may affect the bond strength and the surface integrity of resin-dentin specimens for microtensile testing.

Complementary Feeding Practices Among Mothers of Rural Bangladesh; A Knowledge, Attitude, and Practice Study

Background. In developing countries, inadequate knowledge and cultural practice on complementary feeding (CF) is one of the main reasons for malnutrition. Objective: This study aimed to document the knowledge, attitude, and practices pertaining to CF among the mothers of rural area in Bangladesh. Materials and Methods: A communitybased cross-sectional study was conducted in upazila health complex, kachua, Chandpur from July to December, 2017. A total 408 mothers of the babies aged 6-24 months and children under six months were included. Data were collected from the mothers/caregivers of the children in a pretested semi-structured data collection sheet and analyzed by SPSS version 20. Appropriate statistical tests were done. Statistical significance was considered if p value was <0.05. Results: Knowledge regarding recommended CF practice only 50.8% but feeding should be started at 6 months of age (52.9),thick consistency (40.2%), adequate quantity( 61.8%), and appropriate quality (62.3%) cases. Knowledge in recommended appropriate timing and consistency varied significantly with maternal education. Frequency of CF was not appropriate in many cases. Most common first complimentary food was thick dal with rice/roti, khichuri rice 166(40.7%). One hundred twenty four (30.4%) mothers did not properly clean their hands before feeding and 138(33.8%) of mother used bottle for feeding, force full feeding (56.9%) and environment during feeding playing 72.5% and roaming around 25.5%. Conclusion: CF knowledge and practices are far gap from ideal in our country. Awareness building in the community may change improper feeding practices need health education. KYAMC Journal Vol. 11, No.-1, April 2020, Page 26-31

Theoretical Study on Features of an Overlap-Type and a Pressing-Type Sheet Separation Mechanisms

We examined the behaviors of the paper sheet in an overlap-type sheet separation mechanism and a pressing-type sheet separation mechanism. First, we introduced the models that can calculate the resistance force and feed force acting on the paper sheets in both sheet separation mechanisms. And, based on the calculation results of the resistance force and friction force between the paper sheets, we studied the behavior of the paper sheet in each separation mechanism. As a result, we found that an overlap-type sheet separation mechanism is superior to the pressing-type sheet separation mechanism but it is easily influenced by the feeding force caused by pick-up rollers, and also a pressing-type sheet separation mechanism has robustness for a thickness of paper sheet and for a feeding force caused by pick-up rollers.

Effect of Solidification Pressure on Secondary Dendrite Arm Spacing of Aluminum Alloy

The solidification pressure is one of the most important factors in the counter-gravity casting process. Through testing and analyzing the microstructures of aluminum alloy castings under different solidification pressure, the effect of different solidification pressure on the secondary dendrite arm spacing and grain size is studied. The results show that with the increase of the solidification pressure, the secondary dendrite arm spacing and the grain size of aluminum alloy decreases. When the solidification pressure is 250 KPa, the secondary dendrite arm of aluminum alloy is thick, the SDAS is 37.9μm, but when the solidification pressure increases to 450 KPa, the refinement of grain is obviously, and the SDAS is 20.7μm, which is reduced by 45.3% comparing to solidification under 250 KPa. Moreover, when solidification pressure higher, the effect of feeding force becomes more evident, and the dendrite is broken when the feeding force higher than the strength of dendrite. Therefore, the grain size becomes more and more uniform and thin, and the (SDAS) of aluminum alloy are more and more small.

Current Practice and Future Opportunities for Two-Turn ECAP

Equal channel angular pressing (ECAP) is the most popular severe plastic deformation process used to refine grain structure of metals. However, its application exhibits inherent problems of low productivity and poor utilization of material. In order to address these problems, the ECAP channel with two-turns can be used. Historical examples and current applications of this configuration are provided including route BC version of the process. Route C version of two-turn ECAP is illustrated with a scaled-up process used for processing square inch cross section aluminium billets. To address another problem, that of short billets, it is suggested that future applications of two-turn ECAP are based on the new process of incremental ECAP; it enables decoupling feeding of the material and its deformation and thus reduces dramatically the feeding force for billets, plates and sheets.

Parameters and Experiments on the Precision Forming Process of Spline Cold Rolling

Cold rolling precision forming process of spline is one of the high-efficiency, precision and non-chip forming advanced manufacturing technologies. It has the characteristics such as high forming efficiency, energy-saving, low material consumption and better forming properties of components. The process and principle of involute spline cold rolling precision forming was analyzed. A measuring and testing system for the force and energy parameters in the forming process was set up, and the real-time variation curves of the torque moment of the spindle and the radial feeding force were obtained. Also, the influencing rules of process parameters on the maximum radial feeding force and spindle torque were investigated. Finally, Precision forming experiments of involute spline cold rolling were carried out with optimized parameters. Precision measuring and hardness testing of the tooth outline section shows that the components obtained by the experiments were free of defects. Compared with the spline components obtained from conventional cutting process, the hardness and wear ability was greatly improved, which is suitable for the requirement of application.