Papers by Keyword: Burr

Abstract: A melt drag twin-roll caster (MDTRC) was designed to convert vertical burrs at strip edges to horizontal burrs. A prototype MDTRC was assembled and tested. The forming roll is inclined frontward relative to the top of the solidification roll. Aluminum alloy strips were cast at a higher roll speed and lower roll load than what can be achieved with the conventional twin-roll caster for aluminum alloys. A semisolid layer which exists on the solidifying layer by a lower roll was formed and solidified using an upper roll. In this study, the formability of the semisolid layer and formation of horizontal burrs were investigated.

Abstract: The mechanism and region of burr formation in casting using a vertical-type high-speed twin-roll caster were investigated using a side-dam plate with a window. A383, an aluminum alloy typically used for casting due to its excellent fluidity at semisolid condition was used. The solid fraction of the semisolid metal ejected from the window was low. When solid metal was ejected from the window, no burr formed. The results suggest that a burr formed when the semisolid metal was ejected in gap between the side-dam plate and the side surface of a roll. The semisolid metal was ejected near the point where the semisolid metal on the two rolls met.

Abstract: Most machining processes produce burr as a result of plastic deformation. Exit burr strongly affect product quality during assembly and it is difficult to remove them easily. This work aims at minimizing burr produced in drilling of Al6061/SiCp composite fabricated through stir-casting process using HSCO drill. Analysis of experimental results using ANOVA indicated the influence of cutting conditions and drill geometry in reducing the thrust force as well as burr size. Keywords: Drilling, Al6061/SiCp, HSCO drill, ANOVA, Thrust force, Burr

Abstract: Exit burrs are formed on the end of hole and have some undesirable characters leading to assembly quality problem. Deburring is one of the practical procedures used to solve this problem. Nevertheless, this step is a time consuming and causes high operation cost. This work studied the experimental investigations in drilling forging brass using a special tungsten carbide drilling tools. The exit burr height and workpiece diameter were measured at various spindle speeds and feed rates based on 2^k plus center point experimental design and investigated by analysis of variance (ANOVA). The results of ANOVA indicated that spindle speed and feed rate on exit burr height and workpiece diameter were statistically significant at the level of significance of 0.05.

Abstract: This study aims to develop a cutting method, which enables to generate a localized hydrostatic pressure field in the vicinity of cutting zone in order to improve the machined surface integrity without causing unnecessary plastic deformation. In the previous work, a molecular dynamics simulation was performed using a newly developed cutting tool equipped with a planer jig with a rectangular hole for the cutting chip elimination, and it was confirmed that the developed cutting tool has advantages in giving a relatively high-hydrostatic stress field in the vicinity of the cutting zone and in suppressing the burr formation. In this report, further molecular dynamics simulation was performed in order to clarify the influence of jig shape on the cutting phenomena and machined surface integrity. As a result, it is found that a cutting tool of which front and side except for the rectangular hole are covered by the planer jig is the most advantageous for supplying high hydrostatic pressure and suppressing burr formation.

Abstract: Fabrication of microchannels on titanium alloy with micro-milling is a tough challenge due to the difficultly to remove the burrs formed in machining process. A novel method to gelatinize workpiece surface to control the generation of burr as well as the optimization of cutting parameters are investigated in this paper. Differences existed between the process of micro-milling and that of traditional milling can be accounted for size effect. Influences of feed per tooth, depth of cut and spindle speed on the formation of burr were taken into consideration respectively by single factor method. The topographies of the machined surface with micro-milling were observed and measured by optical microscope. Results showed that the dimensions of burrs increased with the rise of depth of cut. However, it decreased initially, then increased later with the augment of feed per tooth. Sacrifice layer with PMMA was coated and gelatinized on the workpiece surface, which could restrain the plastic deformation of materials during titanium alloy micro-milling. The experimental results presented that the dimensions of burr could reduce greatly by the proposed PMMA coating method compared to materials without coating.

Abstract: Basing on the milling experiment of carbon fiber reinforced plastics (CFRP), the machining surface qualities of different edge shape and coated tools are researched contrastively. The results show that: when the CFRP is milled by general right-hand edge milling cutter, due to the small tool rake angle, bad tool sharpness, and carbon fibers of upper and lower surface are both subjected to upswept cutting force, the burrs appear at the upper surface of workpiece. But there is no burr at the lower surface. When the CFRP is milled by interlaced edge or herringbone edge diamond coated milling cutter, which are designed to left-hand and right-hand interlace, the carbon fiber of workpiece’s upper and lower surface are subjected to downward and upswept cutting force respectively. There is no burr at the upper and lower surface of workpiece. Compared with interlaced edge diamond coated milling cutter, herringbone edge diamond coated milling cutter is more suitable for finish machining of CFRP.

Abstract: In the drilling of forging materials, exit burrs are produced on the end of hole and had some undesirable characters leading to assembly quality problem. Deburring is one of the practical techniques used to solve this problem. However, this technique is a time consuming and causes high operation cost. Hence this work presented an experimental study in drilling forging brass using special tungsten carbide drilling tools. The exit burr size was evaluated at various spindle speeds and lot size. Effect of spindle speed on exit burr height was investigated using analysis of variance (ANOVA). The results of ANOVA indicated that the spindle speed of 415 rpm gave lowest exit burr height and produced higher quantity and quality of products.

Abstract: This study investigated the removal improvement of micro burrs of aluminum alloy materials using vibrated abrasive grinding machining. The image processing technology is used to examine and quantify the micro-hole burr profiles. The experimental results show that the micro burr was uniformly removed as the workpiece is fixture with vertical direction. In addition, the burr removal improvements are effectively influenced by the flowing velocity and the vibration energy of abrasive particles. The flowing velocities are dependent on the size and gravity of the abrasives and the vibration energy is determined by the material properties and the hardness of the abrasives.

Abstract: Cutting technology is one of the important methods to fabricate small-sized precision components in the semiconductor, electro-mechanics, and automobile industries. This paper focuses on high efficiency machining of small hole drilling for PPS (Polyphenylene Sulfide). In this paper, drilling experiments were designed to investigate the influence of the depth of cut on the burr formation. The experimental results obtained are as follows, (1) The thrust force and radial force increase with the increase in feed per revolution and depth-of-cut. (2) On the prevention of burr formation, the step feed is better than the non-step feed. Also, the burr formation decreases with the increase in the feed per revolution. (3) The hole straightness increases with the increase in depth-of-cut.