Spiral Chip Research Articles

Method of Recognizing of Chip Shape Based on Machine Vision Technology

According to the problem of chip shape monitoring in machining process, this paper presents a methods of the recognition of shape based on machine vision technology. First make a image processing such as binary processing、opening operation、expansion treatment and edge detection to the image of chip by researching the features of the image of the typical chip which are C-shape chip、long spiral chip、random chip and zonal chip. Then automatically identifying the chip shape by the features that euler number and number of curvature local maximum. The experiment proved this methods feasible and effectively to identifying the chip shape and classification by the features of image of chip.

Influence of Chip Curl on Tool-Chip Contact Length in High Speed Machining

The tool-chip contact length, as an important parameter controlling the geometry of tool crater wear and understanding chip formation mechanism, is widely investigated in machining. The aim of this paper is to study the influence of chip curl on tool-chip contact length by means of experimental observations with high cutting speed. The relationship between tool-chip contact length, chip radius of curvature and uncut chip thickness was investigated. Experimental results show the effect of increasing spiral chip radius on tool-chip contact length with low uncut chip thickness in high speed machining.

Compact Surface-mount Wideband and Multi-band Internal Chip Antenna for Mobile Handset

A novel and broadband spiral chip antenna is presented in this paper. The size of the proposed antenna is 20 £ 3:2 £ 8mm 3 and is suitable to be embedded in a mobile phone as an internal antenna. Also, this antenna is designed to be installed at the newest mobile handset whose size is 40 £ 93mm 3 . The minimization of this antenna was realized by using spiral line structure on FR-4 of dielectric permittivity r = 4:4. The proposed antenna is SMD type to be easily installed in the practical mobile handset. We use PCB technology which can allow this antenna to be produced massively with low cost. We can get the wideband operation in the upper band by overlapping high order resonances of branch structure. The measured bandwidth (VSWR< 3) of the designed antenna is 160MHz (980{1140MHz) in the lower band and 1230 MHz (1910{3140MHz) in the higher band. The antenna has been designed by a commercial software HFSS.

Understanding and Characterizing the Drilling of Recycled Plastics

Recycled plastics are increasingly being used to manufacture planks used in large-volume applications, including decks, garden, and cloakroom chairs. These products, although manufactured near-to-net shape, often require drilling for assembly purposes. There are very limited data on the machining of plastic material. Manufacturers often rely on data and models established for metals. The machining of plastics, although limited to assembly purposes, or to the removal of excess materials, requires an understanding of the behavior of these materials during the machining in order to obtain better quality parts. It is even more important for recycled plastics, which are inhomogeneous, contain pores, and most often, are made with more than one type of product. This work analyzes the machining of recycled plastics in order to establish and compare their machining models with those traditionally used for metals, and to better understand the behavior of the plastics during machining. The workpiece is drilled at different process conditions and at different temperatures. The process performance indicators such as cutting forces, chip formation, and chip form are analyzed. The originality of this work resides in its study of chip formation and the effects of the preset workpiece temperature on the drilling mechanisms. It is found that there is a range of critical temperatures of transition for plastics similar to the Charpy impact ductile-brittle temperature separating the domain of low cutting force and long and spiral chip from that of high cutting force corresponding to the accordion-type of chip. A parameter describing this phenomenon is defined. It is also found that for low- to moderate-speed operations, the cutting speed has very little effect on the cutting forces, which depend mainly on the feed rate and the workpiece temperature. The relationship between the drilling forces and the feed rate established for metals remain valid, but the exponent of the feed rate for the thrust force is lower. The thrust force and the tangential force are proportional to the feed rate exponent 0.4 compared to 0.8 for metals when drilling workpiece at room temperature or below.

Research on the vibration cutting performance of particle reinforced metallic matrix composites SiCp/Al

The cutting performance of particle reinforced metallic matrix composites (PRMMCs) SiCp/Al in ultrasonic vibration cutting and common cutting (CC) with carbide tools and PCD tools was researched experimentally in this work. The changing rules of chip shape, deformation coefficient, shear angle, surface residual stress and microstructure in ultrasonic vibration cutting are presented. The result shows that when adopting CC, a spiral chip with a smaller curl radius will be obtained. The chip of zig-zag contour, is short and thick. There are numerous sheet cracks both on the face of the chip and on the machined surface. That is to say, the cutting process of metallic matrix composites (MMCs) is not like the cutting process of plastic material, but is similar to the breaking process of brittle material. By comparison, when adopting ultrasonic cutting, the deformation of chip is small, and a loose spiral chip with a larger curl radius that is long and thin is produced. The phenomenon is similar to the vibration cutting of plastic material, but the chip still belongs to the group of plastic or semi-plastic segmental chips due to the structure characteristics of the material itself. Furthermore, the tangential residual compression stress of vibration cutting is larger than that of CC, the axial residual stress has a relationship to the feed rate, and the residual stress does not change obviously with cutting depth and they are of the same order of magnitude on the whole. According to the microstructure, ultrasonic cutting can reduce the influence of tearing, plastic deformation and built-up edge in cutting and can restrain flutter so as to make the cutting process more stable.

Development and evaluation of finishing end mill with high rigidity.

Finishing end mills which can reduce dimensional inaccuracy and surface profile error in the finish process of end milling are presented. Computer simulation against chip geometry and variable distance from work surface to cutter axis are performed for the design of cutter shape with high rigidity. The performance of newly developed end mills are verified through the measurement of spiral chip diameter, cutting force variation and surface profile error in the face milling. it is shown that the magnitude of surface profile error can be reduced from 60% to 70% by the newly developed end mills, compared with the standard type. While the characteristic of surface profile error remains unchanged, for the cutter geometry with standard pitch was adopted. The cutter also possess a sufficient space to extrude chips which are produced in the finish process of end milling.

被削材種および切削速度と切りくず生成現象との関係

Orthogonal cutting of eight kinds of the work materials including cast irons, steels and copper alloy was experimentally photographed at the cutting speeds ranging from 10 mm/min to 200 m/min, in order to organize systematic knowledge on the formation, separation and the final shape of the chip. The results of these tests were as follows:The chip formation phenomenon exhibits characteristic variation of its type at various cutting speeds, inherently to the cut metal. Various steels and the brass show similar tendency of chip formation whereas cast irons behave differently. When the cutting speed is increased, the chip formation mechanism changes from crack type to shear type, and from shear type to flow type. The shape of the chip meantime changes from the powder or fragmental chip to the spiral chip, and from the spiral chip to the helical or tangled chip. At low speed, the chip is mostly separated from the workpiece at the point of the tool tip, while, at high speed, it is separated at the place far from the tool tip.