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Representation of Workpiece Elements
Published in Ken Morling, Stéphane Danjou, Geometric and Engineering Drawing, 2022
Whenever parts need enhanced grip, such as for knobs and adjustment screws, a special surface finish is applied called knurling. Grooves or ridged patterns are pressed into a round-shaped workpiece so that a firm grip is maintained. This helps to prevent a hand from slipping off during rotation. Knurling can also be applied for decorative reasons. Figure 9.19 illustrates a knurled machine element.
Rotor Design
Published in Wei Tong, Mechanical Design and Manufacturing of Electric Motors, 2022
Knurling is the process by which repeated patterns are rolled onto material surfaces, commonly accomplished on a lathe or a rolling machine with one or more hard rollers that contain a certain pattern. Knurling patterns comprise straight, diagonal (left-hand or right-hand), and diamond.
Adhesion testing of printed inks while varying the surface treatment of polymer substrates
Published in The Journal of Adhesion, 2021
Clayton Neff, Edwin Elston, Amanda Schrand, Nathan Crane
Chemical treatments can be readily integrated into a multi-tooled AM machine with the use of micro-pen flame torches or plasma pens. Flame treatment only shows a marginal improvement in adhesive strength with the parameters in this work. Higher temperature polymers may show more benefit from flame treatment as the treatment could be more intense without deforming the substrate. Modifications to the heating parameters could also increase the benefit while use of a torch with a forced continuous flow or a wider flame may increase treatment consistency. Plasma treatments of one, five, and 10 min show equivalent shear strengths when deposited on the gloss side of the ABS substrates. This suggests that the shear strength increase has plateaued and perhaps a shorter treatment time could be used to achieve an equivalent shear strength. Furthermore, a combination of mechanical features and a chemical surface treatment could provide maximum adhesion with benefits from mechanical interlocking and surface chemistry changes. For instance, a knurling tool that is being torched as it is being rotated could provide a texturized surface with adhesion promoting surface chemistry changes.
Analysis of ultrasonic welding process of mild steel and 5052 aluminium alloy
Published in Welding International, 2018
Tomohiro Sasaki, Tatsushi Nagai, Takehiko Watanabe
On the one hand, the welded tip surface is worked with a knurling tool to furnish it with pyramid-shaped or triangular-shaped irregular indentations. These indentations are designed to inhibit slippage but it has been reported that when welding is performed, the penetration and friction of the convexities may damage the weld, causing a reduction in the tensile strength of joints [6]. In respect of this problem, the present authors’ research group has previously reported [7] that the strength of welded joints of mild steel and aluminium alloy is greatly improved by the use of a welding tip worked so as to so that surface is curve-shaped and without convexities. It is surmised that, in addition to the inhibition of damage to the weld, the effects of a tip worked to a curved shape are such that differences in the relative motion of this welding tip and welded material have some effect on the microstructure of the weld but details of this remain obscure.
Influence of various tool shoulder design on hybrid surface composite of AA7075-T651/SiC/graphene through friction stir processing
Published in Canadian Metallurgical Quarterly, 2023
In the present study, various AA7075-T651/SiC/Graphene hybrid surface composites were successfully fabricated using various tool shoulder end features, such as flat, kurl, scroll, and knurling. The effect of various tool shoulder end features on macrostructure, microstructure, microhardness, sliding wear behaviour, and corrosion behaviour have been analyzed, and the following conclusion are derived. The macrostructures have shown that the TSS shoulder has generated sufficient temperature and material flow, resulting in uniform dispersion of the particles within the NZ and obtained defect-free composite compared to other designs of the tool.Fine equiaxed grains and higher grain refinement are observed in the TSS sample compared to other shoulder features. The scroll shoulder design allows a higher heat concentration during FSP, leading to higher plastic deformation inside the NZ.The highest hardness of 197 HV is achieved in the TSS shoulder compared to the other samples. The enhancement in the hardness is due to the combined effect of the Orowan strengthening and the Hall-Petch relation.The lowest COF, volume loss, and wear rate are obtained in the TSS sample. The TSS shoulder feature provides higher grain refinement and hardness which are responsible for the reduction in COF, volume loss, and wear rate. The worn surface of the TSS sample has shown a better distribution of tribofilms on the surface, which indicates the abrasive wear mode.The TSS samples have shown higher corrosion resistance and lower corrosion rate than others. The grain refinement and absence of clusters are responsible for formation of a protective layer that enhances corrosion resistance.