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For carbon fiber-reinforced plastic (CFRP) composite components, especially advanced CFRP components with complex three-dimensional features, surface grinding is often needed to generate final dimensions and functional surfaces. Surface damages are frequently induced during surface grinding, reducing the load-bearing capability and service life of the components. Therefore, it is desirable to perform surface grinding of CFRP in a high-quality and high-efficiency way. Rotary ultrasonic machining (RUM) surface grinding has been investigated to machine CFRP for improved surface quality. Cutting force is one of the most important output variables for evaluating RUM surface grinding. The modeling of cutting force is essential to effectively control the occurrence of surface damages during RUM surface grinding of CFRP. In the RUM surface grinding process, the workpiece material is primarily removed by abrasives on the tool peripheral surface, thus it is essential to investigate the feed-direction cutting force model. However, such models are not available in the literature. In this study, for the first time, a mechanistic feed-direction cutting force model in RUM surface grinding of CFRP is established based on the assumption that the material is removed by brittle fracture. The mechanistic model has one parameter, fracture volume factor of the workpiece material, which needs to be determined by an experiment. There is a good consistency between theoretically predicted trends and experimentally observed results on the relationships between feed-direction cutting force and input variables.

The iso-scallop method has been long adopted to achieve a shorter overall machining length. The efficiency and machining performance of this method are largely dominated by the initial tool path. The preferred direction field supplies the local best feed directions. Usually, the offset paths generated by the iso-scallop method largely deviate from the preferred directions, even though the initial path is strictly along the preferred directions. The matching degree of the offset paths and preferred direction field should be taken into consideration when selecting an initial tool path. This paper presents a novel initial path selection method for the iso-scallop method to make whole iso-scallop tool paths and the preferred direction field consistent as much as possible. A surface is re-parameterized to keep the conformality between the surface and parametric domain, which leads to the more regular offset paths on the new parametric domain. By fitting the vector field, streamlines are generated for representing the preferred feed direction on the parametric domain. The offset similarity metric defined by the initial path and streamlines is constructed to measure the matching degree between offset paths and preferred feed directions. Then the feasible path with the best offset similarity for the streamlines will be selected as the initial tool path. In our case study, feed directions with the maximum strip width are chosen. The test results have shown that the tool paths generated by the proposed method achieved a better matching for the selected feed directions and a shorter overall length compared with some existing tool path generation methods.

Ball-end cutters are widely used in industries of dies, molds, and aerospace, which have the problem of poor machined surface quality due to the low cutting speed near the tool-tip. With the increase in the complexity of parts, it will become more and more difficult to avoid the tool-tip participating in the cutting. In this paper, the velocity effect sensitivity of the ball-end cutter is analyzed, and several key positions, including the intersection points of the CWE boundaries, are selected to describe the cutting speed in three dimensions. The relationships between the cutting speed of the critical points and important variables such as the machining inclination angle and the feed direction were investigated. The optimal range of feed direction is obtained when the tool-tip engages in the contact circle. The core aim of the feed direction selection is to make the tool engagement area in a high position by changing the feed direction, to avoid surface damage and improve the quality of the machined surface. Finally, an experimental study was carried out, and the results corroborate the effectiveness of the selection method. In the experiment, it was also found that cutting-out from the cutter contact position can improve the surface quality in the directions of non-optimal range, and the milling force and chips shape will vary with the change of the feed direction.

Surface milling is an extensively adopted post-processing technique for the assembly of carbon fiber–reinforced polymers (CFRPs) with accurate surfaces. However, CFRPs are hard-to-cut materials due to their anisotropic and laminating characteristics that frequently induce machining damages, such as burrs and interface cracks. During surface milling, the action form at any point on the tool edge on the fiber changes with the rotation of the tool and the cutting tool feeding direction, resulting in varying levels of damage in different machining areas. To ensure the high milling quality of CFRP surfaces, this study established a planning method for cutting tool feed direction for low-damage machining by accounting for the changes in the tool edge and fiber action form during CFRP surface milling. The optimal cutting tool feed direction selection range for low-damage surface milling of CFRP components was determined by calculating the changes in the instantaneous fiber cutting angle and length for different cutting tool feed directions and then analyzing the influence of different cutting tool feed directions on the degree of processing damage of CFRP components. The results indicated that to reduce the burr and interfacial cracking damage in the surface milling of CFRP components, the cutting tool feed direction should be selected from the range 0°–40° relative to the fiber ply direction of the final cutting layer. The results obtained in this study can help determine the cutting tool feed direction for the low-damage surface milling of CFRP components and provide a basis for subsequent research on tool path planning.

Microstructures with proper patterns have an important influence on the functional surface performance of products, including changing surface wettability for different application environments. This paper proposed a method of feed-direction ultrasonic vibration-assisted turning (FUVAT) for fast generation of micro-textured surface. The generation mechanism of surface microstructures was presented by analyzing cutting trajectory and simulating surface topography. Surface texturing experiments were performed on copper 1100. The results show that micro-dimples with regular arrangement and different dimension were successfully obtained on cylindrical surface by controlling proper processing parameters. Several key parameters including amplitude, feed rate, and spindle speed play an important influence on the patterns and shapes of microstructures. The experimental textured surfaces show different wetting properties through wetting tests. It is verified that the FUVAT can be a feasible way to fabricate micro-textured surfaces.

Ball-end cutters are widely used for machining the parts of Ti-6Al-4V, which have the problem of poor machined surface quality due to the low cutting speed near the tool tip. In this paper, through the experiments of inclined surface machining in different feed directions, it is found that the surface adhered damages will form on the machined surface under certain tool postures. It is determined that the formation of surface adhered damage is related to the material adhesion near the cutting edge and the cutting-into/out position within the tool per-rotation cycle. In order to analyze the cutting-into/out process more clearly under different tool postures, the projection models of the cutting edge and the cutter workpiece engagement on the contact plane are established; thus, the complex geometry problem of space is transformed into that of plane. Combined with the case of cutting-into/out, chip morphology, and surface morphology, the formation mechanism of surface adhered damage is analyzed. The analysis results show that the adhered damage can increase the height parameters Sku, Sz, Sp, and Sv of surface topographies. Sz, Sp, and Sv of the normal machined surface without damage (Sku ≈ 3) are about 4–6, 2–3, and 2–3 μm, while Sz, Sp, and Sv with adhered damage (Sku > 3) can reach about 8–20, 4–14, and 3–6 μm in down-milling and 10–25, 7–18, and 3–7 μm in up-milling. The feed direction should be selected along the upper left (Q2: β ∈ [0°, 90°]) or lower left (Q3: β ∈ [90°, 180°]) to avoid surface adhered damage in the down-milling process. For up-milling, the feed direction should be selected along the upper right (Q1: β ∈ (−90°, 0°]) or upper left (Q2: β ∈ [0°, 90°)).

Electron beam melting (EBM) is one of the growing processes of additive manufacturing technology (AMT) to fabricate 3D parts from various difficult-to-process materials such as titanium alloys. A major limitation of the EBM process is the poor surface finish of the produced parts which ultimately demands a subsequent subtractive method (secondary finishing operation) to improve the surface finish for shaping the part to be fit for-end use applications where high surface finish is commonly required. With respect to the EBM layer build direction, the fabricated part has different orientations with varying surface characteristics. Therefore, in order to perform secondary finishing operation (e.g., milling) there are different choices of EBM part orientation to select the direction of tool feed. In this research, 3D parts of titanium alloy (gamma titanium aluminide; γ-TiAl) are additively manufactured through EBM process. The effect of EBM layer/part orientation on the milling performance is further investigated in terms of surface finish improvement and edge chipping evaluation. It has been observed that the EBM layer/part orientation with respect to milling tool feed direction (TFD) plays a vital role in milling performance. Thus, a care must be taken to select the appropriate tool feed direction and layer/part orientation in order to achieve maximum surface finish with minimum edge chipping. The results revealed the vertical milling can be adopted as a secondary finishing operation to be performed on EBM produced parts of γ-TiAl and it allows to significantly improve the poor surface finish generated by EBM ( R a 31 μm). Furthermore, among the available part orientation choices, the part orientation in which the milling tool is fed across the EBM layer build direction is the best orientation resulting into high surface finish ( R a 0.12 μm) with relatively smooth edges (minimum chipping-off).

This paper examines the effect of tool tilt angle on machining strip width in the determination of optimal tool orientation and feed direction in five-axis flat-end milling. The machining strip width is evaluated using the swept profile of the flat-end mill, avoiding both local and global gouging of the tool. An optimization problem is formulated to maximize the machining strip width over feasible gouge-free tool orientations for a constant-feed direction. By solving the optimization problem and analyzing the geometry of the machining strip width, it is shown that identifying the optimal tool tilt angle, instead of following the common practice of setting the tool tilt angle as zero, can significantly increase the machining strip width, especially for 3D free-form surface machining. The optimization has also been extended to identify the optimal feed direction that maximizes the machining strip width at a given cutter contact (CC) point. The minimum curvature direction has been considered as the optimal feed direction at a CC point by researchers. Our results indicate that although the minimum curvature direction is mostly not the optimal feed direction in free-form surface machining, the minimum curvature direction does represent a good approximation of the optimal feed direction at a CC point, in particular for a free-form surface with low-curvature relative to the tool size.

The special mechanical properties of cemented carbide with high strength and hardness will cause complex stress due to excessive force and heat in the process of precision manufacturing, which will affect precision retention and endurance limit. Given the health and environmental threat of conventional flood cooling and the harsh processing environment of dry grinding, minimum quantity lubrication (MQL) has become an irreplaceable method to machining cemented carbide. However, the addition of nanoparticles changes the force and heat during grinding, which makes the influence on the residual stress of cemented carbide complicated. Therefore, based on the single abrasive grinding force model, the effective abrasive particle number was obtained by simulating the distribution of abrasive particles on the grinding wheel surface, and the mechanical stress model was established, which was loaded onto the workpiece in iterative attenuation mode. The thermal stress model was established based on the temperature field model. The final residual stress prediction model was obtained by determining whether the grinding process yields results and carrying out stress loading and stress relaxation. Experimental verification of the model was carried out under four different grinding conditions of YG8. The minimum friction coefficient of 0.385 was obtained under nanofluid minimum quantity lubrication (NMQL). In the precision analysis of the model, the minimum error value was 5.9% in the direction perpendicular to the feed direction of the workpiece in the dry grinding condition, which proved that the residual stress model had certain reliability.

In computer controlled subapertur polishing the formation of mid spatial frequency errors (MSFE) needs special attention. In this work the formation of MSFE in feed direction is investigated using the ADAPT tool from Satisloh.