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Carbon fiber reinforced plastic (CFRP) composites were attractive in lots of applications, in which surface machining processes were always needed after molding fabrication processes to achieve the final functional surface geometry with desired accuracy. To improve the effectiveness and efficiency, rotary ultrasonic surface machining (RUSM) had been applied in processing CFRP composites. With the assistance of vertical ultrasonic vibration in RUSM, cutting forces were significantly reduced, but the surface roughness was increased. To improve the surface conditions and additionally reduce the cutting force for RUSM, the applied ultrasonic vibration should be aligned with surface generation direction (namely horizontal feeding direction). Up till now, there were no reported investigations on RUSM with horizontal vibration and 3D elliptical ultrasonic vibration, formed from the combination of horizontal and vertical ultrasonic vibrations. In this investigation, the horizontal and 3D elliptical ultrasonic vibrations were applied in RUSM. The comparisons among RUSM with 3D elliptical ultrasonic vibration, RUSM with horizontal ultrasonic vibration, and the surface machining without ultrasonic vibration on machining performance and surface quality were conducted. Experimental results showed that RUSM with horizontal ultrasonic vibration reduced both cutting force and surface roughness. With the application of 3D elliptical ultrasonic vibration, both cutting force and surface roughness can be further decreased. The critical horizontal ultrasonic frequency for the overlapping of abrasive grains’ trajectories was analyzed. The mechanisms of RUSM with both horizontal and 3D elliptical ultrasonic vibrations and the reasons for both cutting force decreasing and surface roughness decreasing were also investigated.

Owing to its advantages of freedom to design, improved material utilization, and shortened lead time, additive manufacturing (AM) has the potential to redefine manufacturing after years of evolvement and opens new avenues to produce customized and complex-shaped products. Despite these benefits, AM still suffers problems stemmed from limited material selection, anisotropic material property, low production speed, coarse resolution, etc. In response to these problems, extensive attention has been drawn on integrating AM with fields, which mainly include magnetic field (MF), electric field (EF), and acoustic field (AF). These fields have been proved to be effective in tailoring microstructures, enhancing mechanical properties, focusing and sorting cells, serving as stimuli, etc., thus providing new opportunities to address existing problems and enable new functionalities of AM technologies. This paper presents a review on recent developments and major advances in MF-, EF-, and AF-assisted AM technologies and 4D printing method from aspects of materials, methodologies, and applications. In addition, current challenges and future trends of field-assisted AM technologies and 4D printing method are also outlined and discussed.

In surface grinding of carbon fiber reinforced plastic (CFRP) composites, cutting force is a key factor that controls surface damage, tool wear, cutting temperature, delamination, etc. Surface grinding of CFRP composites using rotary ultrasonic machining (RUM) with vertical ultrasonic vibration has been proven to be an effective method to reduce cutting force. However, the machined surface quality is lowered due to the knocking effects on the machined surface resulted from up-and-down vertical vibration. It has been proven that to decrease cutting force and simultaneously improve surface quality, ultrasonic vibration aligning with surface generation direction (feeding direction) is needed. However, there are limited investigations on RUM surface grinding of CFRP composites with horizontal ultrasonic vibration, and the mechanistic model on cutting force in such a process is not explored. This paper, for the first time, establishes a mechanistic model on feeding-directional cutting force in RUM surface grinding of CFRP composites with horizontal ultrasonic vibration. This modeling development is based on the assumption of brittle fracture material removal mechanism, which is the dominant removal mechanism in such a process. The predicted trends in this model agree well with those in experimentally measured results. This modeling will provide a guidance for the mechanistic modeling development to predict other output variables through the cutting force in RUM surface grinding of CFRP composites.

As one of the ceramic matrix composites (CMCs), carbon fiber-reinforced silicon carbide matrix (C/SiC) composites are promising materials used in various engineering applications owing to their superior properties. Precision surface grinding has been widely applied in the machining of CMC composites; however, the material removal mechanisms of C/SiC composites have not been fully elucidated yet. To reveal the material removal mechanisms in the grinding of chemical vapor infiltration-fabricated C/SiC composites, novel single-abrasive scratch tests were designed and conducted in two typical cutting directions. The experimental parameters, especially the cutting speed, conformed to the actual grinding process. The results show that the grinding parameters (feed rate, spindle speed, depth of cut, and cutting direction) have significant influences on the grinding forces, surface integrity, and affected subsurface region. The tangential force is in general larger than the normal force at the same cutting depth. Furthermore, both the tangential and normal forces in the longitudinal cutting direction are larger than those in the transverse cutting direction. The impacts and abrasive actions at the tool tip mainly caused the material removal. The predominant material removal mode is brittle fracture in the grinding of unidirectional C/SiC composites, because the damage behaviors of the C/SiC composites are mainly the syntheses of matrix cracking, fiber breakage, and fiber/matrix interfacial debonding. These results are rationalized based on the composite properties and microstructural damage features.

Ceramics and ceramic reinforced metal matrix composites (MMCs) are widely used in severe working conditions and have been applied in biomedical, aerospace, electronic, and other high-end engineering industries owing to their superior properties of high wear resistance, outstanding chemical inertness, and excellent properties at elevated temperatures. These superior properties, on the other hand, make it difficult to process these materials with conventional manufacturing methods, posing problems of high cost and energy consumptions. In response to this problem, direct additive manufacturing (AM), which is equipped with a high-power-density laser beam as heat source, has been developed and extensively employed for processing ceramics and ceramic reinforced MMCs. Compared with other direct AM processes, laser deposition-additive manufacturing (LD-AM) process excels in several aspects, such as lower labor intensity, higher fabrication efficiency, and capabilities of parts remanufacturing and functionally gradient composite materials fabrication. Besides these benefits, problems of poor bonding, cracking, lowered toughness, etc. still exist in LD-AM fabricated parts. This paper reviews developments on LD-AM of ceramics and ceramic reinforced MMCs in both bulk parts fabrication and cladding. Main issues to be solved, corresponding solutions, and the trend of development are summarized and discussed.

Purpose The purpose of this paper is to identify if the implementation of ultrasonic vibration in laser engineered net shaping (LENS) process can help to reduce internal weaknesses such as porosity, coarse primary TiB whisker and heterogeneous distribution of TiB reinforcement in the LENS-fabricated TiB reinforced Ti matrix composites (TiB-TMC) parts. Design/methodology/approach An experimental investigation is performed to achieve the results for comparative studies under different fabrication conditions through quantitative data analysis. An approach of microstructural characterization and mechanical testing is conducted to obtain the output attributes. In addition, the theoretical analysis of the physics of ultrasonic vibration in the melting materials is presented to explain the influences of ultrasonic vibration on the microstructural evolution occurred in the part fabrication. Findings Because of the nonlinear effects of acoustic streaming and cavitation induced by ultrasonic vibration, porosity is significantly reduced and a relatively small variation of pore sizes is achieved. Ultrasonic vibration also causes the formation of smaller TiB whiskers that distribute along grain boundaries with a homogeneous dispersion. Additionally, a quasi-continuous network (QCN) microstructure is considerably finer than that produced by LENS process without ultrasonic vibration. The refinements of both reinforcing TiB whiskers and QCN microstructural grains further improve the microhardness of TiB-TMC parts. Originality/value The novel ultrasonic vibration-assisted (UV-A) LENS process of TiB-TMC is conducted in this work for the first time to improve the process performance and part quality.

Laser engineered net shaping (LENS), developed from laser cladding and rapid prototyping, has different promising applications such as aerospace, automotive, marine, tool manufacturing, etc. Due to the features of LENS process, the capability of overhang structure deposition was limited and some geometrical structures cannot be perfectly built. Investigating overhang building mechanisms and angle accuracy are crucial. In this study, the effects of scanning patterns (reciprocating and unidirectional deposition way) and vertical increment (z-increment) on overhang structures in LENS have been investigated. It was found that the overhang deposited in a reciprocating way exhibited higher geometry accuracy than that deposited in a unidirectional way. By optimizing z-increment, the discrepancy between the designed and experimental inclined angles of overhangs greatly decreased. The effects of processing parameters, including laser power, scanning speed, and powder feed rate, on the optimal z-increment were also investigated.

Over the past two decades, a considerable amount of work has been done on zirconia-toughened alumina (ZTA) to take advantage of the recognized toughening effect induced by ZrO2. In fabricating customized or complex-shaped ZTA parts, conventional manufacturing processes, including slip casting and powder metallurgy, are regarded as time-consuming and cost-intensive. In response to these problems, directed energy deposition (DED) has been proposed and utilized to fabricate customized ZTA parts with highly flexible features in a shorter cycle time at a lower cost. Investigations have been reported on studying effects of input variables (such as laser power) in DED of ZTA parts, however, there are very limited investigations on effects of the ZrO2 content. In this investigation, the effects of the ZrO2 content on microstructures and mechanical properties of DED-fabricated ZTA parts are studied. Experimental results show that at lower levels of ZrO2 contents (5 wt%, 10 wt%, and 20 wt%), a novel three-dimensional quasi-continuous network (3DQCN) microstructure is tailored, whereas at higher levels of ZrO2 contents (30 wt%, 35 wt%, and 41.5 wt%), eutectic microstructure dominates the whole part. Both the 3DQCN microstructure and the eutectic microstructure are beneficial for toughening ZTA parts. In addition, the 3DQCN microstructure contributes to hardening ZTA parts.

The superior properties make carbon fiber-reinforced plastic (CFRP) composites attractive in many applications. After CFRPs’ molding processes, additional machining processes are needed to produce final functional shapes with dimensional precision. Edge trimming is the primary process to cut the edge of CFRP composites. To reduce or further solve the problems in traditional machining processes, edge trimming of CFRP composites with rotary ultrasonic machining (RUM) has been proposed and conducted in this investigation. In RUM edge trimming processes, two different tool orientations (RUM edge trimming with tool end face and RUM edge trimming with tool side face) can be performed. The comparisons of machining performance and machined surface quality between these two different RUM edge trimming processes have been conducted. Smaller ultrasonic vibration amplitude in RUM using tool end face or larger ultrasonic vibration amplitude in RUM using tool side face produces smaller surface roughness. Lower feeding-directional cutting force, lower normal cutting force, and lower resultant force are generated in the process using tool side face. RUM using tool end face produces smaller surface roughness, smaller debris width, microcracking, flowed matrix on machined CFRP surfaces, etc.

Titanium (Ti) and its alloys have been successfully applied to the aeronautical and biomedical industries. However, their poor tribological properties restrict their fields of applications under severe wear conditions. Facing to these challenges, this study investigated TiB reinforced Ti matrix composites (TiB-TMCs), fabricated by in-situ laser engineered net shaping (LENS) process, through analyzing parts quality, microstructure formation mechanisms, microstructure characterizations, and workpiece wear performance. At high B content areas (original B particle locations), reaction between Ti and B particles took place, generating flower-like microstructure. At low B content areas, eutectic TiB nanofibers contacted with each other with the formation of crosslinking microstructure. The crosslinking microstructural TiB aggregated and connected at the boundaries of Ti grains, forming a three-dimensional quasi-continuous network microstructure. The results show that compared with commercially pure Ti bulk parts, the TiB-TMCs exhibited superior wear performance (i.e. indentation wear resistance and friction wear resistance) due to the present of TiB reinforcement and the innovative microstructures formed inside TiB-TMCs. In addition, the qualities of the fabricated parts were improved with fewer interior defects by optimizing laser power, thus rendering better wear performance.

Laser additive manufactured zirconia-alumina ceramic (ZrO2-Al2O3) parts demonstrate severe problems resulting from cracking and inhomogeneous material dispersion. To reduce these problems, we propose a novel ultrasonic vibration-assisted laser engineered net shaping (LENS) process for fabrication of bulk ZrO2-Al2O3 parts. Results showed that the initiation of cracks and the crack propagation were suppressed in the parts fabricated by LENS process with ultrasonic vibration. For the parts fabricated without ultrasonic vibration, the sizes of cracks decreased with the increase of laser power. Scanning electron microscope analyses proved that the introduction of ultrasonic vibration was beneficial for grain refinement and uniform material dispersion. Due to the suppressed cracking, refined grains, and homogenized material dispersion, the parts fabricated with ultrasonic vibration demonstrated better mechanical properties (including higher microhardness, higher wear resistance, and better compressive properties), compared with the parts fabricated without ultrasonic vibration.

Although TiB reinforced titanium matrix (TiB-Ti) composites exhibit superior wear resistance and strength, they still demonstrate severe problems resulted from lowered toughness and ductility, as compared with titanium and its alloys. To reduce these problems, this paper tailors a three-dimensional quasi-continuous network (3DQCN) microstructure within TiB-Ti composites by in-situ laser deposition-additive manufacturing process. Results show that the laser power has great impacts on the formation of 3DQCN microstructure and the 3DQCN microstructure is beneficial to both strengthening and toughening effects on TiB-Ti composites. To have a quantitative understanding of strengthening effects, this paper, for the first time, has modeled the yield strength of TiB-Ti composites with 3DQCN microstructure.

Due to their excellent properties, carbon fiber-reinforced plastic (CFRP) composites are attractive in many industries, including aerospace, automobile, sports, etc. The structure of anisotropy and heterogeneity and the high abrasive resistance of carbon fibers make CFRPs difficult to cut in surface grinding processes. Many problems, including high cutting force, high tool wear, severe delamination, and high cutting temperature, are associated with conventional surface grinding processes. To reduce or eliminate these problems, surface grinding of CFRP composites using rotary ultrasonic machining (RUM) has been conducted. Machining variables play dominant roles in such a process. However, no investigations on effects of machining variables on output variables were reported. This paper, for the first time, reports effects of machining variables (ultrasonic power, tool rotation speed, feed rate, and depth of cut) on output variables (cutting force, torque, and surface roughness). The results revealed that the cutting force could be decreased by using higher level of ultrasonic power, higher level of tool rotation speed, lower level of feed rate, or lower level of depth of cut. Lower surface roughness could be achieved by a decrease of ultrasonic power, an increase of tool rotation speed, a decrease of feed rate, or a decrease of depth of cut. The machined CFRP surfaces’ morphology and the characteristics of damaged carbon fibers were, for the first time, analyzed and reported in such a process.

The carbon fiber reinforced plastic (CFRP) composites have superior properties of high modulus-to-weight ratio, high strength-to-weight ratio, good durability, high corrosion resistance, and low thermal expansion coefficient. These properties make them attractive in many different applications, such as aerospace, medical, transportation, and sporting goods. However, CFRP’s properties of anisotropy, inhomogeneity, and abrasive properties of carbon fibers in CFRP composites generate many problems, including high cutting forces, high torque, delamination, high tool wear, decomposition of matrix material, etc., in traditional grinding processes. Surface grinding of CFRP composites using rotary ultrasonic machining (RUM) is used to decrease these problems. However, there is no investigation on effects of workpiece machining orientations in such a process. This investigation, for the first time, studies effects of workpiece machining orientations and machining variables (including tool rotation speed, feedrate, and ultrasonic power) on output variables (including both cutting force in feeding direction and cutting force in axial direction, torque, and surface roughness). The results show that lower cutting forces and torque are generated by using 90° workpiece machining orientation and lower surface roughness is produced by using 0° workpiece machining orientation. The results are discussed and analyzed, and they will fill in the research gaps in RUM surface grinding of CFRP composites.

The purpose of this article was to introduce the concept of selective laser alloying (SLA) to print 3D parts directly from elemental powders, and report findings on an investigation of the governing thermal models of the process. Considering the effects of exothermic reaction between Ti and B during the alloying process, thermal models with three group of parameters were developed to predict the phenomena induced in the selective laser alloying process. To validate these models, a series of experiments, with different molar ratios between Ti and B, were conducted on Renishaw AM250 using premixed elemental Ti and B powders. The experiments validated the SLA concept and the results matched consistently with the models’ predictions, which validated the models.

Ceramic reinforced Ti matrix composites (TMCs) have been widely used under severe friction and heavy loading conditions due to their superior properties. Among different types of ceramic reinforcements, TiB is considered as one of the most suitable ceramic reinforcement materials for TMCs because of its high strength and stiffness, excellent interfacial bonding with Ti matrix, and low induced stress. As a laser additive manufacturing process, laser deposition-additive manufacturing (LD-AM) has been successfully utilized to fabricate Ti-based materials. However, investigations on LD-AM of in situ TiB reinforced TMCs are limited. This investigation, for the first time, reports the tomography analysis of TiB reinforcement within Ti matrix and the formation of novel flower-like microstructure. The influences of reaction energy on part performance have been explored. In addition, the effects of input fabrication variables (including laser power and Z-axis increment) on part performance (including density, microhardness, and compressive properties) have been investigated, providing guidance on selection of input fabrication variables for future research.

Alumina ceramic has been classified as one of difficult-to-manufacturing materials, the traditional manufacturing methods led to high cost and high energy consumption. In comparison to traditional manufacturing methods, laser engineered net shaping (LENS) additive manufacturing (AM) has many good properties to overcome the drawbacks of traditional manufacturing methods. However, the reported investigations on LENS provide limited information for qualities of deposition. In this paper, effects of LENS input deposition variables (laser power, deposition head scanning speed, and powder feeding rate) on deposition quality (such as layer geometry, surface roughness, flatness, powder efficiency, and microhardness) were studied. The obtained results will help to establish an efficient and effective process for ceramics part manufacturing.

In this study, we created an innovative ultrafine three-dimensional quasi-continuous network (3DQCN) microstructure by in-situ laser engineered net shaping (LENS) of TiB reinforced titanium matrix composites (TiB-TMCs). As a rapid solidification process, the LENS process enabled high degree of Ti grain refinement. The in-situ processed eutectic TiB aggregated at these Ti grain boundaries, forming the ultrafine 3DQCN microstructure. The microstructural characterizations of the ultrafine 3DQCN microstructure were investigated. Effects of the TiB reinforcement and the ultrafine 3DQCN microstructure on the mechanical performance of the fabricated parts were studied. The results demonstrated that the TiB-TMCs with the ultrafine 3DQCN microstructure exhibited superior mechanical properties.

Rotary ultrasonic machining (RUM), a hybrid nontraditional process technology combining ultrasonic machining and grinding, has been proven to be a promising method for hole making of CFRP. Due to its advanced capabilities, RUM has been further extendedly applied in surface machining: rotary ultrasonic surface machining (RUSM). Carbon fiber reinforced plastic (CFRP) composites have found extensive applications in areas such as aerospace, automotive, and sports due to their superior material properties. CFRP components are usually near net shaped after molding processes, however, additional surface machining is still required to generate the final dimensions and functional surfaces of the advanced CFRP components especially with three-dimensional features. However, the investigations on RUSM of CFRP are very limited and there are no reported studies on comparisons between RUSM and conventional surface grinding (CSG) of CFRP. In this paper, for the first time, a comparative study between these two processes of CFRP in the aspects of axial and infeed-directional cutting forces, torque, and surface roughness is conducted. In order to better understand the material removal differences between these two processes, the kinematic motions of the abrasive grains are also analyzed and compared.

Laser engineered net shaping (LENS) has been applied as a key technology in direct manufacturing or repairing of high added- value metal parts. Recently, many investigations on LENS manufacturing of Inconel 718 parts have been conducted for potential applications of the aircraft turbine component manufacturing or repairing. However, fabrication defects such as pores, cavities, and heterogeneous microstructures always exist in the parts, affecting part qualities and mechanical properties. Therefore, it is crucial to LENS-manufacture Inconel 718 parts in a high-quality and high-efficiency way. Ultrasonic vibration has been introduced into various melting metal solidification processes for process improvements. However, there are no reported investigations on ultrasonic vibration-assisted (UV-A) LENS of Inconel 718 parts. In this paper, for the first time, UV-A LENS is proposed to reduce the fabrication defects of Inconel 718 parts. The experimental investigation is conducted to study the effects of ultrasonic vibration on microstructures and microhardness of the parts fabricated by UV-A LENS and LENS without ultrasonic vibration. The results showed that ultrasonic vibration could reduce the porosity, refine the microstructure with a smaller average grain size, and fragment the detrimental phase with a uniform distribution, thus enhancing the microhardness of the fabricated parts.

Carbon fiber-reinforced plastic composites have been intensively used for many applications due to their attractive properties. The increasing demand of carbon fiber-reinforced plastic composites is driving novel manufacturing processes to be in short manufacturing cycle time and low production cost, which is difficult to realize during carbon fiber-reinforced plastic composites fabrication in common molding processes. Fused deposition modeling, as one of the additive manufacturing techniques, has been reported for fabricating carbon fiber-reinforced plastic composites. The process parameters used in fused deposition modeling of carbon fiber-reinforced plastic composites follow those in fused deposition modeling of pure plastic materials. After adding fiber reinforcements, it is crucial to investigate proper fused deposition modeling process parameters to ensure the quality of the carbon fiber-reinforced plastic parts fabricated by fused deposition modeling. However, there are no reported investigations on the effects of fused deposition modeling process parameters on the mechanical properties of carbon fiber-reinforced plastic composites. In the experimental investigations of this paper, carbon fiber-reinforced plastic composite parts are fabricated using a fused deposition modeling machine. Tensile tests are conducted to obtain the tensile properties. The effects of fused deposition modeling process parameters on the tensile properties of fused deposition modeling-fabricated carbon fiber-reinforced plastic composite parts are investigated. The fracture interfaces of the parts after tensile testing are observed by a scanning electron microscope to explain material failure modes and reasons.

Post-surgery infection is one of the main causes of orthopedic implant failure. This paper presents a powder-feed 3D printing strategy for fabrication of silver (Ag) incorporated titanium (Ti) alloys as an antimicrobial solution for orthopedic implants. Alloys with various Ag concentration, ranging from 0.5% to 2% by weight, were fabricated through laser engineered net shaping (LENS) process. The composition and surface of the fabricated alloys were characterized through X-ray diffraction, energy-dispersive X-ray spectroscopy, and 3D surface profiling. The mechanical properties, antimicrobial performance, and biocompatibility of the alloys were also investigated. Results showed that LENS fabricated Ti Ag alloys had a marginally higher microhardness and a lower ductility compared to pure Ti. Within only 3 h, Ti Ag alloys significantly reduced the bacterial attachment of both gram-positive and gram-negative strains by one to four orders of magnitudes. These alloys also demonstrated excellent in-vitro biocompatibility to human osteosarcoma cells. For the first time, laser engineered net shaping (LENS) of Ti Ag alloy has been explored as an antimicrobial solution for orthopedic applications and showed great potential for biomedical instrumentation.

Laser engineered net shaping (LENS) has become a promising technology in direct manufacturing or repairing of high-performance metal parts. Investigations on LENS manufacturing of Inconel 718 (IN718) parts have been conducted for potential applications in the aircraft turbine component manufacturing or repairing. Fabrication defects, such as pores and heterogeneous microstructures, are inevitably induced in the parts, affecting part qualities and mechanical properties. Therefore, it is necessary to investigate a high-efficiency LENS process for the high-quality IN718 part fabrication. Ultrasonic vibration has been implemented into various melting material solidification processes for part performance improvements. However, there is a lack of studies on the utilization of ultrasonic vibration in LENS process for IN718 part manufacturing. In this paper, ultrasonic vibration-assisted (UV-A) LENS process is, thus, proposed to fabricate IN718 parts for the potential reduction of fabrication defects. Experimental investigations are conducted to study the effects of ultrasonic vibration on microstructures and mechanical properties of LENS-fabricated parts under two levels of laser power. The results showed that ultrasonic vibration could reduce the mean porosity to 0.1%, refine the microstructure with an average grain size of 5 μm, and fragment the detrimental Laves precipitated phase into small particles in a uniform distribution, thus enhancing yield strength, ultimate tensile strength (UTS), microhardness, and wear resistance of the fabricated IN718 parts.

Carbon fiber–reinforced plastic composites have many superior properties, including low density, high strength-to-weight ratio, and good durability, which make them attractive in many industries. However, due to anisotropic properties, high stiffness, and high abrasiveness of carbon fibers in carbon fiber–reinforced plastic, high cutting force, high tool wear, and high surface roughness are always caused in conventional machining processes. This article reports an investigation using rotary ultrasonic machining in surface grinding of carbon fiber–reinforced plastic composites in order to develop an effective and high-quality surface grinding process. In rotary ultrasonic machining surface grinding of carbon fiber–reinforced plastic composites, tool selection is of great importance since tool variables will significantly affect output variables. In this work, the effects of tool variables, including abrasive size, abrasive concentration, number of slots, and tool end geometry, on machining performances, including the cutting force, torque, and surface roughness, are experimentally studied. The results show that lower cutting forces and torque are generated by the tool with higher abrasive size, lower abrasive concentration, and two slots. Lower surface roughness is generated by the tool with smaller abrasive size, smaller abrasive concentration, two slots, and convex end geometry. This investigation will provide guides for tool selections during rotary ultrasonic machining surface grinding of carbon fiber–reinforced plastic composites.

Based on rapid prototyping and laser cladding, laser material deposition (LMD) can be used to produce a near-net shape component in which the deposition quality and geometry characteristics of the previous layer, especially the first layer, determines the deposition quality and process stability of LDM-ed parts. A theoretical model for the first deposition layer in the LMD process has been developed to estimate the clad geometry (width, depth, and height) depending on the process parameters (laser power, powder feed rate, and scanning speed). This model contains two constants that are calculated based on the experimental results. The theoretical results are discussed and compared with the experimental data from the perspective of mass energy and line mass. The theoretical results are in accordance with the experimental results with reasonable accuracy that indicates the capability of predicting the clad geometry.

Carbon fiber reinforced plastic (CFRP) composites provide excellent properties, which make them attractive in many industries. However, due to the properties of high stiffness, anisotropy, and high abrasiveness of carbon fiber in CFRPs, they are regarded as difficult-to-cut materials. To find an efficient surface grinding process for CFRP, this paper conducts an investigation using RUM. Design of experiment (DOE) is vital to evaluate effects of input variables on output variables, and it could be used to obtain the optimal values of variables in such a process. DOE could also be used to decrease the test numbers, the research cost etc. However, there are no investigations on DOE in such a process. This investigation firstly tests the effects of three input variables, including tool rotation speed, feedrate, and ultrasonic power, on output variables, including cutting force, torque, and surface roughness, at two levels. This investigation will provide guides for future research.