Advances in Manufacturing

Experimental research on the critical conditions and critical equation of chip splitting when turning a C45E4 disc workpiece symmetrically with a high-speed steel double-edged turning tool

Ming-Xian Xu, Liang-Shan Xiong, Bao-Yi Zhu, Ling-Feng Zheng, Kai Yin

2022, 10(2): 159-174. doi:10.1007/s40436-021-00378-7

摘要 ( 2058 )

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Chip splitting is a natural chip separation phenomenon that can significantly reduce cutting energy consumption. To reveal its occurrence mechanisms, a method for obtaining its critical conditions through cutting experiments and establishing its critical equation is proposed in this paper. Based on previous research results regarding the relationship between chip removal interference and chip splitting, the control variables that affect chip splitting are identified by analyzing a geometric model of the cutting process. A total of 366 experiments on turning a C45E4 disc workpiece with a high-speed steel double-edged turning tool based on the dichotomy method were conducted and 51 experimental data on chip splitting critical conditions were obtained. According to these experimental data, a critical equation expressed by a finite-degree polynomial with a cutting thickness equal to the other control variables was fitted. By analyzing the critical surface, it was determined that chip splitting followed a law in which the smaller the cutting thickness and the larger the absolute value of the negative rake angle, edge angle, and edge inclination of the tool, the more likely chip splitting was to occur. Through a verification experiment, it was determined that the derived critical equation could accurately predict the occurrence of 95.24% of chip splitting. It was also determined that the occurrence of chip splitting led to a cliff-like drop in the specific total cutting force with a maximum drop of 51.23%. This research lays a foundation for the rational utilization of chip splitting in tool structure parameter design and cutting parameter energy saving optimization.

The full text can be downloaded at https://link.springer.com/article/10.1007/s40436-021-00378-7

Porosity, cracks, and mechanical properties of additively manufactured tooling alloys: a review

Prveen Bidare, Amaia Jiménez, Hany Hassanin, Khamis Essa

2022, 10(2): 175-204. doi:10.1007/s40436-021-00365-y

摘要 ( 1953 )

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Additive manufacturing (AM) technologies are currently employed for the manufacturing of completely functional parts and have gained the attention of high-technology industries such as the aerospace, automotive, and biomedical fields. This is mainly due to their advantages in terms of low material waste and high productivity, particularly owing to the flexibility in the geometries that can be generated. In the tooling industry, specifically the manufacturing of dies and molds, AM technologies enable the generation of complex shapes, internal cooling channels, the repair of damaged dies and molds, and an improved performance of dies and molds employing multiple AM materials. In the present paper, a review of AM processes and materials applied in the tooling industry for the generation of dies and molds is addressed. AM technologies used for tooling applications and the characteristics of the materials employed in this industry are first presented. In addition, the most relevant state-of-the-art approaches are analyzed with respect to the process parameters and microstructural and mechanical properties in the processing of high-performance tooling materials used in AM processes. Concretely, studies on the AM of ferrous (maraging steels and H13 steel alloy) and non-ferrous (stellite alloys and WC alloys) tooling alloys are also analyzed.

The full text can be downloaded at https://link.springer.com/article/10.1007/s40436-021-00365-y

A maintenance driven scheduling cockpit for integrated production and maintenance operation schedule

Mario Arena, Valentina Di Pasquale, Raffaele Iannone, Salvatore Miranda, Stefano Riemma

2022, 10(2): 205-219. doi:10.1007/s40436-021-00380-z

摘要 ( 1996 )

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The production and maintenance functions have objectives that are often in contrast and it is essential for management to ensure that their activities are carried out synergistically, to ensure the maximum efficiency of the production plant as well as the minimization of management costs. The current evolution of ICT technologies and maintenance strategies in the industrial field is making possible a greater integration between production and maintenance. This work addresses this challenge by combining the knowledge of the data collected from physical assets for predictive maintenance management with the possibility of dynamic simulate the future behaviour of the manufacturing system through a digital twin for optimal management of maintenance interventions. The paper, indeed, presents a supporting digital cockpit for production and maintenance integrated scheduling. The tool proposes an innovative approach to manage health data from machines being in any production system and provides support to compare the information about their remaining useful life (RUL) with the respective production schedule. The maintenance driven scheduling cockpit (MDSC) offers, indeed, a supporting decision tool for the maintenance strategy to be implemented that can help production and maintenance managers in the optimal scheduling of preventive maintenance interventions based on RUL estimation. The simulation is performed by varying the production schedule with the maintenance tasks involvement; opportune decisions are taken evaluating the total costs related to the simulated strategy and the impact on the production schedule.

The full text can be downloaded at https://link.springer.com/article/10.1007/s40436-021-00380-z

Fabrication of micro pin fins on inclined V-shaped microchannel walls via laser micromilling

Da-Xiang Deng, Jian Zheng, Xiao-Long Chen, Guang Pi, Yong-Heng Liu

2022, 10(2): 220-234. doi:10.1007/s40436-021-00382-x

摘要 ( 2045 )

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A laser-micromilling process was developed for fabricating micro pin fins on inclined V-shaped microchannel walls for enhanced microchannel heat sinks. A pulsed nanosecond fiber laser was utilized. The feasibility and mechanism of the formation of micro pin fins on inclined microchannel walls were investigated for a wide range of processing parameters. The effects of the laser output power, scanning speed, and line spacing on the surface morphologies and geometric sizes of the micro-pin fins were comprehensively examined, together with the material removal mechanisms. Micro pin fins with acute cone tips were readily formed on the V-shaped microchannel walls via the piling of recast layers and the downflow of re-solidified materials in the laser-ablation process. The pin-fin height exhibited an increasing trend when the scanning speed increased from 100 mm/s to 300 mm/s, and it decreased continuously when the line spacing increased from 5 μm to 20 μm. The optimal processing parameters for preparing micro pin fins on V-shaped microchannels were found to be a laser output power of 21 W, scanning speed of 100–300 mm/s, and line spacing of 2–5 μm. Moreover, the V-shaped microchannels with micro pin fins induced a 7%–538% boiling heat-transfer enhancement over their counterpart without micro pin fins.

The full text can be downloaded at https://link.springer.com/article/10.1007/s40436-021-00382-x

Experimental and computational analysis of the coolant distribution considering the viscosity of the cutting fluid during machining with helical deep hole drills

Ekrem Oezkaya, Sebastian Michel, Dirk Biermann

2022, 10(2): 235-249. doi:10.1007/s40436-021-00383-w

摘要 ( 1997 )

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An experimental analysis regarding the distribution of the cutting fluid is very difficult due to the inaccessibility of the contact zone within the bore hole. Therefore, suitable simulation models are necessary to evaluate new tool designs and optimize drilling processes. In this paper the coolant distribution during helical deep hole drilling is analyzed with high-speed microscopy. Micro particles are added to the cutting fluid circuit by a developed high-pressure mixing vessel. After the evaluation of suitable particle size, particle concentration and coolant pressure, a computational fluid dynamics (CFD) simulation is validated with the experimental results. The comparison shows a very good model quality with a marginal difference for the flow velocity of 1.57% between simulation and experiment. The simulation considers the kinematic viscosity of the fluid. The results show that the fluid velocity in the chip flutes is low compared to the fluid velocity at the exit of the coolant channels of the tool and drops even further between the guide chamfers. The flow velocity and the flow pressure directly at the cutting edge decrease to such an extent that the fluid cannot generate a sufficient cooling or lubrication. With the CFD simulation a deeper understanding of the behavior and interactions of the cutting fluid is achieved. Based on these results further research activities to improve the coolant supply can be carried out with great potential to evaluate new tool geometries and optimize the machining process.

The full text can be downloaded at https://link.springer.com/article/10.1007/s40436-021-00383-w

Formation of the anomalous microstructure in the weld metal of Co-based alloy/AISI 410 stainless steel dissimilar welded joint

Kai Ding, Yuan-Heng Zhang, Shang-Fei Qiao, Guan-Zhi Wu, Tao Wei, Xia Liu, Yu-Lai Gao

2022, 10(2): 250-259. doi:10.1007/s40436-022-00396-z

摘要 ( 2085 )

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The Co-based alloy/AISI 410 stainless steel dissimilar welded joint was fabricated by the electron beam welding (EBW) technique. The anomalous microstructure containing the element transition zone (ETZ) and/or core of tail-like zone (CTLZ) is in the weld metal (WM) adjacent to the fusion line. The melting temperature difference between the WM and AISI 410 steel, melt stirring effect and element diffusion can trigger the formation of such anomalous microstructure. In particular, the larger distance of the region in WM away from the fusion line, the smaller CTLZ and larger ETZ occurred. Compared with the fine and ellipsoidal precipitates in the as-welded CTLZ, a large number of chain-type clustered precipitates were detected in the CTLZ and ETZ interface after the aging treatment at 566 °C for 1 000 h. The element diffusion under elevated temperature in WM is regarded as the crucial factor for such anomalous microstructure evolution during the aging treatment.

The full text can be downloaded at https://link.springer.com/article/10.1007/s40436-022-00396-z

Experimental technique to analyze the influence of cutting conditions on specific energy consumption during abrasive metal cutting with thin discs

Muhammad Rizwan Awan, Hernán A. González Rojas, José I. Perat Benavides, Saqib Hameed

2022, 10(2): 260-271. doi:10.1007/s40436-021-00361-2

摘要 ( 2015 )

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Specific energy consumption is an important indicator for a better understanding of the machinability of materials. The present study aims to estimate the specific energy consumption for abrasive metal cutting with ultra-thin discs at comparatively low and medium feed rates. Using an experimental technique, the cutting power was measured at four predefined feed rates for S235JR, intermetallic Fe-Al(40%), and C45K with different thermal treatments. The variation in the specific energy consumption with the material removal rate was analyzed through an empirical model, which enabled us to distinguish three phenomena of energy dissipation during material removal. The thermal treatment and mechanical properties of materials have a significant impact on the energy consumption pattern, its corresponding components, and cutting power. Ductile materials consume more specific cutting energy than brittle materials. The specific cutting energy is the minimum energy required to remove the material, and plowing energy is found to be the most significant phenomenon of energy dissipation.

The full text can be downloaded at https://link.springer.com/article/10.1007/s40436-021-00361-2

Study on the reaming process of aluminum alloy 7050-T7451 under different cooling conditions

Zi Ye, Yong-Guo Wang, Xin Yu

2022, 10(2): 272-286. doi:10.1007/s40436-021-00364-z

摘要 ( 1958 )

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Aluminum alloy 7050 is widely used in the aeronautical industries. However, owing to their highly ductile property, chips created during high-speed machining cannot be naturally broken, and long continuous chips are unavoidably formed, impacting the machining stability and quality of the parts. Because a smaller cutting allowance is required compared with conventional machining operations, the behavior of the chips during reaming operation may be more complex and different from those determined in previous investigations. Therefore, studying the characteristics of chip formation and hole quality during the reaming process is essential to improve the machinability of aluminum alloy 7050. In this study, three different cooling conditions were applied to reaming aluminum alloy 7050-T7451 with polycrystalline diamond (PCD) reamers. The finite element models (FEMs) were established to simulate the chip formation. The macro- and micro-morphologies of chips under the three cooling conditions were compared to analyze the chip behaviors. The diameter, surface roughness, and micro-morphologies of the reamed holes were also analyzed to evaluate the hole quality. The results showed that the chip morphology was strongly influenced by the cutting parameters and cooling strategies. It was found that the desired chip morphologies, satisfactory geometrical accuracy and surface quality during the reaming of aluminum alloy 7050-T7451 could be achieved using internal cooling at a spindle speed of 8 000 r/min and a feed rate of 0.01 mm/z. This study also demonstrates the feasibility of an internal cooling strategy for breaking chips when reaming aluminum alloy 7050-T7451, which opens new possibilities for improving the chip-snarling that occurs during hole machining.

The full text can be downloaded at https://link.springer.com/article/10.1007/s40436-021-00364-z

A comprehensive review on residual stresses in turning

Ammar H. Elsheikh, S. Shanmugan, T. Muthuramalingam, Amrit Kumar Thakur, F. A. Essa, Ahmed Mohamed Mahmoud Ibrahim, Ahmed O. Mosleh

2022, 10(2): 287-312. doi:10.1007/s40436-021-00371-0

摘要 ( 1978 )

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Residual stresses induced during turning processes can affect the quality and performance of machined products, depending on its direction and magnitude. Residual stresses can be highly detrimental as they can lead to creeping, fatigue, and stress corrosion cracking. The final state of residual stresses in a workpiece depends on its material as well as the cutting-tool configuration such as tool geometry/coating, cooling and wear conditions, and process parameters including the cutting speed, depth-of-cut and feed-rate. However, there have been disagreements in some literatures regarding influences of the above-mentioned factors on residual stresses due to different cutting conditions, tool parameters and workpiece materials used in the specific investigations. This review paper categorizes different methods in experimental, numerical and analytical approaches employed for determining induced residual stresses and their relationships with cutting conditions in a turning process. Discussion is presented for the effects of different cutting conditions and parameters on the final residual stresses state.

The full text can be downloaded at https://link.springer.com/article/10.1007/s40436-021-00371-0

Thrust force model for ultrasonic-assisted micro drilling of DD6 superalloy

Xiao-Xiang Zhu, Wen-Hu Wang, Rui-Song Jiang, Yi-Feng Xiong, Xiao-Fen Liu

2022, 10(2): 313-325. doi:10.1007/s40436-021-00381-y

摘要 ( 1917 )

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As a typical refractory material, the DD6 nickel-based single-crystal superalloy has important applications in the aviation industry. Ultrasonic-assisted drilling is an advanced machining method that significantly improves machining of refractory materials. The drilling thrust force influences the hole surface quality, burr height, and bit wear. Therefore, it is necessary to predict the thrust force during ultrasonic-assisted drilling. However, there are few reports on the modeling of the thrust force in the ultrasonic-assisted drilling of micro-holes. A thrust force prediction model for ultrasonic-assisted micro-drilling is proposed in this study. Based on the basic cutting principle, the dynamic cutting speed, dynamic cutting thickness, and acoustic softening effect caused by ultrasonic vibrations are factored into this model. Through model calibration, the specific friction force and specific normal force coefficients were determined. The model was verified through ultrasonic-assisted drilling experiments conducted at different feed rates, spindle speeds, frequencies, and amplitudes. The maximum and minimum errors of the average thrust force were 10.5% and 2.3%, respectively. This model accurately predicts the thrust force based on the parameters used for ultrasonic-assisted micro-hole drilling and can assist in the analysis and modeling of DD6 superalloy processing.

The full text can be downloaded at https://link.springer.com/article/10.1007/s40436-021-00381-y

A novel paradigm for feedback control in LPBF: layer-wise correction for overhang structures

Ema Vasileska, Ali Gökhan Demir, Bianca Maria Colosimo, Barbara Previtali

2022, 10(2): 326-344. doi:10.1007/s40436-021-00379-6

摘要 ( 1975 )

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In laser powder bed fusion (LPBF), it is common practice to select process parameters to achieve high density parts starting from simple geometries such as cubes or cylinders. However, additive manufacturing is usually adopted to produce very complex geometries, where parameters should be tuned locally, depending on the local features to be processed. In fact, geometrical features, such as overhangs, acute corners, and thin walls may lead to over- or under-heating conditions, which may result in geometrical inaccuracy, high roughness, volumetric errors (i.e., porosity) or even job failure due to surface collapse. This work proposes a layer-wise control strategy to improve the geometrical precision of overhanging regions using a coaxial melt pool monitoring system. The melt-pool images acquired at each layer are used in a control-loop to adapt the process parameters locally at the next layer in order to minimize surface defects. In particular, the laser duty cycle is used as a controllable parameter to correct the energy density. This work presents the main architecture of the proposed approach, the control strategy and the experimental procedure that need to be applied to design the control parameters. The layer-wise control strategy was tested on AISI 316L stainless steel using an open LPFB platform. The results showed that the proposed layer-wise control solution results in a constant melt pool observed via the laser heated area size starting from the second layer onward, leading to a significant improvement in the geometrical accuracy of 5 mm-long bridge geometries.

The full text can be downloaded at https://link.springer.com/article/10.1007/s40436-021-00379-6

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