Nano-enhanced biolubricant in sustainable manufacturing: From processability to mechanisms

To eliminate the negative effect of traditional metal-working fluids and achieve sustainable manufacturing, the usage of nano-enhanced biolubricant (NEBL) is widely researched in minimum quantify lubrication (MQL) machining. It’s improved tool wear and surface integrity have been preliminarily verified by experimental studies. The previous review papers also concluded the major influencing factors of processability including nano-enhancer and lubricant types, NEBL concentration, micro droplet size, and so on. Nevertheless, the complex action of NEBL, from preparation, atomization, infiltration to heat transfer and anti-friction, is indistinct which limits preparation of process specifications and popularity in factories. Especially in the complex machining process, in-depth understanding is difficult and meaningful. To fill this gap, this paper concentrates on the comprehensive quantitative assessment of processability based on tribological, thermal, and machined surface quality aspects for NEBL application in turning, milling, and grinding. Then it attempts to answer mechanisms systematically considering multi-factor influence of molecular structure, physicochemical properties, concentration, and dispersion. Firstly, this paper reveals advanced lubrication and heat transfer mechanisms of NEBL by quantitative comparison with biolubricant-based MQL machining. Secondly, the distinctive filmformation, atomization, and infiltration mechanisms of NEBL, as distinguished from metal-working fluid, are clarified combining with its unique molecular structure and physical properties. Furtherly, the process optimization strategy is concluded based on the synergistic relationship analysis among process variables, physicochemical properties, machining mechanisms, and performance of NEBL. Finally, the future development directions are put forward aiming at current performance limitations of NEBL, which requires improvement on preparation and jet methods respects. This paper will help scientists deeply understand effective mechanism, formulate process specifications, and find future development trend of this technology.

A Review of Advances in Modeling of Conventional Machining Processes: From Merchant to the Present

This paper presents a review of recent advances in modeling and simulation of conventional metal machining processes, which continue to dominate a significant part of all machining processes, and in recent years, the need for predictive models for machining processes has grown in importance in the digital manufacturing age. Significant advances have been made in modeling the mechanics of cutting in conventional machining, driven by industrial need and enabled by rapid advances in computational power. The paper surveys the state-of-the-art in analytical and numerical modeling of conventional metal machining processes with a focus on their ability to predict useful performance attributes including chip geometry, forces, temperatures, tool wear, residual stress, and microstructure. Also included in the review is a discussion of the industrial use of modeling and simulation tools for conventional machining. Additionally, the practical applicability, implementation benefits, and methodological limitations of conventional machining process modeling have been examined. The paper concludes with a summary of future research directions in modeling and simulation of conventional metal machining processes.

Machinability study of Aluminium 6082 reinforced with boron carbide and titanium by stir casting method using Abrasive water jet machining process

Aluminium Metal Matrix Composite (AMMC) has broad uses in the medical, aerospace, and automobile industries, which have long sought lightweight materials with superior designs and improved properties to improve performance. This analysis has aimed to prepare an AMMC to investigate its machining and mechanical properties. The AMMC is produced using a stir casting process by reinforcing boron carbide and titanium with aluminium 6082. The material's mechanical properties are studied by using wear test, hardness test, and corrosion test. The wear rate increases when the load increases by varying the load and time with speed as a constant. It is found that the hardness of a material is increased due to titanium and boron carbide as the reinforcement particle in the fabricated AMMC. Using the pitting corrosion technique, the corrosion occurs on the AMMC under the estimated time at room temperature. In order to illustrate the machining characteristics of the aluminium metal matrix composite, an abrasive water jet machining process has been used. The experiments use L9 orthogonal Array using Taguchi's method and ANOVA analysis. The input parameters considered are Traverse rate, Stand-off distance, and Nozzle diameter. To find the optimum value of circularity, cylindricity, and surface roughness by varied input parameters. The respective graphs are also plotted. Scanning electron microscopic analysis was performed on the wear-tested specimen and machining surface of the material to determine the distribution of reinforced material and investigate the material's fracture mechanism. It is found that wear tracks, voids, delamination, micro pits, embedded garnet abrasive particles are located on the machined surface of the AMMC.

Engineering working operations based on parameters of product manufacturability using a computer-aided design algorithm

The study aimed to develop an algorithm for computer-aided design (CAD) of working operations. A processing route for machining components was developed based on the criteria of production manufacturability, industrial data and a digital model of the product. The process of machining a workpiece was analysed using a method of theoretical separation. The machining process of a frame workpiece was used as a model. The identified formal parameters formed a basis for developing a CAD algorithm and a model of manufacturing route associated with the mechanical processing of a work-piece applying a condition-action rule, as well as mathematical logic. The research afforded a scheme for selecting process operations, given the manufacturability parameters of a product design. The concept of CAD algorithm was developed to design a production process of engineering products with given manufacturability parameters, including industrial data. The principle of forming a route and selecting a machining process was proposed. Several criteria of production manufacturability (labour intensity, consumption of materials, production costs) were selected to evaluate mechanical processing. A CAD algorithm for designing technological operations considering the parameters of manufacturability was developed. The algorithm was tested by manufacturing a frame workpiece. The developed algorithm can be used for reducing labour costs and development time, at the same time as improving the quality of production processes. The formalisation of process design is a crucial stage in digitalisation and automation of all production processes.

Three-Dimensional Synthesis of Manufacturing Tolerances Based on Analysis Using the Ascending Approach

The present paper develops a new approach for manufacturing tolerances synthesis to allow the distribution of these tolerances over the different phases concerned in machining processes using relationships written in the tolerance analysis phase that have been well developed in our previous works. The novelty of the proposed approach is that the treatment of non-conventional surfaces does not pose a particular problem, since the toleranced surface is discretized. Thus, it is possible to study the feasibility of a single critical requirement as an example. During the present approach, we only look for variables that influence the requirements and the others are noted F (Free). These variables can be perfectly identified on the machine, which can be applied for known and unknown machining fixtures; this can be the base for proposing a normalized ISO specification used in the different machining phases of a mechanical part. The synthesis of machining tolerances takes place in three steps: (1) Analysis of the relationship’s terms, which include the influence of three main defects; the deviation on the machined surface, defects in the machining set-up, and the influence of positioning dispersions; then (2) optimization of machining tolerance through a precise evaluation of these effects; and finally (3) the optimization of the precision of the workpiece fixture, which will give the dimensioning of the machining assembly for the tooling and will allow the machining assembly to be qualified. The approach used proved its efficiency in the end by presenting the optimal machining process drawing that explains the ordered phases needed to process the workpiece object of the case study.

Effect of process parameters on formability in two-point incremental forming-machining of planar and twisted AA5083 blades

The deformation machining process (DMP) involves machining and incremental forming of thin structures. It can be applied for manufacturing products such as curved-surface blades without using 5-axis computerised numerical control machines. This work presents the effect of tool diameter and forming temperature on spring-back and dimensional accuracy of a simple fabricated part. The results of the first phase of the study are utilised to design the fabrication process of a curved surface blade. A feature-based algorithm is used to design the tool path for the forming process. The dimensional accuracy of the final product is improved through warm forming, two-point incremental forming, and extension of the bending zone to the outside of the product edges. The results show that DMP can be used to fabricate complex curved-surface workpieces with acceptable dimensional accuracy.

Industry-Oriented Method for Dynamic Force Identification in Peripheral Milling Based on FSC-LSQR Using Acceleration Signals

Online measurement of milling force play a vital role in enabling machining process monitoring and control. In practice, the milling force is difficult to be measured directly with the dynamometer. This paper develops a novel method for milling force identification called least square QR-factorization with fast stopping criterion (FSC-LSQR) method, and the queue buffer structure (QBS) is employed for the online identification of milling force using acceleration signals. The convolution integral of milling force and acceleration signals is discretized, which turns the problem of milling force identification into a linear discrete ill-posed problem. The FSC-LSQR algorithm is adopted for milling force identification because of its high efficiency and accuracy, which handles the linear discrete ill-posed problem effectively. The online identification of milling force can be realized using the acceleration signal enqueue and the milling force dequeue operations of the QBS. Finally, the effectiveness of the method is verified by experiments. The experimental results show that the FSC-LSQR algorithm running time is within \((0.05s)\) and the calculation error is less than \((10\%)\). The proposed method can make the sampling frequency of the milling force reach 10240Hz by employing QBS, which satisfy the industry requirements of milling force measurement.