Hybrid Manufacturing Processes Research Articles

Hybrid Ants: A New Approach for Geometry Creation for Additive and Hybrid Manufacturing

This research presents a novel and disruptive approach to the simultaneous design and structural refinement of parts manufactured using purely additive, purely subtractive and hybrid additive-subtractive manufacturing processes (HASPs). This research is responding to the increasing need to be able to state with confidence that a particular part design can be manufactured by a particular process. This is viewed as a major barrier to the profitable exploitation of additive and hybrid manufacturing processes. By describing the known part constraints and the mechanisms (limitations) of constituent manufacturing processes, parts are designed using a bio-inspired multi-agent system called ‘Hybrid Ants’. By abstracting manufacturing processes into a set of rules that limit how and where material can be processed, all part geometries created by the Hybrid Ants are inherently ‘manufacturable’ under the current description of the manufacturing capability. The possibility that new knowledge may be elicited from this system is an exciting new paradigm, which could change the way design for additive (or hybrid) manufacturing processes is developed in the future. As will be shown throughout this paper, Hybrid Ants is a closed-loop system, which generatively creates part geometries and then appraises these geometries for structural performance using the finite element method. Stress values are then used in the next loop iteration to refine the geometry ad infinitum. This system is akin to ant (or termite) nest morphogenesis, where nest layouts are optimised for thermoregulation and ventilation. In this research, thermoregulation is analogously exchanged for stress for structural optimisation of engineering components.

Microstructure and mechanical properties of LMD–SLM hybrid forming Ti6Al4V alloy

Laser melting deposition (LMD) and selective laser melting (SLM) are two major metal additive manufacturing technologies that explore the near-net shaping of large components and net shaping of small complex structures. In order to achieve subscale complex structures, researchers proposed LMD–SLM hybrid manufacturing processes. Ti6Al4V is an α–β dual-phase, moderate strength titanium alloy that is widely used in the fields of medicine, aeronautics, and astronautics. In this study, thin (1.5–2.5mm) horizontal, vertical SLM plate and rolled plate are used as substrate materials for the LMD process to analyze tensile properties, microhardness, microstructure, and internal defects. The results show that the LMD process forms a hybrid with the aforementioned plates. The relative density of hybrid-forming area can reach 99.5%, because of the existence of the pores with diameter <20µm. Tensile strength and elongation of the hybrid thus produced can reach respectively 918MPa and 11%, and fractures are located in the LMD zone. Internal layer fracture of the LMD zone increases elongation, whereas layer interface fracture decreases it. The laser deposition process epitaxially generates coarse columnar crystals, and laser remelting reduces the microhardness of the SLM substrate in the 2- to 3-mm-thick grain-increased heat-affected zone (HAZ). The microhardness distributions of the LMD zone, HAZ, and substrate material are found to be 344, 343, and 375 (horizontal SLM); 346, 334, and 386 (vertical SLM); and 351, 328, and 340HV (rolled plate), respectively.

Hybrid Technology Used in Foundry

The paper presents the ways to eliminate shrinkage defects of nature. These techniques are, primarily, technological overlaps, risers and refrigerators. The paper shows that these methods are based on the known principle of feeding, according to which the upper layers of the is the risers for the underlying layers. This provides directional solidification of casting. The paper describes the additive technologies that solve problems, which are unobtainable for conventional technologies. It shows that the thin horizontal layers form a configuration sequentially. Here is realized another principle of feeding that is formulated as follows: each layer feeds itself. There is no difficulty to eliminate shrinkage defects in thin horizontal layers. However, high cost of raw materials and equipment and low productivity disallow wide introduction of additive technologies to manufacture castings. One solution to this problem, which is offered to-date is to create hybrid-manufacturing processes that combine both additive and traditional manufacturing techniques of casting. Traditional manufacturing techniques of castings are macro-level technologies while the additive technology is a micro level. Hybrid technologies, which are in intermediate position, can be attributed to a meso-level of the review of processes occurring in the liquid melt and mold. The paper has shown that the techniques that provide layer-by-layer filling of liquid melt in the mold and (or) layer-by-layer solidification of liquid melt in the mold can serve as one of the examples of hybrid technology in foundry. The paper analyses some of the patents related to the group of casting ingots of two or more different melts, i.e. multilayer » (B22D7 / 02). It conducts an analysis of the patent developed in BMSTU. The main conclusions are as follows: 1. At present, there is a base created for a successful development of hybrid technology in the foundry industry. 2. Hybrid technology allows the production for a period of transition (the period of changing traditional technology) to provide a new quality of castings.

Additive manufacturing–integrated hybrid manufacturing and subtractive processes: economic model and analysis

This article presents economic models for a new hybrid method where additive manufacturing (AM) and subtractive methods (SMs) are integrated through composite process planning. Although AM and SM offer several unique advantages, there are technological limitations such as tolerance and surface finish requirements; tooling and fixturing, etc. that cannot be met by a single type of manufacturing. The intent of this article is not to show a new manufacturing method, but rather to provide economic context to additive and subtractive methods as the best practice provides, and look at the corresponding economics of each of those methods as a function of production batch size, machinability, cost of the material, part geometry and tolerance requirements. Basic models of fixed and variable costs associated with additive, subtractive and hybrid methods to produce parts are also presented. An experimental design is used to study the influence of production volume, material and operating cost, batch size, machinability of the material and impact of reducing AM processing time. A composite response model for the unit cost is computed for the various levels associated with such engineering requirements. The developed models provide insight into how these variables affect the costs associated with engineering a mechanical product that will be produced using AM and SM methods. From the results, it appears that batch size, AM processing time and AM processing cost were the major cost factors. It was shown that the cost of producing ‘near-net’ shape through SM and AM was the decision criteria; which will be critical for tough-to-machine alloys and at multi-batch size.

A novel decision-making logic for hybrid manufacture of prismatic components based on existing parts

The on-going industrial trend towards high value sustainable manufacturing has led to the emergence of hybrid manufacturing processes. This new generation of processes combines the capabilities of a number of individual manufacturing processes on a single platform. Despite the fact that the drawbacks of individual processes have been significantly reduced, the application of hybrid technology has always been constrained by the capabilities of their constituent processes, in particular the capability to utilise various raw materials in terms of shape and size. This paper introduces a novel concept of hybrid process, which consists of combining additive, subtractive and inspection processes. A feature-based decision-making logic is developed, enabling the hybrid process to reuse existing parts/legacy products. An existing part is first measured for obtaining its geometrical information. Feasible manufacturing strategies are provided and then additive, subtractive and inspection processes are utilised interchangeably to add and/or remove material, transforming the existing part into the final part. This indicates that the iAtractive process is not restricted by raw material geometries. Three identical test parts were manufactured from three existing different shaped parts, demonstrating the efficacy of the proposed hybrid process and the decision-making logic in material reuse. New features can be added onto the existing parts and existing features can be removed or further manufactured, giving these parts additional lives, new uses and increased functionality.

My new colleague has artificial muscles: a DEA based approach for inherently compliant robotic systems

When robots and human workers team up, safety should be ensured at all times. In order to improve safety of human–robot collaboration in hybrid manufacturing processes, many different types of compliant robotic drives, serial elastic actuators for instance, have been developed to date. However, most of them still consist of rigid mechanical components in combination with prevailing servo motor and thus bring several disadvantages such as poor power-to-weight ratio. This paper presents our solution approach for realization of biomimetic, inherently compliant artificial muscles based on dielectric elastomer actuators (DEAs). The artificial muscles based on DEAs distinguish themselves from conventional actuators through their favorable characteristics. They (a) work noiseless, (b) feature specific energy density comparable to human skeletal muscles and (c) are capable of storing or even recovering energy, and finally, (d) can adjust their geometry to meet with undefined and unstructured objects or environments. With remaining challenges overcome, the DEAs are expected to provide a significant contribution to safety of industrial robots collaborating with human workers.

Hybrid Manufacturing Technologies for Electromagnetic Structures

Advanced fabrication technologies are poised to revolutionize the manufacturing environment. While the development of additive manufacturing technologies for mechanical components has been rapidly evolving, the application of these methods to the fabrication of RF and microwave components has been limited. Hybrid manufacturing processes, which combine distinct techniques such as fused deposition modeling (FDM), and laser micromachining, enable the creation of complex three-dimensional (3D) electromagnetic components. At NRL, we have investigated the combination of 3D printing techniques with direct-write processes that allow for the metallization, laser patterning and room temperature processing of electromagnetic patterns on 3D printed surfaces. The resolution and print volume achieved with these methods are well suited for the rapid prototyping of electromagnetic structures. Several example structures fabricated using these techniques will be presented.

Hybrid processes in manufacturing

Hybrid manufacturing processes are based on the simultaneous and controlled interaction of process mechanisms and/or energy sources/tools having a significant effect on the process performance. These processes have a large influence on the processing/manufacturing characteristics resulting in higher machinability, reductions of process forces and tool wear, etc. Due to the combined action of processes, it also has an important – and most of the time – positive effect on the surface integrity of machined parts. This paper gives a definition and classification of hybrid processes, followed by a description of principles and future perspectives, benefits on productivity, effects on surface quality and applications of common hybrid processes.

Hybrid manufacturing in micro/nano scale: A Review

In this paper, a total of 57 micro and nano scale hybrid manufacturing processes are reviewed. These processes are categorized in terms of process timing and process type. Process timing is one of the most important aspects of manufacturing, and three different process schemes — concurrent, main/assistive (M/S) separate, and main/main (M/M) separate — are considered. The process type is categorized as either geometrically additive or subtractive, and all hybrid processes are categorized into combinations of additive, subtractive, and assistive process. Features and advantages are described for each of these classifications. Machining is found to be the most common process for both micro and nano-scale hybrid manufacturing. Of micro scale hybrid manufacturing schemes, 74.4% use assistive processes as a secondary process because the main purpose of most micro scale hybrid manufacturing is to improve the quality of the process. In nano scale manufacturing, 61.5% of hybrid manufacturing schemes employ assistive processes, since these processes typically focus on the fabrication of parts that are difficult to fabricate using a single, existing process. Based on a summary of published work, future trends in hybrid manufacturing at the micro and nano scale are suggested.

The development of a novel process planning algorithm for an unconstrained hybrid manufacturing process

The application of state of the art manufacturing processes has always been constrained by the capabilities either from technical limitations such as limited materials and complex part geometries or production costs. As a result, hybrid manufacturing processes – where varied manufacturing operations are carried out – are emerging as a potential evolution for current manufacturing technologies. However, process planning methods capable of effectively utilising manufacturing resources for hybrid processes are currently limited. In this paper, a hybrid process, entitled iAtractive, combining additive, subtractive and inspection processes, along with part specific process planning is proposed. The iAtractive process aims to accurately manufacture complex geometries without being constrained by the capability of individual additive and subtractive processes. This process planning algorithm enables a part to be manufactured taking into consideration, process capabilities, production time and material consumption. This approach is also adapted for the remanufacture of existing parts. Four test parts have been manufactured from zero and existing parts, demonstrating the efficacy of the proposed hybrid process and the process planning algorithm.

A review of hybrid manufacturing processes – state of the art and future perspectives

Today, hybrid manufacturing technology has drawn significant interests from both academia and industry due to the capability to make products in a more efficient and productive way. Although there is no specific consensus on the definition of the term ‘hybrid processes’, researchers have explored a number of approaches to combine different manufacturing processes with the similar objectives of improving surface integrity, increasing material removal rate, reducing tool wear, reducing production time and extending application areas. Thus, hybrid processes open up new opportunities and applications for manufacturing various components which are not able to be produced economically by processes on their own. This review paper starts with the classification of current manufacturing processes based on processes being defined as additive, subtractive, transformative, joining and dividing. Definitions of hybrid processes from other researchers in the literature are then introduced. The major part of this paper reviews existing hybrid processes reported over the past two decades. Finally, this paper attempts to propose possible definitions of hybrid processes along with the authors’ classification, followed by discussion of their developments, limitations and future research needs.

Special Issue on Micro/Nano Machining – Processes, Systems and Control

In recent years, the trend in miniaturization of products is pervasive in areas such as information technology, biotechnology, environmental and medical industries. Micro-machining is the key supporting technology that has to be developed to meet the challenges posed by the requirements of product miniaturization and industrial realization of nanotechnology. Micro-machining techniques can be carried out by techniques based on energy beams (beam-based micro-machining) or solid cutting tools (tool-based micro-machining). Beambased micro-machining have some limitations due to poor control of 3D structures, low material removal rate and low aspect ratio. Moreover, these processes require special facilities and the maximum achievable thickness is relatively small. Some of these limitations can be overcome by tool-based micro-machining techniques using ultra precision machine tools and solid tools used as cutting elements to produce the micro-features with well controlled shape and tolerances. Tool-based micro-machining techniques essentially include precision machining processes as turning, milling, grinding and electrical discharge machining (EDM), whereby material removal is done at the micron level. The advantages of such processes are that almost every material such as metals, plastics and semiconductors can be machined with no limitation in machining shapes. Recently, combinations of conventional material removal processes, such as turning and milling, have been hybridized with non-conventional machining processes like EDM and EDG to fabricate micro-structures with high dimensional accuracy. In order to achieve meaningful implementation of compound micro-machining techniques three important areas are required to be addressed. These are: development of machine tools capable of performing compound micro-machining (i.e. micro turning, micro milling, micro EDM, etc. on the same machine and setup), understanding of process physics to provide relevant background for modeling,measurement, identification of control parameters and application of feedback control in order to control compound and hybrid manufacturing processes and development of compound and hybrid processes. An integrated effort in these areas is needed for successful implementation of tool-based micro-machining. An attempt has been made in this special issue to highlight latest articles on these areas. I would like to express my sincere appreciation to the authors, reviewers and editors for their invaluable contributions for this issue.

Surface Integrity in Hybrid Machining Processes

Hybrid manufacturing processes are based on the simultaneous and controlled interaction of process mechanisms and/or energy sources/tools having a significant effect on the process performance. There are various examples such as laser assisted cutting, vibration assisted grinding and grind-hardening. Hybrid processes have a large influence on the machining characteristics resulting in a higher machineability, reductions of process forces and tool wear, etc. Due to the combined action of processes, it also has an important positive or sometimes negative effect on the surface integrity of machined parts. This key-note/overview paper gives first a definition and classification of hybrid processes. It is then followed by a description of the principles and applications of some common hybrid processes, highlighting the effects on the surface and sub-surface quality. The paper is largely based on the results of an on-going working group within the International Academy for Production Engineering (CIRP).

Ramp-up of hybrid manufacturing technologies

Hybrid manufacturing technologies provide a high potential in enhancing manufacturing process capabilities in terms of new product properties and sustainable production. Combining two or more technologies in one process or machine result in a larger range of options for the creation and optimization of technology chains. Sustainability is an important objective when using hybrid processes but also economic targets can be achieved. The aim of this paper is to present a method for detecting and evaluating hybrid manufacturing technologies and implementing them at the right moment into an existing production environment. A decision has to be made, whether a certain hybrid technology is suitable or not. To make this decision a risk-and-potential analysis of manufacturing technologies was developed. In the first part this article will provide an introduction to hybrid manufacturing processes. Further a design approach for hybrid technologies is shown. The second part concentrates on the possible implementation of manufacturing technologies during the ramp-up phase into the production environment.

Water‐rinsable or so‐called ‘No Clean’ Solder Pastes? The Attempt of a Comparison from the Technical and Environmental Viewpoint

In SMD as well as in hybrid manufacturing processes, considerable quantities of CFC are still being used in 1991 for the cleaning of component groups. The second BlmSchV, as amended, (status at 12 December 1990), prohibits the use of R‐113 for surface treatment plants as of 31 December 1992. Pursuant to developments in solder pastes, some products are already available which render the use of CFCs superfluous. Two methods in particular are emerging, which work either completely without cleaning or use water as a cleaning medium. A critical comparison is made of the properties of the relevant solder pastes in these categories.

ISHM news

The ISHM CAN‐AM Chapter recently organised a half‐day programme of paper presentations followed by a tour of a local hybrid facility. The event took place on 26 April at the Holiday Inn, Montreal (Pointe Claire), Quebec, with the theme of the papers concentrating on advances in hybrid manufacturing processes and some coverage of SMT.