Additive Subtractive Manufacturing Research Articles

Geometric simulation of 5-axis hybrid additive-subtractive manufacturing based on Tri-dexel model

5-axis hybrid additive-subtractive manufacturing is a new and promising technology for many industrial applications. Because of its complexity, the machining simulation is very important to verify the effectiveness of tool path. However, most simulation methods are proposed for subtractive manufacturing and additive manufacturing separately. This paper presents a novel geometric simulation technique for the 5-axis hybrid additive-subtractive manufacturing, which is based on Laser Engineered Net Shaping (LENS) and milling. In the proposed method, 5-axis additive swept volume elements are represented with Tri-dexel models and then converted into triangular meshes for visualization. Workpiece after additive manufacturing can be then used as a workblank for subtractive manufacturing simulation. Finally, a geometric simulation module is developed based on SIEMENS NX software to demonstrate the feasibility of the proposed simulation method.

Energy Consumption Model for Additive-Subtractive Manufacturing Processes with Case Study

There has been a growing trend in industry towards the development of integrated manufacturing centers that combine several manufacturing processes, such as the mill-turn center. As additive manufacturing becomes a more widely adopted technology, combining additive with subtractive manufacturing in one machine is a logical evolution to provide the benefits of final parts made from raw materials with the dimensional tolerance and surface finish expected in many applications. An energy consumption model was created that accounted for the energy consumption during primary metal production, deposition, and machining phases of wire-based and powder-based additive-subtractive manufacturing processes. This model was applied to a case study where the energy consumption to produce sub-sized, sheet type, and plate type (size) tensile bars was calculated. It was found that the wire-based process consumed less energy during deposition, whereas powder-based was less energy consumptive during primary metal production and machining. The findings suggest that given the present understanding of the respective technologies’ capabilities, the desired final net shape will dictate the preferred manufacturing process with respect to energy consumption considerations.

A novel 6-axis hybrid additive-subtractive manufacturing process: Design and case studies

Additive manufacturing has been employed in numerous areas owing to its advantages of fabricating complex geometries and creating less material waste. Nevertheless, parts manufactured by additive manufacturing processes tend to have poor surface quality and low dimensional accuracy. To overcome the limitations of additive manufacturing technologies, the favorable capabilities of subtractive manufacturing, i.e., high surface quality, can be integrated to form a hybrid process. A novel 6-axis hybrid additive-subtractive manufacturing process is proposed and developed in this paper. The hybrid process is realized using a six degrees of freedom (DOF) robot arm, equipped with multiple changeable heads and an integrated manufacturing platform. Based on the obtained results from different case studies, the hybrid additive-subtractive process has shown to have potentials in reducing production time, fabricating parts with better surface quality by removing the staircase error, manufacturing high quality freeform surfaces through the dynamic adjustment of tool axis direction, and eliminating the need for support structure because of the 6-DOF flexibility.

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.

Topology optimization for hybrid additive-subtractive manufacturing

Hybrid additive-subtractive manufacturing is gaining popularity by making full use of geometry complexity produced by additive manufacturing and dimensional accuracy derived from subtractive machining. Part design for this hybrid manufacturing approach has been done by trial-and-error, and no dedicated design methodology exists for this manufacturing approach. To address this issue, this work presents a topology optimization method for hybrid additive and subtractive manufacturing. To be specific, the boundary segments of the input design domain are categorized into two types: (i) Freeform boundary segments freely evolve through the casting SIMP method, and (ii) shape preserved boundary segments suppress the freeform evolvement and are composed of machining features through a feature fitting algorithm. Given the manufacturing strategy, the topology design is produced through additive manufacturing and the shape preserved boundary segments will be processed by post-machining. This novel topology optimization algorithm is developed under a unified SIMP and level set framework. The effectiveness of the algorithm is proved through a few numerical case studies.

A Comparison of Energy Consumption in Wire-based and Powder-based Additive-subtractive Manufacturing

The objective of this work is to compare the energy consumption associated with the creation of a small volume of steel by wire-based additive-subtractive manufacturing and powder-based additive-subtractive manufacturing. Additive manufacturing is a growing area of research, encompassing many different processes aimed at producing final products. However, many additive processes lack the ability to achieve dimensional tolerance and surface finish required for many applications: i.e., post-processing could be required. Combining additive with subtractive manufacturing in one machine tool enables the production of parts with tighter dimensional tolerances and smoother surfaces. In this work, an energy consumption model was created; it considered the contributions of primary metal production, deposition, and machining when calculating the total energy consumed to create a 100mm x 100mm x 1.5mm volume of steel. It was found that for the entire process chain, the wire-based and powder-based processes consume similar amounts of energy. The greatest difference between the two processes is that the energy requirement for the deposition component during the wire-based process is 85% less than in the powder-based additive process. This finding suggests that from an energy consumption perspective, there is value in wire-based additive-subtractive manufacturing.