Multi-Material Capability of Laser Induced Plasma Micromachining

Presently surface micro-texturing has found many promising applications in the fields of tribology, bio-medical engineering, metal cutting, and other functional or topographical surfaces. Most of these applications are material-specific, which necessitates the need for a texturing and machining process that surpasses the limitations posed by a certain class of materials that are difficult to process by laser ablation, owing to their optical or other surface or bulk characteristics. Laser Induced Plasma Micromachining (LIPMM) has emerged as a promising alternative to direct laser ablation for micro-machining and micro-texturing, which offers superior machining characteristics while preserving the resolution, accuracy and tool-less nature of laser ablation. This study is aimed at understanding the capability of LIPMM process to address some of the issues faced by pulsed laser ablation in material processing. This paper experimentally demonstrates machining of optically transmissive, reflective and rough surface materials using LIPMM. Apart from this, the study includes machining of conventional metals (Nickel and Titanium) and polymer (Polyimide), to demonstrate higher obtainable depth and reduced heat affected distortion around micro-features machined by LIPMM, as compared to laser ablation.

Concept for Function Block Enabled Process Planning Towards Multi-Site Cloud Collaboration

In global enterprises an essential challenge is how to enable efficient sharing of knowledge, capacity, and resources in order to meet demands on speed, flexibility and adaptability. This paper highlights challenges and aspects regarding framework and technical platform for process planning that enable global multi-site collaboration. To get an industrial perspective, this topic is discussed in the context of Sandvik Coromant’s globally distributed application centers. Further on, function block technology as enabling technology to achieve flexible and adaptable process planning as a part of the framework is presented and discussed together with results from the on-going research work.

A Low-Cost and High-Resolution Micro Machine Tool With Toggle-Based Mechanism

The products of 3C, bioscience, medical industry, and aerospace industry are becoming smaller and smaller. The components of the products are made of various materials with complex 3D shapes requiring high accuracy in their dimensions and contours. An accurate micro-/meso-scale CNC machine tool is an essential part of this technology. A new type of CNC micro machine tool with a toggle-like mechanism having the characteristics of low-cost and fine-resolution was developed. With geometric reduction principle, the machine can provide finer feed resolution and better positioning accuracy without using high-end driving components and controller. The kinematics model and characteristics of the machine were derived and analyzed. Modal analysis and dynamic compliance analysis were employed to design a light-weight structure with good stiffness. The accuracy calibration results showed the machine can reach a positioning accuracy of 500 nm. Prototype of the machine was built, and furthermore some micro machining examples were demonstrated in this paper.

Representation and Exchange of Digital Catalogues of Cutting Tools

Information management for manufacturing resources such as cutting tools is an important research topic in the context of cloud manufacturing. Vendors and customers usually use catalogues to communicate information for such manufacturing resource. Incompatibilities of information in syntax, semantics, and structure among supply chains often result in inefficient manual sharing and management of the catalogue information. It is difficult for cloud based applications to pool information from various sources. This communication failure calls for a system neutral solution for data modeling and exchange to enhance interoperability of the cutting tool catalogue information. Previous studies has present solutions for representation of the cutting tool information with STEP AP242 (ISO/DIS 10303-242) with semantic classification referring to a PLib (ISO 13584, Part Library) based dictionary. This approach can be extended for the catalogue modeling, due to functionalities for specification and configuration control of general product variants in the same standard. With a modeling approach with standardized information schemas, system architecture to guide implementation is proposed to enhance the communication in practice. Relative elements to represent vendors’ catalogues and customers’ requirements are modeled. Associations to the PLib-based dictionary complete semantics and enable information mapping between vendors and customers. Principles of the mapping are identified to facilitate implementation of related software systems. Prototypes are developed to verify the proposed system architecture. The proposed solution is promising to migrate to other types of products than cutting tools, because the data models are based on the general product models defined in AP242.

Simulation-Based Optimization of Electricity Demand Response for Sustainable Manufacturing Systems

Electricity demand response is considered a promising tool to balance the electricity demand and supply during peak periods. It can effectively reduce the cost of building and operating those peaking power generators that are only run a few hundred hours per year to satisfy the peak demand. The research on the electricity demand response implementation for residential and commercial building sectors has been very mature. Recently, it has also been extended to the manufacturing sector. In this paper, a simulation-based optimization method is developed to identify the optimal demand response decisions for the typical manufacturing systems with multiple machines and buffers. Different objectives, i.e. minimizing the power consumption under the constraint of system throughput, and maximize the overall earnings considering the tradeoff between power demand reduction and potential production loss, are considered. Different energy control decisions are analyzed and compared regarding the potential influence on the throughput of manufacturing system due to the different control actions adopted by throughput bottleneck machine.

Multi-Scale Surface Characterization and Control Based High Density Measurements

It is widely observed that today’s engineering products demand increasingly strict tolerances. The shape of a machined surface plays a critical role to the desired functionality of a product. Even a small error can be the difference between a successful product launch and a major delay. Thus, it is important to develop measurement tools to ensure the quality and accuracy of products’ machined surfaces. The key to assessing the quality is robust measurement and inspection techniques combined with advanced analysis. However, conventional Geometrical Dimensioning and Tolerancing (GD&T) such as flatness falls short of characterizing the surface shape. With the advancements in metrology methodology utilizing digital holographic interferometry, large amount of surface data can be captured at high resolution and accuracy without changing platform or technique. This captured High Definition Data (HDD) enables the mining of more valuable information from machined surfaces that most current industry practice cannot achieve in a timely manner. Such new metrology system opens the torrent of observable events at plant floor and increases the transparency of machining processes. This presents great opportunities to characterize machined surface into a new level of details, which can be applied in production quality evaluation and process condition monitoring and control. This research work proposes a framework of a multi-scale surface characterization for surface quality evaluation and process monitoring. Case studies are presented to show how proposed metrics could be applied in surface quality evaluation and process monitoring.

Joint Production and Energy Modeling of Sustainable Manufacturing Systems: Challenges and Methods

This paper proposes a framework for addressing challenges of joint production and energy modeling of sustainable manufacturing systems. The knowledge generated is used to improve the technological readiness of manufacturing enterprises for the transition towards sustainable manufacturing. Detailed research tasks of the framework are on the modeling of production, energy efficiency, electricity demand, cost, and demand response decision making. Specifically, the dynamics and performance measures of general manufacturing systems with multiple machines and buffers are modeled to integrate energy use into system modeling. The expressions of electrical energy efficiency and cost are then established based on the electricity pricing profile. Finally, joint production and energy scheduling problem formulations and the solution technique are discussed. New insights are acquired based on the applications of the established model in system parameter selection, rate plan switching decision making, and demand response scheduling. Appropriate implementation of this research outcome may lead to energy-efficient, demand-responsive, and cost-effective operations and thus improve the sustainability of modern manufacturing systems.

Fabrication of Hierarchical Micro-Nano Structures and Structural Coloring Effect of Polymer Substrate

Recently, structural coloring using hierarchical micro-nano structures as a technical field to implement a color without using a chemical colourants and dye is being developed as an attentional technology. The principle of structural coloring is that by the diffraction or multi-interference of light from a material containing a periodic or quasiperiodic structure on the length scale of the wavelength of visible light. For these reason, our research have verified the structural coloring effect on the polymer substrate by fabricate a hierarchical micro-nano structures. Firstly, we have fabricate a nano and hierarchical micro-nano structured mold for verify the structural size effect. Through the replication of structures on the PMMA substrate, we have measured optical properties in the range of visible light. As a results, the surface of nano structured PMMA showed a blue color according to induced the light. Furthermore, color intensity was increased according to increase the aspect ratio and diameter. In contrast, hierarchical micro-nano patterned surface showed iridescent colors.

Wedge Radius Effects in Mechanical Exfoliation of HOPG: A Molecular Simulation Study

We study the effects of wedge bluntness in mechanically exfoliating graphene layers from highly ordered pyrolytic graphite (HOPG), a layered material. Molecular dynamics simulations show that the layer initiation modes strongly depend on the wedge radius. Force and specific energy signatures are also markedly affected by the radius. Cleaving with a larger wedge radius causes buckling ahead of the wedge; larger the radius more the buckling. A critical depth of insertion of 1.6 A° is seen necessary to cleave a single layer; this is also found to be independent of wedge radius. Hence, with accurate positioning on an atomically flat HOPG surface it is possible to mechanically cleave, using a wedge, a single sheet of graphene even with a blunt wedge.

AFM-Based Nanoscratching: A 3D Molecular Dynamics Simulation With Experimental Verification

In this paper, a developed three-dimensional model for AFM-based nanomachining is applied to study mechanical scratching at the nanoscale. The correlation between the scratching conditions, including applied force, scratching depth, and distant between any two scratched grooves, and the defect mechanism in the substrate/workpiece is investigated. The simulations of nanoscratching process are performed on different crystal orientations of single-crystal gold substrate, Au(100), Au(110), and Au(111). The material deformation and groove geometry are extracted from the final locations of atoms, which are displaced by the rigid indenter. The simulation also allows for the prediction of normal and friction forces at the interface between the indenter and substrate. An AFM is used to conduct actual scratching at the nanoscale, and provide measurements to which the MD simulation predictions are compared. The predicted forces obtained from MD simulation compares qualitatively with the experimental results.