The past few decades have seen substantial growth in Additive Manufacturing (AM) technologies. However, this growth has mainly been process-driven. The evolution of engineering design to take advantage of the possibilities afforded by AM and to manage the constraints associated with the technology has lagged behind. This paper presents the major opportunities, constraints, and economic considerations for Design for Additive Manufacturing. It explores issues related to design and redesign for direct and indirect AM production. It also highlights key industrial applications, outlines future challenges, and identifies promising directions for research and the exploitation of AM's full potential in industry.

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Design for additive manufacturing: trends, opportunities, considerations, and constraints

Advances in soft robotics, materials science, and stretchable electronics have enabled rapid progress in soft grippers. Here, a critical overview of soft robotic grippers is presented, covering different material sets, physical principles, and device architectures. Soft gripping can be categorized into three technologies, enabling grasping by: a) actuation, b) controlled stiffness, and c) controlled adhesion. A comprehensive review of each type is presented. Compared to rigid grippers, end-effectors fabricated from flexible and soft components can often grasp or manipulate a larger variety of objects. Such grippers are an example of morphological computation, where control complexity is greatly reduced by material softness and mechanical compliance. Advanced materials and soft components, in particular silicone elastomers, shape memory materials, and active polymers and gels, are increasingly investigated for the design of lighter, simpler, and more universal grippers, using the inherent functionality of the materials. Embedding stretchable distributed sensors in or on soft grippers greatly enhances the ways in which the grippers interact with objects. Challenges for soft grippers include miniaturization, robustness, speed, integration of sensing, and control. Improved materials, processing methods, and sensing play an important role in future research.

https://onlinelibrary.wiley.com/doi/pdf/10.1002/adma.201707035

Soft Robotic Grippers.

An overview on 3D printing technology: Technological, materials, and applications

In an effort to improve customization for today's highly competitive global marketplace, many companies are utilizing product families and platform-based product development to increase variety, shorten lead times, and reduce costs The key to a successful product family is the product platform from which it is derived either by adding, removing, or substituting one or more modules to the platform or by scaling the platform in one or more dimensions to target specific market niches This nascent field of engineering design has matured rapidly in the past decade, and this paper provides a comprehensive review of the flurry of research activity that has occurred during that time to facilitate product family design and platform-based product development for mass customization Techniques for identifying platform leveraging strategies within a product family are reviewed along with metrics for assessing the effectiveness of product platforms and product families Special emphasis is placed on optimization approaches and artificial intelligence techniques to assist in the process of product family design and platform-based product development Web-based systems for product platform customization are also discussed Examples from both industry and academia are presented throughout the paper to highlight the benefits of product families and product platforms The paper concludes with a discussion of potential areas of research to help bridge the gap between planning and managing families of products and designing and manufacturing them

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Product platform design and customization: Status and promise

Design for manufacture and assembly (DFM) has typically meant that designers should tailor their designs to eliminate manufacturing difficulties and minimize manufacturing, assembly, and logistics costs. However, the capabilities of additive manufacturing technologies provide an opportunity to rethink DFM to take advantage of the unique capabilities of these technologies. As mentioned in Chap. 16, several companies are now using AM technologies for production manufacturing. For example, Siemens, Phonak, Widex, and the other hearing aid manufacturers use selective laser sintering and stereolithography machines to produce hearing aid shells; Align Technology uses stereolithography to fabricate molds for producing clear dental braces (“aligners”); and Boeing and its suppliers use polymer powder bed fusion (PBF) to produce ducts and similar parts for F-17 fighter jets. For hearing aids and dental aligners, AM machines enable manufacturing of tens to hundreds of thousands of parts, where each part is uniquely customized based upon person-specific geometric data. In the case of aircraft components, AM technology enables low-volume manufacturing, easy integration of design changes and, at least as importantly, piece part reductions to greatly simplify product assembly.

Design for Additive Manufacturing

With the rapid increase in oil and gas consumption in the world’s energy consumption structure, the pace of global oil–gas pipeline construction has accelerated. Pipeline accidents that cause huge economic losses occur frequently, so inspection and maintenance of oil and gas pipelines have become critical issues. This paper presents a helical-contact deformation measuring method based on a multi-purpose helical drive in-pipe robot that can be used in harsh 3D unknown enclosed near-circular environments, such as oil–gas pipelines. This measuring device has a simple structure and does not need an additional driving module to rotate the measuring device. The device can rotate together with the robot’s driving wheels and measure pipe diameters ranging from 180mm to 210mm. Eccentricity analysis and simulation are also conducted. Experiments in Plexiglas pipe are carried out to draw the pipe shape and test the eccentricity of the measuring device.

https://www.actapress.com/PaperInfo.aspx?paperId=45456

Helical-contact deformation measuring method in oil–gas pipelines

This paper presents an integrated system structure for product development. Haptic modeling, due to its growing applications to different aspects of product development, is envisioned as the core technology for the proposed product development system structure. Because of the fact that haptic modeling is developed based on physical laws, it is anticipated as the natural link between the virtual world and practical applications. Since haptic shape modeling is based on material properties and related shaping methods that require high update frequency, this paper also proposes an effective spatial run-length encoding (S-RLE) algorithm for 3D representations of both object shapes and shaping tools. Force measurements from a robot machining system are used to determine the coefficients of a simple machining force model.

Haptic modeling as an integrating tool for product development

Haptic-Based Function Analysis and Shape Modeling of Multi-Material Product: A Case Study

In this paper, a set of constraints is derived by Youla parametrization and frequency-domain analysis for the road disturbance transfer functions and the load disturbance transfer functions of a quarter car model when acceleration measurements are considered. Simulation results are given to show what the constraints will bring to the performance of vehicle suspension systems. Furthermore, based on the existing study, it can be shown that any road disturbance response and any load disturbance response, which are achievable using full state feedback including acceleration measurements, can be achieved using only two kinds of special measurements with any arbitrarily small tolerance.

Achievable Dynamic Response for Vehicle Suspensions with Acceleration Measurements

When compressing a soft bellow, the bellow will contract and pump out the fluid inside the bellow. Utilizing this property, we propose a novel actuation method called compressing bellow actuation (CBA), which can output fluidic power and tendon-driven force simultaneously. Based on the CBA method, a double-acting soft actuator (DASA) combining fluidic elastomer actuator (FEA) and tendon-driven metacarpophalangeal (MCP) joint is proposed for robotic finger design. The proposed DASA exhibits both compliance and adaptiveness of FEAs, and controllability and large output force of the tendon-driven methods. The fluid in the bellow can be either air or water or even integration of the two, thus constituting three different actuation modes. Mathematical modeling of the relationship between bellow compression displacement and DASA’s bending angle is developed. Furthermore, experimental characterizations of DASA’s bending angle and blocking force are conducted at different actuation modes. The double-acting method can availably promote the bending angle of an FEA by up to 155%, and the blocking force by up to 132% when the FEA is water-filled. A soft robotic hand with a forearm prototype based on the DASA fingers is fabricated for the demonstration of finger motion and gripping applications.

/pdf/double-acting-soft-actuator-for-soft-robotic-hand-a-bellow-3jvsmzvw.pdf

Yonghua Chen

Papers

Helical-contact deformation measuring method in oil–gas pipelines

Haptic modeling as an integrating tool for product development

Haptic-Based Function Analysis and Shape Modeling of Multi-Material Product: A Case Study

Achievable Dynamic Response for Vehicle Suspensions with Acceleration Measurements

Double-Acting Soft Actuator for Soft Robotic Hand: A Bellow Pumping and Contraction Approach