Jouni Partanen

Additive manufacturing in the spare parts supply chain

As additive manufacturing (AM) evolves to become a common method of producing final parts, further study of this computer integrated technology is necessary. The purpose of this research is to evaluate the potential impact of additive manufacturing improvements on the configuration of spare parts supply chains. This goal has been accomplished through scenario modeling of a real-life spare parts supply chain in the aeronautics industry. The spare parts supply chain of the F-18 Super Hornet fighter jet was selected as the case study because the air-cooling ducts of the environmental control system are produced using AM technology. In total, four scenarios are investigated that vary the supply chain configurations and additive manufacturing machine specifications. The reference scenario is based on the spare parts suppliers current practice and the possible future decentralization of production and likely improvements in AM technology. Total operating cost, including downtime cost, is used to compare the scenarios. We found that using current AM technology, centralized production is clearly the preferable supply chain configuration in the case example. However, distributed spare parts production becomes practical as AM machines become less capital intensive, more autonomous and offer shorter production cycles. This investigation provides guidance for the development of additive manufacturing machines and their possible deployment in spare parts supply chains. This study contributes to the emerging literature on AM deployment in supply chains with a real-world case setting and scenario model illustrating the cost trade-offs and critical requirements for technology development.

Rapid manufacturing in the spare parts supply chain: Alternative approaches to capacity deployment

Purpose – The purpose of this paper is to describe and evaluate the potential approaches to introduce rapid manufacturing (RM) in the spare parts supply chain.Design/methodology/approach – Alternative conceptual designs for deploying RM technology in the spare parts supply chain were proposed. The potential benefits are illustrated for the aircraft industry. The general feasibility was discussed based on literature.Findings – The potential supply chain benefits in terms of simultaneously improved service and reduced inventory makes the distributed deployment of RM very interesting for spare parts supply. However, considering the trade‐offs affecting deployment it is proposed that most feasible is centralized deployment by original equipment manufacturers (OEMs), or deployment close to the point of use by generalist service providers of RM.Research limitations/implications – The limited part range that is currently possible to produce using the technology means that a RM‐based service supply chain is feasi...

Digital manufacturing-driven transformations of service supply chains for complex products

Purpose – The purpose of this paper is to explore the forms that combinations of digital manufacturing, logistics and equipment use are likely to take and how these novel combinations may affect the relationship among logistics service providers (LSPs), users and manufacturers of equipment. Design/methodology/approach – Brian Arthur’s theory of combinatorial technological evolution is applied to examine possible digital manufacturing-driven transformations. The F-18 Super Hornet is used as an illustrative example of a service supply chain for a complex product. Findings – The introduction of digital manufacturing will likely result in hybrid solutions, combining conventional logistics, digital manufacturing and user operations. Direct benefits can be identified in the forms of life cycle extension and the increased availability of parts in challenging locations. Furthermore, there are also opportunities for both equipment manufacturers and LSPs to adopt new roles, thereby supporting the efficient and sust...

Novel additive manufactured scaffolds for tissue engineered trachea research

Abstract Conclusions: This study demonstrates proof of concept for controlled manufacturing methods that utilize novel tailored biopolymers (3D photocuring technology) or conventional bioresorbable polymers (fused deposition modeling, FDM) for macroscopic and microscopic geometry control. The manufactured scaffolds could be suitable for tissue engineering research. Objectives: To design novel trachea scaffold prototypes for tissue engineering purposes, and to fabricate them by additive manufacturing. Methods: A commercial 3D model and CT scans of a middle-aged man were obtained for geometrical observations and measurements of human trachea. Model trachea scaffolds with variable wall thickness, interconnected pores, and various degrees of porosity were designed. Photocurable polycaprolactone (PCL) polymer was used with 3D photocuring technology. Thermoplastic polylactide (PLA) and PCL were used with FDM. Cell cultivations were performed for biocompatibility studies. Results: Scaffolds of various sizes and porosities were successfully produced. Both thermoplastic PLA and PCL and photocurable PCL could be used effectively with additive manufacturing technologies to print high-quality tubular porous biodegradable structures. Optical microscopic and SEM images showed the viability of cells. The cells were growing in multiple layers, and biocompatibility of the structures was shown.

Multitool and Multi-Axis Computer Numerically Controlled Accumulation for Fabricating Conformal Features on Curved Surfaces

In engineering systems, features such as textures or patterns on curved surfaces are common. In addition, such features, in many cases, are required to have shapes that are conformal to the underlying surfaces. To address the fabrication challenge in building such conformal features on curved surfaces, a newly developed additive manufacturing (AM) process named computer numerically controlled (CNC) accumulation is investigated by integrating multiple tools and multiple axis motions. Based on a fiber optical cable and a light source, a CNC accumulation tool can have multi-axis motion, which is beneficial in building conformal features on curved surfaces. To address high resolution requirement, the use of multiple accumulation tools with different curing sizes, powers, and shapes is explored. The tool path planning methods for given cylindrical and spherical surfaces are discussed. Multiple test cases have been performed based on a developed prototype system. The experimental results illustrate the capability of the newly developed AM process and its potential use in fabricating conformal features on given curved surfaces. [DOI: 10.1115/1.4026898]

The integrations of biomaterials and rapid prototyping techniques for intelligent manufacturing of complex organs

In the human body, an organ is a composite of different tissues in an ordered structural unit to serve a common function [1]. Ordinarily, cells self-assemble into tissues before forming an organ. There are at least three different tissues in a complex organ, such as the liver, heart, and kidney. Currently, complex organ failures are the first cause of mortality in developed countries despite advances in pharmacological, interventional, and surgical therapies [2]. Orthotopic organ transplantation is severely limited by the problems of donor shortage and immune rejections [3]. Extracorporeal support systems perform some specific functions within a limited time period [4]. Cell encapsulation techniques face the problems of capsule loss, low stability, and poor efficiency [5]. Cell sheet technique cannot rescue tissues with in‐ creased thicknesses above 80 μm [6]. Decellularized matrices are hard to be repopulated by multiple cell types [7]. On the other hand, stem cell research has emerged as one of the most high-profile and promising areas of 21st century science [8-10]. Typically, autologous adi‐ pose-derived stem cells (ADSCs) represent one of the most abundant, easily cultured, rapid‐ ly expanded, and multipotent cell source [11]. It has been a long-term goal in this field to manufacture complex organs from biocompatible materials (including non-immune patient derived cells) and computer-aided design (CAD) models in a fast, easy, cheap and automat‐ ic manner.

Challenges to implementing additive manufacturing in globalised production environments

This paper presents the current state of additive manufacturing (AM) implementation in complex supply chains, focusing especially on the globalised consumer electronics industry. A literature review sought to identify bottlenecks to technology transfer, while a qualitative study was carried out using interviews with case company personnel. Finally, an industry survey was used to quantitatively evaluate current production costs and delivery times for AM units. The results highlight the considerable barriers to transferring AM technology to engineering applications. However, there is an untapped potential for manufacturing applications in small-series and pre-series production at the product refinement stages. Furthermore, future projections of AM production throughput and cost reductions will disrupt organisational supply chains. This will lead organisations to create faster design, development and manufacturing cycles, unlocking novel applications and introducing new possibilities to change product architecture at any stage of the product development while compressing the supply chain and allowing for quick responses to changing customer demands.

Nanofibrillar cellulose-alginate hydrogel coated surgical sutures as cell-carrier systems

Hydrogel nanomaterials, especially those that are of non-human and non-animal origins, have great potential in biomedical and pharmaceutical sciences due to their versatility and inherent soft-tissue like properties. With the ability to simulate native tissue function, hydrogels are potentially well suited for cellular therapy applications. In this study, we have fabricated nanofibrillar cellulose-alginate (NFCA) suture coatings as biomedical devices to help overcome some of the limitations related to cellular therapy, such as low cell survivability and distribution out of target tissue. The addition of sodium alginate 8% (w/v) increased the NFCA hydrogel viscosity, storage and loss moduli by slightly under one order of magnitude, thus contributing significantly to coating strength. Confocal microscopy showed nearly 100% cell viability throughout the 2-week incubation period within and on the surface of the coating. Additionally, typical morphologies in the dual cell culture of spheroid forming HepG2 and monolayer type SK-HEP-1 were observed. Twelve out of 14 NFCA coated surgical sutures remained intact during the suturing operation with various mice and rat tissue; however, partial peeling off was observed in 2 of the coated sutures. We conclude that NFCA suture coatings could perform as cell-carrier systems for cellular based therapy and post-surgical treatment.

Implementation of Industrial Additive Manufacturing: Intelligent Implants and Drug Delivery Systems

The purpose of this study is to demonstrate the ability of additive manufacturing, also known as 3D printing, to produce effective drug delivery devices and implants that are both identifiable, as well as traceable. Drug delivery devices can potentially be used for drug release in the direct vicinity of target tissues or the selected medication route in a patient-specific manner as required. The identification and traceability of additively manufactured implants can be administered through radiofrequency identification systems. The focus of this study is to explore how embedded medication and sensors can be added in different additive manufacturing processes. The concept is extended to biomaterials with the help of the literature. As a result of this study, a patient-specific drug delivery device can be custom-designed and additively manufactured in the form of an implant that can identify, trace, and dispense a drug to the vicinity of a selected target tissue as a patient-specific function of time for bodily treatment and restoration.

Producing parts with multiple layer thicknesses by projection stereolithography

We present a novel method to increase the manufacturing speed and versatility in lithography-based additive manufacturing processes. Usually, a part made with additive manufacturing consists of equally thick layers that are fabricated upon one another. We use a projection stereolithography (PSL) system to manufacture parts containing several layer thicknesses, which reduces the manufacturing time and adds controllability to the system. The method is based on the possibility to control the cure depth by adjusting the operation wavelength. To demonstrate the applicability of the PSL system for this purpose, we used two different operation wavelengths to produce parts that include 50- and 300-µm layers. The method presented in this paper can be used in several PSL techniques to increase their performance by offering a new tool to control the layer thickness without affecting the manufacturing resolution.