Small Batch Production Research Articles

Evaluation of flexible automation for small batch production

Traditionally it has been difficult to use automation in small batch production with high variation in volumes and high mix of products. However, this is changing as there exist new types of flexible automation. The purpose of this paper is to understand the requirements on enterprises to use automation in small batch production, and evaluate flexible automation technologies suitable for small batch production. The study is based on literature reviews and interviews. Identified requirements are for example to change between manual access and automation, and easy programming. The results show that a flexible mobile robot automation may fulfill a majority of the identified requirements.

Application of Micro Structured, Boron Doped CVD-diamond as μEDM Tool Electrodes

High precision cavities are used for micro injection and micro embossing tools in the field of tool making and are mainly used for small batch or mass production of micro parts. In order to fabricate a large quantity of parts, wear resistant tool materials are required. In possession of a high hardness and a high Young's Modulus, such materials are often hard or even impossible to machine by conventional fabrication processes. Being independent of the work piece's mechanical properties, Micro-Electrical Discharge Machining (μEDM) is predestined for this case.μEDM is based on the modification of state of the art process technologies and universal machine tools applied for electrical discharge machining operations [1,2]. Besides the adjustment of the electrical parameters, the μEDM-process is also determined by the tool electrode's material which has a big influence on the material removal rate VW, the electrode's wear behavior, as well as the process results concerning surface quality and dimensional accuracy [3]. Experimental investigations aim at decreasing the wear of tool electrodes using novel electrode materials. To assure an efficient process, short production times and low tool wear ϑ are demanded. Therefore, electrodes with excellent electrical and thermal conductivity along with a high mechanical strength have to be used.Boron doped CVD-diamond is fulfilling these criteria. Microstructures within thin CVD-diamond foils are realized by direct structuring utilizing laser ablation and by indirect structuring using micro-structured copper substrates in the CVD-process, which transfer the micro-structure onto the growing diamond layer. Experiments were conducted in order to identify suitable EDM-parameters for different workpiece materials, namely steel 90MnCrV8, silicon carbide SiSiC and tungsten carbide K40F, which lead to lower tool wear ϑ and high accuracy.

Scenario-based Manufacturing Data Analytics with the Example of Order Tracing through BLE-Beacons

The progressing digitalization in manufacturing companies results in a continuously increasing available database. These data are a key resource for maintaining competitiveness on a global market. Nevertheless, most manufacturing companies struggle in creating benefits from these data. In an empirical study, conducted in 2017 by WZL of RWTH Aachen University and ITEM of University St. Gallen, a low level of efficiency and maturity in applying Manufacturing Data Analytics has been identified even though the potentials especially for quality management are well known. The study shows a lack of specific use cases for the application of Data Analytics in manufacturing companies as one of the most important obstacles. Therefore, this paper presents the approach of a Scenario-based Manufacturing Data Analytics. The developed approach is applied on the order processing in single and small batch production companies. Nine different Data Analytics application scenarios were derived based on the specific challenges and the data availability. With the example of order tracing, one specific scenario is described in detail by using the established CRISP-DM framework. Additionally, this paper describes a Data Analytics application scenario to improve Order Tracing by implementing a new concept for indoor-localization based on BLE-beacons.

Interface architecture design for minimum programming in human-robot collaboration

Many metal components, especially large-sized ones, need to be ground or deburred after turning or milling to improve the surface qualities, which heavily depends on human interventions. Robot arms, combining movable platforms, are applied to reduce the human work. However, robots and human should work together due to the fact that most of the large-sized parts belong to small-batch products, resulting in a large number of programming for operating a robot and movable platform. Targeting the problem, this paper proposes a new interface architecture towards minimum programming in human-robot collaboration. Within the context, a four-layer architecture is designed: user interface, function block (FB), functional modules and hardware. The user interface is associated with use cases. Then, FB, with embedded algorithms and knowledge and driven by events, is to provide a dynamic link to the relevant application interface (APIs) of the functional modules in terms of the case requirements. The functional modules are related to the hardware and software functions; and the hardware and humans are considered in terms of the conditions on shop floors. This method provides three-level applications based on the skills of users: (1) the operators on shop floors, can operate both robots and movable platforms programming-freely; (2) engineers are able to customise the functions and tasks by dragging/dropping and linking the relevant FBs with minimum programming; (3) the new functions can be added by importing the APIs through programming.

A Virtual Training Based Programming-Free Automatic Assembly Approach for Future Industry

Currently, the automated assembly depends on advance programming, which is suitable to large-batch products assembly; however, it does not fit in the assembly of small-batch products due to the large amount of preparatory work including assembly planning and robot programming. Therefore, those assemblies in small batch largely rely on human interventions, which is a system-level problem. Targeting the problem, this paper presents a novel programming-free automated assembly planning and control approach based on virtual training. Within the context, the 3-D models of products are used, including general assembly features of each component. The features are used in a search-based planner to generate assembly sequence, and to plan assembly path. Then the virtual assembly simulation is carried out based on the generated assembly plan, where the collisions and contacts are captured and passed to the planner to regenerate a new path. The new path is simulated in the virtual world. The simulation process is repeated until an executable strategy is obtained. In the real world, the physical robots perform the actual assembly by following the trained sequences and paths that are calibrated according to the real positions and orientations of the components. A proof-of-concept case study is carried out in robot operating system environment to validate this approach.

A KBE CAPP framework for qualified additive manufacturing

Additive Manufacturing (AM) is going to perform a key role in customized or even small-batch production due to its enlarged design freedom, decreased processing constraints and a non-obvious relationship between the processing cost and complexity. However, the AM production result is not stable because there is a lack of a full processing chain management tool to control the quality. To achieve qualified AM, this paper proposes a knowledge-based process planning (KBE CAPP) framework to solve three main issues: feasibility, suitability and stability in AM production. A developing CAPP prototype system based on this framework is presented for method demonstration.

PRODUCTION PLANNING IN CONDITIONS OF MASS CUSTOMIZATION BASED ON THEORY OF CONSTRAINTS

In accordance with the requirements of the modern market, small and medium-sized enterprises (SMEs) need to offer a wide range of products tailored to the specific and individual requirements. The success of many enterprises, which work in mass production system and use economic effect of scale production slowly is a thing of the past. There are many enterprises, generally small and medium manufacturing in unit and small batch production, for which it is necessary to develop optimal methods of production planning, taking into account the flexible production requirements, matched to the time-varying customer’s demand. The article presents the production planning based on TOC in conditions of mass customization. Presented solutions are used in modern practice.

Анализ перспективных алгоритмов объемно-календарного планирования позаказного производства мебели

The article discusses the algorithms employed in automated systems for master production scheduling in the applicability of their produce-to-order furniture. Small batch and custom production of furniture occupies a significant market share, as we do, and in the countries of Western Europe. Also, it is a prospective direction of development for other industries, focused on the end user. Most of the existing national planning systems designed for large-scale and mass production, in which the main role takes enterprise performance. Therefore, the main indicator, which is used by the optimization of scheduling, is the moment of completion of the last job. However, custom production is much more complex factors affecting the success of the enterprise as a whole: a key indicator in this case is the completion of all work no later than the specified time, not their early completion (within the terms established by treaties with customers). Also in the custom and small-scale production, it takes an important role time index spent on readjustment of the equipment associated with the transition to a different type of output. If these and other indicators do not have a significant role in large-scale production, the small-scale productions of these indicators have a significant impact on the performance of the enterprise, and they can no longer be neglected. In this paper, the three most promising mathematical algorithms (algorithm simulated annealing, genetic algorithm and artificial neural network), which allow us to optimize schedules based on several criteria applied to the problem of master production scheduling, customized production of furniture.

On-Machine Estimation of Workpiece Deformation for Thin-Structured Parts Machining

The workholding process in small batch production is one of the least automated processes in machining. In order to ensure appropriate workholding, it is necessary to estimate actual deformation of the workpiece. Recently, near net shape technologies, such as thin-wall casting and additive manufacturing, have become common. Increased requirements for the finish machining of thin-structured parts has increased the need for the appropriateness of workholding to be evaluated. An objective of this study is to investigate an on-machine estimation method that can evaluate the actual deformation of parts with thin-structures. Thin-structured parts are usually held by means of multipoint fixturing or vise fixturing. A hybrid estimation method combining FEM analysis and local strain measurements is adopted to estimate the deformation. The effectiveness of the proposed method is evaluated with example problems. The results indicate the feasibility of the on-machine estimation of the deformation of thin-structured parts.

Early warning systems for multi-variety and small batch manufacturing based on active learning

Multi-variety and small batch production is one type of mainstream production methods. Currently, methods of enterprise risk warning have been abundantly researched by scholars, but the effect of its application to the multi-variety and small batch manufacturing practices is not ideal. In this stud y, the authors apply the transductive support vector machine and active learning to the study of enterprise risk and early warning methods. The experiment utilizes real-world enterprise data and demonstrates that this method may meet the practical needs of the enterprise risk early warning systems and contributes to solving problems of multi-variety and small batch manufacturing operations.

Fashion garment manufacturing – FGM and cyclability theory

This article, derived from an ongoing research, presents the possibilities of reducing the inappropriate disposal of textile residues generated by the fabric cutting sector of the Fashion Garment Manufacturing (FGM). The raw material used is very varied, resulting in a large number of productive processes. FGM produces clothing that has as its main features a short life cycle, a high rate of diversification and differentiation, and small production batches, resulting in few similar parts. The production process is differentiated according to the characteristics of the fabric and the look of the garment. During the production process, at least 10% of textile waste is generated during the cutting process, which is constantly discarded in an inadequate way. The Cyclability theory is researched aiming at the possibility of reduction in the generation of waste and elimination of inappropriate disposal. The case study presents the action research carried out in three small Brazilian companies to study the applicability of the Cyclability theory.

Analysis of EU Safety Control Regulations for Cosmetics: Market Strategies for the Korean Cosmetic Industry

Recently, risks in the export and local industry have been increasing due to the rapid change of the domestic and global environment. The cosmetics industry which creates high value addition in small quantity batch production and is eco-friendly is no exception. So the cosmetic industry as cutting-edge technology and brain intensive industry could lead to the future oriented fourth industry revolution suitable to our state that run short of natural resources. Meanwhile, the EU is on an upward trend of common policy application scope with its own legal system and policy discretion unlike other international organizations. Thus, this paper would like to analyze their safety control regulations for cosmetics, a sector which has been consistently growing in Korea. EU cosmetics regulations could be classified largely into EU certification and procedure, RP nomination, CPNP registration, labelling, PIF documentation. Also this study suggests the advancement strategy for the use of overseas market expansion after the analysis of various factors and purchasing pattern of consumers and market characteristics in order to enter into diverse market of cosmetic industry.

Incremental forming of Cu-35Zn brass alloy

Incremental Sheet Forming (ISF) and particularly its Single Point (SPIF) variant has been studied intensively over the last years given the potential for low-cost prototyping and small batches production. Numerical and experimental works have been covering a widespan of materials and geometries. This paper fills an important gap regarding studies of the SPIF process applied to brass alloys, and particularly the commonly used Cu-35Zn brass alloy. Despite being a material widely used in industry for centuries, with excellent cold formability and innumerous applications, there is still no relevant information on the mechanical response and properties of this material under SPIF. This research is based in SPIF experiments with brass alloy sheets with different thicknesses (0.50, 0.70 and 1.00 mm), to obtain data such as forming forces or forming fracture lines to be compared against standard forming limit diagrams or against other materials under ISF. Other data like friction during the process was evaluated as well. Fifteen sets of experiments were conducted, using different values of step down (0.10, 0.50 and 1.00 mm) and two forming tools with diameters 10 and 15 mm.

Intelligent Approach for Part Family Searching and Cutting Tool Matching in FMS

Flexible Manufacturing System (FMS) is an automated manufacturing system which is suitable for small and medium batch production. Usually FMS can not only satisfy existing parts machining, but also have the ability to adapt to new parts machining when the products changes with the market demand. The automation of new parts process planning is hard to achieve because of the limitation of the current CAPP technology, the complexity of FMS, and diversity of parts.To solve the problems above, this paper proposes an intelligent approach to determine machining family and cutting tool for new parts using case-based reasoning method which is based on artificial intelligence technique and artificial neural network, part family search and tool matching are the important part of CAPP especially for variant CAPP. In this new approach , first, the existing parts are considered as cases, the relationship among parts information, machining families and cutting tools from the existing parts in FMS is established by means of artificial neural network and the relational model is obtained after ANN is trained with the cases, then the two key problems, searching the machining family automatically and matching tool set from huge cutting tool group intelligently for new parts machining can be realized in FMS, This paper aims to make the existing FMS adapt to the new parts machining when market demanding changing, improve the intelligent level of FMS and the enterprise's ability to response market rapidly and provide technical support for intelligent manufacturing.

Experimental study on the limit test method of polypropylene sheet incremental forming

Incremental forming can satisfy the requirement of small batch and individual production of polymer sheet. The forming limit is the main basis for judging the incremental forming properties. At present, the incremental forming limit of sheet metal usually uses crack as the failure criterion. Polypropylene (PP) sheet is sensitive to the incremental forming temperature, and the thickness variation does not follow the cosine theorem. There is a lack of systematic research on the incremental forming limit test method so far. For the first time, this paper proposes a limit test method of PP sheet incremental forming, where the wrinkling is proposed as failure criterion. The method to fast determine the wrinkling forming limit angle θmax is given by utilizing the combination of the revolving body with circular surface and conic workpiece and the interpolation iterative approximation of forming angle. PP sheet with 2.85-mm thickness is selected as the experimental object. The wrinkling forming limit angle θmax is 64° according to the above process method.

Development of a low-cost wax injection mold with high cooling efficiency

Reduction of the time and cost during the research and development stage of a new product is an important issue. Rapid tooling techniques can reduce the time to market compared to conventional machining approaches. In general, reduction in cooling time plays an important role on cycle time in manufacturing time. Wax injection mold fabricated from aluminum-filled epoxy resin can be employed for small-batch productions of wax patterns. However, the cooling time is much longer compared to metallic wax injection molds due to poorer thermal conductivity. In this study, three kinds of cooling-channel layouts were employed to fabricate wax injection molds for low-pressure wax injection molding using rapid prototyping and rapid tooling techniques. The effects of three kinds of wax injection molds on the cooling time during the low-pressure wax injection molding were investigated. It was found that the reduction in cooling time about 87% can be obtained when a wax injection mold with conformal cooling channels is compared to a conventional wax injection mold fabricated by Al-filled epoxy resin. The manufacturing cost reduction for a wax injection mold with high cooling efficiency about 63% can be obtained using the method proposed in this work.

An experimental study to investigate the micro-stereolithography tools for micro injection molding

PurposeThe use of microstereolithography (μSL) parts as micro-injection molding (μIM) tools greatly reduces the time and cost to product and offers unique solutions for complex design issues. However, they present challenges to designers because of their strength, thermal characteristics and shorter lifetimes as compared to other mold materials. The purpose of this study is to use SL to build rapid injection mold tools directly combining microfeatures for short-run production.Design/methodology/approachIn total, three tool inserts were produced. Two different μSL mold inserts were produced and evaluated in terms of different build approaches of micro features. One of the inserts includes micro features built horizontally, while the other one collaborates features built vertically, both having same geometrical dimensions. To evaluate the replication capability of prototype tools, two different thicknesses were set for micro features, that is, 30 and 120 μm. The mold inserts were assembled on a metallic mold frame and tested with polypropylene (PP).FindingsIt was observed that using inappropriate resin to fabricate the mold inserts can lead to inaccurate geometrical dimensions of the tool. Therefore, the material with high glass transition temperature (Tg) and low thermal conductivity is preferred. Also, the results of this research work showed that the processed material and technology play an important role both on part quality and tool life. After investigating the tool failure mechanisms during the injection, it was observed that tool failure occurred mainly because of excessive flexural stresses and ejection forces during the cavity filling and part ejection phases, respectively.Originality/valueThe paper describes the capability of μSL mold inserts for the production of small batches of micro-cantilevers which are used in MEMS relays.

Development of tooling concepts to increase geometrical accuracy in high speed incremental hole flanging

Incremental Sheet Forming (ISF) has been developed as a flexible manufacturing technology for small batch production and prototyping. ISF can also be used to form additional features or stiffening elements such as hole flanges. Incremental Hole Flanging (IHF) operations seem to be a promising alternative to conventional hole flanging. If it was possible to exploit the extended formability of ISF while achieving accuracy and process times of conventional hole flanging, IHF could substitute conventional flanging operations in many cases. However, the long process times and limited geometrical accuracy hinder industrial take-up. In this work, two different tooling concepts which allow incremental hole flanging operations at high speeds are investigated. The first tool is designed as a single forming tool that offers high flexibility and a comparison to conventional Incremental Hole Flanging. The second tool consists of four forming tools to improve the geometrical accuracy of hole flanges. In order to achieve high speeds, the experimental setup is installed on a turning machine. Compared to hole flanging with a conventional CNC machine, the forming time to expand a hole from 50 mm to 100 mm could be reduced from 1680 s to 15.7 s. The geometrical accuracy of the parts formed with the second tool concept could be improved significantly (up to 3 times regarding to the mean surface deviation to at maximum speed). Furthermore, it is shown that forming at high speeds has no significant influence on the characteristics of sheet thickness, strain, forces or geometrical accuracy.

Design and construction of a variable-aperture gripper for flexible automated assembly

Abstract The growing market demand for a wide variety of product models and small batch production makes flexible robotized production systems an emerging need in industry. Today, in manufacturing applications, general purpose grippers are not very considered, and robot end effectors are properly designed for the specific task with a strongly limited versatility. Flexibility is thus usually obtained by using a different tool for each family of parts: a tool changing system allows the robot to rapidly replace the tool on the end effector; tools are stored in a tool magazine allocated in the workcell. However, such systems are expensive and their use can affect the working cycle-time. This paper presents the design and testing of a variable-aperture, cost-effective gripper, capable of adapting its aperture (grasp width) to different handling demands, without affecting the working-cycle time of the production system. The solution proposed consists of (1) an electrically-actuated mechanism, which allows it to satisfy flexibility requirements, by regulating the aperture in hidden time; (2) a pneumatically-actuated mechanism to achieve high performance in open/close operations. Simulations and preliminary tests showed that this type of design can be a suitable solution to increase flexibility in robotized workcells without increasing the cycle time.

물류창고 불출자 로드밸런스율 증대 휴리스틱 알고리즘 개발

Companies are pursuing the management of small quantity batch production or JIT(Just-in-time) system for improving the delivery response and LOB(Line Balancing) in order to satisfy consumers' increasing demands in the current global economic recession. And in order to improve the growth of production for reducing manufacturing cost, improvements of the Load Balancing have become an important reformation factor. Thus this paper is aimed at warehouse which procures materials on the assembly line in procurement logistics of automotive logistics and proceed with research on heuristic algorithm development which can increase the Load Balancing of workers. As a result of this study, when applied the primary target value, it was verified that the whole workers decreased from 28 to 24. Furthermore, when specified the secondary target value and applied algorithm once more, it was verified that the Load Balance Ratio was improved from 44.96% to 91.7%.