Small Quantity Production Research Articles

Direct Polymer Additive Tooling - Economic Analysis of Additive Manufacturing Technologies for Fabrication of Polymer Tools for Injection Molding

This research project aims to analyze the economic feasibility of Additive Manufacturing (AM) as supportive technology in Injection Molding (IM) tool manufacturing by estimating the potential cost-savings and lead-time reduction. Cost and lead-time considerations during small part quantity production are analyzed by developing an extended estimation model for the integration of AM in tool production. Based on six different real reference parts, the developed model shows the projected savings and the current limitations of AM applications in tool production due to material constraints. Furthermore, this extended model offers a holistic view on part cost and lead-time information, by considering tooling as well as production phases in IM and integrating tool life as a key variable. Hence, this research project closes a literature gap and facilitates the integration of AM into the IM process chain.

Influence of cutting temperature when drilling carbon black reinforced polyamides

Polymer materials have many fields of application, such as in agriculture and agribusiness, medicine, consumer science, the automotive industry, for sports equipment etc. These materials are generally produced by injection molding, in-mold shaping and extrusion. A machining process is essential however both for small quantity production for complex and accurate shapes. Moreover, it is known that the demand for machining, especially with respect to the drilling of polymer materials has increased. In this study, the cutting temperature for drilling pure polyamide and carbon black reinforced polyamide was investigated as well as the effects of drill point angle, cutting speed, and feed rate on cutting temperature making use of Taguchi and ANOVA statistical methods. Among the selected drilling parameters, the most significant was found to be the drill point angle and the least effective the feed rate.

Research on Korean Small and Medium Sized Component Manufacturing Enterprises’ International Competitiveness’ Enhancement under Korea-China FTA’s Effects

Korea has made China as a second domestic market, meanwhile ensured Korea’s economy new vitality and growth impetus by signing FTA with China. Some research predicts Korea’s GDP growth will add extra 0.92~1.25% by the effects of Korea-China FTA. This FTA is influencing all the enterprises in Korea. Korean small and medium-sized enterprises (SMEs) play an important role in Korea’s economic development, Technology innovation, balance of social and economic development, etc. Among these SMEs, small and medium-sized manufacturing enterprises (SMMEs) which take up 10.7% of all enterprises and 22.6% of all employees, SMMEs are Korea economy’s solid chassis. Korea-China FTA is influencing Korea’s SMEs international environment which thus changes their global competitiveness. Analyzing hydraulic cylinder enterprises case can help find advice for future competitiveness of Korean SMMEs’ future competitiveness which represents Korean’s economic competitiveness. This paper analyzed the International Environmental changes of Korea-China FTA’s Effects on Korean Small and Medium Sized Components Manufacturing Enterprises and tried to find suggestions to enhance international competitiveness for them. This paper promoted a case study of Korean hydraulic cylinder industry which is considered to be the representative of Korean component SMMEs. Then this paper made a survey to detect Korean hydraulic cylinder manufacturing enterprises’ basic conditions, import & export status, international environmental changes, major errors and current international competitiveness compared to national and international competitors. After the case study, the component SMMEs’ international competitiveness enhancement suggestions were deduced as follows: Firstly, Korean components SMMEs can enhance ‘China out-sourcing’ and ‘Korean out-sourcing’ to decrease their production cost. Secondly, Korean components SMMEs can enhance their differentiation advantages such as diverse small-quantity production to maintain national market and block international competitors meanwhile looking for potential foreign buyers. Thirdly, Korean components SMMEs can enhance their production management technologies, Know-how technologies, and R&D technologies, and then chalk out new ideas and programs to improve the competitiveness. Fourthly, Korean components SMMEs should avoid excessive competition, enhance cooperation, and get used to the new vertical + horizontal relationship between significant company and SMEs to obtain synergy advantage

Experimental Investigation and Modeling of Single Point Incremental Forming for AA5052-H32 Aluminum Alloy

Single point incremental forming (SPIF) is highly flexible sheet metal forming process used for small quantity production and new product development. The product with high strength, good surface finish, and higher formability has paramount importance in industrial and marine applications. SPIF has been carried out on AA5052-H32 aluminum alloy which has high strength and difficulty in the conventional forming process. The response characteristics such as surface roughness \(({R}_{\mathrm{a}})\) and maximum forming angle \((\varnothing _{\mathrm{max}})\) were evaluated by considering the independent process parameters such as spindle speed, table feed rate, step depth, tool diameter and sheet thickness through the design of experiments. The step depth and sheet thickness are the most influencing parameters for average surface roughness and maximum forming angle, respectively. It is found that neither the surface roughness nor the forming angle of formed sheets feels the effects of spindle speed significantly. An empirical relation has been formulated, and experiments were carried out to verify the reliability of the developed regression model.

A Comparative Study of Recognition Rate of Color QR Code Printed on Tyvek and Cotton Material

This purpose of this study to analyze effect material properties have on change in QR code recognition rate according to change of materials by comparing recognition rate of color QR code. QR code applied to textile materials has the advantage of being washable and being applicable to lost child prevention goods or clothes or a person with dementia through record of information relating to the material or input of additional information, differently from QR code printed on the conventional paper. An effective method of entering QR code in textile materials is Digital Textile Printing(DTP), that facilitates printing by rapidly applying diverse information, and small quantity production. It is possible to tailor various QR codes according to use. Regarding samples to use, cotton material used in clothing products and Tyvek material recently applied to clothing and related products were selected. Reactive dyes were used for cotton, pigment was used for Tyvek, and QR code was printed with an inkjet printer by direct printing method. Printing methods and surface textures are different between cotton and Tyvek. It was revealed that consequent print results and results of recognition rate were different. Regarding color to be printed, 2015 S/S - 2017 S/S color presented by Pantone was used. Color combination affected recognition rate of color QR code. Understanding color combination, material properties and print characteristics may be helpful in increasing recognition rate of color QR code, and may contribute to usability of color QR code applied to textile materials in the future.

Investigation and optimization of deformation energy and geometric accuracy in the incremental sheet forming process using response surface methodology

Incremental sheet forming (ISF) is a promising manufacturing process that features benefits of reduced forming forces, enhanced formability and greater process flexibility. It also has a great potential to achieve economic payoff for rapid prototyping applications and for small quantity production in various applications. However, limited research has been conducted from the sustainability point of view, particularly for energy consumption. More consumed energy will generate more heat and affect tool and product wear. Also, geometric accuracy is still one of the dominant limits for the further development and commercialization of the ISF technology. Therefore, the aim of this study is to investigate how different process parameters affect the consumed energy during the forming process and also find the optimal working condition for lower deformation energy with higher geometric accuracy. A Box-Behnken design of 27 tests for pyramid-forming processes have been performed for a multi-objective optimisation that considers four factors: step down, sheet thickness, tool diameter and wall angle at three levels. The deformation energy during the forming process was calculated based on the measured forming forces. It was found that the deformation energy heavily depends on the sheet thickness because of higher plastic energy required to deform the material. Increasing step-down size within a limited range or decreasing the wall angle is also an effective approach to reduce the deformation energy. Moreover, the effects of various process parameters on the global geometric accuracy have also been investigated. The geometric error has been empirically predicted by quadratic equations giving the influence of the most influential forming parameters. It was concluded that the geometric quality is largely determined by the quadratic effect of wall angle, the linear effect of sheet thickness and the interaction effect of thickness and step down. Finally, the optimal working conditions for both independent and simultaneous minimisation of deformation energy and geometric error during the pyramid-forming process are provided.

Group Technology Applied in Quality Management System

This paper is based on a company that manufactured the nuclear power components. This paper Studies the quality management that aimed at characteristics of multi specification and small batch production. The components which are produced at this company have been used in new energy field. Quality of nuclear power components can meet the technical requirements or not is very important to the operation and safeguard of nuclear power station in future. Group technology combined with statistical process control technology and applied in the quality management system to analyze the testing data of each working procedure in multi-kind and small-quantity production to achieve the goal of improve and control the quality of the product.

수주형 제조산업에서 QR 코드를 활용한 생산공정관리 방법연구

Only small numbers of medium-sized manufacturers have adopted a production management system. They have difficulty maintaining production cost and progress management, because they have used the ways that win a contract, not mass production system like a big company. Also a small company has to change standard features of products whenever customers want, by means of non-standardization and small quantity production method. As a result, it has been very difficult for a small company to establish a proper production management system. So, this paper tried to make a study about increasing production management system , using QR codes in a small-sized manufacturer with the ways that win a contract, based on real application case.

굴삭기 부품 용접 자동화라인의 셀생산방식 적용을 위한 시뮬레이션 연구

Mixed model production system means that various products are manufactured alternately in a line, and it has become a popular system in the era of multi-product small-quantity production. However, in the mixed model production system using flow line, the unbalance among stations is not inevitable because the workloads of stations cannot be the same. Thus, flow line system has been replaced to cellular manufacturing system for reducing the loss of waiting due to the unbalance of stations. In this paper, we introduce the simulation case study of an automated welding line which produces the parts of excavator. The factory has considered replacing the mixed model flow line to the cellular manufacturing system based on FMC concept. The increase of production quantity is estimated about 26.7%, and the lead time is reduced more than 55%. Furthermore sensitivity analyses are conducted considering the changes of product-mix.

Incremental Forming of Hole-Flanges in Polymer Sheets

Hole-flanging by single-point incremental forming (SPIF) is an emerging sheet forming process with a high potential economic payoff for rapid prototyping and small quantity production. So far, applications have only been performed in metals but the aim of this article is to evaluate the feasibility of using polymers. Special emphasis is given to the deformation mechanics of the process and the physics behind the occurrence of failure by fracture along the wall flange. The investigation draws from the independent determination of the mechanical properties, fracture toughness, and formability limits of polyethylene terephthalate (PET) and polycarbonate (PC), to experimentation in a CNC machining center equipped with an apparatus for multi-stage SPIF. The work is supported by circle grid analysis and results show that PET is appropriate for producing hole-flanged parts with vertical walls due to its capability of withstanding high levels of deformation at room temperature.

Basic Study on Laser Forming of Curved Surfaces with Simulation

Laser forming is a technology that produces plastic deformations in sheet materials by generating local heat stress. It is useful for prototype or small-quantity production because it does not require dies or molds. Although many studies on laser forming have been done, few have been on forming curved shapes. This paper deals with a method for generating the scanning paths and determining the scanning conditions for laser forming of a curved shape. The scanning paths are derived as the maximum and minimum curvature lines. Since the two curvature lines are orthogonal, they don’t affect each other in forming. The scanning speed is decided by an approximation equation derived from experiment and FEM analysis according to the angle of the bend at the irradiation point. The effectiveness of the scanning paths and the scanning speed determined by the proposed method are confirmed through experiments.

A versatile agile agent-based infrastructure for hybrid production environments

To meet the requirements of modern production, where short time to market, production driven by customer requirements and low cost small quantity production are important issues, we have developed an agent-based software infrastructure for agile industrial production. This production is done on special devices called equiplets. A grid of these equiplets connected by a fast network is capable of producing a variety of different products in parallel. The multi-agent-based software infrastructure is responsible for the agile manufacturing. This agent-based model also fits well in a production environment where the production is done by humans instead of equiplets. This is what we call a hybrid production environment.

Investment Casting – Rapid Tooling Approach

Investment casting is synonym with producing precision components and investment casters usually take up the order if the volume is huge enough. This is due to high and unjustifiable tooling cost and long lead times associated with the development of metal moulds for producing wax (sacrificial) patterns for customized single casting or small quantity production. One of the feasible solutions is opt rapid tooling. In so- called rapid investment casting the most critical process will be building the investment shell and protecting it from thermal crack. This work investigates the shell crack and counter. In this work pattern are modeled on rapid prototyping machine. During the ceramic shell preparation cracking is reported. Hence a remedy is explored as to control the thermal expansion of the pattern build material-acrylonitrile butadiene styrene (ABS) by using different build styles. Thermal expansion of five distinct styled ABS rapid samples were tested on Dilatometer. The investigation indicates the possibility of 63% reduction in thermal expansion of the pattern, which is very very encouraging.

On Non-Dendritic Microstructure Formation during Sand Casting of A356 Alloy

The purpose of this study was to develop a new method for formation of non-dendritic microstructure during sand casting of aluminum alloys without any previous special processing. For this purpose, sand molds with three different types of running systems were designed. The first design included a traditional reverse tapered vertical sprue. The second design was similar to the first one except for a conical sand core placed inside the lower half portion of the sprue creating a narrow gap for the flow of the melt into the mold. In the third design, the core was fitted with metal chills. Molten A356 alloy was then cast from fully liquid state under gravity and centrifugal casting conditions in the molds and the microstructures of the castings were studied. The results showed that non-dendritic microstructure could be achieved by using the last design under low superheat temperature and centrifugal casting conditions. The findings can pave the way for small quantity production of semisolid castings in expendable molds.

Hole-flanging by incremental sheet forming

Incremental forming of hole-flanges in sheet metal parts is an emerging process with a high potential economic payoff for rapid prototyping and for small quantity production. However, as with all new sheet metal forming processes, there is need for examining its deformation mechanics and describing the physics behind the occurrence of failure.How metal fails, how pre-cut holes influence strain and stress in single point incremental forming, and how these subjects can be brought together in order to understand the overall formability of hole-flanging by multi-stage incremental forming are still not well understood. However, they are of great importance for improving the performance and industrial applicability of the process.This paper attempts to provide a new level of understanding for the process by combining circle grid analysis and independent characterization of the mechanical properties and formability limits of the material with the fabrication of conical and cylindrical hole-flanges. Experimental observations, measured strain paths and material formability limits by necking and fracture allow concluding that hole-flanging by incremental forming gives rise to a new mode of deformation, not found in conventional incremental forming of sheet metal blanks without pre-cut holes, and to failure by fracture without previous localized necking.

Development of Digital Quasi-embossing Technology with an Inkjet Printer

Emboss technology utilizing hot-stamping method can produce stereo-printed images with metallic gloss. Conventional emboss method needs an engraved plate and consequently becomes costly especially for a small quantity production. We have developed a new technology with combining UV-curable inkjet printing and hot-stamping processes, where any engraved plates are not used. The new technology called “Quasi-embossing Technology” consists of the following three steps: (1) On the basis of three-dimensional image data, stereo-printed images are formed with a UV-curable inkjet printer, where the print-head accompanying a UV irradiation setup scans several times. (2) A metallic foil which has a hot-stamping adhesive layer is placed on the stereo-printed image with supplying heat and pressure from the back of this foil. (3) After having been cooled, the surplus foil around the stereo-printed images made from UV-curable inkjet ink is removed. Finally three-dimensional products with metallic gross are obtained. This technology is applied to produce various products including conventional emboss printing ones.

S1402-1-2 短期・長期計画の協調による日程階層型スケジューリング手法に関する研究([S1402-1] S1402生産システムの新展開(応用・実践1))

It is important to manage the manufacturing system efficiently to acquire competitive edge in the current era of advanced information technologies and market globalization. Production scheduling is one of the important elements for managing the manufacturing system. Mass customization with small quantity production is a main trend these days, so information divergence tends to increase between the detailed daily work schedules in manufacturing level and mid/long-term schedule in management level. In this research, the cooperated scheduling method in which the mid/long-term scheduler and the daily work scheduler fine-tune independently each schedule is proposed.

Strategies and limits in multi-stage single-point incremental forming

Multi-stage single-point incremental forming (SPIF) is a state-of-the-art manufacturing process that allows small-quantity production of complex sheet metal parts with vertical walls. This paper is focused on the application of multi-stage SPIF with the objective of producing cylindrical cups with vertical walls. The strategy consists of forming a conical cup with a taper angle in the first stage, followed by three subsequent stages that progressively move the conical shape towards the desired cylindrical geometry. The investigation includes material characterization, determination of forming-limit curves and fracture forming-limit curves (FFLCs), numerical simulation, and experimentation, namely the evaluation of strain paths and fracture strains in actual multi-stage parts. Assessment of numerical simulation with experimentation shows good agreement between computed and measured strain and strain paths. The results also reveal that the sequence of multi-stage forming has a large effect on the location of strain points in the principal strain space. Strain paths are linear in the first stage and highly non-linear in the subsequent forming stages. The overall results show that the experimentally determined FFLCs can successfully be employed to establish the forming limits of multi-stage SPIF.

SOA 환경 기반의 의류 생산지원 시스템 설계 및 구현

SOA는 기존 애플리케이션들이 가진 기능을 사업적인 의미를 가지는 기능 단위로 분류하고, 표준화된 호출 인터페이스를 통해 서비스라는 컴포넌트 단위로 재조합한다. 본 논문에서 개발한 시스템은 생산원자재의 절약과 주문 시 생산 시점 예측한다. 그리고 적정한 재고 유지로 원부자재 구입비용과 생산비용을 절감하여 회사의 경쟁력을 증가시킨다. 또한 업체의 생산 공정 및 원부자재 수급 현황을 정확히 분석하여 이를 반영한 SOA 기반의 다품종 소량 생산을 위한 생산관리 시스템을 설계하고 구현하였다. SOA sorts function of old applications by function unit that have business meaning, and through standard call interface, do orchestration by component unit of service. System that developed in this paper predicts production point of time when order with frugality of production raw material. And reduce original register resources purchase expense and production costs in proper stock and increase company's competitive power. Also, design and implementation production management system for many species small quantity production of SOA base that reflect this analyzing correctly company's manufacturing process and original register resources supply and demand present condition.

Statistical Analysis of Experimental Parameters in Ultrasonic Machining of Tungsten Carbide Using the Taguchi Approach

The objective of this paper is to study the influence of operating parameters of ultrasonic machining of tungsten carbide on the machining characteristics. The effectiveness of the ultrasonic machining process with tungsten carbide is evaluated in terms of the material removal rate and the surface finish quality of the work piece produced. Tungsten carbide as a super hard and high wear‐resistant material has been used widely in industries. Powder metallurgy technology is the common method for producing tungsten carbide components. However, this method is obviously too costly and time consuming for small quantity production, such as product prototyping. It is expected to make the prototypes by a material removal process, such as ultrasonic machining. In this paper, an experimental study on the ultrasonic machining of tungsten carbide is presented using a systematic approach. Practical aspects are given on the characteristics of tungsten carbide as functions of the type of abrasive slurry, their size and concentration, nature of the tool material, and the power rating of the machine. The optimum combination of various input factors for the ductile chip formation in the machining of tungsten carbide has been determined by applying the Taguchi approach and the F‐test.