1、INTERNATIONAL JOURNAL OF PRECISION ENGINEERING AND MANUFACTURING Vol.13,No.7,pp.1239-1242 JULY 2012 /1239 DOI:10.1007/s12541-012-0164-6 1.Introduction A spring guide pin for a press die set is usually manufactured via machining process such as cutting and turning in order to achieve dimensional accu
2、racy and sufficient strength.1 However machining process is highly energy consuming because it uses up much material and time.Also it requires extra steps such as heat treatment in order to attain necessary strength.Fig.1(b)shows the spring guide pin produced via machining process,and there is about
3、 60%material loss with machining process(Fig.1(a).The paradigm of manufacturing technology is shifting towards sustainable production(Fig.2)in this age of energy crisis.Sustainable production is achievable by minimizing environmental effects during the whole manufacturing cycle of a product.Such pro
4、duction can be designed by means of minimal manufacturing that uses minimal material and energy while producing least amount of waste.There are number of research on going concerning environmental effects due to manufacturing methods.2-4 Fig.1 Spring guide pin made by machining process:(a)before and
5、(b)after machining process Fig.2 Shift of paradigm in manufacturing technology Green Alternative Processing Technology for a Spring Guide Pin of Stamping Die Set Myeong-Sik Jeong1,Sang-Kon Lee1,Ji Hyun Sung1,Kang-Eun Kim1,Shinok Lee2,Kang-Won Lee2,and Tae-Hoon Choi1,#1 Green Transformation Technolog
6、y Center,Korea Institute of Industrial Technology,Daegu,Republic of Korea,704-230 2 Daegu-Gyeongbuk Regional Division,Korea Institute of Industrial Technology,Daegu,Republic of Korea,704-230#Corresponding Author/E-mail:thchoikitech.re.kr,TEL:+82-53-580-0131,FAX:+82-53-580-0130 KEYWORDS:Green manufac
7、turing,Sustainable production,Multi-stage forging,Spring guide pin,FE-analysis In this research,a multi-stage cold forging process for a spring guide pin of stamping die set is designed through alternative process for sustainable production.Highly energy and material consuming process needs to be co
8、nverted to an energy saving process.Up to now,a spring guide pin for stamping die set is usually manufactured by machining process in order to achieve dimensional accuracy.However,machining process has some disadvantages such as excessive material loss,low productivity,and poor mechanical properties
9、.In order to overcome these problems,a multi-stage cold forging process is applied to manufacturing spring guide pin for achieving less material loss and higher productivity.Multi-stage forging process requires careful design steps to prevent the defects of the final product.So,the design must consi
10、der the material flow during the whole process and the loading limit of the press in order to avoid product defects such as folding and underfilling.To develop multi-stage forging process for spring guide pin the forming load and material flow at each step is analyzed using a commercial finite eleme
11、nt code,DEFORM.The guide pin is then manufactured by the developed multi-stage forging process,and is compared to the simulation results.Also the efficiency of the developed forging process is compared to the machining process.The developed process is a green manufacturing process minimizing materia
12、l loss,which achieves cost reduction through improved material usage and productivity compared to the more widely used machining process.Manuscript received:December 30,2011/Accepted:January 25,2012 KSPE and Springer 2012 1240 /JULY 2012 INTERNATIONAL JOURNAL OF PRECISION ENGINEERING AND MANUFACTURI
13、NG Vol.13,No.7 Therefore such energy consuming process needs to be converted to an energy saving process.For this purpose forging process is applied to manufacturing the spring guide pin for achieving less material loss and higher productivity.However a wide spread of such process is limited by two
14、barriers:the geometrical inaccuracy and the insufficient strength caused by defects such as underfills and folds.These barriers can be overcome if the material flow is fully understood for the given geometry.In this study,multi-stage forging process for spring guide pin of a press die set is designe
15、d considering the material flow using the FE-analysis.To design multi-stage forging process for spring guide pin the forming load and the material flow at each step is analysed using commercial finite element code DEFORM.Then,the result is compared to the original process for assessing the efficienc
16、y of the developed process.2.Design of cold forging process 2.1 Development of the forging stage During cold upsetting of an axisymmetric object,the maximum strain is dependent on the number of forming stages.To avoid defects such as buckling during upsetting process with large deformation,a number of forming stage needs to be determined based on the geometry of plastic deformation.The initial diameter(D0)and length(Lt)of the billet for spring guide pin is 24.5 mm and 219 mm respectively.Also th
