Study on an automotive refill opening cap compound process based on punching and incremental forming

Transcription

1 Indian Journal of Engineering & Materials Sciences Vol. 25, June 2018, pp Study on an autootive refill opening cap copound process based on punching and increental foring Zhiguo An a *, Zhengfang Li a, Tianhua Feng b & Janjian Qie a a College of Mechanical-electronic and Autoobile Engineering, Chongqing Jiaotong University, Chongqing, , China b Bioengineering College, Chongqing University, Chongqing , China Received 2 Noveber 2015; accepted 26 July 2017 An autootive refill opening cap anufactured through the traditional punching process usually perfors with lower rigidity, and the punching process increases the production cost and anufacturing cycle, which goes against the fast fabricating requireent in odern industry because of the ulti-die produced. In this paper, the copound process, adopting increental sheet foring (ISF) and punching foring, was used to anufacture the part to solve the probles above by utilizing ISF in the pre-foring stage and punching foring in the subsequent stage. Four paraeters, including the pre-foring height (PH), the pre-foring press aount (PPA), the pre-foring tool diaeter (PTD) and the pre-foring angle (PA), were taken as test factors in the pre-foring stage, and the ax thickness reduction percentage (MTRP) was taken as the test target. The effect of the factors was analyzed using the finite eleent ethod and an orthogonal test for the target. The orthogonal test result shows that the ajor factors were the PH and the PPA, and the secondary factors were the PA and the PTD. The PTD and the PA were obtained through a ean analysis as 8 and 40, respectively. A function showing the relationship between the ajor factors and the target was established through the response surface ethod to obtain the interaction effect between the PH and the PPA for the target. The PH and the PPA were found by a response surface ethodology to be 15 and 0.5, respectively. The copound process was verified through an experient. Keywords: sheet foring; increental sheet foring; copound process; response surface ethod With the developent of odern industry, fast foring technologies are increasingly used and studied, and increental sheet foring (ISF) technology has been extensively developed. This technology is also called layered anufacture technology, which increases sheet deforation through sall region contact between the oving rigidity tool and the etal sheet, so this technology can reduce the aount of research and the developent cycle and raise productivity. The technology does not need to anufacture the corresponding die or only requires the production of half of the die. Jeswiet et al. 1 and Eens et al. 2 coprehensively reviewed increental foring developents through recent years. Ki and Yang 3 adopted the increental foring ethod to iprove the part forability. Young and Jeswiet 4 successfully anufactured a cone with a steep draw angle through ISF. Skjoedt et al. 5 researched the deforation of cylindrical cups with vertical walls through ISF, successfully anufacturing this part. Cui and Gao 6 investigated *Corresponding author (E-ail: azgcqu@163.co) three ulti-pass strategies of ISF to produce holeflanging parts. Manco et al. 7 researched the effect of the tool path in single increental foring for the part forability, gaining a feasible tool path of ISF. Malhotra et al. 8 investigated the effect of the tool path for aterial flow phenoenon, using the copound tool path to eliinate the aterial flow during ISF. Xu et al. 9 changed the aterial paraeters and sheet size in increental foring to iprove the part forability. Li et al. 10 successfully anufactured the coplex autootive covering panels through ISF. Liu et al. 11 investigated ulti-pass increental foring to produce cylindrical cups with vertical walls. Kopac et al. 12 and Hussain et al. 13 described soe disadvantages of ISF regarding two aspects: (i) Increental foring was eliinated with the foring angle, while its thickness distribution was less hoogeneous than punching foring. (ii) ISF had low precision, and the part was directly obtained through this technology with fine precision. In the anufacturing of an autootive covering panel, the foring quality of the parts was not satisfied using only increental foring, but the

2 251 AN et al.: PUNCHING AND INCREMENTAL FORMING production cycle and cost could be increased using only the punching process. The autootive refill opening cap anufactured through the traditional punching process usually perfors with less rigidity. In this paper, the copound process, cobining increental sheet foring with punching, is developed to anufacture the part. Using increental sheet foring in the preforing stage and punching in the subsequent stage will decrease the production cycle and cost while satisfying the rigidity of this part. Four paraeters, including the pre-foring height (PH), the preforing press aount (PPA), the pre-foring tool diaeter (PTD) and the pre-foring angle (PA), are taken as the test factors in the pre-foring stage, and the ax thickness reduction percentage (MTRP) is taken as the test target. The effect of the factors will be analyzed through the finite eleent ethod and an orthogonal test for the target. The ajor factors are the PH and the PPA, and the secondary factors are the PA and the PTD. The PTD and the PA are obtained through ean analysis as 8 and 40, respectively. The function, which shows the relation between the ajor factors and the target, can be established through the response surface ethod to gain the interaction effect between the PH and the PPA for the Fig. 1 Foring schee of the autootive refill opening cap Table 1 Tensile test result of the AA5052 aluinu alloy sheet with a 0.6 thickness for three directions Material (AA5052) Orientation Yield strength (MPa) Ultiate yield strength (MPa) Elongation (%) Young s odulus (GPa) 0.6 Rolling (0) Diagonal (45) Transverse (90) target. The PH and the PPA will be obtained by a response surface ethodology as 15 and 0.5, respectively. The copound process is verified through experient. Test Methodology The foring schee of the autootive refill opening cap is shown in Fig. 1. The ulti-step copound process, including pre-foring, blanking, drawing and bending, will be adopted using ISF in the pre-foring stage and punching foring technology during the subsequent stage. The effect of the foring quality is investigated with paraeters such as the PH, the PPA, the PTD and the PA. As a result, the ipact trend of every paraeter can be obtained for the MTRP in increental foring through a nuerical siulation. The affection degree of the paraeters is then deterined for the foring quality by the orthogonal test. Single factor test A single factor test can obtain the effect trend of a single factor for the foring quality in ISF, thus decreasing the range values of the processing paraeters and providing accurate inforation for the orthogonal test. The single effect of each paraeter will be found for the MTRP through the finite eleent

3 INDIAN J. ENG. MATER. SCI., JUNE ethod to provide a foundation for the orthogonal test. The aterial basal paraeters are gained through a tensile test with an AA 5052 aluinu alloy sheet, given in Table 1. The sheet can be siplified as a transverse anisotropic aterial in the nuerical siulation to iprove the calculation efficiency, and the aterial s echanical properties are given in Table 2. Figure 2 shows the finite eleent esh that is established through the finite eleent software. The ipact trend of the single factor will be obtained for the MTRP by siulating increental foring under different values of the single factor, as shown in Fig. 3. Figure 3(a) shows the ipact trend of the PH for the MTRP in increental foring, Fig. 3(b) displays the effect trend of the PPA for the MTRP in increental foring, Fig. 3(c) reveals the ipact trend of the PTD for the MTRP in increental foring, and Fig. 3(d) shows the effect trend of the PA for the MTRP in increental foring. The steady increase is shown in Fig. 3 between each paraeter and the MTRP in increental foring. Orthogonal test Four paraeters, including the PH, the PPA, the PTD and the PA, are taken as the factors of the orthogonal test, Table 2 Mechanical properties of the AA5052 aluinu alloy sheet with a 0.6 thickness Material (AA5052) 0.6 Density (kg/ 3 ) 2690 Young s odulus (GPa) 70.7 Poisson s ratio 0.33 Tensile yield strength (MPa) 190 Ultiate tensile strength (MPa) 355 Tangent odulus (GPa) 26.6 Hardening exponent 0.13 Fig. 2 Finite eleent esh of increental foring Fig. 3 The effect of each paraeter on the ax thickness reduction (a) effect of the pre-foring height, (b) effect of the pre-foring press aount, (c) effect of the pre-foring tool diaeter and (d) effect of the pre-foring angle

4 253 AN et al.: PUNCHING AND INCREMENTAL FORMING and the level of every factor is deterined by the data fro the single factor test, in which an MTRP of 4.5% was the data selection standard. The factors and levels are shown in Table 3. The test schee and results are presented in Table 4. The results are analyzed through a ean analysis ethodology, and the effect of these factors is given in Table 5. The PH and the PPA are the ajor factors for the MTRP. Therefore, the interaction of the two factors can be considered for the effect of the target, so the two factors are not directly obtained through the ean analysis ethodology. The PA and the PTD have a saller effect on the test target, and therefore, the two factors can be deterined by the ean analysis ethod, in which the iniu of the target is viewed as the standard to select the two factors, such as a PA of 40 and a PTD of 8. Interaction Analysis Response surface ethodology The response surface ethodology includes atheatical ethods and statistical ethods, which are used to test, odel and analyze data. The ultiple responses are influenced by any variables, and the responses will be optiized. This ethod views the response as a function of several factors using graphic technology to display this function, which directly provides the ost optial condition fro the test design for scholars. The coon response odels are classified as first-order odels and second-order odels, respectively shown in Eqs (1) and (2): y x 0 i i i1 (1) 2 0 ixi iixi ijxi x j i1 i1 i j y (2) where 0 is the constant effect and i is the linearity effect. and ε are the nuber of tests and aberration effects, respectively. ii and ij are the second-order effect and interaction effect, respectively. In this section, the secondorder odel is established to study the interaction of the PH and the PPA for the effect of the MTRP, which is used to optiize the ajor factors, and this odel is also expressed by a atrix, as given in Eq.(3): y1 1 x11 x12 x1 k 1 y 2 1 x x x k 2 Y y 3, X 1 x x x k,, 3 y n 1 x n1 xn2 xnk n n (3) Response surface analysis In this section, the interaction between the PH and the PPA is investigated, and the rando cobinations containing the PH and the PPA can be siulated using finite eleent software. Thus, the corresponding MTRP, which is resented in Table 6, can be obtained. Central coposite face-centered designs are two-level designs that allow fitting second-order response surfaces Table 3 The level of the orthogonal test Level A B C D PH, PPA, PTD, PA, Table 4 Schee and results of the orthogonal test Test A B C D MTRP Table 5 The ean analysis of the results Level A B C D MTRP Su Mean Table 6 The response surface test Test A B C D PH, PPA, PTD, PA, MTRP

5 INDIAN J. ENG. MATER. SCI., JUNE efficiently. The two factors and three levels, such as pre-foring height (PH: 15/20/25 ), pre-foring press aount (PPA: 0.5/0.75/1 ), are considered to perfor 9 experients (Table 6), the design of which uses one center point at each block. Each fitting odel and its coefficients are estiated according to the fit statistics: R 2, R 2 -adjusted, R 2 -predicted, and RMSE. The full odel has a good fit if the R 2 statistics approach 1 and the RMSE is little. The significance level in the whole analysis is α = The odel adopted to explain the MTRP for AA5052 aluinu alloy is shown in Table 7 and obtained: y A B (4) The odel is ainly consisted of the first-order ters and its p value is less than α with a nonsignificant lack of fit. In the fitted odel, residuals are noral and i.i.d. showing a p value= in the Shapiro-Wilk norality test. The response surface is produced using the established odel, as shown in Table 7. The iniu of the MTRP is located at a PH of 15 and a PPA of 0.5. Results and Discussion The ost optial paraeters are deterined through the orthogonal test and the response surface ethodology, and they are a PH of 15, a PPA of 0.5, a PTD of 8 and a PA of 40. These paraeters are used to siulate the deforation of the pre-foring part in increental foring. The result of the nuerical siulation is taken as the optiization group, and the iniu of the MTRP is taken as the control group fro the orthogonal test. The results of the two groups are shown in Fig. 4. Figure 4(a) shows the result of the Table 7 Statistical results for MTRP with AA5052 aluinu alloy MTRP Paraeter estiates Estiate Std. Error t value Pr(> t ) Intercept < PH < PPA Suary of fit R RMSE 0.18 Adj. R Pred. R Fig. 4 Results of the siulation (a) control group and (b) optiization group

6 255 AN et al.: PUNCHING AND INCREMENTAL FORMING control group obtained by the nuerical siulation with an MTRP of 6.64%, and Fig. 4(b) shows the result of the optial group obtained by the nuerical siulation with an MTRP of 4.4%. The rigidity of speciens fabricated is often estiated according to Eq. (5): R AE (5) Where R is the rigidity index; A is the cross-sectional area, and E is Young s odulus. If the part fabricated obtains a high value of R, it will have a great rigidity. A plays a key role to iprove the rigidity of speciens due to the fact that E is a constant. The sectional thickness of parts, which has a positive influence on the rigidity, is a ajor factor for A. Therefore, The MTRP decreased through the optial ethodology, which efficiently iproved the rigidity of the part after deforation. The siulation course of the copound process is shown in Fig. 5. Experient The foring equipent and device, independent researching and developent are used to anufacture the pre-foring part, as shown in Fig. 6. The tool oving code can be obtained by CAM software, Fig. 5 The siulation course of the copound process Fig. 6 The equipent and device of increental foring

7 INDIAN J. ENG. MATER. SCI., JUNE Fig. 7 The pre-foring part through trial production with the copound process. The following conclusions have been drawn: The autootive refill opening cap should be anufactured through the copound process based on punching and increental sheet foring by adopting increental foring in the pre-foring stage and punching foring in the subsequent stage. The non-die process can be adopted in the process of autootive refilled opening cap foration. The optial paraeters can be deterined by an orthogonal test and the response surface ethodology and have a PH of 15, a PPA of 0.5, a PTD of 8 and a PA of 40. The optial paraeters efficiently decrease the part s MTRP, which iprove the echanical properties of the part. Acknowledgeents This study has received funding fro National Natural Science Foundation of China under grant No , and the Science and Technology Research Project of Chongqing Municipal Education Coission, China (Grant No. KJ ). Fig. 8 The autootive refill opening cap which is iported into this foring equipent adopting the optial paraeters to anufacture the pre-foring part, as shown in Fig. 7. The autootive refill opening cap is then produced through blanking, drawing and bending after pre-foring, which is presented in Fig. 8. The part is successfully anufactured through trial production with the copound process, the viability of which has been verified. Conclusions In this paper, the copound process, cobining punching with increental sheet foring, has been researched to anufacture a part using increental sheet foring in the pre-foring stage and the punching process in the subsequent stage, which can decrease the production cycle and cost while satisfying the foring rigidity of this part. The part has been anufactured References 1 Jeswiet J, Micari F, Hirt G, Braley A, Duflou J R & Allwood J M, CIRP Ann Manuf Technol, 54 (2005) Eens W C, Sebastiani G & vanden Boogaard A H, J Mater Process Technol, 210 (2010) Ki T J & Yang D Y, Int J Mech Sci, 42 (2000) Young D & Jeswiet J, Proc IMechE Part B: J Eng Manuf, 218 (2004) Skjoedt M, Silva M B, Martins P A F & Bay N, J Strain Anal Eng, 45 (2010) Cui Z & Gao L, CIRP J Manuf Sci Technol, 2 (2010) Manco L, Filice L & Abrogio G, Proc IMechE Part B: J Eng Manuf, 225 (2011) Malhotra R, Bhattacharya A, Kuar A, Reddy N V & Cao J, CIRP Ann Manuf Technol, 60 (2011) Xu D K, Malhotra R, Reddy N V, Chen J & Cao J, J Manuf Process, 14 (2012) Li J C, Hu J B, Pan J J & Geng P, Int J Adv Manuf Technol, 62 (2012) Liu Z B, Li Y L & Meehan P A, Mater Manuf Process, 28 (2013) Kopac J & Kapus Z, J Mater Process Technol, 162 (2005) Hussain G, Gao L & Dar N U, J Mater Process Technol, 186 (2007)