水下机器人AUV叶片冷锻钉头几何缺陷英文文献和中文翻译(4)

Fig。 7。 Velocity vector of the material ﬂow during pin head embossing at different punch stroke at diameter = 3 mm, distance to edge = 0。7 mm and depth = 2 mm。

Distance to the Edge, DTE (mm)

Fig。 9。 The effect of DTE to width of the bulging。

shows that in increasing the 1 mm depth, i。e。, from 1。5 to 2。5 mm, the increment is only about 0。04%。 Therefore for this process, the optimized parameters were at embossing depth of 2。0 mm and punch diameter of 3。0 mm。 The pin head is intentionally designed to allow the part to be ﬁrmly ﬁxed during assembly and based on the result, it is clear that the DTE has the most signiﬁcant effect。 But due to design constraint, the value of DTE is limited to 1 mm to prevent from affecting the mating part i。e。, the hub。 As shown in Fig。 8(c), there is a larger increment in the area ratio as the distance increases。 There is approximately a 3% increment or about

0。7 mm2 of the total area; thus, increasing the distance by about

0。3 mm, i。e。, from 0。7 to 1。0 mm。 Purposely, the distance of 2。0 mm is carried out to observe the effect, and the ﬁlling region for this case is evidently almost perfect or has no defect at approximately 99。2% ﬁlled。 Based on the result, it is clear that the DTE is the most signiﬁcant parameter to the ﬁllingability of the embossed pin head。 But since the value of the DTE Š l, therefore 1 mm was choosen。

In other case, the size of the bulging was estimated。 Fig。 9 shows the effect of DTE to the width of the bulging generated from the sim- ulation。 The larger the DTE, the lower the defect observed。 Fig。 10 shows the material ﬂow pattern of the investigated parameter i。e。, the DTE of the embossed part。 Here, three different DTEs were stud- ied (0。7, 0。8, and 1。0), and the FE simulation results showed that there is a signiﬁcant effect on the material ﬂow with respect to the punch stroke。 With the small punch stroke, the right end of the fea- ture, the material seems to ﬂow outward to the right section。 Until

Fig。 8。 The effect of (a) punch diameter, (b) embossing depth and (c) distance to edge to the ﬁlling ratio。

It can be observed that as the punch stroke increases, the mate- rial follows the punch and the cavity can only be formed after the

1。0 mm stroke。 This is because, at the beginning i。e。, stroke less than

1。0 mm, the material tends to ﬂow outward to form bulging instead of cavity。 Only after the 2。0 mm punch stroke, the material tends to ﬂow into the workpiece to form cavity as shown in Fig。 7。

Since the pin head is located at the edge of the workpiece, the geometries that may affect its accuracy are embossing depth, punch diameter, and the distance to edge (DTE), which can be referred in Figs。 2 and 4。 To study the effect of these features on the embossed pin head, a parametric study and optimization were performed。 As a result, the increasing diameter is caused in less unﬁlled area as shown in Fig。 8(a) or the higher diameter, the higher the ratio of ﬁlled to unﬁllled area。 The effect of depth to the ﬁlling ratio is less compared with the punch diameter。 Fig。 8(b)

the end of the process, the material is continuously forced to ﬂow toward the edge, and the height and width of the bulge increases。 With an increased DTE, the effect of bulging height and width can be clearly seen。 Similarly, by increasing the DTE, the distribution of the stress is more uniform (Fig。 11)。

Other alternative is to study the inﬂuence of the tapered punch on embossed part features。 To this purposes, the stress distribution and material ﬂow analysis with respect to the punch stroke were investigated。 The results are shown in Figs。 12 and 13, respectively。文献综述

Here, the 2◦, 5◦, and 10◦ tapered angle punches were studied。 As 水下机器人AUV叶片冷锻钉头几何缺陷英文文献和中文翻译(4):http://www.youerw.com/fanyi/lunwen_98515.html