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可可1983

<p>实在太多，没有时间了，请兄弟姐妹大家一起来帮忙！</p>

可可1983

<p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span lang="EN-US" style="FONT-SIZE: 12pt;"><font face="Times New Roman">4.2 Rules for determining the bending sequence<p></p></font></span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span lang="EN-US" style="FONT-SIZE: 12pt;"><font face="Times New Roman">the following two rules are identified for determining the bending sequence with minimum number of bending steps, before considering how to satisfy any constraints on the bending sequence itself:<p></p></font></span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt 18pt; TEXT-INDENT: -18pt; mso-list: l0 level1 lfo1; tab-stops: list 18.0pt;"><font face="Times New Roman"><span lang="EN-US" style="FONT-SIZE: 12pt;">1.<span style="FONT: 7pt &quot;Times New Roman&quot;;">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span></span><span lang="EN-US" style="FONT-SIZE: 12pt;">If two walls, x and y, are connected by a bend, and y is bent from x, x is the parent and y is the child. The child wall must be bent before its parent. This is the first and the basic rule for the determining bending sequence. It is also called the child-and-parent rule.<p></p></span></font></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt 18pt; TEXT-INDENT: -18pt; mso-list: l0 level1 lfo1; tab-stops: list 18.0pt;"><font face="Times New Roman"><span lang="EN-US" style="FONT-SIZE: 12pt;">2.<span style="FONT: 7pt &quot;Times New Roman&quot;;">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span></span><span lang="EN-US" style="FONT-SIZE: 12pt;">The second rule is that all the leaves of a bending tree or the terminal nodes may be bent at the same step.<p></p></span></font></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span lang="EN-US" style="FONT-SIZE: 12pt;"><font face="Times New Roman">There are exceptions to the second rule. For example, the spatial positions of the bending lines and the bending directions must be taken into consideration. If two walls are to be bent in opposite directions, they should not be bent in the same step. Otherwise too much blank-holder force would be required to hold the strip. This is called the bending direction rule. Further, bending operations should be designed in a station as symmetric as possible. This is known as symmetry rule. Of course, the die structure must also be considered. As already mentioned previously, when too many bending operations are designed on one station, mounting of bending punches may be difficult and the die structure may be too complex, resulting in increased tooling cost and decreased tool life. This is the structure rule. They are extracted from the practical design knowledge and may be applied either in determining the bending sequence or when the bending operations are assigned to the stations of a progressive die.<p></p></font></span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span lang="EN-US" style="FONT-SIZE: 12pt;"><font face="Times New Roman">To simplify the procedures only the basic rule(child-and-parent rule)and the second rule are to be applied in the algorithm presented below for a computer to generate a default bending sequence. The user may always override the computer-generated sequence by applying the complementary rules.<p></p></font></span></p>

zhihot

<p>4.2确定折弯次序的规则</p><p>在考虑如何进行折弯操作本身之前，以下的两条规则用来以最少的折弯次数来确定折弯次序：</p><p>1.有两壁，X与Y，他们由一个折弯连接，Y是从X上折弯得到的，X是父项，Y是子项，子项必须在父项之前完成---这是判定折弯次序的第一条规则，叫做父子规则；</p><p>2.第二条规则是一个折弯上或节点上的所有分叉可在一个折弯上完成；</p><p>对于这条规则，有例外的情况，比如当折弯线是空间线或者弯曲方向必须考虑时，如果两壁弯曲方向相反，就不能在一步上完成，否则的话条料上就会有太多地方需要施加控制非折弯区的力，这被叫做弯曲方向法则；还有，一个工作站上的折弯操作应尽可能对称，这叫对称规则；当然，模具结构也必须考虑，就象前面提到的，当许多折弯操作被设计在同一个工作站，可能会使弯曲冲头的装配变得困难，冲头结构也会变的很复杂，这将导致加工成本的增加和冲头寿命的降低，这叫结构规则。</p><p>这些规则是从设计实践中得来的，可被应用于确定弯曲次序或者是连续模中弯曲工作站的布置。</p><p>为了简化程序，只有第一和第二规则被应用于时下计算机进行缺省的折弯次序的生成；用户可能总要跳过缺省操作，而应用补充规则。</p><p>&nbsp;</p><p>&nbsp;</p><p><font color="#0909f7" size="4">原因：热心肠的人们，用户操作：金钱20，,对用户：zhihot奖励2个金币!--happybird3</font></p>

[此贴子已经被happybird3于2006-4-20 11:40:32编辑过]