ÿþ <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=gb2312"> <title>[metalworking technique]Bending---Higrade(Qingdao) Moulds & Products Co., Ltd. China stamping die,higrade stamping die|China press die ÿChina progressive company/manufacture/supplier,China sheet metal parts</title> <meta name="keywords" content="[metalworking technique]Bending,China stamping die |China press die ÿChina progressive company ÿmanufacture,supplier,China sheet metal parts"> <meta name="description" content="Located in Qingdao, China, Higrade Stamping specializes in stamping die, progressive die, sheet metal parts, including stainless steel/iron stamping parts, Galvanized sheet stamped parts,and so on.Excellent stamping die manufacturer, supplier."> <link href="../css.css" rel="stylesheet" type="text/css"> <script> function autoResize() { try { document.all["test"].style.height=test.document.body.scrollHeight document.all["testbottom"].style.height=testbottom.document.body.scrollHeight document.all["testtop"].style.height=testtop.document.body.scrollHeight } catch(e){} } </script> </head> <body bgcolor="#FFFFFF" leftmargin="0" topmargin="0" marginwidth="0" marginheight="0"> <!-- ImageReady Slices (-1) --> <table width="1003" border="0" align="center" cellpadding="0" cellspacing="0" id="__"> <tr> <td colspan="2"><iframe id=testtop style="height:expression(1); aho:expression(autoResize())" src="../top1.asp" scrolling="no" frameborder="0" width="100%"></iframe></td> </tr> <tr> <td width="260" valign="top" background="../images/index_06.jpg" bgcolor="#FAFAFA" style="background-position:top; background-repeat:repeat-x;"><iframe id=test style="height:expression(1); aho:expression(autoResize())" src="../left2.asp" scrolling="no" frameborder="0" width="260"></iframe></td> <td align="center" valign="top" background="../images/index_07.jpg" bgcolor="#FFFFFF" style="background-position:top; background-repeat:repeat-x;"><table width="660" border="0" align="center" cellpadding="0" cellspacing="0"> <tr> <td height="30"></td> </tr> <tr> <td height="35" background="../images/title.gif" style="background-repeat:no-repeat;"><table width="560" border="0" cellspacing="0" cellpadding="0"> <tr> <td width="44"></td> <td width="328" height="30" valign="top" class="STYLE9-2"><div align="left">News Center</div></td> <td width="188"></td> </tr> </table></td> </tr> <tr> <td height="10" class="STYLE6"></td> </tr> <tr> <td class="STYLE6"><table width="100%" border="0" align="center" cellpadding="0" cellspacing="0" class="STYLE3_5"> <tr> <td height="35"><div align="center"><strong>[metalworking technique]Bending</strong></div></td> </tr> <tr> <td><div align="center"> <table width="90%" border="0" cellspacing="0" cellpadding="0"> <tr> <td class="STYLE6"><DIV align=left> <DIV align=left><STRONG>Bending</STRONG> is a common metalworking technique to process sheet metal. It is usually done by hand on a box and pan brake, or industrially on a brake press or machine brake. Typical products that are made like this are boxes such as <A title="Electrical enclosure" href="http://www.higradegroup.com">electrical enclosures</A>, rectangular <A title="Duct (HVAC)" href="http://www.higradestamping.com">ductwork</A>, and some firearm parts such as the receiver of the <A title=AKM href="http://www.higrademould.com">AKM</A> <A title=AK-47 href="http://www.higradegroup.com">AK-47</A> variant.</DIV> <DIV align=left>&nbsp;</DIV> <DIV align=left>Usually<STRONG> bending</STRONG> has to overcome both tensile stresses as well as compressive stresses. When bending is done, the residual stresses make it spring back towards its original position, so we have to overbend the sheet metal keeping in mind the residual stresses.</DIV> <DIV align=left>&nbsp;</DIV> <DIV align=left>When sheet metal is bent, it stretches in length. The bend deduction is the amount the sheet metal will stretch when bent as measured from the outside. A bend has a radius. The term bend radius refers to the inside radius. The bend radius depends upon the dies used, the metal properties, and the metal thickness.</DIV> <DIV align=left>&nbsp;</DIV> <DIV align=left>Many software packages refer to the K-factor for bending sheet metal. K-factor is a ratio that represents the location of the neutral sheet with respect to the inside thickness of the sheet metal part. The bend allowance is the length of the arc of the neutral axis between the tangent points of a bend in any material.</DIV> <DIV align=left>&nbsp;</DIV> <DIV align=left>BD = 2*(R + T) - BA </DIV> <DIV align=left>BA = À*(R + K*T)*A/180 </DIV> <DIV align=left>K = (180 * BA)/(À*A*T) - R/T </DIV> <DIV align=left>&nbsp;</DIV> <DIV align=left>where:</DIV> <DIV align=left>&nbsp;</DIV> <DIV align=left>BA = bend allowance </DIV> <DIV align=left>R = inside bend radius </DIV> <DIV align=left>K = K-Factor, which is t / T </DIV> <DIV align=left>T = material thickness </DIV> <DIV align=left>t = distance from inside face to neutral sheet </DIV> <DIV align=left>A = bend angle in degrees (the angle through which the material is bent) </DIV> <DIV align=left>&nbsp;</DIV> <DIV align=left>&nbsp;</DIV> <DIV align=left> <TABLE class="" width="100%" border=0> <TBODY> <TR bgColor=#d9d2c3> <TD bgColor=#f0f0f0 height=30> <DIV align=center><STRONG>news title</STRONG></DIV></TD> <TD bgColor=#f0f0f0 height=30> <DIV align=center><STRONG>creatime </STRONG></DIV></TD></TR> <TR> <TD bgColor=#f9f9f9 height=30> <DIV align=center><A onmouseover="javascript:this.style.cssText='CURSOR: hand;'" style="CURSOR: hand" href="http://www.higradestamping.com/news/newsen24.htm" target=_blank>Effective Method to Control Cost of...</A></DIV></TD> <TD width="33%" bgColor=#f9f9f9 height=30> <DIV align=center>2008-9-16</DIV></TD></TR> <TR> <TD bgColor=#f9f9f9 height=30> <DIV align=center><A onmouseover="javascript:this.style.cssText='CURSOR: hand;'" style="CURSOR: hand" href="http://www.higradestamping.com/news/newsen23.htm" target=_blank>Progressive Stamping Die</A></DIV></TD> <TD width="33%" bgColor=#f9f9f9 height=30> <DIV align=center>2007-4-26</DIV></TD></TR> <TR> <TD bgColor=#f9f9f9 height=30> <DIV align=center><A onmouseover="javascript:this.style.cssText='CURSOR: hand;'" style="CURSOR: hand" href="http://www.higradestamping.com/news/newsen22.htm" target=_blank>The advantages of Higrade Stamping</A></DIV></TD> <TD width="33%" bgColor=#f9f9f9 height=30> <DIV align=center>2007-4-26</DIV></TD></TR> <TR> <TD bgColor=#f9f9f9 height=30> <DIV align=center><A onmouseover="javascript:this.style.cssText='CURSOR: hand;'" style="CURSOR: hand" href="http://www.higradestamping.com/news/newsen21.htm" target=_blank>The Structure of the Export of the ...</A></DIV></TD> <TD width="33%" bgColor=#f9f9f9 height=30> <DIV align=center>2007-4-26</DIV></TD></TR> <TR> <TD bgColor=#f9f9f9 height=30> <DIV align=center><A onmouseover="javascript:this.style.cssText='CURSOR: hand;'" style="CURSOR: hand" href="http://www.higradestamping.com/news/newsen12.htm" target=_blank>Situation and Development of China...</A></DIV></TD> <TD width="33%" bgColor=#f9f9f9 height=30> <DIV align=center>2006-11-26</DIV></TD></TR> <TR> <TD bgColor=#f9f9f9 height=30> <DIV align=center><A onmouseover="javascript:this.style.cssText='CURSOR: hand;'" style="CURSOR: hand" href="http://www.higradestamping.com/news/newsen8.htm" target=_blank>Higrade Stamping in China</A></DIV></TD> <TD width="33%" bgColor=#f9f9f9 height=30> <DIV align=center>2006-11-15</DIV></TD></TR></TBODY></TABLE></DIV></DIV></td> </tr> </table> </div></td> </tr> <tr> <td><div align="center"> <table width="100%" border="0" cellspacing="0" cellpadding="0"> <tr> <td width="75%" height="35" align="left"><div align="center">Author:Shirney Chen</div></td> <td align="center"><div align="center">Time:2009-6-30</div></td> </tr> </table> </div></td> </tr> </table></td> </tr> <tr> <td>&nbsp;</td> </tr> </table></td> </tr> </table> <table width="1003" border="0" align="center" cellpadding="0" cellspacing="0"> <tr> <td>&nbsp;</td> </tr> <tr> <td bgcolor="#1B80B4"><iframe id=testbottom style="height:expression(1); aho:expression(autoResize())" src="../bottom1.asp" scrolling="no" frameborder="0" width="100%"></iframe></td> </tr> <tr> <td>&nbsp;</td> </tr> </table> <!-- End ImageReady Slices --> <script type="text/javascript"> var gaJsHost = (("https:" == document.location.protocol) ? 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