Because they extend under the mold parting surfaces, tunnel gates can reach surfaces or features that are not located on the parting line. The gates typically feed surfaces oriented perpendicular to the mold face. Depending upon their design, they degate during ejection or mold opening (see figures 7-33 and 7-34). Tunnel gates that degate during mold opening often require a sucker pin or a feature similar to a sprue puller to hold the runner on the ejector half of the mold. The runner must flex for the gate to clear the undercut in the mold steel.
The gate may break or lock in the mold if the runner is too stiff or if the ejector pin is too close to the gate. Normally,the ejector pin should be at least two runner diameters away from the base of the gate.
The orifice edge closest to the parting line must remain sharp to shear the gate cleanly. When molding abrasive materials such as those filled with glass or mineral,make the gate of hardened or specially treated mold steel to reduce wear. Also,consider fabricating the gate on an insert for easy replacement. The drop angle and conical angle must be large enough to facilitate easy ejection (see figure 7-35). Stiff materials, glass-filled grades for example, generally require drop angles and conical angles at the high side of the range shown in the figure. The modified-tunnel gate design (see figure 7-36) maintains a large flow diameter up to the gate shearoff point to reduce pressure loss and excessive shear heating.
[ 本帖最后由 szlxm123 于 2007-6-26 06:16 编辑 ]作者: szlxm123 时间: 2007-6-26 06:17
Curved-tunnel gates permit gating into the underside of surfaces that are oriented parallel to the parting plane (see figure 7-37). Unlike mold fabrication for conventional tunnel gates, the curved, undercut shape of this design must be machined or EDM burned on the surface of a split gate insert. The curved gate must uncurl as the runner advances on guided posts during ejection.作者: 大奔 时间: 2007-6-26 15:39
这样的结构我5年前就会了作者: yangchaofeng 时间: 2007-6-27 08:18
很标准,很好.顶一下作者: cwh74597810 时间: 2007-6-27 10:54
不错!作者: zhouyali500 时间: 2007-6-28 21:43
很好，顶下作者: wfzdxx 时间: 2007-7-12 13:09
学无止境作者: luoshidong5 时间: 2007-8-25 12:34
顶～～～～｀｀｀｀｀作者: moon 时间: 2007-8-26 00:54
could you please provide the original file?作者: zwa197359 时间: 2008-5-3 14:53
很好。顶一下。作者: huangxsq 时间: 2008-5-3 18:46
不错,现在用的很普遍.作者: qxd5651888 时间: 2008-5-23 14:51
很好。顶一下作者: jody.li-88 时间: 2008-5-23 20:36
浇口我也知道好多，可是现不知道怎么来和大家拿来分享。作者: lfenger 时间: 2008-12-20 21:13
不错啊！作者: nb999999 时间: 2008-12-21 21:46
好东西,顶一下。作者: wangshaocun2006 时间: 2008-12-23 09:52
dddddddddddddddddddddd作者: kmode8888 时间: 2008-12-23 14:11
GOOD,THANKS作者: 983634286 时间: 2009-6-9 11:44
这样的结构我早就想学了作者: liangchang123 时间: 2009-6-9 11:56
顶顶
顶
顶顶作者: xuxingfa 时间: 2009-8-16 22:52
已下载,j看了再说,谢谢；作者: BINGECHEN 时间: 2009-8-17 00:27
做过牛角,是自己摸索的,总算看到资料了
