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求助翻译一段模具设计方面段落
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A method of diecasting runner design that induces a restricted flow can save process costs and improve quality. The design criteria involved in a new, restricted-flow method of diecasting runner design directly contradict some rules that many in the diecasting industry have adopted for decades without questioning. The seasoned diecaster will immediately recognize two aspects of the new runner design that do not fit into conventional wisdom. First, high pressure diecasting design rules say that the melt should experience the least possible amount of resistance up to the gate so that sufficient machine power will be conserved to inject the melt through the gates, where the smallest cross section is typically located. Second, traditional diecasters believe that an expansion of the runner following the smallest cross section will result in air entrainment. The new runner design contradicts both of these tenants. But when compared with traditional diecasting, the restricted-flow method improves yield, reduces porosity, enhances mechanical properties and, in some cases, reduces cycle time. And it does so with no other capital equipment than existing cold- or hot-chamber HPDC machinery, which is used without any modification. High pressure diecasters are facing significant challenges in keeping process costs down and meeting higher standards of quality. The push to reduce costs has made diecasters more sensitive to the need to increase productivity, reduce rejection rates and improve material yield. The latter is especially significant for those casting magnesium alloys due to the associated higher recycling costs. To answer those demands, the new runner design technique employs a constriction of the melt flow. This is done by using a much thinner runner with a tightened section that pre-conditions the melt by both shearing the flow and accelerating it well before it reaches the gate. The restriction exhibits the smallest cross section in the runner and is followed by a gentle or nonexistent expansion in the melt flow direction. When the expansion is nonexistent, a parallel port to the melt pre-conditioner opens abruptly into a larger runner. In most cases, a plunger velocity lower than that used with a typical HPDC runner is employed without risking cold runs, and the melt is allowed to fill the casting cavity through conventional gates at a lower velocity. This allows restricted-flow runners to yield both the higher casting quality associated with greater melt velocities and the more controlled fill front and better venting obtained with lower gate velocities. Evidence from industry trials demonstrates that almost all machines in use today are capable of injecting melt through very small cross sections while still successfully filling a casting cavity, and a casting's mechanical properties improve with use of the restricted-flow runner, indicating that the degree of porosity is lower. |
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爱与雨下(金币+2): 感谢你的热情支持！~ 2011-09-17 19:11:21
cyyclark(金币+1, 翻译EPI+1): 谢谢楼主的翻译，但是很不专业，而且很多地方无法理解。 2011-09-19 21:13:04
sltmac(金币+5, 翻译EPI-1): 有些地方时自己翻译的，还有很多地方时机器翻译的吧？EPI先撤销了，多加几个BB 2011-09-20 13:57:02
爱与雨下(金币+2): 感谢你的热情支持！~ 2011-09-17 19:11:21
cyyclark(金币+1, 翻译EPI+1): 谢谢楼主的翻译，但是很不专业，而且很多地方无法理解。 2011-09-19 21:13:04
sltmac(金币+5, 翻译EPI-1): 有些地方时自己翻译的，还有很多地方时机器翻译的吧？EPI先撤销了，多加几个BB 2011-09-20 13:57:02
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一个压铸设计方法产，该方法产生受限流从而达到节约过程成本和提高品质的目的 。设计尺度包含了一种新的压铸受限流的方法，该方法与与在压铸工业中采用了几十年的一些方法相悖。老练的金属铸造工能够马上看出这种新的设计在很多方面与传统的方法经典设计不同。首先，高压压铸设计准则认为在到达阀门前，融化过程应该经历尽可能少的阻力，这样才能有足够的动力将融化的金属注入阀门，该阀门是典型的最小横截面。其次，传统的铸造工认为压铸器的扩展应该遵循最小横截面，这样可以产生空气夹层，而新的设计均与与这两种观点相悖。但当与传统设计比较时，受限流设计法能够提高产量，减少孔隙率，增强机械特性并在某种程度上减少循环时间。除了柱顶装置外，只有已有的低温室或高温室HPDC装置能够做到这些，且使用起来无需任何更改。高压压铸技术面临着两个严重的挑战，即降低过程成本消耗和提高质量标准。减少成本的需求使得压铸器对提高产量的需求，减少注入率以及提高产品质量更敏感。后者对于铸造镁合金尤为明显，主要原因在于其高循环成本。为解决这些需求，新的压铸器在熔体流动过程中使用了一个压缩物。通过采用一个具加紧切片的薄压铸器在经过阀门前将熔体流剪断并加速即可完成。其局限性为压铸器内的最小通过面并紧跟在熔体流动方向的温和甚至不存在的膨胀。当没有膨胀时，通向熔体流的回溯机的平行端突然打开并进入一个更大的流道。多数情况下，采用无危险冷却通道的低于经典HPDC通道柱塞速度，并允许熔体通以低速过常规阀门并进入铸造腔。限制流通道能够产生于快熔体流速有关的高铸造质量以及更易控制的前充量并在低阀门流速下将其排除。工业测试显示几乎所有当今使用的机器都能够使注入熔体通过很小的横截面并成功填满铸造腔，一个铸造机器属性在使用限制性流动通道后的提高表明其孔隙率较低。 |
2楼2011-09-17 12:52:11
