Lowering binder percentages will reduce the amount of volatile organic compounds produced during nobake operations.
降低粘结剂的加入量可以减少硬化期间产生的挥发性有机化合 物的量。
that produced a failed mold on the line. Te failures caused backups in the entire operation. According to Walker, Denison’s main problem areas
were related to moisture and sand temperature. In the Texas summers, days start at 21C with 20% humidity, but by the afternoon, ambient temperatures can reach 32-38C with humidity close to 100%. Actual sand temperatures range from 4C in the winter to 39C in the summer. “At each level of temperature or moisture [change], we saw an effect on the way molds were setting up, work time and strip time,” Walker said. “Trough extensive testing and trying different methods of application, we now understand when and how to adjust to the variables. We are operating with low to high sand temperatures now with no negative effects on the sand mold or casting quality.” At the same time, Denison Industries reduced the costs associated with binder material and reworked castings and lowered the amount of volatile organic compounds (VOCs) produced in its nobake operations.
Charting the Variables
Denison gained confidence in its molding operation by first taking a magnifying glass to it. Te metalcaster performed a complete documentation of its nobake process, examining and testing individual equipment capabilities and improvements, resin binders, core release agents and their compatibility with resin bind- ers, shakeout properties, calibration methods, and long- and short-term core strength values. “When we first started testing, we were trying to improve the nobake line itself because of its issue of releasing cores
空气湿度和砂温有关。在得克萨斯州的夏天，早晨气 温为70F（21℃），湿度为20％，但到了下午，环境 温度可以达到90-100F（32-38℃），湿度接近100％ 。砂子的实际温度范围为冬季的40F（4℃）至夏季的 102F（39℃）。
“在每一个温度或湿度变化的水平，我们看到它如何 影响造型固化、工作时间和脱模时间，”Walker说：“ 通过全面的测试，应用不同的方法，我们现在理解何时 和如何调整参数，我们采用不同温度的砂造型，却没有 对砂型和铸件质量造成负面影响。”
同时，丹尼森工业公司降低了粘结剂材料和返工铸 件的成本，并降低了自硬砂产生的挥发性有机化合物 （VOCs）。
影响因素图表 丹尼森工业公司认真对待该问题，因此就拥有了造型 的信心。
铸造厂记录了完整的自硬砂工艺，包括检查和测试单 台设备的能力和改进、树脂粘结剂、芯盒脱模剂以及其 与树脂粘结剂的兼容性、落砂性能、标定方法以及终强 度和即时砂芯强度。
沃克说：“从我们第一次测试开始，我们就在设法改 进自硬砂生产线，因为存在砂芯和砂型的脱模问题、侵 蚀和老化缺陷。 不过说真的，我们试图为我们的产品找
Spring 2012
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