product news/產品新聞
if the model is not in stock,” Vrielink said. Te development engineer also sees a significant advan-
tage in the higher quality. Te 3D print corresponds 1:1 with the computer model, while hand-crafted products can result in small variances. Te more complicated the shape of the pump wheel, the higher the savings for printing in this production process. A good example is the screw-centrifugal wheel, a tapered wheel that must correspond exactly with the model. Te shape of this wheel must be very precise to avoid imbalances. Nevertheless, Nijhuis must polish the castings afterwards to remove any existing imbalances. Oc- casionally, castings must be polished for more than one day at the chip removal department of the Nijhuis pump factory. Sand printing takes care of the imbalances during the draft phase in the computer. Te casting is much more precise and requires much less follow-up work. Another advantage of using voxeljet printing technology is the use of fine quartz sand. Compared to hand-crafted sand molds, these castings have a smoother surface. Tis is reflected in the lower energy consumption of the pump. “Moreover, a sand mold is printed for each wheel, while
we use standard models and cast more excess. Excess casting material must be removed by machine, which costs time,” Vrielink said. In the case of castings made of hard materials, this may mean even longer follow-up work. Tis is not the case for 3D processes: Here, the effort required for machin- ing the parts is restricted to a minimum due to smaller allowances. At the development department, Vrielink and his col- leagues had been looking for a 3D printing technology. However, such technology was unaffordable. However, voxeljet has accelerated the development of this technology, and costs have been reduced significantly. “But if the part is more complex, sand printing represents
an attractive alternative. Certainly for prototypes, individual pieces or small series,” Vrielink said. In his view, 3D printing will replace some of the conventional production methods. At the Nijhuis pump factory, the castings produced with sand molds from voxeljet are installed into the pump and extensively tested on a separate test stand. But Vrielink is convinced of their quality. “By using this technology, Euro- pean foundries can significantly improve their competitive situ-
ation.” ■ Visit
www.voxeljet.de/en for more information.
不过，手工制作过程中会存在微小的差距。泵轮的形状 越复杂，打印成本降低的越多。螺旋离心轮是个很好的 例子，其锥形轮必须与模具完全吻合，必须做到非常精 确以避免失衡。因此，Nijhuis公司必须对铸件进行抛 光，去除存在的失衡。在Nijhuis泵工厂的芯片移除部 门，铸件的抛光有时候需要不只一天时间。在计算机草 图阶段，砂型模打印就可处理失衡现象。这样的铸件更 加精确，并且需要很少的后续加工。 使用voxeljet打印技术的另一个优点是使用了优质的 石英砂。与手工制作砂型相比，石英砂铸件的表面更加 光滑，从而降低了泵的能耗。 Vrielink说：“此外，可以针对每一个轮毂打印砂 型，过去用普通的砂型做铸件，必须考虑铸件的加工余 量，加工余量将被加工掉，需要时间。”对于硬质材料 的铸件，可能意味着需要更多的加工时间。3D打印避 免了这样的情况，由于只有少量的余量，部件所需的加 工量降到最小程度。 在研发部门，Vrielink和他的同事曾对3D打印技 术进行了大量研究。然而，这项技术的研发非常昂 贵。voxeljet公司已经加快了这项技术的研发速度，并 且成本已显著降低。 Vrielink说：“在部件更复杂的情况下，打印砂型将 成为具有吸引力的替代选择。当然，对于样件、单件或 小批量产品来说同样如此。”他认为3D打印技术将取 代一些传统的生产方式。 Nijhuis公司已将使用voxeljet打印出的砂型生产 的铸件安装在泵上，并在独立测试站进行测试。但 是，Vrielink坚信产品的质量。他说：“使用这项技
术，欧洲的铸造厂将能够显著提高竞争力。” ■ 了解更多信息，请访问
www.voxeljet.de.
Voxeljet’s 3D printer VX4000 can print sand molds up to 4 x 2 x 1 m.
Voxeljet公司的3D打 印机VX4000可以打印 尺寸为4 x 2 x 1 m的 砂型。
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FOUNDRY-PLANET.COM | MODERN CASTING | CHINA FOUNDRY ASSOCIATION December 2014
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