Could Slower be better? Assessing Sintering Time, Temperature, and Area Tradeoffs in 3D Printing by Polymer Sintering

慢一点会更好吗？

• 批准号: 1851728
• 负责人: Nathan Crane
• 金额: $ 19.82万
• 依托单位: Brigham Young University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-08-07 至 2022-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1851728&HistoricalAwards=false
• 关键词: Could; Slower; better; Assessing; Sintering

3D printing (additive manufacturing) is enabling dramatic changes in design, manufacturing, and distribution. While this has created many new opportunities, the materials and the properties available with 3D printing are still much more limited than those available with traditional processes such as machining and injection molding. This award supports fundamental research to enable expansion of the range and functionality of materials used in 3D printing processes that form components by locally heating (sintering) a polymer powder (usually with a laser). As the range of available materials expands, the processes can be used more widely. The continued expansion of additive manufacturing through improved material properties, increased variety of materials, and reduced production costs, will help achieve the full benefits of additive manufacturing including low-cost customized products, faster development times, and more personalized medicine. Additive manufacturing via sintering of polymer powders has typically used a scanning laser to heat the materials quickly. The tightly focused laser creates large thermal gradients and short sintering times. Relatively few materials can densify reliably without degradation under these conditions. A single material (nylon 12) composes a large majority of all polymer-sintered components. However, a solution may be to use lower intensity light for longer time. Build rate may be maintained or improved by heating larger areas using large laser spot sizes or by sintering an entire layer with a single exposure. Longer processing times will require a transition from process characterization based on energy input to temperature history. The objective of this research is to understand the effects of sintering time, temperature, and area in polymer sintering. This will be done by modeling process outcomes based on processing temperature and time, rather than optical energy input--enabling application of viscous sintering theory to guide process development. Viscosity and sintering rates of test materials will be measured to calibrate sintering models while stiffness, strength, and viscosity measurements of heated materials will be used to identify the processing window which avoids degradation. A projection-sintering system will be developed to measure sintering outcomes (porosity, stiffness, and strength) with varying exposure time, temperature, and area. Models will be developed to identify combinations of processing time and temperature that achieve equivalent material properties. These models will be used to predict tradeoffs in material properties, build rate, and resolution between alternative machine architectures using point, line, and area-based heating methods. They will also accelerate selection and development of new polymer sintering materials.

3D打印（添加剂制造）正在实现设计，制造和分销的巨大变化。尽管这创造了许多新的机会，但3D打印的材料和属性仍然比传统工艺（例如加工和注入造型）更有限。该奖项支持基本研究，以扩大3D打印过程中使用的材料的范围和功能，这些材料通过局部加热（烧结）聚合物粉（通常带有激光）来形成组件。随着可用材料范围的扩展，可以更广泛地使用该过程。通过改进的材料特性，增加材料的种类和降低的生产成本，添加剂制造的持续扩展将有助于实现添加剂制造的全部收益，包括低成本定制产品，更快的开发时间和更多个性化的药物。通过烧结聚合物粉末的添加剂制造通常使用扫描激光迅速加热材料。紧密聚焦的激光产生了较大的热梯度和短时间的烧结时间。 在这些条件下，相对较少的材料在没有降解的情况下可靠地致密。 单个材料（尼龙12）构成了所有聚合物插图的大部分。但是，解决方案可能是在更长的时间内使用较低的强度。 通过使用大型激光斑点尺寸加热较大的区域，或通过一次曝光烧烤整层，可以维持或改善构建速率。 更长的处理时间将需要根据能量输入到温度历史的过程表征过渡。 这项研究的目的是了解聚合物烧结中烧结时间，温度和面积的影响。 这将通过基于处理温度和时间而不是光学能量输入来建模过程成果来完成，从而实现粘性烧结理论来指导过程发展。将测量测试材料的粘度和烧结速率以校准烧结模型，而加热材料的刚度，强度和粘度测量将用于识别避免降级的加工窗口。将开发一个投影插图系统，以测量烧结的结果（孔隙度，刚度和强度），并具有不同的暴露时间，温度和面积。 将开发模型以确定处理时间和温度的组合，以实现等效材料。 这些模型将用于预测材料属性，构建速率和使用基于点，线和基于区域的加热方法的替代机器架构之间的折衷。它们还将加速新聚合物烧结材料的选择和开发。