第5章 选择性激光烧结成形技术
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天津科技大学 Tianjin University of Science & Technology
天津科技大学 Tianjin University of Science & Technology
Galvanometer n.检流计 天津科技大学 Tianjin University of Science & Technology
天津科技大学 Tianjin University of Science & Technology
简介
选择性激光烧结工艺，又称选区激光烧结，由美国德克萨斯大 学Dechard于l989年研制成功。美国DTM公司已经商品化。 SLS工艺是利用粉末材料(金属粉末或非金属粉末)在激光照射 下烧结，在计算机控制下层层堆积成形。SLS的原理与SLA十 分相似，主要区别在于所使用的材料。 SLA所用的材料是液态的紫外光敏可凝固树脂，而SLS则使用 粉状的材料。这是该项技术的主要优点之一，因为理论上任何 可熔的粉末都可以用来制造模型，这样的模型可以用作真实的 原型制件。 研究SLS的有DTM公司、EOS公司、3D Systems公司、北京隆源 公司、华科大、华北工学院和南航大学等。
A leveling roller spreads each layer of powder over the surface of
the build chamber, as the fabrication piston moves down one layer, while the powder delivery piston moves upward to supply powder to the process.
SLS系统的工艺原理和基本组成
SLS系统基本 组成： C02激光器、 光学系统、粉 料送进与回收 系统、升降机 构、工作台、 构造室等。
立体光刻固化的缺点
立体光刻固化只能使用感光性材料。 立体光刻固化有两个步骤，首先模型在真正的立体光刻固化设 备里固化到很高的程度(>95％)；然后将做成的模型放到烘箱 里，使模型进一步交联，直至完全固化。 产品毛坯必须用溶剂清洗。 在树脂池中，模型仍然是相当柔软的产品坯。 支撑必须从产品毛坯或凝固的模型中用人工清除。 感光性丙烯酸吸收氧，而环氧基树脂具有吸湿性，模型完全凝 固后，也很容易碎掉。 几天或几周后，没有支撑的壁就会变形，如果把模型翻转或支 撑起来这种情况就会消失。最新的环氧基树脂没有这些明显的 特征。
A nitrogen atmosphere is maintained in the fabrication chamber to
prevent the possibility of a dust explosion caused by handling the powder. Unlike stereolithography, no supports are required with SLS since overhangs, and undercuts are supported by the solid powder bed. Additionally, no final curing is required, however, surface finishes are not as good as those achieved with stereolithography and since the objects are sintered. they are porous. Depending on the application, it may be necessary to infiltrate the object with another material to improve mechanical characteristics.
Selective Laser Sintering
方法介绍
天津科技大学 Tianjin University of Science & Technology
Selective Laser Sintering (SLS®, registered trademark by DTM™ of Austin, Texas, USA) is a process that was patented in 1989 by Carl Deckard, a University of Texas graduate student. Its chief advantages over Stereolithography (SLA) revolve around material properties. Many varying materials are possible and these materials can approximate the properties of thermoplastics such as polycarbonate [化]聚碳酸酯, nylon, or glass-filled nylon.
天津科技大学 Tianjin University of Science & Technology
Copper Pellets
Part
Ramp
Ceramic plPlate
模具制造过程原理
天津科技大学 Tianjin University of Science & Technology
SLA vs. SLS: A Summarized Comparison
作业：
1. 立体光刻快速原型制造技术的优缺点分析？ 2. 激光选择烧结SLS原型制造技术的原理以及系统组成？
3.
4.
5.
是否需要设计支撑，并说明其原因。教材89页 激光选择烧结SLS原型制造技术为什么要求预热，如 何控制预热温度？为什么需要氮气保护？89页 117页 激光选择烧结SLS原型制造技术中，粉末材料一般有 几种组合？ 描述采用激光选择烧结SLS原型制造技术直接制造模 具的最常用工艺过程？113-114页
天津科技大学 Tianjin University of Science & Technology
Selective Laser Sintering
The entire fabrication chamber is sealed and maintained at a
temperature just below the melting point of the plastic powder. Thus, heat from the laser need only elevate the temperature slightly to cause sintering, minimizing thermal distortion, facilitating fusion to the previous layer and greatly speeding the process
The surface of the tightly compacted powder is selectively heated
with a concentrated infrared (IR) beam from a CO2 laser. The powder is melted where the IR beam strikes under guidance of the x-y scanner causing the particles to fuse together.
逆向工程与快速成形技术 Reverse Engineering and Rapid Prototype Technology
第5章 选择性烧结快速成形技术
Selective Laser Sintering
天津科技大学 Tianjin University of Science & Technology
Material Properties: The SLA (stereolithography) process is limited to photosensitive resins which are typically brittle. The SLS® process can utilize polymer powders that, when sintered, approximate thermoplastics quite well.
Surface Finish: The surface of an SLS® part is powdery, like the base material whose particles are fused together without complete melting. The smoother surface of an SLA part typically wins over SLS® when an appearance model is desired. In general, SLA is a better process where fine, accurate detail is required. However, a varnish-like coating can be applied to SLS® parts to seal and strengthen them. Varnish n.清漆, 凡立水, 光泽面, 掩饰 v.修饰
天津科技大学 Tianjin University of Science & Technology
ቤተ መጻሕፍቲ ባይዱ
Selective Laser Sintering
Selective laser Sintering (SLS) is in principle similar to
stereolithography. In this process however, fabrication of a physical model/part is effected by selectively melting a finely powdered (50 µm) thermoplastic material.
立体光刻固化的优点
立体光刻固化，也称作三维光刻，是目前快速原型工艺 中最精确的方法。它的精度受到设备的限制。 复杂模型，或者是比成型室尺寸大的模型，可以由单个 的局部模型组合成任意复杂的完整的模型。 模型可以通过喷砂处理和抛光来进行精加工处理 未交联单体可以再利用，完全聚合的树脂可以当作普通 的废物。
天津科技大学 Tianjin University of Science & Technology
Support Structures: SLA parts typically need support structures during the build. SLS® parts, because of the supporting powder, sometimes do not need any support, but this depends upon part configuration. Marks left after removal of support structures for parts cause dimensional inaccuracies and cosmetic blemishes. Blemish n.污点, 缺点, 瑕疵 vt.弄脏, 玷污, 损害 Machining Properties: In general, SLA materials are brittle and difficult to machine. SLS® thermoplastic-like materials are easily machined.
天津科技大学 Tianjin University of Science & Technology
Galvanometer n.检流计 天津科技大学 Tianjin University of Science & Technology
天津科技大学 Tianjin University of Science & Technology
简介
选择性激光烧结工艺，又称选区激光烧结，由美国德克萨斯大 学Dechard于l989年研制成功。美国DTM公司已经商品化。 SLS工艺是利用粉末材料(金属粉末或非金属粉末)在激光照射 下烧结，在计算机控制下层层堆积成形。SLS的原理与SLA十 分相似，主要区别在于所使用的材料。 SLA所用的材料是液态的紫外光敏可凝固树脂，而SLS则使用 粉状的材料。这是该项技术的主要优点之一，因为理论上任何 可熔的粉末都可以用来制造模型，这样的模型可以用作真实的 原型制件。 研究SLS的有DTM公司、EOS公司、3D Systems公司、北京隆源 公司、华科大、华北工学院和南航大学等。
A leveling roller spreads each layer of powder over the surface of
the build chamber, as the fabrication piston moves down one layer, while the powder delivery piston moves upward to supply powder to the process.
SLS系统的工艺原理和基本组成
SLS系统基本 组成： C02激光器、 光学系统、粉 料送进与回收 系统、升降机 构、工作台、 构造室等。
立体光刻固化的缺点
立体光刻固化只能使用感光性材料。 立体光刻固化有两个步骤，首先模型在真正的立体光刻固化设 备里固化到很高的程度(>95％)；然后将做成的模型放到烘箱 里，使模型进一步交联，直至完全固化。 产品毛坯必须用溶剂清洗。 在树脂池中，模型仍然是相当柔软的产品坯。 支撑必须从产品毛坯或凝固的模型中用人工清除。 感光性丙烯酸吸收氧，而环氧基树脂具有吸湿性，模型完全凝 固后，也很容易碎掉。 几天或几周后，没有支撑的壁就会变形，如果把模型翻转或支 撑起来这种情况就会消失。最新的环氧基树脂没有这些明显的 特征。
A nitrogen atmosphere is maintained in the fabrication chamber to
prevent the possibility of a dust explosion caused by handling the powder. Unlike stereolithography, no supports are required with SLS since overhangs, and undercuts are supported by the solid powder bed. Additionally, no final curing is required, however, surface finishes are not as good as those achieved with stereolithography and since the objects are sintered. they are porous. Depending on the application, it may be necessary to infiltrate the object with another material to improve mechanical characteristics.
Selective Laser Sintering
方法介绍
天津科技大学 Tianjin University of Science & Technology
Selective Laser Sintering (SLS®, registered trademark by DTM™ of Austin, Texas, USA) is a process that was patented in 1989 by Carl Deckard, a University of Texas graduate student. Its chief advantages over Stereolithography (SLA) revolve around material properties. Many varying materials are possible and these materials can approximate the properties of thermoplastics such as polycarbonate [化]聚碳酸酯, nylon, or glass-filled nylon.
天津科技大学 Tianjin University of Science & Technology
Copper Pellets
Part
Ramp
Ceramic plPlate
模具制造过程原理
天津科技大学 Tianjin University of Science & Technology
SLA vs. SLS: A Summarized Comparison
作业：
1. 立体光刻快速原型制造技术的优缺点分析？ 2. 激光选择烧结SLS原型制造技术的原理以及系统组成？
3.
4.
5.
是否需要设计支撑，并说明其原因。教材89页 激光选择烧结SLS原型制造技术为什么要求预热，如 何控制预热温度？为什么需要氮气保护？89页 117页 激光选择烧结SLS原型制造技术中，粉末材料一般有 几种组合？ 描述采用激光选择烧结SLS原型制造技术直接制造模 具的最常用工艺过程？113-114页
天津科技大学 Tianjin University of Science & Technology
Selective Laser Sintering
The entire fabrication chamber is sealed and maintained at a
temperature just below the melting point of the plastic powder. Thus, heat from the laser need only elevate the temperature slightly to cause sintering, minimizing thermal distortion, facilitating fusion to the previous layer and greatly speeding the process
The surface of the tightly compacted powder is selectively heated
with a concentrated infrared (IR) beam from a CO2 laser. The powder is melted where the IR beam strikes under guidance of the x-y scanner causing the particles to fuse together.
逆向工程与快速成形技术 Reverse Engineering and Rapid Prototype Technology
第5章 选择性烧结快速成形技术
Selective Laser Sintering
天津科技大学 Tianjin University of Science & Technology
Material Properties: The SLA (stereolithography) process is limited to photosensitive resins which are typically brittle. The SLS® process can utilize polymer powders that, when sintered, approximate thermoplastics quite well.
Surface Finish: The surface of an SLS® part is powdery, like the base material whose particles are fused together without complete melting. The smoother surface of an SLA part typically wins over SLS® when an appearance model is desired. In general, SLA is a better process where fine, accurate detail is required. However, a varnish-like coating can be applied to SLS® parts to seal and strengthen them. Varnish n.清漆, 凡立水, 光泽面, 掩饰 v.修饰
天津科技大学 Tianjin University of Science & Technology
ቤተ መጻሕፍቲ ባይዱ
Selective Laser Sintering
Selective laser Sintering (SLS) is in principle similar to
stereolithography. In this process however, fabrication of a physical model/part is effected by selectively melting a finely powdered (50 µm) thermoplastic material.
立体光刻固化的优点
立体光刻固化，也称作三维光刻，是目前快速原型工艺 中最精确的方法。它的精度受到设备的限制。 复杂模型，或者是比成型室尺寸大的模型，可以由单个 的局部模型组合成任意复杂的完整的模型。 模型可以通过喷砂处理和抛光来进行精加工处理 未交联单体可以再利用，完全聚合的树脂可以当作普通 的废物。
天津科技大学 Tianjin University of Science & Technology
Support Structures: SLA parts typically need support structures during the build. SLS® parts, because of the supporting powder, sometimes do not need any support, but this depends upon part configuration. Marks left after removal of support structures for parts cause dimensional inaccuracies and cosmetic blemishes. Blemish n.污点, 缺点, 瑕疵 vt.弄脏, 玷污, 损害 Machining Properties: In general, SLA materials are brittle and difficult to machine. SLS® thermoplastic-like materials are easily machined.