添加剂制造中SLS的过程

Tue Feb 02, 2021

SLS in Additive Manufacturing is used to convert 3D CAD designs into physical parts, in a matter of hours.

What is the Selective Laser Sintering definition? SLS stands for Selective Laser Sintering, a 3D printing or Additive Manufacturing (AM) technique. SLS uses a process calledsintering, where powdered material is heated to near-melting temperatures, causing particles to bond together to form a solid.

SLS可以使用多种材料 - 最常见的是尼龙,但有时也是塑料和金属。

由于它能够生产以前“不可能”的零件(继续阅读以获取更多信息)和材料的高回收率,因此自1990年代初期其商业化以来,SLS在工业环境中一直很受欢迎。

SLS是initially developed in the 1980s by Carl Deckard and Joe Beaman under the sponsorship of the Defense Advanced Research Projects Agency (DARPA), a research and development agency of the U.S. Department of Defense.

While SLS technology is far from new, it’s still used primarily for industrial applications. The precise laser used in the SLS process enables highly accurate manufacturing, even of complex parts. For this reason, SLS is widely used forrapid prototyping以及低量定制零件的生产。

On the other hand, the use of powerful lasers and powdered material made it impractical for most small scale or home use, particularly as SLS printers are substantially more expensive than other popular technologies such as融合沉积建模(FDM) 3D printers.

More recently, developments in powder bed fusion technologies have revived interest in SLS, which now falls behind FDM and Stereolithography (SLA) in popularity.

选择性激光烧结(SLS):预处理SLS模型

EveryAdditive Manufacturing(AM) technique has its limitations, and SLS (Selective Laser Sintering) is no exception. In particular, SLS is not suitable for printing sharp edges or thin walls, and designs that incorporate these features will need to be altered during pre-processing. For example:

  • 零件thin wallscan be analyzed using a design product that includes athin walls analysisfeature. This feature simulates the printing process, helping the designer ascertain whether their design is likely to print successfully. If it isn’t, they can make appropriate changes before printing.
  • 适用于零件锋利的边缘, designers can use their CAD software’sfilletingfeature to round those edges off in preparation for a successful print.

要记住的其他点:

  • 如果一个项目结合了过于复杂的几何形状,设计师可以使用geometry simplification tools在他们为SLS的数据准备过程中,以确保他们的设计已准备好打印。
  • 同样,为了节省重量,许多SLS零件都是印刷的空心,设计人员可以使用自动化工具来帮助他们“空心”设计,并包括逃生孔,以允许打印后去除未插入的材料。
  • If working with fully-functioned design software, designers should usesimulation modelingtechniques to see how their design is likely to fare during the printing process and when subjected to real-world use.

Finally, before a 3D model is ready to print, it must be ‘sliced’ into 2D layers (also known as cross sections) which the SLS printer will use to guide its laser across each layer of powdered material. While some free ‘slicers’ are available to completedata preparationfor SLS, their reliability may be questionable, and professional designers are advised to work with a recognized software package for their pre-processing needs.

如果您的组织开发了处理用于SLS打印的预处理的应用程序,或者您是SLS机器制造商,希望将软件添加到您的投资组合中,则空间可以在这里提供帮助。金宝搏的后续网站188bet金搏宝

空间利用超过35年的3D建模专业知识,提供了全面的预处理功能,可以使用我们的预制库将其包装到您的软件应188bet金搏宝金宝搏的后续网站用程序中。这是扩大应用程序或硬件产品提供的现有功能的理想方式,可以帮助您区分产品与竞争对手的产品sls 3D printing.

To find out more about how Spatial can assist, check out our industry-proven3D建模软件开发工具包to get started.

添加剂制造中SLS的过程

Image2

The Selective Laser Sintering process resembles that of other powder bed fusion technologies in the following ways:

  1. 设计师使用A生产3D模型Computer-Aided Design(CAD)程序。
  2. 设计分为薄(2D)层。
  3. The split design is sent to the SLS printer.
  4. A leveling roller spreads a thin layer of powdered material across the printer’s build platform.
  5. A CO2laser traces a cross-section on the material, heating and fusing it together.
  6. Once a layer is complete, the build platform is lowered to allow space for the next layer of powder.
  7. 每层完成后,未使用的材料将回收。
  8. 重复SLS过程,建立层层,直到零件完成为止。

During the printing process, SLS parts are encompassed by unsintered powder. This extra powder supports the part during printing, removing the need for support structures.

Selective Laser Sintering: Post-Processing

SLS的第一步后期处理is part recovery. Newly SLS printed parts are encased in a porous cocoon partly sintered powder, which must be broken open to remove the part. While this process would be messy in a home environment, SLS is mainly used in industrial settings, where specially designed cleaning chambers are used that incorporate airtight enclosures with an inlet for compressed air.

Once cleaned, SLS-printed parts are examined and tested to ensure they meet the original specifications. Since SLS parts are prone to shrinkage and warping, this process must ensure each part is fit for purpose.

最后,大多数SLS零件都被染色和/或涂层,以使其为真实世界的使用做准备。染料和涂料范围从纯化妆品到高度功能,包括:

  • Scratch-resistant
  • Reflective or non-reflective
  • Polarized
  • Durable

SLS Material Recovery

Recovering left-over material is an essential part of the SLS manufacturing process.

自从粉状材料supports SLS parts during printing, far more powder is used than is needed for the actual part. However, because all powder within the build chamber is pre-heated to aid the sintering process, ‘used’ powder is less effective than unused powder for future SLS printing. Due to this,SLS打印专家建议最多使用50%的再生粉末for any SLS printing project.

Different Types of SLS Systems

从根本上讲,有两种不同类型的SLS系统:工业和桌面。

Industrial SLS Systems

工业SLS系统已经存在了十年s, and have been used by leading players in a wide variety of industries, including aerospace, automotive, and tooling. Industrial SLS systems use one or more high-powered CO2lasers.

由于其大小和热量要求,工业SLS系统需要惰性环境来确保粉末不会氧化。结果,这些系统还需要专门的设备来管理空气摄入和去除。他们还需要工业电源。

Desktop SLS Systems

Desktop SLS systems use a similar process to industrial systems but are packaged into a machine that can easily fit into a small business or hobbyist environment. These systems use lower-powered diode or fiber lasers rather than CO2激光器,部分负责其成本降低。

由于其尺寸较小,桌面系统还需要更少的烧结过程加热,从而消除了对空气管理系统的需求,并使它们能够以标准的交流电源运行。

SLS Materials

术语SLS通常描述基于塑料的烧结,尽管它也可以用作包括塑料,金属,玻璃,陶瓷和复合材料的材料烧结的全术语。尽管烧结过程所需的温度各不相同,但该过程在所有材料中保持相似。

When SLS is applied to metals, the term direct metal laser sintering (DMLS) is typically used. The process is exactly the same as described earlier in this article, but the sintering process requires significantly more heat than plastic-based sintering.

SLS优势和缺点

Image3

像任何制造过程一样,SLS既有优势又具有缺点。

SLS advantages include:

  • Self-supporting.As SLS parts are built, hollow spaces are filled with unsintered powder. As a result, SLS prints are self-supporting and don’t require additional support structures.
  • Design freedom.Because there’s no need for support structures, designers have far more freedom to create parts that fulfill their objectives without worrying about manufacturing feasibility. As a result, many parts that were considered ‘impossible’ due to the constraints of traditional减法制造现在可以使用SLS添加剂制造制造技术。
  • Speed.自从the nylon powder used in SLS only requires very brief laser-exposure to be sintered, SLS printing is among the fastest 3D printing technologies. Unlike other techniques such as FDM, with SLS, there is practically no tradeoff between printing speed and ensuring high quality.
  • Easy to dye.SLS prints are naturally porous and absorb moisture and other liquids easily. This porous nature makes SLS parts ideal for coloring, particularly when using a hot bath process.

SLS disadvantages include:

  • 多孔而脆弱。The porous nature of SLS parts can compromise their structural integrity. While they typically have excellent tensile strength, SLS parts are inflexible and can fail under relatively low levels of deformation. For this reason, SLS prints are often used as proof-of-concept prototypes. SLS-produced parts can also have a roughsurface finish.
  • Prone to shrinkage and warping.The nylon powder used in SLS is subjected to high temperatures during sintering and subsequently cools rapidly. As a part cools, it also contracts, which can lead to inaccuracies in printed parts — most often in sharp edges and corners.
  • Waste.尽管可以重复使用SLS印刷的粉末,但大多数SLS专家建议在以后的印刷品中最多使用50%的再生粉末,如上所述。结果,SLS打印过程中始终存在浪费的元素。
  • Cost.Even a desktop SLS printer can cost between $5,000 - $40,000 — far more than comparable printers that use other AM techniques. As you would imagine, industrial-scale SLS printers become very expensive, very quickly.

何时使用SLS

The most popular use of SLS is in rapid prototyping, where its speed and self-supporting nature make it ideal. SLS makes it easy for designers to create and test a wide range of prototypes without being constrained by the need to include structural supports or use more traditional manufacturing techniques such as injection molding.

哪些行业依靠SLS?

Due to the advantages it confers, SLS has been heavily used in the aerospace, automotive, and medical industries.

在航空航天和汽车制造商使用mainly metal and composite powders to achieve high levels of durability, medical manufacturers usually prefer thermoplastic polyurethane (TPU) — a flexible and highly durable plastic with excellent mechanical properties, durability, and resistance to oils and chemicals.

SLS通常在价格不是主要考虑的情况下使用,至少在购买资本设备方面。SLS系统可能非常昂贵,这是该过程主要用于工业环境的主要原因。

However, capital expense aside, manufacturers that produce lots of low-volume parts — e.g. prototypes — can actually save on costs with SLS. SLS is widely used to produce low-volume and bespoke parts, largely because it makes it easy to produce these without the considerable expense of工具.

常见用例包括:

  • Custom tools and fixtures
  • Fuel tanks
  • Air ducts
  • 建筑模型
  • Flight rated components for unmanned aerial vehicles
  • Automotive designs
  • Artistic sculptures

SLS的下一步是什么?

Image4

Right now, SLS is primarily limited to industrial uses — primarily due to the high cost of SLS 3D printers, but also due to the use of powerful laser and powdered materials. For now, if you are a hobbyist or home creator, other techniques like FDM and SLA are more affordable options. In industrial settings, however, SLS systems can be extremely valuable.

As with all AM techniques, however, SLS relies on the manufacturer’s ability to produce highly accurate and optimized 3D models. And, given the limitations of SLS — particularly its inability to print parts with thin walls or sharp edges — certain software functions are essential for creating and optimizing those models.

为了了解空间如何帮助您在硬件和软188bet金搏宝金宝搏的后续网站件解决方案中构建强大的SLS功能和全面的预构建库,contact us today.

Subscribe to the D2D Blog

No Comments Yet

让我们知道您的想法

Baidu