异形水路

相思故人

Conformal Cooling

Introduction

Injection molding is a process by which plastic pellets are melted and then forced into a mold, where the material forms its final shape. Once the cavity is filled, coolant disperses through cooling lanes within the mold in order to bring parts down to an appropriate dispensing temperature. According to Khan et al. (2014), part cooling is an important part of the process to produce quality parts but consumes 50% to 80% of the cycle time per build. Conventional cooling paths are machined in straight lines. A coolant flows through the channels at a given temperature and pressure, optimizing cycle time and part quality. This method produces flawed results because straight paths cannot provide consistent cooling throughout the mold cavity. Cooling rates for a given mold segment depends, in part, on its proximity to cooling channels. Non-uniform cooling across parts leads to longer cycle times, uneven cooling, warpage, and scrap.

What is Conformal Cooling?

Conformal cooling is a promising alternative with growing acceptance. Cooling channels follow with the part’s contours to facilitate faster and more uniform cooling. Until recently this simple concept has been difficult to execute. Some of the geometries required in conformal cooling are impossible with traditional machining. The emergence of additive manufacturing (AM) has increased the availability of conformal cooling to mold designers. Using direct metal laser sintering (DMLS) or other additive manufacturing techniques, complex cooling channels can be optimized during the mold design phase rather than post-processed at suboptimal locations

Design for

Conformal Cooling According to Park and Pham (2009), there are three different techniques to be employed when designing conformal cooling channels: zigzag, parallel, and spiral; see Figure 1. Depending on the geometry of a part, these methods may be used in combination or on their own. The zigzag pattern, also known as a series cooling path, has part regions cooled one after the other rather than at the same time. Cooling in series is generally not preferred unless parts are small enough that the delay is negligible. The parallel channel design allows for different areas of the mold to be cooled at the same time. Park and Pham (2009) acknowledged that the main drawback for the parallel cooling method is that it requires a lot of coolant. The spiral conformal cooling channel design is often used with parts that have curvature or spherical elements. When designing conformal cooling channels, Park and Pham (2009) recommend using an injection molding software package in order to identify temperature zones Figure 1 – There are three main coolant flow strategies for conformal cooling channels, zigzag (series), parallel, and spiral (Park and Pham, 2009). 3 | P a g e within a mold so that the conformal cooling channels can be separated and optimized within each region instead of across the whole part. The EOS whitepaper by Mayer (2005) is often cited when describing the design guidelines for conformal cooling channel diameter and location. The author, however, notes that the recommendations are no different than they were for conventional cooling practices. Because conformal cooling opens up design capabilities, those channel guidelines become more relevant. As shown in Figure 2, the hole diameter (b), centerline distance between holes (a) and distance from the centerline to the cavity (c) are proportional to each other and related to the mold wall thickness. Conformal cooling channels manufactured through DMLS or other AM technology have some design limitations. For example, the smaller and longer the channels are, the more difficult it is to remove the support powder material after the print job has completed. According to Xu et al. (2001), there are four factors at play which define the feasibility region for length and diameter of the cooling channels: coolant pressure and temperature variations, ability to remove support material, and the actual part geometry. In general, Mayer (2005) recommends that the channel diameter should range between 4 and 12 mm, but that may have to change based on the other parameters described above. Another limitation to using DMLS is the size restriction. Print beds for laser sintering machines typically run between 250x250x325 mm for the EOSINT M 280 and 500x500x500 mm for the 3DSystems ProX 400. Given the current cost for some powdered metals as well mold size constraint, there is still room for other conformal cooling technologies to support the industry’s needs.

Driving Forces of Conformal Cooling

Although the concept of conformal cooling has been around for at least a decade, momentum is finally starting to build. As Augustin Niavas from EOS stated in an interview with European Tool and Mould Making, the tool and die manufacturers are still learning about the technology and are waiting to see where the industry goes (“Interview,” 2014). Unless these manufacturers already own 3D printers it is a significant investment to enter into manufacturing molds with conformal cooling channels. Companies that either manufacture or provide 3D printing services are currently the main drivers for conformal cooling. They recognize the potential gains for the tooling industry and see their printers as the means for obtaining those savings. Figure 2 – Channel size (b), distance to the next channel (a), and distance to the wall cavity (c) are all related to the part wall thickness and proportional to each other (Mayer, 2005). 4 | P a g e Fraunhofer, in Germany, is one of the research organizations also investigating the potential of conformal cooling. According to a press release from November 2014, the organization was the first to bring conformal cooling to the EuroMold trade fair in 2014 (“Cost-effective”, 2014). Additionally, under Horizon 2020 by the European Union, which funds research projects throughout the region, a project called Intelligent and Customized Tooling (IC2) investigated new and more efficient tooling methods. The project contained finds about the benefits of conformal cooling but was not exclusively about that technology (“Community,” 2014).

翻译：

介绍

注射成型是将塑料球熔化并强制进入模具的过程。材料形成最终形状。一旦填充空腔，冷却剂就会通过冷却通道分散。为了使零件降低到合适的点胶温度而进行的模具。据可汗et

Al。（2014）零件冷却是生产高质量零件的重要工序，但消耗50%。每个构建周期的80%。常规冷却路径是直线加工的。冷却剂在给定的温度和压力下流过通道，优化循环时间和零件质量。这种方法产生错误的结果，因为直道不能提供一致的冷却。

整个模具腔。给定模具段的冷却速度在一定程度上取决于它的接近程度。

冷却通道。零件间的不均匀冷却导致循环时间延长，冷却不均匀，翘曲和废料。

什么是保形冷却？

适形冷却是一种很有前途的替代方案。冷却通道跟随零件的外形便于更快更均匀的冷却。直到最近，这个简单的概念才被提出。难以执行。在共形冷却中所需的一些几何形状是不可能的。传统的加工。添加剂制造（AM）的出现增加了模具设计的共形冷却。采用直接金属激光烧结（DMLS）或其他添加剂制造技术，复杂的冷却通道可以在模具设计阶段优化。

而不是后处理在次优的位置。

保形冷却设计

据公园和范（2009），有三种不同的方法被采用时设计共形冷却通道：锯齿形、平行式和螺旋形；见图1。根据零件的几何形状，这些方法可以组合使用或单独使用。锯齿形图案，也被称为一系列冷却路径，有部分地区冷却后，而不是在同一个时间。除非零件足够小以致延迟，否则一般不喜欢串联冷却。可以忽略不计的.平行通道设计允许模具的不同区域在相同的温度下冷却。时间。公园和范（2009）承认，对于并联冷却方法的主要缺点是

它需要大量的冷却剂。螺旋形共形冷却通道的设计经常用到零件。有曲率或球形元素。当设计形冷却通道、公园和Pham（2009）推荐使用注塑软件包，以确定温度区。

图1

图1 -共有三种主要的冷却剂流动策略冷却通道，曲折（系列），平行和螺旋。在模具内，使共形冷却通道可以在每个内部分离和优化。区域而不是整个部分。EOS白皮书由Mayer（2005）经常被描述的设计规范形冷却通道直径和位置。然而，提交人注意到这些建议没有。与传统冷却方式不同。因为共形冷却打开了设计。

能力，这些渠道准则变得更加相关。

如图2所示，孔直径（b）孔（a）与中心线到空腔（c）之间的中心距离成正比，与模壁厚度有关。随形冷却水道的制造方法是通过或其他技术有一定的设计局限性

图2

例如，通道越小，时间越长，就越难移除。打印作业完成后支持粉末材料。据徐等人。（2001）有四个确定冷却通道长度和直径的可行性区域的因素：冷却液压力和温度变化，去除支撑材料的能力，和实际的部分几何。一般来说，Mayer（2005）建议通道直径在4之间和12毫米，但这可能要改变的基础上描述的其他参数。

另一个限制使用DMLS是大小限制。一般用于激光烧结机的打印床在250x250x325毫米EOSINT M 280和500x500x500毫米的3dsystems PROX400。考虑到一些粉末金属的当前成本以及模具尺寸限制，仍然有空间。对于其他保形冷却技术，以支持该行业的需要。共形冷却的驱动力。

虽然共形冷却的概念已经存在了至少十年，但势头终于到来了。开始建造。从EOS在欧洲模具采访Augustin Niavas说制造，工具和模具制造商仍在学习技术，并等待看到。

行业走向何方（“面试”，2014）。除非这些制造商已经拥有3D打印机，否则利用共形冷却通道进入制造模具的重大投资。公司制造或提供3D打印服务是目前共形性的主要驱动因素冷却。他们认识到工具行业的潜在收益，并将他们的打印机视为手段。

为了得到那些积蓄。

图2 -通道大小（B），到下一个通道（a）的距离，以及与

壁腔（c）都与零件壁厚有关，并与每个壁面成正比。其他，在德国，夫琅和费是研究潜力的研究机构之一。随形冷却。根据2014年11月的一份新闻稿，该组织是第一个带形冷却到欧洲模展交会2014（“成本效益”，2014）。此外，下欧洲联盟的地平线2020，为整个地区的研究项目提供资金，一个项目所谓的智能化、可定制的工具（IC2）研究新的更有效的方法。这个项目包含了关于共形冷却的好处，但不完全是关于这个问题的。

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carlosliu

翻译这么多，辛苦了。