在电子产品制造应用中,印刷电路板装配在很大程度上是以自动化方式完成的。各种不同设计的机器人负责执行SMD放置、焊接、自动化光学检测(AOI)等步骤。但到目前为止,电容器、电源线圈、连接器等有线组件的通孔安装一直是例外。此步骤目前仍然主要是通过手动装配完成的,原因在于这是一个复杂的过程,无法轻松实现自动化。
这正是位于德国萨尔茨基特市(Salzgitter)
解决此挑战是开发解决方案的主要动机。Glaub的团队充满热情地投入工作,该解决方案现已投入使用,其完全不同于常规解决方案。装配过程是由来自ABB的双臂协作YuMi机器人完成的,凭借两个机械臂,该机器人组装电路板的速度是传统机器人的两倍。
超紧凑型“GL-THTeasy”机器人作业单元的自动化过程如下所述:通过输送带向机器人提供装有电容器的泡罩包装。泡罩包装上的DataMatrix码可帮助识别物品。然后,YuMi从泡罩包装中一个接一个地抓取电容器,并将其精确地放置在印刷电路板上。或者,它也可以从ESD容器中或者振动输送带上取出或取下电子组件。随后立即从下方进行焊接。该装置将通过再循环系统将空的泡罩包装移除,然后将装有电容器的泡罩包装自动送入。
有针对性的装运箱拾取
到目前为止,这一切听起来都很合乎逻辑,我们可能会奇怪,为什么此装配过程之前没有实现自动化。答案在于:机器人无法应对组件进给的高度可变性和组件定位的细微误差。这意味着之前的一些机器人解决方案在编程方面非常复杂和繁琐,而且在实践中并不特别可靠。
但是,Glaub的新型机器人作业单元首次使用智能相机,拥有来自康耐视的先进图像处理技术。康耐视是工业图像处理领域的市场领导者之一。通过使用3D表面传感器来检测泡罩包装中组件的位置,该传感器还允许从装运箱中或振动输送带上进行有针对性的拾取,以便随后使用2D相机进一步测量电容器和印刷电路板。
>机器人技术与图像处理的智能结合
因此,图像处理对于该概念取得成功起着至关重要的作用。Glaub的工程师与位于德国温德堡(Wendeburg)的M-VIS Solutions GmbH合作,选择了适合该应用的智能相机。康耐视的解决方案合作伙伴M-VIS公司开发了一种使用多台智能相机的解决方案,这些相机用于采集泡罩包装上的DataMatrix码,并精确地测量和定位每个单独的组件。
M-VIS Solutions首席执行官Vitali Burghardt解释道:“通过对组件和印刷电路板进行100%的绝对测量,GL-THTeasy可以弥补组件、抓取、工件托架和输送带方面的所有误差。” 这意味着不完全匹配的组件将会被立即移除。
每个作业单元配备8台相机,包括2台3D相机
作为可行性研究的一部分,M-VIS(由康耐视提供支持)选择了8台相机,每个机械臂配备4台。1套In-Sight 7802M视觉系统用于测量元件,并提供必要的信息,以纠正夹持器的位置。另一套In-Sight 9912M系列视觉系统用于测量电路板,并在必要时纠正夹持器的动作,以将组件准确地放置在电路板上。3D-A5060是一款3D表面扫描相机,其配备康耐视正在申请专利的3D LightBurst技术,并内置VisionPro图像处理软件,可以清楚地“看到”元件在进料线上的位置。
此外,这种方法还有一个优势:由于运动是基于相机控制的,因此操作员无需编程即可生成新的放置模型。所产生的相机图像将作为该操作的基础。这不仅简化和加快了装配,同时也简化和加快了生产线转换。因此,GL-THTeasy机器人作业单元提供了灵活自动化的关键示例,可为满足当前和未来需求提供智能解决方案。
缩短周期时间并加快成本摊销
ABB YuMi机器人的两个机械臂可全天候同时工作,从而能够以非常短的周期时间高速进行24/7操作,根据需要安装的组件和给料类型,该时间可能不到3秒。成本摊销周期也令人印象深刻,距离GL-THTeasy机器人首次投入使用仅约14个月。因此,新的机器人作业单元在多个方面的得分都很高,这有力地支持了其应用,包括创新、可靠性、效率和未来可行性。毫无疑问,继Glaub和M-VIS之后,这种智能解决方案将在未来吸引许多其他电子制造公司以这种灵活、高效的方法来实现印刷电路板装配工艺步骤自动化。
一位客户曾明确地询问我们是否能够找到一种解决方案来使此步骤实现自动化
Glaub Automation & Engineering GmbH
This challenge was the major incentive to developing a solution. Glaub's team enthusiastically set to work and the solution is now already being used — and it is highly unconventional. The assembly is done by a dual-arm collaborative YuMi robot from ABB, which — thanks to its two arms — can assemble the circuit boards twice as fast as a conventional robot.
The automated process in the ultra-compact “GL-THTeasy” robot cell takes place as follows: The robot is provided with blister packs with capacitors, for example, via a conveyor line. A data matrix code on the blister pack allows the item to be identified. YuMi then grips one capacitor after another from the blister pack and places it precisely on the printed circuit board. Alternatively, it can also remove the electronic components from an ESD container, for example, or a vibratory conveyor. This is immediately followed by soldering from below. Empty blister packs are removed by the installation via a recirculation system and full ones are then automatically fed in.
Targeted bin picking
This all sounds quite logical so far, and we may wonder why this assembly process was not automated before now. The answer: robotics was unable to cope with either the high variability in the component feeding or the slight inaccuracies in positioning the components. This meant that the few previous robotic solutions were extremely complex, elaborate in terms of programming, and not particularly reliable in practice.
However, Glaub's new robot cell uses smart cameras for the first time, boasting state-of-the-art image processing technology from Cognex, the market leader in industrial image processing. The position of the components in the blister packs is detected using 3D surface sensors — which also allow targeted picking from the bin or the vibratory conveyor, in order to then further measure the capacitors and printed circuit boards with the help of 2D cameras.
A smart combination of robotics and image processing
Image processing thus plays a crucial role in the success of this concept. Glaub’s engineers worked together with Wendeburg-based M-VIS Solutions GmbH to choose the cameras suitable for this application. Cognex’s solutions partner M-VIS developed a solution with several cameras that both capture the data matrix codes on the blister packs and precisely measure and locate each individual component.
Vitali Burghardt, CEO of M-VIS Solutions, explains: “With the 100% absolute measurement of components and printed circuit boards, GL-THTeasy compensates for every inaccuracy in terms of components, gripping, workpiece carriers and conveyor belts.” This means that components that do not fit exactly are immediately eliminated.
Eight cameras per cell, including two 3D cameras
As part of a feasibility study, M-VIS — supported by Cognex — chose eight cameras, four for each robot arm. An In-Sight 7802M vision system measures the parts and provides the necessary information to correct the position of the gripper. A further system from the In-Sight 9912M series measures the circuit board and if necessary corrects the gripper's movement when it is placing the component on the board. The 3D surface-scan camera 3D-A5060 with patent-pending 3D LightBurst technology and integrated VisionPro image processing software “sees” the position of parts in the feed line.
Niko Glaub explains this step in more detail: “In each process step, the cameras capture the actual position of the component, the gripper and the circuit board in relation to the electronic component. In other words, the ‘legroom’ of the components is aligned with the actual dimensions of the assembly positions. First of all, this allows the component to be automatically found and removed, and then enables totally accurate through-hole mounting on the basis of actual position data.”
This approach offers a further advantage: since the movements are controlled based on cameras, the operators can generate a new placement model without programming. The camera images produced serve as a basis for this. This simplifies and accelerates not only assembly but also conversion. The GL-THTeasy robot cell is thus a prime example of flexible automation offering a smart solution for both current and future requirements.
Short cycle time, rapid amortization
ABB YuMi's two arms work simultaneously round the clock, allowing 24/7 operation at high speed with a very short cycle time, which can be under three seconds depending on the components to be installed and the feed. The amortization period is also impressive, coming to around fourteen months from GL-THTeasy's first use. The new robot cell therefore scores points on several counts, which support its use: innovation, reliability, efficiency and future viability. With Glaub and M-VIS, there is no doubt that this smart solution will persuade many other electronic manufacturing companies in the future to automate the process step for printed circuit board assembly with this flexible and efficient method