基本元件是一个旋转抓取单元，它与三维搬运系统等部件相连。为了找到合适的解决方案，首先要确定样本容器的尺寸和所需的扭矩。此外，还必须考虑是否需要处理不同的容器。
所需的扭矩
样本容器本身的特点决定了相应的技术要求。我们必须明确打开和关闭它需要多大的扭矩。务必事先用将来要用的容器测试所需的扭矩，而且是在尽可能真实的条件下。在手动灌充样本容器时，螺纹可能会被含有葡萄糖或盐的介质污染。封闭后，液体变干，就会发生粘连或产生结晶。那么在打开容器时就需要更高的过程力。如果只用全新的容器进行测试，有可能会将技术要求定得太低。
如果采用了形锁合连接，可以大幅降低抓手上的力。而力锁合抓取则需要更大的力。
通过 Festo 的标准解决方案，可以实现高达 5 Nm 的扭矩和高达 200 N 的抓取力（取决于组件）。我们也可按要求提供其他规格。
容器的尺寸
根据容器的高度和直径可得出所需的冲程。
对于不同尺寸的容器，除了较长的 Z 运送行程外，也应采用较大的抓取行程，这样才能仅用一个系统满足尽可能多的要求。
整体解决方案的复杂性由此大大降低。
不同的螺纹距
在一个应用中运送不同的样本容器时，不仅尺寸经常有很大区别，盖子的螺纹节距也不尽相同。
在打开和关闭时，旋转和提升运动要同时同步，这在软件方面可能很难实现。因此，Festo 为 EHMD 旋转抓取模块开发了一个带 Z 补偿的安装适配器。该适配器可在开合过程中自动补偿盖子的螺纹距，最大可达 10 mm。借助这种带被动滑块的简单机械解决方案，Z 轴在旋转过程中就不需要受控移动。也不需要对同步进行编程，使得流程大大简化。
固定容器
在打开和关闭盖子时，必须额外固定容器，以抵消打开或关闭扭矩。对于这项任务，一般可以使用夹持单元或另一个抓手，这个抓手可通过不同的冲程来适应不同的容器尺寸。根据容器自身情况而定，通过被动夹紧装置实现简单的形锁合可能也足以固定容器。
Reliable closing
When the cap is closed, two threads have to be aligned. It’s possible that the cap will be placed onto the vial askew. This misalignment can result in the predefined closing torque being reached during tightening although the cap has not been correctly closed. In order to rule out this risk without expensive sensor technology, Festo has integrated a “thread engagement step” into the process. After the cap has been placed on the vial, it’s initially turned 360° anticlockwise using only slight pressure in order to align the threads on the cap and the vial. The cap is then tightened while monitoring the angle of rotation. The torque is then tested indirectly using a motor current measurement within a specified window. If no error messages are generated during this process, the vial has most probably been reliably closed.
Decapping solutions from Festo
The great number of different sample vials alone results in a wide range of technical requirements for automated opening and closing. Festo offers a large portfolio of solutions as part of its compact handling systems, from complete rotary gripper modules to solutions consisting of individual standard components to customer-specific further and new developments.
Rotary gripper module EHMD
The EHMD is the most compact rotary gripper module in its class and is especially well-suited for opening and closing small sample vials like the ones used in HPLC applications. The maximum torque value of 0.3 Nm is enough for opening vials with capacities of up to 15 ml. An optional module compensates for the cap thread pitch during rotary motion, making adaptation to a great variety of cap types and thread pitches really easy. The rotary gripper module is available in two versions: fully electric or with pneumatic gripper. Both allow for infinite rotation.
Hybrid rotary linear module DSL-16- ... -SA
The DSL-16- ... -SA is ideally suited for applications that require high torque values and gripping forces. Vials with round neck and sealing cap or cover can be gently and reliably opened with this thin, compact module with an adjustable torque of up to 1.7 Nm. The combination consisting of pneumatic stroke and gripping motion with precisely adjustable and easy-to-monitor electric rotary motion makes sample handling reliable and reproducible .
Combination of EHPS and ERMO
By combining electric standard gripper EHPS and electric rotary actuator ERMO many different requirements can be fulfilled. With the EHPS, there are three types you can choose from, with different stroke lengths for small to medium-sized vials. The ERMO is available in four sizes with maximum torques from 0.15 to 5 Nm. The rotary actuator consists of a mechanical system with permanently mounted motor and drive system (motor controller), integrated web browser technology and matching connecting cables.
Customer-specific developments
By using standardised components from Festo, a wide variety of requirements can be covered cost-effectively, with high quality and for extremely small spaces. Festo can modify existing products or develop entirely new solutions to meet very specific requests or challenges. The sooner we get involved in the planning process, the greater the advantages are for the customer. For example, Festo USA developed an extremely compact solution for sample handling that was perfectly integrated into the customer’s system, using Festo standard components and a modified rotary gripper module. This approach resulted in minimal complexity with maximum productivity and process reliability.