The basic component is a rotary gripper unit that is combined with, for example, a 3D handling system. The point of departure for finding the right solution involves the dimensions of the sample vial and the required torque. Whether or not different vials will need to be handled is also decisive.
The sample vials themselves dictate the technical requirements. What needs to be determined is how much torque is required to open and close them. The amount of required torque should always be tested in advance with the vials which will be used later on – under conditions which are as realistic as possible. If the sample vials are filled manually, the thread may be contaminated with, for example, glucose or salt-containing media. After the vial has been closed, the liquid dries out and become sticky or crystallises. Considerably higher forces are required for opening in this case. If testing is conducted exclusively with brand-new vials, there is a risk that the technical requirements are not made strict enough.
The force at the gripper can be reduced significantly if a positive-locking connection is used. On the other hand, friction-locked gripping requires much higher forces.
Torques of up to 5 Nm and gripping forces (depending on design) of up to 200 N can be implemented with standard solutions from Festo. Other torques are available on request.
The vial has to be held in place while the cap is being screwed on or off in order to counteract the closing or opening torque. A clamping unit or a second gripper, for example, can be used here, since the stroke can be adapted to the different vial sizes. Depending on the vials, simple positive locking with passive clamping may also be sufficient.
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.