In today’s manufacturing market, robotics are integral to many operational processes as business owners continue to streamline their production lines. Though in addition to the robots themselves, there exist a plethora of end effectors that can further enhance the performance of the automated element. These consist of robot grippers and robot tools, within which both electric and pneumatic variants exist.
The decision on whether to utilise an electric or pneumatic end effector can depend upon the task at hand. The utilisation of a pneumatic gripper, historically, has proven to be better suited to high volume, low variety production. Though now, taking into consideration industry 4.0 and lean manufacturing, consideration should be given to low volume, high variety production, in keeping with evolving consumer demand. With this in mind, the design and development of the pneumatic gripper is also evolving.
There are some limitations to using a pneumatic gripper, though again, this does depend upon the task at hand. Electric grippers can be better controlled, or rather the force they apply. The opening and closing (movement) of an electric gripper can be moderated, whereas a pneumatic gripper’s cannot. They can simply open or close, there is no intermediary force; lack of pressure simply results in loss of grip. But that’s not to say that they are less favourable. They simply need to be utilised differently.
One such pneumatic gripper that has seen a significant increase in uptake of late, is the vacuum gripper. Their adaptability to multiple product iterations dictates that the gripper heads do not need to be changed, promoting increased product throughput. They also tend to be a gentler alternative to a standard gripper.
Let’s consider a scenario within an automated conveyor system where a gripper is needed to pick up multi packs of crisps. An electric gripper would in this instance not be the best choice, simply because of the delicate nature of the product. An electric gripper could potentially result in damaged goods, costly product recalls and ultimately unhappy consumers. An appropriately sized vacuum gripper, taking into consideration the dimensions of the product and its weight, would successfully engage with the product without affecting quality.
There are also weight restrictions to consider when deciding if and where to implement pneumatic powered grippers. Whilst vacuum grippers are ideally suited to the handling and manipulation of several products, differently shaped products, multi-dimensional and density products, such as food items and packaging, they could not be considered for use within an automotive production environment, for obvious health and safety reasons.
The integration of automated robotics, coupled with pneumatic handling equipment, is not as complicated as it may sound. In addition to the need of an electrical supply to power the robot an air supply, by way of an air compressor, is also required, in order that the pneumatic gripper can open or close. Or in the case of a vacuum gripper, suction can be achieved. This does however pose the problem of additional piping and wiring that shall need attending to ensure that the robot cycle is not compromised.
One such robot, that has been designed specifically to operate off either an electrical or pneumatic input, is the LBR iiwa, the world’s first series produced lightweight, sensitive robot; KUKA’s seven axis, truly collaborative robot. The energy supply system for the external components is hidden within the kinematic structure at axis seven. The LBR iiwa is available with two different types of media flange; both pneumatic and electrical energy supply. Both media flanges have a hole pattern conforming to DIN ISO 9409-1-50-7-M6. The media flange IO pneumatic is a universal interface that enables the user to connect electrical and pneumatic components to the robot flange and thereafter, utilise either electrical or pneumatic powered end effectors or tooling.
Whilst we need to consider the application into which the LBR iiwa is implemented, taking into consideration its maximum payload of 14kgs, its collaborative nature means it can be both equipped with a vacuum gripper and work alongside humans safely, making it the perfect work assistant within applications such materials handling and picking and packing, in a number of industries. Thanks to its joint torque sensors, the LBR iiwa can detect contact immediately and reduces its level of force and speed instantly.
There exist a range of tailor made, flexible vacuum griper solutions adapted specifically for collaborative robots. Coupled with the LBR iiwa, you’ve a decentralised automated solution that is perfect for utilisation within the fourth industrial revolution, or i4.0, aligned with the smart factory concept; the factory of the future.