Used for lean industrial processes, assembly robots have increased production capabilities in the world of manufacturing. They have dramatically increased consistency as well as the speed of production. In addition, assembly robots save human workers from dull, hazardous and tedious assembly line jobs. With advances in technology, assembly robots can now complete complex assembly processes which they were previously incapable of.
To cater to the world of manufacturing, end of arm tooling can be customized for each assembly line robot. They can also be integrated with additional options such as robotic vision to help improve the accuracy and efficiency of sorting identifiers or part orientation. Also, engineers are adapting their processes, products, and parts to the unique requirements of assembly robots.
How to make things easier for assembly robots
While there are a good number of the design guidelines used for improving mechanized and manual assembly processes also apply to assembly robots others are just specific to robots. For instance, robots can’t hold a tool in one hand and a part in the other. Most of them are one-handed and can only move along three to four axes. For this reason, products should be designed in such a way that they are assembled in layers from the bottom going up.
Products that are not designed for robot assembly require more work because they have to be accessed from multiple sides. When an assembly is reoriented, it only adds cycle time without necessarily adding value. Furthermore, it also increases fixture costs. For the same reasons, manufacturers should design parts that stay in place even after they’ve been installed by the robots. To better the situation, the parts can be designed with snap fits to eliminate the need for bonding, fastening, and welding later on. Since robots cannot move in the way as ‘hard automation, manufacturers should create parts with self-aligning features such as chamfers or lips to help the robot insert them.
What to consider when designing an assembly
When it comes to automation, parts should just fall into place because forcing them to fit means that there is a problem. Therefore, one of the first things to consider when designing an assembly is if your components want to go together. Another thing to consider is how well the parts are made. Because robots are flexible, they can quickly adapt to assembling different products. However, this does not mean that they can compensate for parts that are inconsistent.
How the parts are going to be presented and fed to the robot is also something to consider. For instance, parts that are meant to be supplied from vibratory feeders should be designed in such a way that they don’t overlap or tangle. The robot should be able to pick up a part once it’s in the output track and insert it without having to manipulate the process further.
Designing the assembly line process
It is always best to limit the number of operations each assembler performs on manual assembly lines. This also applies where robotic work cells are used. In theory, only one robot could be used to assemble a small product from start to finish. Practically, this is nearly impossible. This is because, as the number of tasks to be performed by the robot increases so does the cost of the cell and the machine’s reliability decreases. Therefore, it is better to group tasks together in a way that is sensible to the assembly process as well as the robot.
For instance, if one set of parts can be handled by a gripper and another set of parts by a vacuum cup, then it makes more sense to use two different robots for each set of parts instead of a single robot with a tool changer and two grippers. The time that the robot will spend changing grippers would have been used to assemble more products.