Making the Transition from Manual to Robotic Assembly
There's nothing like watching an assembly robot at work. The tireless reliability and efficiency are a sight to behold. However, effective robotics systems don't just happen spontaneously. They take a lot of planning. The devil is in the details. Anticipating and resolving problems early on can mean avoiding headaches down the road.
In particular, when transitioning from manual assembly to robotics, it's important to discern exactly what workers are doing when they assemble a product's various parts. Human beings can often do what it takes to get a part to fit, even if it is slightly out of spec-which can ultimately lower quality and increase scrap.
A robot, on the other hand, is much more consistent and less tolerant of parts differences. As a result, engineers need to clearly define a range of part variances so the assembly system can identify acceptable parts. They may ultimately have to tighten parts specifications, or redesign the product and its constituent parts so it will be easier for a robot to assemble. This is an often underappreciated aspect to robotics-that it forces assemblers to clean up their act.
In some ways, this process is similar to that used in streamlining manual assembly. For example, reducing the number of parts in a product will cut costs and increase process reliability, regardless of the type of equipment used to assemble it. However, other guidelines are more specific to robots.
For example, unlike human assemblers, a single robot cannot hold a part in one hand and a tool in the other. Therefore, products should be designed so they can be assembled in layers from the bottom up, without having to be reoriented midway through their assembly-wasted motion that serves only to increase cycle times.
Similarly, because robots still cannot move with quite the same repeatability as dedicated, "hard" automation, it is a good idea if parts have self-aligning features, such as lips or chamfers, to help the robot insert them.
Throughout this process, operators should be consulted on the nuances of their work: how they identify good parts; what techniques they may use to facilitate assembly. Encouraging input from employees can provide the insight necessary to create an effective, total application.