By Joe Campbell, senior manager of applications development, Universal Robots
Thirty years ago, full servo-controlled robots of any kinematic configuration were rarely deployed in injection molding applications. The most common approach was to deploy a simple three-axis, point-to-point Cartesian robot that was machine mounted. With enough Z (vertical) stroke to reach the centerline of the platen, these very simple robots quickly extracted parts from the mold and delivered them to totes or conveyors.
Twenty years ago, full servo-controlled Cartesian robots became common, providing greater precision and control of the end-of-arm tools. Fifteen years ago, molders began applying six-axis robots in increasing numbers.
Watch cobots from Universal Robots tend injection molding machines at Dynamic Group in Minnesota, Alpha Corporation in Japan, and at Xiamen Runner in China
This evolution was driven by several technical and business drivers that continue today:
Post-mold processes. Customers are requiring molders to deliver more complete parts and assemblies, and molders are glad to increase their value. Degating, trimming, polishing, decorating, assembly, wrapping and packaging are now common tasks that are perfect candidates for automation.
Improved surface finish. Customers are setting very high standards for surface finishes, which require parts to be carefully handled from the mold to the final package or shipping container.
Shorter product life cycles. The pace of product updates and new introductions requires constant change in manufacturing processes.
High mix/low volume. Product customization, small lot sizes and on-demand production to reduce inventory are driving short runs, making setup even more demanding.