Why Collaborative Robots Are the New Solution for Injection Molders


The ability of collaborative robots to work alongside humans, freeing them from repetitive tasks, makes it a new and ideal option for different manufacturing plants, including injection molding plants.

More than thirty years ago, servo-controlled robots, regardless of their kinematic configuration, were rarely used in injection molding applications. A common approach was the deployment of simple point to point robots mounted on a machine. These robots had enough vertical strokes to reach the platen centerline to extract parts from molds. They would then deliver these parts to conveyors or totes.

Why Collaborative Robots Are the New Solution for Injection Molders

More than ten years later, the use of servo-controlled robots became common in injection molding plants. These provided greater control and precision of the end-of-arm tools.

Fifteen years ago, injection molders started to employ the use of four-axis robots. This technological advancement was due to several business and technical needs.

Impact of automated injection molding with four-axis robots

Post mold processes

Clients expected injection molders to deliver complete assemblies and parts. Molders were able to meet client expectations by automating processes such as trimming, degating, decorating, trimming, wrapping, assembly, as well as packaging.

Improved surface finishes

Because of the high standards set by clients for surface finishing, injection molding plants required to ensure that parts are handled with care throughout the molding process to the finished product. The best way to do this is by use of four-axis injection molding robots.

Short production cycles

Four-axis robots could be programmed to adapt to the ever-changing product updates and models. This was easier to do as opposed to constantly training human workers to deliver the same.

Low volume/ high mix demands

Small lot sizes, on-demand production for inventory reduction, and product customization all drove short runs, which made setup more demanding. This made injection molding a service best left to four-axis robots.

Over the last decade, plastic processing plants have adopted a new automation level, which involves the use of collaborative injection molding robots. These robots come with an advantage over the four-axis robots because they include a safety feature. They are easy to program, highly mobile, and have motion sensors that make it possible for them to work alongside humans.

Here are the factors that make collaborative robots the best automation technology for injection molding companies.

Can execute pre and post mold processes with maximum flexibility – collaborative robots can place inserts into molds and move parts through to post-molding processes. This calls for complex motions as well as demanding positioning and angling. Collaborative robots have the flexibility to offer both.

Reduces the cost of tools – the four-axis robots require sophisticated tools to compensate for the kinematic limitations. Collaborative robots have flexibility and range of motion that eliminate the gripper and tooling complexity and costs.

Simple part extraction – without ejectors, it can be challenging to remove complex parts. However, collaborative robots have a dexterity that allows them to pull these parts gently from the mold.

Low maintenance needs – collaborative robots come sealed to reduce maintenance needs and increase uptime. This is an advancement from the Cartesian robots that required regular maintenance.  

Efficient utilization of floor space – in any injection molding plant, floor space is an expensive factor. With more pre and post-molding processes, the demand for floor space around a machine is at an all-time high. With the flexibility of the collaborative robot, it creates free space for secondary operations.

Easier access to machines – mounting a collaborative robot on a molding machine allows easy access when molds need to be changed, which requires access by the maintenance department.

Reduced overhead clearance – one drawback with the Cartesian robots was that the vertical axis extended above the centerline. This means that the ceiling height was required to be at least as high as the vertical axis extension. Collaborative robots can be mounted over injection machines, even in low ceiling conditions.    

With the low cost and high return on investment, collaborative injection molding robots are the future of injection molding.