Robots are becoming more prevalent on the floor of many plastics shops, particularly injection molding facilities, and they come in all shapes and sizes.
Robots also can be in other processes to reduce costs. They often are used in part removal, assembly and packaging.
Robots come with a range of strokes and payload options for automation on both vertical and horizontal injection molding presses, from 15 tons to more than 6,000 tons. Small robots are manufactured to do myriad tasks throughout the molding process. Conversely, one of the largest robots was designed to outfit a 6,750-ton injection molding press.
A typical robot can have a horizontal stroke range up to 10,000 mm, while vertical strokes range from about 1,000 mm to 3,000 mm. Typical payloads range up to nearly 300 pounds.
One automation option is a cartesian or linear robot, often referred to as a beam robot. These machines have been at work on shop floors for years, particularly in injection molding facilities. These robots have been used in injection molding shops to load and unload machines.
Options can include a three-axis Cartesian beam for flexibility, with a two-axis CNC wrist for precision. The smallest beam robots can operate with a three-axis all-serve sprue picker.
Large full-servo traverse robots can automate extraction of large, heavy molded parts used in the appliance, automotive and industrial construction end markets. Options are available for molding machines from 1,500 tons and larger.
Three-axis robots, or top entry robots, are the workhorses of plastic injection molding automation, used on horizontal plastic injection molding machines (top entry automation applications) and applications requiring higher speed, such as part picking, in-mold decorating, in-mold labeling, insert loading, inspection, stacking and palletizing.
Six-axis robots are gaining traction. These labor-saving machines are increasing in popularity in the United States. These robots are used for flexible automation on both horizontal and vertical plastic injection molding machines increasing flexibility for upstream and downstream operations and allowing utilization of a larger working envelope.
Gains in productivity, quality, product lifecycle flexibility, and labor savings are driving the interest in automation among large and small companies alike. Meanwhile, trends in multi-shot molding, in-mold labeling and decorating, and composite part fabrication are boosting the demand for advanced manufacturing methods.
Smaller robots are becoming more common press side. The trend toward “flexible feeders” continues. Instead of using a vibratory feeder bowl and escapement track to line up metal inserts, to present to an injection molding machine mounted robot to insert load inserts into the molding machine, now users are considering to go with a press side robot fitted with a camera that can look at inserts moving on a conveyor, to pick them up, and then place them in the mold of the injection molding machine. This flexible automation approach allows future application change overs or even to produce shorter run jobs with a flexible feeder and still get the ROI.
Collaborative robots are designed to operate safely side-by-side with human operators without the need for protective guarding. These robots are typically smaller, to ensure the safety of employees working nearby.
SCARA (selective compliant assembly robot arm) 4-axis robots have a circular work envelope with a broad range of movement for added flexibility. They range in size from 180 mm to 1,200 mm. SCARA robots are typically employed in plastic injection molding automation applications for loading and unloading vertical injection molding machines.
Smaller side entry robots are single-axis machines focused on a specific application. These options are perfect for extreme high applications.
Simple servo sprue pickers are pick-and-place robotic devices used for sprue removal or part and runner separation on the floor of injection molding facilities. These machines frequently range in size to fit 15- to 300-ton plastic injection molding machines. They are offered with a range of vertical strokes from 450 mm to 800 mm as popular options for injection molding machines form 25 tons to 350 tons.