Machine Tool Tending

Automating Loading And Unloading: Using Robots To Tend Machines

Time spent on unloading and loading is lost production time. Robotic machine tool tending minimizes this waste by quickly swapping out one part for the next. Whether tending a lathe, mill, press or molding machine — adding a robot boosts utilization and lowers costs. Today, most manufacturing operations are automated, but in many businesses machines still wait for an operator to unload one part and load the next. Over an eight hour shift fatigue sets in and output suffers, but a robot does the job exactly the same way every cycle. If you're not using robots to load and unload production machines, you're losing capacity and missing an opportunity to cut costs. You're also exposing employees to work requiring repetitive lifting motions, with the potential to cause injury.

Machine tending is an ideal task for modern robots. With high speed, accuracy and repeatability — supplemented as needed by vision systems — they can pick the next part from an input chute or conveyor and be ready for the operation to finish. At the end of the cycle the machine controller opens the access door and signals the robot to enter. A double-handed gripper retrieves the finished piece from the chuck or fixture, inserts the next piece and quickly withdraws. The machine then closes the door and resumes processing. While the chips are flying, the plastic flowing or the press stamping — the robot can then perform secondary operations. Trimming, deburring and gauging are common tasks done while the machine is in-cycle and before placing the part on a pallet or output conveyor. Some cells are even designed so one robot hands the part off to a second.

Brief stoppages are inevitable with manual loading and unloading. Operators are interrupted, have other duties and need the occasional break — all of which can result in machines standing idle. Robotic tending allows machines and cells to run through breaks and shift changes, and can even enable “lights-out” manufacturing. As a result, capacity increases, allowing the business to take on more work. The direct savings from automating machine tending can be considerable, yet are often dwarfed by the overhead dilution and increased margins from doing more with the existing machines. What's more, as the robot can be mounted above or directly on the machine there's no need to put it where the operator would stand, so loading and unloading can still be done manually, if necessary.

Machine tending robots are suitable for a wide variety of manufacturing operations. Anywhere discrete parts need to be removed from or loaded into a machine is a potential application. Machining, molding and stamping processes are only some of the places where using a robot can increase capacity, cut costs and improve safety.

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DISPELLING ROBOTIC MYTHS

Myth:
Robots are hard to program.
Truth:
Robots are easy to program and a good integrator will provide adequate training and ongoing support.