What is a cobot and why should CNC machine shops consider them? Learn about the benefits and applications of cobots for CNC machining.
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What is a Cobot?
Collaborative robots, or “cobots”, are growing in popularity in manufacturing and industrial settings, particularly in machine shops. Unlike traditional robots, cobots work safely around people and do not need to be enclosed behind a barrier or safety fencing. Due to their built in safety features, cobots work collaboratively with their human counterparts, assisting in tasks and taking on the repetitive, mundane, and dull work. In machine shops, cobots tend machines all day and night. They keep the “spindle turning” by loading and unloading parts consistently without breaks, increasing throughput and reducing machine idle time.
Cobots are vastly different from traditional industrial robots associated with large factories and assembly lines. They are smaller, less expensive, and more flexible. Cobots differ from traditional robots in the following ways:
Safety. Cobots do not require safety fencing or other barriers and can share workspaces with humans. They have built in safety features that make them slow down or stop completely if a human comes into its work area.
Flexibility. Cobot arms have the flexibility to handle various tasks. They are not limited to a single task or operation and can be redeployed as needed. Cobots can roll between different machines on a shop floor and tend two machines at once.
Ease of use. Cobots are easier to program than traditional robots. The latest generation of cobots like Productive Robotics' OB7 require no programming at all and can be “taught” tasks by physically showing them what to do.
Cobots vary in size and specifications for handling a wide range of parts. Machine shops can choose the most suitable cobot depending on their part sizes and their machine cell environment.
Payload and reach. The payload of a cobot is the weight that the robot arm can lift. Cobots have a range of maximum weights. The reach of a cobot is the distance that the robot arm can reach. If you want to tend two machines for example, you will need a robot arm that has a longer reach to accommodate both machines.
Articulated arm and joints. Cobot arms provide flexibility for tending CNC machines and handling a wide range of industrial tasks. With seven axes of movement, an OB7 cobot has a unique advantage in a CNC machine tending environment. It can reach around the CNC machine and load parts without blocking access for the operator, which is not possible with a six-axis cobot. In addition, OB7's seven-axis motion allows it to reach around obstacles and fit into tighter spaces.
Collaborative Robots Working with Machine Operators
Cobots are becoming increasingly popular in machine shops because they are perfectly suited for handling machine tending tasks. Just like a human, cobots load and unload machines, but they don’t take breaks, get sick, or go on vacation. Cobots take on the tedious, repetitive, and error-prone tasks that workers find monotonous, or that contribute to bottlenecks in production. By taking on the machine tending process, cobots maximize spindle utilization and free up operators to handle other valuable tasks.
Cobots Offer Simplicity and Value in Manufacturing
Many cobots offer “easy programming” but still require a programming language that is difficult for those who have no programming experience. Cobots like OB7 from Productive Robotics require no programming at all, making it easy for machine operators. They simply “show” it what to do and the cobot learns. It can take a few hours to set up a machine tending cell and begin automating on the same day.
So what does a cobot do exactly when it tends a machine? Cobots handle the “repetitive” tasks that a machine operator normally does, such as:
Opening and closing a machine door
Loading and unloading blanks or parts
Staging material for processing or inspection
Recording pertinent data
Deburring, polishing, grinding
Whether you are running thousands of parts or as little as 5 parts, a cobot keeps your machines running consistently until the job is done. Operators can then shift their focus to work on other tasks like post-CNC quality inspection or setting up new jobs. Cobots don’t need a break and can work "lights out", making chips after you go home for the night.
Machine Compatibility and Set Up
Cobots can tend all types of machines, including mills, lathes, presses, EDMs, plasma cutters, grinders, and presses. Next generation cobots like OB7 from Productive Robotics can work with any brand of machine without interfacing into the machine, making the setup process simple and fast. OB7 cobots also have 7 axes or degrees of freedom (like a human arm) which provide a key advantage for machine shops:
Flexibility to reach around doors and into machines: A cobot like OB7 that has 7 axes provides a unique benefit for machine tending. The cobot can be placed to the side of the machine door and reach around and into the machine to load the part without blocking access for the machine operator. This is due to the extra flexibility and dexterity of the 7th axis, which is not possible with a 6 axis cobot
Many cobots come with robot stands that have wheels, allowing you to roll the cobot and position it in front of a CNC mill, lathe, or other machine to load blanks and unload finished parts. Material is staged on a worktable for the robot to pick up and load into the machine. Many machine shops use their own equipment to create custom tooling, fixturing, and end-of-arm tooling as well.
Productive Robotics offers mill and lathe packages that include all of the robot accessories necessary to work with your machines. This simple solution eliminates the need for complex integration and works with all types of machines.
Large Runs or High Mix/Low Volume
It’s easy to understand the value that cobots bring to CNC machining operations for running high volume jobs. Cobots keep the spindle turning without breaks, and they can even run unattended overnight and weekends for “lights out” manufacturing capabilities. But what if you don’t have high runs or if you do custom work? Can you still benefit from cobots? The answer is yes.
Cobots shine in high mix/low volume environments as well, and many small to midsize machine shops are using them to their advantage. A great benefit of cobots is their flexibility and ability to move between different machines. For example, if you are running a job of 10 parts with a long cycle time, the cobot can complete that job and free up your operator until it’s done. You can then run the robot on a different job in a matter of minutes.
Cobots also reduce idle machine time by working on second ops that involve longer cycle times. Their small footprint and flexibility make them as useful in high-mix, low-volume (HMLV) environments as they are in low-mix, high-volume (LMHV) environments.
Loading CNC Machines with Cobots
Cobots can be equipped with a range of grippers that are suitable for picking up all types of materials, from metal, to composites, to high-density polymers, to sheet materials.
Tooling options. End-of-arm tooling or grippers are the “fingers'' that the robot uses to pick up parts. These can be electric, pneumatic, or custom-made to handle various items and workpiece materials. There are a range of tooling options that can be used to pick up parts of different sizes. They can also handle delicate materials and small items.
Dual Grippers: A dual gripper is another time saving option that allows you to speed up production by using two grippers in one. With a dual gripper, you can unload a completed part then immediately reload a new part, eliminating the extra trip to and from the machine. This is great for tending a lathe and allows you to reduce machine wait time during part reloading, which can greatly reduce cycle time. See video: Dual Grippers
Productive Robotics manufactures its own cobot grippers and dual grippers. In addition, all cobots from Productive Robotics are compatible with other end-of-arm tooling options on the market.