Design for Robotic Assembly
Cars, stove-tops, medical devices, and computer parts… What do they all have in common? Assembly robots are building them as we speak. Robotic assembly is gaining speed in the manufacturing of goods used every day across the globe. “The only way to make assembly processes cost-effective for North American manufacturing is with robotics and automation,” says Chris Blanchette, National Account Manager Assembly and Aerospace for FANUC America Corporation in Rochester Hills, Michigan. Proof is in the pudding as the Robotic Industries Association showed Assembly orders up by 96% compared with the same quarter last year; this made for record-breaking sales for the first half of 2014!
You may think that it is risky or difficult to design a robotic assembly system that works perfectly for you. Don’t fear; that is why RobotWorx is here! We have put the following resources together to help you design your next assembly automation system.
Identify the Assembly Application:
Assembly robots haven’t met many applications they can’t handle. Whether it is welding automotive components, palletizing, dispensing, moving and holding a part in place for attachment, painting, or building a solar panel, there is a perfect assembly design for you.
Choose Your Assembly Robot:
There are many robotic configurations available for assembly robots.
1. Six-Axis Robots provide optimal strength, flexibility, and reach to complete the desired task. They are compact, highly dexterous, nimble robots to engage assemblies from all angles. They are playing an ever-increasing role in the assembly space. We recommend the FANUC R-2000iA/165F or the Motoman HP6.
2. SCARA Robots stand for “Selective Compliant Assembly Robot Arm.” They are 4-Axis robots that are ideal for high-speed assembly. It gets its name as the arm is selectivity compliant in the X-Y direction but rigid in the “Z” direction to help with many types of assembly operations, such as inserting a round pin in a round hole without binding. RobotWorx recommends the Motoman HM-20-1000 or the KUKA KR 10.
3. Delta Robots have smaller payloads, but unparalleled acceleration and speed. They resemble a ceiling-mounted spider as motors in the base move the three linked arms. Its major mechanical axes act on the robot face-plate in parallel rather than in series which allows it to be quick and precise. Speeds of 10 millimeters per second are typical while also accommodating improved repeatability at the tool tip which means it is perfect for small part assembly. One of our top Delta robots is the FANUC M3iA/6s or the Motoman MPP3.
4. Dual Arm robots have helped to ease complex assembly applications by doing tasks such as holding one part and inserting another part into it. For flexible parts or components, such as tubing and hoses, dual arms can work together to simplify the tooling and enable the application to be done in a simpler way. A Dual Arm we recommend is the Motoman DIA10.
5. Collaborative robots are a rapidly emerging area of industrial robotics also entering assembly space. They are specially designed to operate alongside human coworkers on an assembly line without the need for safety guarding. Take a look at the FANUC CR-7iA or the Universal Robot collaborative robots that we offer.
Choose Your Assembly Software
The machine vision software available these days is incredibly beneficial in guiding robots to precise part location, and inspection. In addition, force sensing equips assembly robots with the sense of touch in all 6 degrees of freedom. It measures the forces and torque applied at the EOAT and offers the robot control system feedback for hybrid force-compliance movement control of the end-of-arm tool. These options are transforming assembly lines and clean rooms.
Consider electronics whose assembly tolerances are getting tighter as the parts and pieces are getting smaller. The necessary precision, consistency, and minimal cost required all make robotics assembly a critical part of the production process.
“People can’t do the really fine tasks that are called upon for assembling next-generation mobile devices or wearables,” says Rush LaSelle, Director of Automation at Jabil Circuit Inc. “The product life cycles aren’t long enough to support customized machine tools.”
“In our world, in electronics manufacturing, there are robotic solutions and flexible automation that’s capable of getting to the level of precision that we can now take advantage of the technology,” says Rush LaSelle, Director of Automation at Jabil Circuit Inc. “Labor rates in China and other parts of the world are rising, and so everybody is looking for a lower cost alternative.”
Fortunately, the complex assemblies and sensor-based technologies are getting better, cheaper, and more user-friendly. The user interface is now advanced enough so a highly skilled worker is no longer necessary. Visual servoing has enabled the robot world to achieve precision assembly better than 10 microns.
Choose Your EOAT
End of arm tooling can be purchased standard or customized for each assembly robot to cater to the manufacturing requirements. They can range from grippers, vacuum cups, 3-jaw chucks, high-speed spindles, cylinders, or drills.
A standard EOAT is mass produced and can easily be ordered as we work with several different suppliers to ensure that customers get the best available. A standard EOAT can be easily accessed and will not lengthen the build time for your robot, however it is designed to fit a number of products, and may not be the perfect fit for your specific needs.
If you choose the customized route, engineers designing the system decide which end effectors would be best for the application and then fabricate and build to the specification. This will add time to the build but ultimately a custom EOAT can produce better functionality during production. RobotWorx can contract companies to build custom end effectors that can potentially be done EOAT in-house.
Choosing the right EOAT can ensure groping is done correctly. This is a key feature where the robot moves the EOAT close to the location of assembly and transitions into groping where the robot makes a pattern around the part where it’s supposed to be assembled. It moves slowly and progressively, in different pre-programmed patterns, to make contact and sense the forces, motion, and direction, and then act according to drive the parts together.
The important thing is to spend the money on the correct EOAT for the job since sensing and control capability are the key.
Choose Your Workspace
Assembly is able shrink the footprint of work cells by creating complex systems that combine multiple operations by using different tooling. Ultimately, a part produced in this type of system gets assembled and checked, all at once.
A robot workcell is necessary to complete a system that includes the robot, controller, and other peripherals such as a part positioner and safety environment. Custom cells are built to customer specifications and allow for the limitations and challenges often found in an industrial setting. They are ideal for applications a standard workcell would not be able to perform.
Robots are currently successful at tackling many complex assembly applications such as assembling gear boxes for Kawasaki motorcycles. Flexibility to build different gear boxes is key with Kawasaki with their many different types of motorcycles. Originally, the task was completed by fixing a bearing case on a surface and a hand pressing to drive the bearing into the bore.
Robotic assembly enabled a flexible cell to be created with fixtures for different gear boxes. The design allowed it to carry the crankcase and move it over the fixture where the bearings are mounted, and hold it there while the press comes down and drives the case into the bearing. This enabled the robot to use position control to transition to a soft absorb mode as it holds the crankcase over the bearing, and then return to position control mode and carry on with the job.
Choose RobotWorx for help on your next Assembly Design
Agile robots augmented with force sensors and vision are unstoppable. Watching coordinated assembly robots work tirelessly, accurately, quickly, and precisely is the reflection of a very promising future for automation.
RobotWorx, a certified integrator for FANUC, Motoman, ABB, Universal Robots, and KUKA robotics, and works with customers to build these robotic assemblers on a regular basis. Our team of engineers, technicians and salesmen will work with you to select the right assembly robot, end effector, controller and safety package to fit your application’s needs and your facility’s space requirements.
For more information about what RobotWorx experts can do for you, contact us today at 740-251-4312.