In North America robots have generally been seen as scary for shop floor workers. Some of them are afraid that robots will steal their jobs. I am not saying that job relocation as a result of automation doesn't happen. In some cases, companies can be badly structured and the introduction of robots results in job lost. In the following example though, this company has expanded from 0 to 42 robots and has hired 50 new employees during the same time span.
The machining world has been using robots for a little while. Mostly to do machine tending. Although, with a lot of technological progress, industrial robots are now ready to do machining. In fact, with processes that must deal with more crazy shapes and differing rigidities, an industrial robot can be a great alternative.
Recently, during Robobusiness, a Workshop on Advanced Manufacturing was held. As a sponsor of the event, we've put together a little video with some sequences coming from our customers to ask the question: "What is advanced manufacturing?" Is it experts pushing he boundaries of robotics? Or is it making robots accessible for everyone? In fact, the workshop answered mostly the latter question. Many discussions seemed like a flashback from the recent RIA Collaborative Robot Workshop. Here are a few notes and afterthoughts.
What is flexible grasping and manipuation? Can you benchmark flexibility to compare different approaches? These are fundamental questions being studied at NIST, the National Institute of Standards and Technology. The NIST robotics' testbed for manufacturing consists of several labs located in three buildings on the main NIST campus. Combined, these serve as a resource for research in robotics for advanced manufacturing and material handling.
STAMINA (Sustainable and Reliable Robotics for Part Handling in Manufacturing Automation) is an ambitious industry led automation project looking to handle a wide variety of parts in a manufacturing plant for automotive parts. The flexibility, robustness and ease of integration of the 3-Finger Adaptive Robot Gripper made it the right choice to quickly build a useful test bed.
The decision has been made to automate a manual handling process. The automation concept has been chosen. Now is time to look into the details on how we will pick, hold and place those parts. The cost of the gripping units itself is not a big part of an automation project. Suction cups can be as little as $10 and an electric gripper can be several $1,000; but these costs represent a small fraction of the whole project. That is why grippers are too often the last aspect to be analyzed in an automation project. But grippers have a direct impact on cell performance and throughput. When budgeting and choosing grippers, it is important to consider performance, purchase cost and even more importantly recurring costs that will come from using the gripper in production. Let's assume that you have analyzed the performance of different gripping options and now want to analyze which one will be the most cost-effective. This article explains how to compare the cost difference between robot gripper options for your automation project.
SMED is a manufacturing technique that targets the reduction of setup time for a given manufacturing process. SMED stands for: Single Minute Exchange of Dies. This technique was developed in the printing world so this is why it uses the word 'dies'. This technique though, can be applied to every automated manufacturing process these days and is an important tool of lean production. The SMED has been invented by Shiego Shingo, a Japanese industrial engineer who successfully helped companies reduce their changeover time. One of his books claims to reduce the setup or changeover time by 94% (going from 90 minutes to 5 minutes). This article will give you the key points of this technique, but I really encourage you to read his book to have a deeper understanding of the details involved.
Investment casting (also known as lost wax casting) is a fairly old manufacturing process. It is used in several industries to produce precise parts with complicated geometries. This post presents an overview of the process as well as several examples of robotic automation solutions and providers.
Grippers consisting of vacuum cups, pliers, or finger assembly are some of the most common EOATs (End Of Arm Tooling) to be used on industrial robots. To ensure economical and practical success in automation projects, choosing the right gripper is essential. After all, this is where the rubber hits the road. This article focuses on technical factors, from a process and part perspective, that must be taken into account when choosing the right gripper for your application.The process:
What will be done with your robot? Automation projects vary greatly from one to another.
- The task itself : The tasks to be done by a robot often determine the type of gripper that should be used. A very fast loading/unloading requirement will favor vacuum cups but a slower process will favor pliers or fingers for accuracy.
- Cycle time: The speed needed for clamping and/or opening or closing the gripper will determine cycle time. The cycle time will also determine acceleration and resulting G force from the gripper, a heavier gripper will put more G stress on the robot and cause wear on its parts. You must remember that robot specifications for maximum acceleration are calculated by the sum of the gripper weight and the part, so more gripper weight means less weight from the part you handle. In addition to this specification, reach and EOAT weight will determine the resulting torque at the robot base; again we will seek to minimize the gripper weight. This is why many modern grippers favor the use of hollowed aluminum parts.
- Precision need: Some assembly work will require great precision, a mechanical gripper, actived by servo-electrical motors, would be ideal. Part sorting processes will require gripper adaptability to ensure parts can be sorted, especially those ranging in size or that are positioned differently from each other.
- Environmental need: Not all gripper types can be used in every process. In the food and pharmaceutical industries for example, hydraulic actived grippers are forbidden since there is a risk of oil spilling and contamination. In many clean room industries vacuum and pneumatic grippers are also not recommended since they can create flow of particles in the air. Grippers used in less clean environments like foundries, machining and welding are exposed to dirt and particles so they must be protected. Corrosive or toxic environments in nuclear or chemical industries also create special considerations for protecting the gripper to ensure its stability and safety of use. In most applications the gripper must be failsafe. Dropping a banana on the floor has no serious effect but spilling chemicals or radioactive materials can be catastrophic and/or toxic in some cases.
Knowledge of the part to be manipulated is crucial in determining which gripper should be used. The main factors are:
- Size: Except for vacuum grippers, all other grippers need to grip parts with a parallel or angular closing. This means the bigger the part, the more reach gripper fingers will require. In all cases, the gripper must have enough reach to handle parts but not in excess since longer fingers create more torque on the tool and the robot.
- Shape: The shape of an object will determine which kind of grasp can be done. Flat surfaces can be handled by vacuum or magnet types of grippers while other shapes will be handled by jaw, claws or multiple fingers. When using encompassing or fingertip grasps, calculating finger reach must be taken into account.
- Weight: To ensure grasping holds, a gripper must have enough force to meet the weight of the part and time the acceleration it can withstand during the process. A designer cannot simply use maximum clamping force since damage to the part or the gripper may occur.
- Surface type: The type of surface upon which a grasp will occur will also be an important factor when estimating friction.
Calculation of the clamping force must account for a part's weight, maximum acceleration during the process, surface friction and maximum stress the part and gripper can withstand.
In an upcoming piece, I will expose some of the economic arguments for automation projects in various industries.
This article summarizes that the more adaptability and flexibility provided by a gripper, the better. Adjustment of the clamping position, angle, rotation possibilities and grasping methods will protect your investment from future retooling costs.
An article by Rob Centner on welding consumables first appeared in The Fabricator, a trade journal for the Fabricators & Manufacturers Association (FMA) out of Rockford, Illinois. The FMA is a professional organization, which provides the tools, resources, and a community of companies who work together to improve the metal forming and fabricating industry. Since the subject is pertinent to all welding environments, including robotic welding, I thought we should revisit these important aspects of welding.
There are several important areas to look at when considering welding consumables such as: