Welding robots and lean manufacturing learn to play together
With careful analysis and planning, automation can be an integral, cost saving component of lean manufacturing.
Lean, one of the hottest buzz words in manufacturing, has to do with cutting the fat out of manufacturing processes, including minimizing work-in-process (WIP); eliminating processes that add no value to the product; increasing inventory turns; and building into processes the flexibility to change from one part or process to another in the least amount of time. These all are great ideas, but why haven't companies been implementing them all along?
Many manufacturing companies historically have been able to maintain bloated or inefficient methods because of brand strength or huge profit margins. However, global competition is causing these companies to ask questions about how to survive in the coming decades. Something has to change. It's become too difficult to lower prices enough to beat the competition and satisfy customers with the status quo.
The lean paradigm addresses these concerns, and it works, which is why it has taken root and is growing quickly. But an unfortunate side effect of moving toward lean manufacturing is the trend to eliminate robotic automation, as if robots somehow are contrary to the goals of lean manufacturing. Properly planned for and strategically implemented in a lean environment, robots can effectively cut costs, increase throughput, and improve profitability. Robotic technology has come of age, and it will only become more flexible, more affordable, and more applicable to modern methods as time goes on and technology advances.
First, the Proper Foundation
Before introducing automation, you first must understand your processes thoroughly. Introducing automation and robots into an inefficient process simply might help you be inefficient with less labor, even though you may eliminate cost from your product and maybe even experience a decent return on investment (ROI). But a time will come when you've removed as much inefficiency (excess material handling, WIP, and unnecessary labor) as possible. Then what?
The first step is to know where your costs are. How much are you reallyspending on material handling? How much does it reallycost you to keep those stacks of inventory between processes? Can some simple material handling devices, such as robots, reduce or eliminate human labor? Can rearranging your machinery or product flow eliminate inventory stacks all around the factory?
Ninety percent of the factories I visit have significant WIP sitting between machines and in the aisles, and every piece of product required someone to move it to its present location and to move it again to the next place or machine—a costly process.
Many books, consultants, and seminars teach the lean process and methods. As you begin moving toward lean manufacturing, keep in mind that you don't have to implement all lean methods before you even consider robots. In fact, the opposite is true. Robots (assuming they actually are applicable to your processes) should be part of the upfront planning that goes into a lean implementation. If you consider robotic automation in tandem with your lean planning, then your investment in time and machinery to get lean can provide an even greater ROI potential. Why?
Remember that robots simply are tools for removing labor costs from your product. This is especially important in the welding department, where many companies are forced to implement robots because skilled labor increasingly is difficult or impossible to find. While "lean" is about removing labor from your product, robots accomplish the same purpose. As a result, they are perfectly applicable to lean manufacturing methods, and probably to whatever becomes the next hot trend in manufacturing, because robots work and act like people, but don't require an hourly wage.
Now is the time to begin thinking about how robots can provide further labor savings, improve quality, and improve safety and ergonomics beyond just getting lean. Given the correct application, robotic automation can supercharge an already lean process, especially if it's part of the plan from the beginning.
It's All About Flexibility
What can be more flexible than a six-axis, infinitely programmable machine that mimics the motion of a human arm? And as computer technology continues to advance, a robot's controller also will think more and more like a human. Robots should be a coveted part of any lean implementation. So why have robots received black eyes from so many companies that are becoming lean?
Part of the problem has been the learning curve of the robot industry itself. Because robots cando amazing, complex tasks, we somehow believe we oughtto use them that way. The problem is, some of the perceived flexibility from expensive, complicated machines may be thwarted by increased downtime or increased difficulty in operations or training. In this case, simplecan mean flexible. In the world of robotic welding, this idea may be manifested by installing multiple simple cells, each doing simple tasks, rather than one expensive, complicated cell that can do everything but can't be operated or maintained.
Given robotic technology's incredible potential, it is more important than ever to work smarter, not harder, primarily by learning to utilize the best and most appropriate tools available. Although welding robots are not easily applied in some environments, significant technical advances have made them more flexible and broader-reaching than ever before:
- New, more reliable seam-tracking technologies open up more opportunities for robotic welding.
- Offline programming allows the robot to continue running while the next job is being programmed on a PC.
- External cell controllers and advanced software options allow more flexibility on the shop floor. Routine tasks, such as maintenance, program editing, or looking up something in an e-manual, can be performed on the robot's cell controller while the robot continues to run.
- Modern robot controllers feature superior computer power.
- New and proven welding technologies, including twin-wire welding and special processes for welding gaps and thin materials more reliably, broaden welding automation applications.
High Part Volumes Unnecessary
High part volumes aren't required to take advantage of robotic welding technologies. The only real differences between high-volume and low-volume applications are the initial setup and programming time and the changeover frequency. Offline and more user-friendly programming methods are helping to minimize setup time. Changeovers can be minimized or eliminated with smart fixture design and robot cell controllers that give the operator or programmer maximum flexibility.
What this means in practical terms is that certain upfront investment—for example, increased cost for flexible and quick-change tooling (allowing you to run smaller lot sizes), or an offline programming package—can contribute significantly to your ROI. Many companies hesitate to invest in such options, because they seem expensive or unnecessary, but these companies typically do not understand the tremendous amount of money wasted by their inefficient processes. A quote for an expensive flexible fixture is highly visible, and represents something you have to write a check for, whereas the salary and benefits paid to a technician to perform continuous changeovers are absorbed in overhead, and are therefore invisible. Remember, understand your processes and where your costs really lie.
Even in high-volume applications, it still is necessary to maintain flexibility, because design changes, model-year changes, and other product changes always are lurking. Although the ROI may take longer, flexible or quick-change tooling can be a worthwhile investment.
Automation also increases throughput, decreases non-value-added labor, and makes your processes leaner by providing:
- Status lights in the robot cell to alert operators when the robot is stopped.
- Schedule of parts being welded, part in queue, and parts recently finished
- Tracking and logging of weld times, arc times, changeover times, overall cycle times, downtimes, and reasons for downtime.
- A data analysis system — Don't just collect data and put it in a file. Learn from the data and work to solve the problems and become even leaner.
- All pertinent data available in the robot cell—programming manuals, operator manuals, maintenance manuals, help screens, troubleshooting tips, even remote monitoring by the robot supplier to help solve service problems as quickly as possible.
- Offline programming to program new or updated parts while the robot is in production.
Think intelligently about whether robotic technology can make your lean implementation even more effective. Discuss these ideas with your robotic suppliers, who can help you identify all the ways that robots may be able to optimize your efforts to trim the waste in your environment and help you become as lean as possible.
Robots and lean manufacturing really can learn to play together.