Peter Kronfeld
Peter Kronfeld
Peter Kronfeld, born in 1962, has always taken great interest in the subject of technological change in the economy, society and business. This already started when he was a student of economics and communication and he has been keeping track of these topics as a journalist and as managing director of HighTech communications GmbH until today.

Seven tips for using robotics in SMT production

Alessandro Bonara, Fertigungsleiter bei ASM

(image: copyright HighTech communications GmbH)

“No honeymoon period for robots”

As previously reported, SMT solution provider ASM does not exclude its own production facilities from advances in digitization and automation. For some weeks now, a robot has supported the company’s in-circuit testing activities. To find out what rules electronics manufacturers should follow with regard to their own robotics projects, I spoke with Alessandro Bonara, who is in charge of ASM’s SMT production.

 

1. Employ robots primarily in “3D” areas

When analyzing potential areas for deploying robots, ASM followed the 3D rule and initially focused on areas that are dull, dirty and/or dangerous. Alessandro Bonara: “One such example is the in-circuit testing station, or ICT station for short. The process involves a relatively dull series of steps: take the PCB from the carrier, scan the board ID, place the board into the correct ICT station, close the cover, run the test, open the cover, take out the board, and place it into the pass or fail carrier depending on the result. We believed that this would be the perfect job for a robot so that a human would be freed up to perform more demanding tasks.”

2. Flexible production requires flexible robots

The employees in an SMT factory must be able to perform various tasks in order to be flexibly deployable where needed. “We place the same demands on our robots. Using permanently installed robots that perform only a single job and require expensive third-party programming is not really an option in a flexible SMT factory. Fortunately, we now have cobots – collaborative robots that are mobile, flexible, and don’t require special cages or safety barriers,” explains the plant manager.
Accordingly, the first such robot in use at ASM will help with separating clusters in addition to its in-circuit testing job, which it most likely will do entirely on its own during a so-called ‘ghost shift’ in the middle of the night. During the two-day shifts, it will use other tools to separate clusters in a different location. Once this has been implemented, there are already plans to use the robot for simple tasks in the machine production as well.

3. 80 percent today is better than 90 percent tomorrow

Classic robotics require a careful analysis of all the work steps before an overall process is designed for the specific robot, which is then programmed in minute detail, usually by external specialists.
For Alessandro, this approach is obsolete: “Today’s SMT lines must be able to accommodate quick setup changeovers so that they can run new products at the drop of a hat. Optimizing only net throughput times is a recipe for disaster in a flexible production environment. Setup and changeover times are much more critical today, and that includes any robots that may be involved.” This is where modern cobot platforms like the Sawyer from Rethink Robotics are at their best, because teaching them is easy. You simply guide the robot’s arm through all the work steps in a type of learn mode and enter a few settings directly on the robot or over the network. This makes it easy to teach and/or change the robot without having to delve deeply into the secrets of robotics programming. “Of course, an expert could spend a few days to optimize the program and speed it up, but what would be the use in a high-mix production environment? It’s more important that the robot can be quickly deployed for other products, processes and work steps. If the robot workstation turns out to be a major bottleneck, you can always improve it from an 80-percent efficiency level to 90 or 95 percent.”

4. Programming in-house is more flexible

Tip 4 goes in the same direction. ASM wanted the programming to be done by its own process engineers, not any IT people. “We did not want to depend on the availability of external specialists or waste a lot of time on briefings, process explanations or documentations for non-SMT people,” explains the ASM manager. While this may actually cost a little more in the short run, it will make the factory more flexible. For the same reason, ASM develops the tools for the robot in-house and builds them with 3D printing techniques.

5. Management must support robotics experiments

Learning takes time and lots of trial and error. Some managers may not approve. Flexible robotics also represent new territory for electronics manufacturers. To stay flexible (see above), you must give your employees sufficient time for adjusting the robotic workstations via programming, etc. Alessandro Bonara is confident: “We are a trailblazer in this field. But collecting this experience helps us to build up competencies that will give us a competitive advantage in the future. If you can’t convince management in advance of this benefit, your robotics projects will get stuck in the mud.”

6. Warning: Set aside sufficient time for safety approvals

With their movable eyes on the display, Sawyer cobots don’t just look cute – they are harmless and designed from the ground up to work side-by-side with humans. You can place an arm or hand in the robot’s travel path without danger, because the robot’s sensors and slow speed prevent any injuries. No cage is needed, unless the robot has a sharp knife or something similar attached to its arm, but not everyone knows this.
“In Germany, the trade associations must certify the robot’s safety. If you don’t have an operating permit, you cannot get any insurance protection in Germany. Unfortunately, most trade association inspectors are only familiar with traditional robotics concepts and follow the old cardinal rule “No cage, no operating permit,” says Alessandro Bonara. His tip: If you want to employ cobots, you should investigate trade association and operating permit requirements from the start and prepare risk analyses for the inspectors.

7. Calculate costs smartly

If you employ and optimize robots no longer for a single process step in classic high-volume production, you must also recalculate their investment cost.
ASM calculates costs based on the installation of an entire workstation. While humans incur wages, ancillary costs as well as costs for training and tools, robots incur purchasing costs along with the costs for programming and tools. On this basis, the cobot workstation at the in-circuit tester is expected to cost approximately €70,000 during the first year. This amount includes purchasing, programming, testing, tools, approvals, etc. On the other hand, the robot will operate in two shifts. “Robots have become much cheaper. Their easier programming reduces costs as well. Using a cobot quickly pays for itself where humans have to perform dull, dangerous or otherwise unattractive work and if the cobot can be employed at various workstations,” explains Alessandro Bonara.

ASM: Cobot Workflow at ICT Station

1. Cobots takes PCB out of the tray

2. Cobot positions PCB for scanning

3. Cobot inserts PCB into ICT station

4. Cobot closes ICT – ICT starts automatically

5. After ICT is completed, cobot opens ICT box and takes out PCB

6. Depending on ICT result, cobot places PCB in Fail or Pass trays

7. If trays are empty cobot takes them away with ASM-made vacuum tooling

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