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Precision Under Pressure
The Challenge
Tackling the degradation of a critical robotic laser welding and assembly cell by restoring full automation and advancing precision to meet the evolving demands of micro-component manufacturing.
Client Overview
Our client, a prominent player in micro-component manufacturing, known for their contributions to various sectors within the electronics industry, found themselves facing a critical challenge.
Initial Engagement
We were initially introduced to this client as Keyence custom automation integration providers, where we successfully completed a unique computer vision automation project for their QC department. The client then asked us to take on a more complex challenge: reviving a robotic assembly and laser welding cell that had been a cornerstone of their manufacturing process.
The Aging System
This custom-built automated work cell, which included three Fanuc robots, multiple cameras, and a galvo-directed laser—a device that uses tiny, rapidly moving mirrors to precisely direct the laser beam—was originally designed for lights-out, fully automatic operation. At its peak, the machine was a reliable workhorse, producing thousands of micro-welded parts daily with +/- 25um accuracy. However, over time, the cell’s performance began to deteriorate due to normal wear and tear, leading to a host of operational issues.
The robotic assembly and laser welding work cell with the door of the machine guarding open.
Compounding Challenges
To compound the situation, the original robotic and automation equipment manufacturer and integrator no longer had any technical documentation for the project, and none of the original engineers were available to provide engineering support. The integrated robotic system, once precise and dependable, started to drop parts prematurely, pick up multiple parts at once, and fail to place parts accurately into the weld fixtures. The weld fixtures themselves had become contaminated with oxidation and weld slag, further degrading the accuracy of the welds. As a result, the laser weld locations began to drift outside of allowable tolerances, causing high reject rates during inspection.
Our Mission
The task was twofold:
1) Bring the automated machine back to its original automatic functionality.
2) Augment the machine’s design to allow for automated assembly and automated welding of even smaller components. Since the robotic integrated machine was originally built, the client’s assembly projects have been shrinking in size, requiring increased precision. Eventually, the requirements for precision placement and weld location exceeded the machine’s capability.
Enhancing Robotic Welding and Assembly
The Solution
Revamping the welding cell with enhanced fixtures, innovative solutions, and precision-focused adjustments.
Fixture Redesign and Enhancement
To address the multitude of issues, we began by redesigning the weld fixtures. The original fixtures, plagued by oxidation and weld slag, were replaced with new ones made from 300 series stainless steel, offering greater durability and resistance to contamination. These fixtures were also modified to provide better clearance for the laser beam, ensuring more accurate and consistent welds. Next, we redesigned the weld clamps, incorporating a new form and compression mechanism that helped alleviate the problem of parts sticking to the clamps after welding.
Incorporating Vibratory Elements
However, simply upgrading the fixtures wasn’t enough. We quickly realized that the tiny components being processed by the automated machine were too small and light to be positioned accurately in the fixtures by the robots alone. During our observations, we noticed machine operators using a simple yet effective technique: tapping the fixture with a pencil to vibrate the parts into place just before welding. Parts were placed in a stack in the fixture, which would shake back and forth in large strokes. However, the parts were so small and light that they would get caught on bits of oxidation or weld slag on the fixture or, on clean fixtures, stick against the polished metal surface.
We realized that we could add a vibratory element to replicate the operator’s pencil tapping to settle the tiny parts into place. Without an easy way to quantify the optimal vibration amplitude or frequency, we knew we had to experiment with a small motor, preferably remote-controlled, with variable pulse settings. But where could we find such a device that was readily available to test…?
Unconventional Problem Solving
After a quick brainstorming session, we decided to visit a specialty store known for its unique range of personal products. We found a small, pill-shaped device with exactly the features we needed—remote control, adjustable intensity, and multiple frequency settings. Our hyper-focus on finding the best solutions often leads us to unconventional approaches—and sometimes, unconventional places. Despite our detailed explanation that the device was intended for an engineering application requiring precise vibratory modulation, the cashier appeared unconvinced of the technical merit of our purchase and insisted on fully sanitizing the device before completing the transaction. It would appear that our justification failed to meet his expectations of standard engineering equipment.
Once back at the workshop, we fabricated a 3D printed mount for the device, attached it to the weld fixture, and to our satisfaction, it worked flawlessly. A short pulse at maximum intensity was all it took to vibrate the tiny parts perfectly into place on the first try. Armed with a reproducible reference for frequency and amplitude, we later sourced a tiny vibratory motor, designed a housing for it, and wired it to a dedicated variable power supply in the control cabinet, to be activated by the PLC with the option to disable in the HMI.
A dedicated power supply for the vibratory motor was integrated into the control panel.
Optimizing Precision with iRVision
To resolve the robot’s pick-and-place precision issues, we turned to Fanuc’s iRVision software. By creating bounding areas around each component, the Fanuc software ensured that only parts meeting specific distance criteria were selected, significantly reducing the occurrence of multiple pickups and improving placement accuracy.
The robotic welding and assembly work cell in operation.
Precision Elevated: Achieving Automated Manufacturing Excellence
The Outcome
A transformed and enhanced welding cell that delivered outstanding precision and met production goals with remarkable efficiency.
The optimized robotic assembly and laser welding cell successfully completed an order of 4,000 assemblies by our promised deadline. The client’s QC team was particularly pleased with the consistency and precision of the laser weld locations, which exceeded their expectations.
After extensive testing and adjustments, we restored and enhanced the automated machine’s functionality beyond its original capabilities. By addressing each issue, we achieved a 99% yield over 400 consecutive welded assemblies in fully automatic mode—a successful turnaround from the machine’s previous state, where automatic mode was unusable.
Aligned for Precision
Future Development
Addressing new challenges to push the limits of precision in micro-component manufacturing.
Enhancing Y-Axis Precision
Building on the success of the initial project, we are now collaborating with the client to enhance the precision of the Y-axis linear actuator. During the production run, we observed a slight drift in the laser weld locations, which we traced to the linear actuator responsible for positioning the weld head in the Y-axis. Although the actuator was adequate for larger assemblies, it lacked the precision required for the increasingly smaller components our client was manufacturing. Even though the beam is steered by a galvo head, the laser module itself needs to be positioned between fixtures using a linear actuator, making its accuracy critical to the process.
Laying the Groundwork for the Next Phase
This insight has laid the groundwork for the next phase of our factory automation integration collaboration. We are currently working on improving the accuracy of the laser slide’s Y-axis to ensure consistent weld accuracy for the smallest components. Additionally, we are making fixturing and programming changes to reduce setup times for a broader range of assembly sizes. These custom enhancements will not only increase precision but also improve the overall efficiency and flexibility of the machine.
Ongoing Collaboration for Continuous Improvement
Our ongoing automation system integration work with the client reflects our commitment to pushing the boundaries of what this robotic assembly and welding cell can achieve, ensuring that it remains a cornerstone of their manufacturing production line for years to come.
Our technical and strategic collaboration with the client is ongoing, as we continue to explore innovative ways to optimize their processes and maintain their competitive edge in the market.
Our commitment to innovation and precision makes Zaic Design a trusted partner for companies looking to elevate their automated manufacturing processes and achieve new levels of accuracy and efficiency.
With a strong foundation in custom automation integration, precision engineering, prototyping, pre-production planning, project management, and R&D, we specialize in overcoming complex challenges in micro-component manufacturing and beyond.
Enhance your production capabilities with custom automation solutions designed to meet the unique demands of your industry. Whether you need advanced robotic systems, precision welding solutions, or automated assembly processes, Zaic Design has the expertise to transform your operations and drive measurable results.
Schedule your free consultation today and discover how Zaic Design can revolutionize your operations with cutting-edge automated solutions tailored to your needs.
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