Guitar manufacturing is an industry known for its intricate, hand-made production processes. But even in such industries, automation is increasingly playing a role for a number of reasons—from alleviating workers’ ergonomic issues to improving quality and aiding materials inspection.
I was recently invited by Tyler Robertson, robotics engineer at Taylor Guitars in El Cajon, Calif., to see how automation is increasingly being used within the company’s handwork-intensive production operations. He explained that, at the El Cajon facility, Taylor Guitars currently produces around 100 guitars a day. At the company’s Tecate, Mexico, facility, some 600 guitars are produced each day.
Robertson came to Taylor Guitars a little over two years ago based on his experience as an application engineer specializing in robotics programming and robot software integration at In-House Solutions in Canada. Before working at Taylor Guitars, Robertson developed custom robot programs for complex processes in the plastics, aerospace and fabrication industries. He developed expertise in these industries working with robot end users, integrators and OEMs for job shop welding, laser and water jet cutting, and robotic machining, finishing and drilling applications.
Robertson was keen to discuss how Taylor Guitars has been using automation technologies for well over a decade now and how he is being challenged to expand the use of automation at the company to further improve the production processes and quality of Taylor Guitars’ already world-renowned products.
The wood
My tour of Taylor Guitars’ production operations started as you might expect—in the wood receiving area. Common wood types used by Taylor Guitars include ebony, mahogany, rosewood, cedar and spruce. All inspections of the wood before processing are performed by hand because of fluctuations in materials.
“To automate this inspection process would be a nightmare,” Robertson said, “not only because of differences in the woods, but also the differences between and within in each batch of wood. Getting the lighting correct for robotic vision inspection of wood, due to these differences, is very difficult and inefficient. I’ve looked into x-ray, ultrasound and CT scanning methods, but these are either not well-developed for wood scanning or are very expensive and geared more toward the lumber industry.”
Despite the difficulties in automating wood inspection, there are other steps in initial wood processing that could be more automated, Robertson said, as he pointed out multiple pallets of wood stacked nearly to the ceiling. “We get 2,000 blocks of wood in each day for the manufacture of guitar necks and heads. These blocks of wood are stacked and inventoried by hand,” he said.
When it comes to tasks like this, Robertson said workers at Taylor Guitar are very open to the idea of automation. In fact, while Robertson guided me through this portion of the tour, a manager in the department approached him with suggestions for automation.
As often as such automation discussions occur with workers around the company, Robertson noted that “automation is still in its infancy here,” and he is the only full-time staff person focused on automation in addition to his work providing tech support for production. “There’s lots of opportunity for automation here,” he said. The challenge is prioritization and focus on the projects that can deliver the clearest benefits first.
Like most manufacturers today, Taylor Guitars faces what Robertson referred to as the “ticking clock issue” of increasing numbers of pending retirements. Taylor Guitar is known for having little turnover among its staff; and having been in operation since 1974, a wave of pending retirements looms for the company. This is troubling for Robertson in an environment where it is not simple to automate many of the tasks due to the high degree of material variances.
Beyond retirement issues, another example of the need for Robertson’s investigation into automating the critical wood inspection and classification processes at Taylor Guitars is highlighted by the personal circumstances of a key Taylor employee in this department. Though this employee is not retiring any time soon, she is leaving the company because she is getting married and moving away.
“Finding people who want to work at Taylor Guitars is not difficult,” Robertson said, “but finding experienced people is not easy and getting them up to speed on our processes takes time.”
Describing one of the projects he is starting that involves automating the inspection of neck blanks and ebony fingerboards, Robertson pointed out that it’s not just the workforce timing issue he faces, but also the typical return on investment issues. While such challenges are common, Robertson noted that he has the benefit of what he called the “Bob factor,” as in Bob Taylor, the owner of Taylor Guitars. “Bob may give the green light for a project based on his experience and ability to recognize the production benefits it would bring,” regardless of any projected return, Robertson said.
Tracking guitars
One aspect of automation that is a critical part of the production process at Taylor Guitars is the tracking of each guitar as it moves through production by means of an RFID chip placed on each guitar top—which is among the first guitar components made in Taylor Guitars’ production process.
“No information is stored on the RFID chip,” Robertson said, “but it creates a digital thread for us that allows each guitar to be tracked throughout production. If problems arise at any point, we can follow this digital thread to determine the source of the problem.”
Highlighting an example of the effectiveness of the digital thread, Robertson described a time when the company was experiencing issues with guitar finishes. Using the digital thread created by tracking the RFID chip through production, they were able to trace the problem back to the sanding process.
Robertson added that having this digital thread in place also helps the company comply with environmental and regulatory requirements.
The necks
We then moved into the guitar neck milling area of the plant where several 20+-year-old Fadal CNC machines carve the necks out of wood blocks. “We’re starting to feel the pain with these older CNC machines as they age,” Robertson said, noting that it’s not just maintenance issues, but data collection. “I want to have a SCADA system hooked into these machines” to help track and monitor resource management, he said.
Looking across racks of recently glued head stocks and necks in this area of the plant, Robertson explained there are a “lots of process considerations” when it comes to automating and/or speeding up guitar production. By this he meant that what might make sense to automate and move through quickly from a process point of view might not make sense for the materials. “For example, we have to let the wood rest after gluing before moving it on to the next assembly step to make sure it reacts correctly.”
Clarifying the importance of wood-working knowledge in Taylor Guitars’ business over automation technology knowledge, Robertson noted: “I have a degree in systems engineering, but my boss is a cabinet maker.”
This reality is underscored in the guitar body production department where Robertson pointed out that “nothing in this department is a focus for automation.” The only possible exception to this rule would be in bringing in a robot for some sanding applications to address worker ergonomics.
To alleviate ergonomic issues in this intensive hand-working area, Robertson said that workers here move around constantly to perform different duties. “This part of the process could be done in an assembly line fashion,” he said, “but by moving workers around it avoids repetitive stress injuries and keeps workers’ interest high.”
One area where automation technologies do play a part in this segment of the guitar production process is bending wood to form guitar sides. Robertson said that all of the company’s side benders are made in house and use Automation Direct DirectLogic DL06 and DL105 PLCs and Groschopp dc gear motors.
The use of automation is key here because each type of wood has a different bending recipe, Robertson said. He explained that these recipes direct the application of different pressures and temperatures.
Robertson also pointed out the Epilog laser cutting system in this department that is used to cut wood for the guitars’ internal bracing—a key component of a guitar’s signature sound. Robertson created a touch screen for this machine to ease the brace-cutting process for workers. Previously, the workers had to look up and enter precise codes into the machine to cut bracing to correct specifications for the various types of guitars. The touch screen he created simplifies the selection process by allowing workers to tap an area of the screen identified by the guitar model for which they are creating the bracing. Once this selection has been made, the proper codes are automatically loaded and the worker only needs to place wood blanks into machine for laser cutting to specifications.
Pickups
The three most automated parts of Taylor Guitars’ production processes are assembly of the piezo pickups, spraying of the polyurethane finishes on the guitars and buffing of the guitars’ finish.
Assembly of the company’s ES2 piezo pickups begins with a vibratory feeder that feeds the pickups’ crystals onto a conveyor where a Cognex 7010 camera determines the polarity of crystals. These two-sided crystals have a silver (positive polarity) side and a bronze (negative polarity) side. Crystals fed onto the conveyor bronze side up are re-routed through the feeder so that they are all silver side up before being picked by an Epson G3 robot.
In total, three Cognex cameras are used in the pickup assembly process, Robertson said—one to determine polarity of each crystal’s exposed side via a color-sensor camera, another to verify quality of the assembly process, i.e., correct placement of the three crystals into the pickup’s foil, and assessing final assembly of the pickup.
As the crystals are being selected for correct polarity, a worker puts foil down in the pickup molds. The paper backing on the pickup foil is peeled off and discarded by custom Taylor tooling, after which the Epson robot places insulation on the foil and then installs the printed circuit board (PCB). The first robot that picked the crystals off the conveyor then places the crystals into the slots on the pickup assembly. Once the crystals and PCB are in place, the assembly is folded and a second Epson G3 robot brings the assembly to a foil wrapping station.
Another important aspect of the pickup assembly process is the use of Keyence LR-T sensors to detect presence or absence of parts in pickup assembly.
Finishing
The use of a robot to apply a urethane finish to the guitars electrostatically began in the early 2000s, Robertson said. The system for this spray robot application was designed in a joint project between Taylor Guitars and Pinnacle Technologies, a robotics system integrator firm. The system includes an ABB IRB 2400 robot and Rockwell Automation MicroLogix PLCs.
A consistent spray pattern is repeatedly achieved on the various guitars produced by having the robot move the guitar parts under a stationary sprayer. Having a fixed sprayer and moving the guitars under it achieves a better finish, Robertson said, than by fixing the sprayer to a robot arm and having it move around the guitar part.
“My rule of thumb,” Robertson said, “is if the tool is heavier than the part, it’s better to move the part than the tool.”
Buffing
Early this year, the company upgraded its robotic buffing system. Robertson noted that this was one of the first areas ever automated at Taylor Guitars because of the intense ergonomic issues involved in having workers position guitars against high-speed rotating buffers.
The previous buffing system handled 80-85 percent of the buffing process, with the new system handling 95-98 percent of the process. Final finishing, Robertson stressed, is still done by hand.
Like the robotic spraying system for guitar finish application, the robotic buffing system is another joint Taylor Guitars/Pinnacle project that uses an ABB IRB 4600 robot and Rockwell Automation CompactLogix PLCs and Kinetix drives. “The Allen-Bradley motors, inverters and PLCs handle compensation of the buffing wheels,” Robertson explained, which is key to maintaining the correct pressure of the buffing wheels against the guitars.
The ABB robot programs in the buffing system were initially programmed via a root teach pendant. Robertson said he then refined these programs in MasterCam to fine-tune robot movements based on each guitar’s CAD models. “It takes about a week to prove out the process for each guitar type,” he said.
Balluff RFID readers in the buffing area are used for digital thread tracking. Though these RFID readers are only used for tracking now, Robertson said he plans to use them to trigger programs in the Allen-Bradley controls to initiate the proper buffing program for the associated guitar.
The robotic buffing system previously used by Taylor Guitar before this year’s upgrade has been re-purposed by ABB for use in the company’s Tecate factory where buffing is still done by hand. “This will be their introduction to using robots in the Tecate factory,” Robertson said.
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