and the consistency we need,” he points out.

“If we had people handling our wafers, our yields would be horrendous,” adds Kane. Because the razor-thin solar wafers are brittle and extremely fragile, they could not be handled by human operators without high rates of breakage, he explains. This problem can be avoided with robots designed to be gentle. One method used by vendors, including ABB, Adept and others, is the use of Bernoulli grippers. Based on the Bernoulli effect, these grippers rely on a high-velocity airstream to ensure that wafers are lifted gently without contact being made.

For its solar cell wafer handling area, Evergreen Solar relies on high-speed Delta-style parallel robots, primarily ABB Flexpickers supplied by ABB or Manz Automation, a Germany-based robotic integrator, says Kane. “Between EverQ and Devens, we’ve got almost exactly 100 parallel robots in production,” he notes. The four-axis, three-arm parallel robots are overhead mounted, and can handle more than 150 picks per minute. Integrated vision technology not only provides robot guidance for wafer picking, but also for quality inspection. “We look for cracked cells or edge defects, things like that,” Kane relates.

In its solar panel production areas, Evergreen relies on Kuka robots in at the Devens plant, and on robots from Reis Robotics, a German supplier based in Obernburg, in its EverQ operations. “They’re mostly large, six-axis robots for handling fairly large payloads. The panels typically weigh up to 30 or 35 pounds and the end-effectors can weigh quite a bit more than that,” says Kane. “We have about 28 six-axis robots in Devens.” A variety of robot models are used, some on gantries for axial movement, others stationary, for numerous glass handling and panel assembly applications.

In the panel production area in particular, Evergreen has found the flexibility of robots to be useful during the fine-tuning of its production processes. In one instance, for example, modification of a tape head on a robot that applies edge gaskets to the solar modules required a corresponding change in motion—a task that was made easy by simply reprogramming the robot, says Kane.

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In fact, as noted by Fanuc’s LaSelle, the flexibility of robots is especially important in an emerging industry such as solar, in which many manufacturers are start-ups that are still perfecting their processes. “There are a multitude of people in the space that have a product, and from a physics and lab standpoint, it’s fantastic. But from a manufacturing standpoint, it’s in need of refinement,” LaSelle observes. This is where robot manufacturers and experienced robot integrators can help, he notes. The work that Fanuc has done with Energy Innovations, a solar industry start-up, is a good example, LaSelle says (see “Robots Make Modules Manufacturable,” ).

Robot makers say that in many cases today, new robot installations are either going in to replace jobs that were previously done manually, or they are being designed into new, greenfield factory operations. Fixed automation is an alternative for some tasks, but many jobs can only be done by robots, vendors contend, due to a need for speed, flexibility and other factors.

As solar technology advances, for example, solar cells are being made increasingly thin—going from about 300 microns to 150 microns or thinner—making them impossible for humans to handle without significant breakage, says Adept’s Dulchinos. ABB’s Busch concurs. “There are companies that are testing our Flexpicker down to a thickness of 160 microns, and even thinner,” Busch says. The trend will necessitate the use of robots such as the Flexpicker and Adept’s Quattro s650, a four-arm parallel robot, these men say.

The payback from robots for solar industry users can come typically in a year, and definitely within two years, says Adept’s Dulchinos. “If you can drive twice the throughput out of the same amount of factory space, you cut your overhead expenses in half, because they’re going out on twice the volume. So the justification for robots is you drive much higher throughput out of a factory” he says. “You save labor, you lower scrap and you improve quality.”