Whether it's the latest "Star Wars" prequel or an automotive factory, everybody loves big robots. These days, though, more and more of the action is happening at the smaller end of the spectrum. Tabletop robots are becoming increasingly common, doing everything from driving fasteners and dispensing adhesives to creating solder joints in the electronics sector.

According to Vladimir Siroky, president of I&J Fisnar Inc. (Fair Lawn, NJ), there are a number of reasons for this trend, not the least of which is cost. Siroky says his company, which specializes in liquid dispensing, began marketing robotic systems in the mid-1990s. Since that time, prices have fallen as much as 50 percent, making the technology available to manufacturers for whom it would have been prohibitively expensive in the past.

"We have units for under $5,000," he says. "Now a job shop of two people can afford [robotics]. Even a hobbyist making trinkets can afford it these days."

Another reason for the growth in the small robot market is increased capability. Robots these days not only cost less, they do a lot more. On the one hand, robots are easier to use. On the other, they are able to provide greater functionality, especially when combined with machine vision.

In fact, according to John Dulchinos, vice president and general manager of robotics for Adept Technology Inc. (Livermore, CA), in many cases vision is an "integral part" of what small robots do.

As an example, he cites an application in which one of his company's Cartesian robots was put to work driving tiny screws into computer disk drives. This was necessary because there was some "float," or uncertainty, in the fixturing. The system overcame the uncertainty by using machine vision to find the exact location for the screws.

"We really drive a tight coupling with vision," Dulchinos says. "It almost becomes a requirement."

Thomas Rougeux, sales manager for Visumatic Industrial Products Inc. (Lexington, KY), agrees. His company, which specializes in automatic fastener feeding and driving equipment, offers of number of systems built around both SCARA and Cartesian robots. In addition to locating holes, his company's systems can perform inspections and create a permanent records of their work.

As an example, Rougeux describes a robotic cell his company built for a seat belt manufacturer. To eliminate rejects, the cell confirms that all the necessary components are present before driving a single screw. After performing its screwdriving operations, the system creates a digital file so the part will be NIST traceable.

"Plan, do, check," says Peter Cavallo, sales manager for Denso Robotics (Long Beach, CA), summing up his company's philosophy when it comes to its robots. "We've made sure that any of the products we introduce can work with vision."

Ease of Use

In terms of programming, today's interfaces are far more intuitive than in the past. Most systems are programmed using a linked PC or teaching pendant. In an interesting twist, EFD Inc. (East Providence, RI) has developed a system whereby the operator can use a personal data assistant to program its dispensing robots. And the company is adding Bluetooth wireless technology to this setup to make it friendlier still.

Whatever the interface, the latest generation of programs automatically interpolates lines and arcs in three dimensions, often employing Windows-based software to make programming far easier than in the past. With some packages, CAD programs can be used to input coordinates at the start of the process.

"Once you know the building blocks of the routine, it becomes easy.... If you play Nintendo, you've just had your first lesson," says Siroky. He adds that many of his customers implement their robots without any help, simply ordering them from the company sight-unseen.

Fabio Okada, product manager for automation at Liquid Control (North Canton, OH), notes that when it comes to programming, especially in dispensing applications, the key isn't just inputting the basic pattern for, say, a bead of adhesive in the groove of a cell phone housing; it's fine tuning that dispensing line so you get just the right amount of material precisely where you want it.

"The basic pattern can take 10 minutes to a half hour," Okada says. "The fine tune can take hours.... That's where the new interfaces can make a real difference."

According to Okada, when his company made its first foray into robotics, customers needed a 3-day training course to learn how to create their dispensing patterns. Worse yet, because the process was so complicated, when it came time to reprogram for a new model or product line 6 months down the road, those same customers would have forgotten all they had learned the first time around. Inevitably, that would mean a visit from a technician or some kind of refresher course. Now the training process takes about a half hour.

Cavallo compares the situation to that of personal computers, which have become infinitely more user friendly over the years. "You used to need code. Not anymore," he says.

Getting it Right

Then there is the question of quality. Whether it's dispensing, fastening or soldering, there's just no way a human being can be as precise as a robot. This is especially true for larger product runs, or when working with small assemblies or extremely small parts.

In the area of dispensing, for example, a small tabletop Cartesian system like the I&J2200 from I&J Fisnar, the Loctite 203 benchtop robot from Henkel Corp. (Rocky Hill, CT), the Contour 400 XYZ system from Liquid Control or the Ultra TT series from EFD Inc. can dispense dots or beads with a positional accuracy and repeatability of 0.01 millimeter.

Parts can be fixtured either individually or grouped on a pallet, with the robot performing a gasketing, sealing, potting or filling operation on each assembly in turn. In a semiautomated tabletop setting, the operator simply loads the parts to be treated by the dispensing operation, then unloads them when the robot is done.

The situation is similar when it comes to soldering in the electronics sector. Fancort Industries Inc. (West Caldwell, NJ), for example, offers a number of automated soldering stations built around the Janome series of tabletop Cartesian robots distributed by Jamac Inc. (Elk Grove Village, IL). These systems perform both point and line soldering, with a repeatability of 0.01 millimeter in a work envelope from 320 to 584 millimeters wide and 377 to 629 millimeters wide, depending on the model.

In the area of threaded fasteners, robots have no problems handling parts that are too tiny for clumsy human fingers. Companies like Visumatic offer turnkey systems, complete with controllers, drivers and feed systems. Similarly, PennEngineering (Danboro, PA) offers Cartesian systems that work with its proprietary Stickscrews-lightweight "sticks" of up to 110 serially connected hex head screws-for fast, efficient fastening. AIMCO (Portland, OR) offers a number of benchtop screwdriving systems based on both SCARA and Cartesian robots; the same is true of Kolver USA (Westford, MA) and VSI Automation Assembly (Auburn Hills, MI). Coupled with torque control and monitoring, these kinds of systems deliver virtual perfection in terms of precision and quality.

Indeed, Rougeux believes it is this quality, coupled with robotics' flexibility, and not price that is often the true deciding factor for companies making their first investment in robotics. On the one hand, manufacturers need to be able to change on the fly to accommodate shorter and shorter product life cycles, especially in electronics. On the other, OEMs these days have little if any tolerance for defective products from their suppliers, seeing such defects for what they are-added cost and waste.

Citing the example of a Tier 1 auto supplier manufacturing HVAC systems, Rougeux notes that by providing a product that will not squeak or rattle down the road, a supplier can save its OEM customers tens of thousands of dollars.

"The Lean-Sigma movement is demanding quality," Rougeux says. "Incorporating robotics makes our customers more competitive.... It's an area in which we can keep jobs in the United States."

In terms of the type of robot used in small, tabletop applications, the choice has traditionally been Cartesian systems. But that is changing as performance goes up and cost comes down for robots of all kinds.

For example, while Cartesian systems are still the least expensive, SCARA robots-the fastest of the different robot types-are becoming increasingly affordable. They have also become easier to program, another former selling point for Cartesians.

The result has been compact SCARA robots like the Adept Cobra 600, the small end of the IX series from Intelligent Actuator Inc. (Torrance, CA), the E2C line from EPSON Robots (Carson, CA), Denso Robotics' HS series, the Janome JS series, and the SR4+ and SR6+ from Stäubli Corp. (Duncan, SC).

Similarly, five- and six-axis robots are coming down in price and becoming more precise-a problem when compared to SCARA and Cartesian systems in years past. Subsequently, diminutive models like the Pro Six from Epson Robots, the RV-2AJ from Rixan Associates Inc. (Dayton, OH), the AdeptViper, the UPJ from Motoman Corp. (West Carrollton, OH), the VP series from Denso Robotics, and Thermo Electron's CataLyst-5, manufactured by Thermo CRS Ltd. (Ontario, Canada) and distributed by Robots Dot Com Inc. (New Berlin, WI), are beginning to encroach on SCARAs.

These units offer repeatability of 0.02 or 0.03 millimeter, depending on the model. Because of their flexibility, they can perform parts handling operations that might be beyond the ability of a SCARA or Cartesian.

Glen Blok, president of Robots Dot Com Inc., says his company has sold a number of CataLyst-5 robots, which do everything from dispense adhesive to load parts into a machining station. With a payload rating of just 1 kilogram and a 660-millimeter reach, the small 5-axis unit is ideal for small jobs.

As Dulchinos puts it, "They enable applications that could not be automated... without a lot of pain."

The net result of these developments is a kind of downward pressure, resulting in the expansion of robots into areas outside of the automotive arena, where they have traditionally been most common. Specifically, five- and six-axis robots are now encroaching on SCARAs while SCARAs are beginning to take over from Cartesians, and Cartesians are displacing hard automation.

By way of example, Dulchinos cites a cellular phone manufacturer that recently implemented about 60 six-axis AdeptViper robots. In the beginning, the customer had doubts the six-axis machines were up to the task. But in the end they proved a success.

"There was an exhaustive qualification process," Duchinos said. "We really had to prove that our AdeptViper had the speed and precision of a SCARA."

"We used to do mostly Cartesian," says Rougeux. "Now we're seeing about fifty-fifty because the cost of SCARAs is coming done."

As is the case with larger robots, when creating a new system it's important to take into account the size payload the robot will be handling, so it will be up to the task. Liquid Control, for example, offers the C-450, a small, robust Cartesian system with heavy-duty motors and slides to accommodate the heavier equipment associated with dispensing hot-melt adhesives. Similarly, I&J Fisnar offers a wide range of robots with different payload ratings and work areas. It also has Cartesian robots that are open ended on one side to facilitate the easy handling of larger parts.

When thinking about small robots, bear in mind that terms like "tabletop" and "desktop" are fairly broad terms, and that, in fact, different types of systems require different types of mounting.

Self-contained Cartesian systems, for example, can be easily implemented as true benchtop units. There are plenty of manufacturers who mount their integrated robots and platforms on rolling carts, which can then be pushed from station to station, wherever they happen to be needed.

SCARA robots, on the other hand, because of their speeds and the size and weight of their moving parts, need to be securely mounted; this means a solid, firmly attached work surface.

Five- and six-axis robots also need a good solid mounting, although depending on their size and the nature of their application, they can be employed in a fairly portable mode. As an example, Blok cites the case of a parts-unloading CataLyst-5 that was mounted on a table that could be rolled from press to press. He warns, though, that to make this work, the table had to be securely and precisely attached to each different station.

Whatever the robot, and whatever the application, manufacturers that are new to robotics tend to like what they see. According to Jonathia Ang, EFD's international marketing manager for machine integration, it's not unusual for companies to start out with a single trial version and then come back for more.

"People don't realize the hidden costs involved in a manual process," Ang says, citing issues like defective products, wasted material and lower throughput. "When they move into [robotics] all these costs become apparent. In today's environment you cannot afford to not be on your toes."