Tanya M. Anandan, Contributing Editor, Robotic Industries Association
Plastics molders' best friends come in all shapes and sizes. One thing they have in common – they're all robots.
Robots are not new to plastics processing, but they're certainly garnering more attention. Cartesian or linear robots, sometimes called beam robots, have traversed the industry for decades, loading and unloading injection molding machines with deft speed. By brands often exclusive to the industry, such as Sepro, Yushin, and Whittmann Battenfeld. But a closer look reveals traditional robot manufacturers like ABB, Stäubli, and KUKA, plus a new breed of cage-free collaborative robots making moves in plastics.
New, four-axis linear servo robot for pick-and-place injection molding applications features a unique design. (Courtesy of ENGEL North America)Gains in productivity, quality, product life cycle flexibility, and labor savings are driving the interest in automation among large and small companies alike. Meanwhile, trends in multi-shot molding, in-mold labeling and decorating, and composite part fabrication are boosting the demand for advanced manufacturing methods.
Record-Breaking
The North American robotics market had its strongest year ever in 2014, according to statistics from the Robotic Industries Association. Other than automotive, the largest increase is in plastics and rubber at 25 percent. By all accounts, 2015 is poised to break more records.
In turn, some robot OEMs are ramping up to meet the demand, including Whittmann Battenfeld with a reported $1 million expansion at its Connecticut plant and Yushin with a $2 million expansion in Rhode Island. These robots not only make plastics, they create jobs.
According to the International Federation of Robotics, which tracks worldwide stats, 2013 was also a record-setting year. IFR notes that the plastics and rubber industry continuously increased installations between 2009 and 2013, posting a 110 percent increase. Get the full story here.
So why the big surge and who has the most to gain? Well, it depends on who you ask.
In this 'Why I Automate' episode, a plastics manufacturer explains how they grew their business and workforce with robotics automation.
Productivity Gains
ABB Robotics recently opened a new robot factory at its North American headquarters in Auburn Hills, Michigan. Helen Ke Feng, ABB's Global Segment Manager – Plastics, credits productivity improvements as one of the top reasons plastics processors adopt robots.
"We've seen cases where customers have achieved 15 to 30 percent productivity increase after they installed robotic automation," she says. "That means a lot in terms of competitiveness and also their overall production costs."
Feng says another goal is to improve quality to increase yields. "This is especially beneficial with some of these carbon fiber composite materials, where the material cost is extremely high. If you can save raw material costs, it benefits you on the overall production costs as well."
With product life cycles getting shorter and part changeover getting more frequent, flexible automation is definitely an advantage.
Jay Sachania, General Manager of Automation for ENGEL North America in York, Pennsylvania, attributes the upsurge to cost savings, flexibility, and cycle time. Founded in 1945 and rare in the plastics industry, ENGEL does it all. This family-owned Austrian company not only manufactures injection molding machines, but it also supplies robots and other automation equipment, and provides turnkey systems integration.
Global markets include automotive, medical, packaging, electronics and consumer goods. Clearly, ENGEL has insight from several vantage points into the fast-paced world of plastics processors.
"Customers are basically asking for the cell to do as much as possible during the molding process," says Sachania. "With some of the applications out there, there's no way a person can maintain the cycle time requirements for a high-speed application. A person simply can't keep up."
This video shows a fully automated injection molding cell for automotive dashboards that combines three production processes into one cell.
ENGEL is the only injection molding machine manufacturer that offers a tie-bar-less design, and is celebrating the 25-year anniversary of its patented technology. This video shows ENGEL's tie-bar-less machine in action.
A typical injection molding machine has four tie bars, two upper and two lower, that help stabilize the moving platens. ENGEL's design eliminates these bars entirely while still maintaining the parallel position of the platens. This allows for large molds to be used on a smaller machine and is ideal for robotic automation, as there are no tie bars to get in the way.
Speed
In addition to its established viper line of linear robots, ENGEL recently introduced its e-pic linear servo robot (pictured previously) geared for pick-and-place applications on low-tonnage injection molding machines. The e-pic has a unique, hinged design that allows it to operate in a large work envelope but fold in on itself for a compact footprint when needed. Plus it's made of lightweight composite materials for faster cycle times and less energy consumption.
"It's a design that didn't exist in the market," explains Sachania. "If you look at the kinematics of that particular robot, you will see that the x-axis, as we call it, moves in and out. It basically moves out of the way if there's a mold or some other obstruction in its path."
This video demonstrates the ENGEL e-pic robot. Note the unique movement of the "x-axis" as shown at 3:07 in the video.
Beyond the Cartesian axes, the c-axis on the end of this robot arm provides a rotational up-and-down wrist-like movement. Gaining in popularity, linear robots with servo wrists in a, b and c axes are designed for complex demolding and secondary operations.
Sachania says the advantages of linear robots are speed and cost. Compared to 6-axis articulated robots common to machine tending applications in many other industries, Cartesian robots are generally less expensive.
Shelf-mounted six-axis articulated robot allows for more flexible handling of parts in injection molding machines. (Courtesy of ABB Robotics)"They are much faster," he says. "You're looking at more cycle time advantages because you don't have to manipulate the axis around."
He says ENGEL, as a systems integrator, considers each application individually to determine the best solution, whether it's a Cartesian robot or a 6-axis articulated robot, or yes, even a SCARA. Check out the whirling SCARAs in this production cell for an intricate sensor housing requiring 15 inserts per cavity in a four-cavity mold.
Flexibility
Six-axis articulated robots are renowned for their dexterity and flexibility. ABB's Feng compares them to their Cartesian cousins.
"In the machine tending area, when the weight of the part is smaller and especially when the cycle time is shorter, it's mainly the Cartesian or linear robots that you see in injection molding. But when you need manipulation inside the mold, like for insert molding, or when you're taking the part out and you need some combination of work outside of the machine, then you see more of the six-axis robots. That's the trend. Customers are looking into the six-axis robots that can offer them more flexibility, especially right now when product life cycles are getting shorter."
"In the past, six-axis robots have been viewed by injection molders as expensive and somehow complicated to operate," explains Feng. "But as the technology advanced, the cost of robots declined, and the programming of robots became easier, those injection molders or plastics processors began to realize the benefits of using more robotic automation in their production. Even in China, they're using six-axis robotic solutions to address the challenges of increasing labor costs. They can't find skilled operators. In the U.S. and Europe as well, there is ongoing reshoring production."
Feng says six-axis robots play a larger role when you have a complicated, or complex, molded part.
"If it's a complicated part, you can't directly eject it from the mold. Because of the mold or space limitations, you need the six-axis robot to help you rotate the part and maneuver it out of the mold. The benefit of that is you can have the robot doing two jobs. Not only taking the part off the mold, but also while it's waiting for the mold to be reopened, you can have the robot performing additional work. That increases productivity and is why six-axis robots are getting more popular in plastics processing."
Six-axis robots can be shelf-mounted on top of the injection molding machine or mounted next to the machine.
"ABB has both shelf-mounted and floor-mounted robots," says Feng. "It really depends on the space availability and also the overall factory layout. If you have limitations overhead, then you may prefer to have a robot next to the machine on the floor. If you have floor space limitations, then you may be looking at the shelf-mounted robot."
Full Integration
Robots in this industry come in coats of many colors. Sometimes they're gold, or blue, and other times green. Nevertheless, they perform their tasks as assigned and represent their respective brand-of-the-moment with distinction.
See how a six-axis and a SCARA, both Stäubli robots, team up to mass-produce brake light switches in this injection molding cell.
In this video, composite automotive brake pedals are manufactured in a one-shot process using an ENGEL insert injection molding machine serviced by an ENGEL easix robot (pronounced E-A-six, for easy six-axis integration). Compared to steel brake pedals, the composite part results in a weight savings of approximately 30 percent, according to the company.
Sachania says ENGEL's easix robot is fully integrated with the injection molding machine, so you only have one control system and one programming language. This improves ease of use. It also has cycle time advantages and cost savings, since you don't need to integrate two separate platforms from different providers.
"Automotive has been, and still is, the main industry for robotics and automation use given the size of plastic automotive parts like bumpers and dashboards," says ABB's Feng. "Besides automotive, we see robots used in packaging, especially for in-mold labeling, and in consumer electronics and consumer housewares. It could either be robots near the machine, doing machine tending, or robots in downstream processing, like in deburring, polishing or assembling. Or even in end-of-line production, doing the packing and palletizing of plastic products."
In this video, KUKA robots work in tandem producing plastic fans in an injection molding cell.
Composites, the Next Wave
The adoption of composite materials across broader industry is a growing trend. Carbon fiber reinforced plastic (CFRP) is increasingly used to reduce the weight of components and boost fuel efficiency, especially in the transportation industry. Some of the carbon fiber parts are even stronger than the steel parts they replace.
"In the past, the main user of carbon fiber reinforced plastic has been aerospace," explains Feng. "Their volume is small and the processing time is long, so you see a lot of manual production."
"However, there's this environmental push coming in the automotive industry, especially in North America where they are trying to reduce the weight of vehicles," she continues. "CFRP is one of the options they are investigating. They need to meet the requirements of mass production of automotive parts and also they need a stable, high-quality process making high-quality parts at relatively faster speeds. That's where we see automation can help, so we already have some initial studies underway.
Robots can be used in the picking and placing of the cut prepreg pieces, as well as in automated tape lay-up (ATL) and automated fiber placement (AFP). Here's a jumbo-sized AFP project where you wouldn't want your process to be off, even a smidgen.
"Because of the material change and processing change, it has some new challenges that we need to find solutions for," says Feng. "That's the other area we are looking into, such as cutting, trimming, and drilling of composite components, and material handling among workstations. We also see the joining of the composite parts."
The composites world will continue to present new challenges and opportunities for automation and robotics. We'll be watching.
ROI for SMEs
With labor costs steadily rising, the skills gap widening, and robot technology costs coming down while ease of use is going up, robotic automation is no longer the exclusive domain of multinational conglomerates. Small to medium-sized enterprises (SMEs) can cash in on robots too.
In this video case study, a small injection molder learns you don't have to be a large company to realize the productivity benefits of robotic automation. The integrated cell uses a vision-guided ABB IRB 1600 robot to load/unload an injection molding machine processing pre-fabricated plastic components for ear protectors. The robot also facilitates plastic waste removal and part inspection.
What was previously a manual process is now a fully automated cell that can run around the clock, even in a lights-out scenario.
"That's really a big improvement for them," says ABB's Feng. "They are a very small company in a country with high labor costs. However, they are gaining very strong competitiveness in the world market. It doesn't matter if you're a multibillion dollar company or a small enterprise, there's always a way that robots can help you."
This article was originally published at Robotic Industries Association. You can read the full version at their website.
