January/February 2012
Factory Automation

Small multi-axis industrial robots add new twist to lean manufacturing

Small robots offer ultimate in repeatability, flexibility

Fast Forward

  • The development of small multi-axis robots is reflective of the evolution of small robots making them useful in more applications.
  • Smaller robots offer the ultimate in repeatability and flexibility for a range of manufacturing tasks.
  • Two recent installations using small robots illustrate how small footprint functionality increases productivity.
 
By Charlie Miller

Axis1Lean manufacturing is a term that has many interpretations. To some, it primarily means low cost. To others, its core is to realize the highest productivity possible while virtually eliminating waste. Other definitions focus on minimizing human capital and optimizing process motion and flow. Whatever the interpretation, in general, it is to do more with less.

While all of these concepts are clearly related, according to popular sources, the macro view of lean manufacturing has evolved into "the creation and maintenance of a production system, which runs repetitively, day after day, week after week, in a manner identical to the previous time period."

In recent years, industrial robots have helped add a flexibility component to lean manufacturing by allowing multiple parts to be run on a single line, thus better leveraging the investment on capital equipment. While robots offer the ultimate in repeatability, they do not need to perform the same motion to do so. The strength of robots is their inherent ability to be changed, adding a valuable dimension of flexibility to the production process. Rather than running repetitively day after day, they provide precisely repeated motion within a specific production cycle, with the ability to achieve the precise repetition of a completely different motion for the next production cycle, all with what amounts to the simple flip of a pre-programmed switch.

As robots continue to expand their application base from their automotive and heavy industrial roots, smaller, more lightweight robots are being developed, adding a new component to the translation of lean manufacturing. Larger robots are built for stability, strength, and reach, being able to lift and move heavy objects longer distances. Smaller robots, by comparison, are designed for tasks with a lighter payload where a compact work envelope is required.

If the parts to be handled are less than 5kg and the distance travelled is less than 500mm, then some of the newer, compact 6-axis robots available are viable options. Smaller robots are ideal for assembly, machine tending, pick-and-place, dispensing, and packaging applications. Often referred to as tabletop robots, they can be mounted from a variety of angles, from a ceiling, wall, or shelf, allowing for the design of the most efficient work flow possible.

The development of small multi-axis robots is reflective of the evolution of small robots and the considerations that have led to their emergence. For example, the recently introduced IRB 120 is ABB's smallest ever 6-axis robot, weighing just 25kg (55 lbs), with a standard payload of 3kg (6.6 lbs) and a reach of 580mm. When the design work first began on the IRB 120, it was intended for assembly work in the electronics industry. The idea was to make an affordable robot suited to low-cost countries where electronics are typically manufactured. But they soon caught on, domestically and abroad, as other industries found these robots improve productivity and are easily integrated into new and existing production lines. The installed base has extended to a variety of industries including pharmaceutical, packaging, food and beverage, automotive, and solar photovoltaic manufacturing. One of the key features of this new class of smaller, compact robots is they are able to work very close to other machinery in a production line. A typical base for these robots is 18 centimeters by 18 centimeters, the size of half a piece of A4 paper.

This class of robots typically weighs just 25 kilograms and has a very compact turning radius, enabled by the robots symmetric architecture, without offset on the second axis. This ensures the robot can be mounted close to other equipment, and the slim wrist enables the arm to reach closer to its application.

These compact robots also offer an advantage when mounting the robot upside-down, as it can be installed at a relatively low height, once again saving space. At the same time, these robots do not sacrifice reach. Typical "stroke" measures 411 millimeters, which is long compared to its total reach of 580 millimeters.

The size of controllers for this new class of robots has been reduced, as well, by as much as 80% compared to conventional robot controllers. These small robots are also becoming available for Clean Room ISO 5 applications.

Two recent installations using small robots demonstrates how the small footprint functionality is easy to integrate into existing lines while providing the same functionality as larger, more traditional industrial robots.

L'Oréal cosmetics

The international cosmetics industry is a competitive, fast-paced business. When demand from hair salons across Europe skyrocketed in 2009 for L'Oréal's INOA (the world's first ammonia-free permanent hair color), the French cosmetics giant made plans to ramp up production.

L'Oréal Canada needed to set up a packaging line in Montreal for hair coloring products quickly. The highlight of the solution was a brand-new, small robot.

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ABB IRB 120 robot places tubes of L'Oréal INOA hair coloring dye into boxes.

At the time, L'Oréal Canada's flagship plant in Montreal had two production cells that churned out some 150 million units a year of hair-coloring liquids and creams. The facility was asked to begin manufacturing large quantities of INOA in only four months.

"It was a huge challenge," recalled Guy Fafard, the plant's technical supervisor. "When we discussed it with our production manager, he said there was no way we could design and install a new production line in such a short period of time. He said it simply couldn't be done. But we had to find a way to make it happen."

Fafard turned to PharmaCos Machinery, a local leader for turnkey solutions in pharmaceutical and cosmetics packaging equipment that often does custom, needed-it-yesterday production projects for L'Oréal Canada. Within days, the company's technological development director, Sylvain Gauthier, was walking the floor of the busy plant with Fafard to get a firsthand feel for the project.

"It was a complicated mandate," said Gauthier, who worked as a technician at the L'Oréal Canada plant for 10 years before joining PharmaCos a decade ago. In addition to the tight deadline and the use of an explosion-proof tube filler (because INOA uses small amounts of alcohol in place of ammonia), the new line needed to be able to take tubes, put them in trays, and load them (plus an instruction sheet) into a ready-to-ship package.

According to Gauthier, such a two-step, two-micro-stop cartoner process would normally be done manually. However, it was critical the new line always keep moving, because a stop would cause the pressurized fill to overfill the first tube (due to the positive pressure in the reservoir). He also had to respect the plant's production philosophy of having only a single operator for small lines such as the INOA project. "My only option,"Gauthier recalled, "was to design and build a new conveyor based on a 29mm center-to-center tray and a small robot."

While talking to ABB's Canadian office, Gauthier learned ABB was in the process of bringing its smallest ever six-axis robot to market. Such a small robot would fit the limited space requirements of the workspace, be easy to set-up, begin production quickly, and be easily accessible for frequent maintenance. All while providing the precision necessary to deftly handle the product, and the future flexibility to be easily reprogrammed for different tube sizes and configurations as consumer demands change.

After a 3-D model with ABB's RobotStudio design simulation software, it took Gauthier only two months to build, assemble, and test the new line. The solution integrates a Kalix cartoner system, an IRB 120 robot from ABB, and an Allen-Bradley programmable logic controller (PLC) to keep count and control input and output. "Once we got it going, it worked like a charm," said Gauthier.

BDMO custom packaging manufacturer

Vivabox gift packages are distinctive, and in Belgium, consumers know they contain quality products. The packages have become so successful-they number about half a million per year-they have become a brand in their own right.

Vivabox is one of packaging producer BDMO's largest product lines at its factory in Meulebeke, a town in Flanders, Belgium. The manufacturing process of the actual box and its lid involves several stages, all of which are automated on various product lines. For example, the carton has to be cut, scored, folded, and taped. After that, the relevant printed cover is applied.

Until recently, the last part of the process was not automated. It involved inserting a thermoplastic tray, and different trays are used to hold different gifts. For example, one may be used to hold four miniature bottles of malt whisky, while another might hold coffee sachets, two cups, and saucers.

These thermoplastic trays were inserted by hand because they are relatively thin-they flex, and the fit has to be tight. Up to that point of the process, automation produces 1,000 boxes every hour. That meant up to seven people were needed to keep up with the flow of boxes, one every three seconds.

 Axis3
An invert mounted ABB IRB 120 run 16 hours a day, inserting 1,200 packaging trays an hour.

Could the insertion of the tray also be automated? That was the question BDMO put to Viscon, a local systems integrator, after Daniel Callewaert, BDMO's maintenance manager, saw a roadside video wall that promoted their robotics and transport automation expertise.

After several rounds of consultation and due diligence, Viscon's proposed a "pick-and-place" system that could handle 1,200 trays an hour. The tight fit problem was resolved by using the 6-axis functionality of ABB's IRB 120 robot; it inserts the tray at an angle before pushing it firmly down to the base and onto spots of glue.

The resulting solution now runs 16 hours a day in two shifts, and the personnel head count has gone down from seven to three. Needless to say, the cost savings have been significant. The solution was fine-tuned after the initial trial, and this boosted the placement rate to 1,400 trays, thereby adding additional reserve capacity.

"The earlier production speed of 1,000 Vivaboxes was determined by the manual insertion process," said Pieter Debucquoy, BDMO's maintenance coordinator. "The robotic solution gave us an immediate 20% boost, and after the fine tuning we have the possibility to add an additional 15%." Ironically, the preceding part of the process has become the new bottleneck.

BDMO produces more than 10 million packages a year. With the flexibility of robots to easily adjust to a variety of packaging shapes, sizes, and construction geometries, looking ahead, BDMO is likely to deploy additional smaller robots to automate other packaging production processes.

ABOUT THE AUTHOR

Charlie Miller, vice president of sales for ABB Robotics, has more than 25 years of experience in the industrial robotics industry. Miller started in the Flakt Division of ASEA in 1985 (Flakt was later rolled into ABB in the 1988 merger of ASEA and Brown Boveri.), and he has been in numerous positions including project engineering, project management, proposal engineering, proposal management, business unit manager, product management, and sales management. For more information, please contact sales.info@us.abb.com.