Robotic solutions are making a strong impact in the design of new packaging machines. The trend is driven, in part, by expiring patents for the mechanical design of Delta robots which has created a marketplace opportunity for suppliers. But the bigger issues driving adoption are the mechanical flexibility of robotic solutions, versus fixed automation, and new control strategies.

Robotics and software

These approaches allow machine line controllers with advanced motion and kinematics capability to directly control the robot, providing higher performance and potentially lower cost solutions. The result for packaging users and OEMs is new possibilities in terms of robotic capabilities, improved line integration, better overall machine speeds and quicker product changeover times. The challenge is selecting the best robotic integration approach for the application and determining the impact on overall machinery design.

“One of the most exciting developments in packaging machines is the trend away from 'black box' controllers for robotic applications,” says Rami Al-Ashqar, motion control product manager for Bosch-Rexroth. “Robotics are becoming more embedded and integrated into the whole machine design and engineers have the same robot controller doing other tasks such as PLC I/O and general purpose motion. Engineers are integrating the kinematics and robotics directly into the overall machine controls, rather than using the black box approach.

Al-Ashqar says, in the past, packaging OEMs typically used standard robots. But now this has opened up, especially with the mechanical design patents for the Delta robot expiring and the packaging OEMs offering replacement solutions for the Delta robot and simplifying integration for the end user.

“Using this approach, robotics is now part of the machine,” say Al-Ashqar. “Engineers can program robotic functions more easily and the same controller can control multiple robots or control the robot and a six-axis case packer all in one controller. Systems are embedded into the control scheme of the machine, versus a stand-alone system.”

Since the patents on the Delta robots ran out near the end of 2007, OEMs and integrators have been developing different solutions. There are still many question marks on the direction this will take and, ultimately, what solution will be best. Suppliers are testing the water since the design is open for anyone to make and some OEMs are making their own Delta arms.

“It will take another year or 18 months to see what control approach will be the best,” says Al-Ashqar. “Is it to have an integrated solution or to go directly to the end user and sell a robot or to partner with OEMs to sell their own robots? There are many different factors but our emphasis is finding good control solutions and partnering with OEMs.”

Robotic programming options

A primary challenge is engineers who are used to programming in a robotic language because it is the way they have done it for years and years. Now, vendors are saying you don't have to do that and you can program your application and control the robot by writing the code in logic. Some vendors are embedding the robotic language into their software scheme, so that presents a challenge for how to interface or handshake between the robotics subsystem, I/O and other motion on the machine.

It's the question of how to integrate this embedded robotic control into the machine. Software integration is the key obstacle and it represents the primary difference between the offerings of various vendors.

“The question is what kind of language does the supplier provide for robotic programming? Are we giving them a robotic language like they are used to or asking them to program from scratch using ladders. It is a choice and a completely new toolset. This is where control vendors are competing and providing different solutions,” says Al-Ashqar.

Al-Ashqar says the performance of the hardware is also important if the machine integrates robotic, motion control and I/O processing using a single controller. The key is maintaining performance and still delivering a Delta robot, 150+ picks per minute.

He says speed is the critical factor and the reason why OEMs are using robotic solutions. But versus standard robots, embedded robotic solutions are also making it easier to integrate the robotic control scheme into the rest of the machine and delivering lower overall costs.

Line controller integration

“There is an increase of robotics usage in both primary and secondary packaging, along with a strong desire from a technology standpoint, to control the robot with the machine line controller, eliminating the need for a dedicated robot controller,” says Bob Hirschinger, product marketing manager for Logix Motion at Rockwell Automation. Typical applications where robotics is being used include pick-and-place infeed control, case packers and palletizing.

Hirschinger says that, especially with some Delta patents expiring, the range of robot arm options has been increasing and the cost of robotic solutions has been decreasing as new suppliers enter the market. Some OEMs are designing and building their own robotic arm solutions and, in many cases, these vendors and OEMs look to standard, off-the-shelf control solutions to control the robots. Often, these off-the-shelf control solutions are the same PAC-based controllers used to control the rest of the packaging line.

By integrating control of the robot into the main line controller, engineers can use common hardware and programming tools, provide a much higher degree of robot integration and provide higher system performance than when a dedicated purpose robot controller is used. Advantages include common servo drives and motors, common control system hardware and I/O, common vision and safety solutions, a single application program based on one or more of the standard IEC 61131-3 programming languages and a common EOI with customized robot control screens and integrated recipe management.

Increased use of robotics in packaging is driven by users looking for more flexible lines and quicker product changeover times with the ability to run a broader range of products on a common line. Robots offer more configurable mechanical solutions than fixed automation. Simple recipe changes can change the type of product a Delta robot, for example, is picking and placing rather easily compared to a fixed mechanical actuator. The system is fully programmable and it is easier to handle multiple product types on the same line.

The impact of more robotics in packaging machine design is driving the performance of machines, quicker product changeover and designs that result in more flexible machines that handle a broader range of products. Users can select new recipe data at the operator interface and automatically the machine configures itself for the new product, eliminating the need for costly manual changeover. Access to production information is improved, along with collection of more data for analyzing the performance of the machine and monitoring production.

“The approach uses less fixed automation and is totally flexible,” says Hirschinger. “When a new recipe is selected, the machine including the robot automatically reconfigures itself for the new product. With the robot operated by the line control, it is much easier to manage that recipe information and the single control system also makes it easier to achieve FDA validation than with a separate control system.”

Robotics growth in packaging

According to John Kowal, global marketing manager for Elau, there is rapid growth in robotic primary and secondary packaging applications, as opposed to the more traditional stand-alone articulated robots with big footprints doing palletizing and case packing,

“A major trend is the packaging OEM either designing their own arms or using ours within a packaging machine frame, along with a robotic software library to do the kinematics and control the rest of the machine from a single program running on a single processor,” says Kowal.

“Robotics in packaging is less about repetitive tasks and more about controlling space and controlling product. A robot is a simple way to accomplish these complex and dynamic tasks.”

Elau worked with packaging OEM Cavanna to add continuous motion to its robotic cartoner at Interpack. Replacement of intermittent carton transport with continuous motion during the filling process was made possible by the integration of a fourth axis, which opens an additional degree of freedom for the head of the pick-and-place and simplifies presentation of individual products.

Cavanna's G35 robotic island is the heart of a fully automatic inline machine for primary and secondary packaging of wafer cookies of two different sizes. The line has the capability to flow wrap individual wafers, fill a display carton in a product configuration with 12 wafers each and then flow wrap the resulting open-top display multipack.

The packing line offers an upstream conveyor system that regulates flow of unwrapped product into parallel lanes. An integrated buffer system stacks 21 rows of 16 large products or 37 rows of smaller products. Next, the conveyor system transfers products to a stream feeding system with multiple servo-driven conveyor belts that single lane the products into a horizontal Zero 5 flow wrapper which, in turn, packs up to 500 products per minute.

The flow wrapper transfers the packaged product to the infeed of the G35 robotic island. The EF version has two robots and packs products into lidless display cartons, so a third robot for closing is not needed. The first robot picks four carton blanks and forms, closes and seals the cartons with hot melt glue. This process utilizes an intermittent infeed, after which the displays go through the filling procedure continuously. A servo-driven inline feeding system supplies the filled cartons to the downstream horizontal flow wrapper, a Zero 5 machine which overwraps up to 50 display cartons per minute.

Kowal says the robot systems developed by Cavanna represent a technological leap and are an example of packaging robotics replacing systems based on fixed automation.

A second example from Interpack is a tray-packing robot from Oystar A+F that replaces four separate machines and the conveyors connecting them. The system uses three twin-delta robot arms running the company's SetLine end-of-line packaging system.

SetLine is designed to pack various shapes and sizes of single cups, cup sets and bottles into trays or cases, with the ability to sleeve the primary packages into multipacks. Quick-change format parts are provided for the different cup types and sizes. The modular design can stand alone or be directly integrated with a filling machine and tray erector.

The end result is continuous motion at rates up to 30,000 bottles or 43,000 cups per hour, with a range of pack patterns and sleeve configurations possible. In the demonstration at Interpack, SetLine created four-flavor rainbow packs from single flavor packs diverted from their respective fillers at up to 500 trays per hour.