The P200 Balcony Casepacker by Serpa Packaging Solutions, Visalia, CA (www.serpapackaging.com), is the first such machine to run cases and trays on the same equipment. The P200 collates the product to achieve the correct pattern, loads the product into the case or tray, then seals, and discharges it.

Designed for pharmaceutical, nutraceutical, personal care, and medical device packaging, the seven-axis servo-driven case packer is an advanced iteration of the company's signature P200. The machine can pick and erect 20 cases per minute. Its balcony design uses a pair of bi-fold doors that open up to provide convenient full walk-in access to all of the drive components from the operator side of the machine, considered to be the first balcony-design case packer designed and built in the United States.

The machine's operating capabilities are made possible by integrated electric drives and control and linear motion solutions by Bosch Rexroth, Hoffman Estates, IL (boschrexroth-us.com). Serpa collaborated with local automation distributor Applied International Motion, La Verne, CA (aimotion.com), to specify and implement the Bosch Rexroth motion and servo control system.

The servo-controlled erector motion has two camshaft-profile axes that drive a parallel link arm. The arm picks up the case and erects it in the same area where the loading takes place. Because the loading and case erection occurs in the same area, it reduces the overall footprint and maximizes the speed of the P200. The standard machine footprint is about 8 ft × 6.5 ft wide.

Serpa used Rexroth's IndraDrive intelligent digital servo drives, IndraDyn servo motors, and a linear Ball Rail system. The motion and logic was programmed with Rexroth IndraWorks software. Instead of a mechanical drive, Serpa used Rexroth's servo system to create an electronic line shaft with cam profile movement. The P200 uses multi-axis synchronization with the ability to change motion profiles on the fly. Of the seven axes, four are synchronized using electronic cam shafts and three are point-to-point axes.

To achieve proper forming of the case, the erector and walking beam motion are tightly synchronized through SERCOS III (Serial Real-time Communication System) with the IndraDrives. The drives use cross-communication linking, with only one drive needing a field bus interface. The other drives use interface to communicate to the PLC from the master drive, no matter which field bus is chosen.

The IndraDrive servo drives provide distributed intelligence, which will close all the loops down in the drive. The drives also provide 230 to 480 VAC auto-ranging input voltage, absolute feedbacks to eliminate homing, and a built-in “personality module” or SD memory card for laptop-free replacement in minutes. The drives can store up to eight electronic cam profiles of 1,024 points each.

The IndraDrive servo drive's internal virtual master axis and precise synchronization allow smooth motion even while the machine is running at high speeds. This reduces the loads placed on the mechanical parts of the machine, ensuring reliability. All motion and programmable limit switch (PLS) outputs are based on a virtual master axis. Serpa also used Rexroth IndraDyn synchronous motors for their scalability and compact construction with increased torque density, absolute encoders, and high-resolution resolvers. And Rexroth's IndraWorks software was used to cover the entire range of engineering tasks and tools, project planning, programming, parameterization, visualization, operation, diagnostics and maintenance capabilities

In addition to servo control, smooth linear motion was necessary for the P200. Serpa chose a Rexroth linear Ball Rail system to help ease the load. The cantilever design of the balcony case packer causes large moment loads on the linear bearings. Rexroth linear Ball Rails have high rigidity and help reduce deflection of the machine components, letting axes run smooth at higher speeds. And with lube reservoirs located inside the runner block, the Ball Rails do not need to be lubricated as often, thereby reducing maintenance costs.

Director of Marketing Rich James, says Serpa reduced its installation and start up times by 30 to 35% using the Rextroth drive and control system. In addition, Serpa used 25% fewer parts on the P200 compared to its previous model because it now uses fewer drive components and fewer cables.

“Besides reducing the part count, another advantage Rexroth provided was helping with rapid changeover,” says James. “We can do a rapid, no-tools changeover in five minutes or less.” The fast changeover is attributed to the ease of switching axes to different electronic cam shaft profiles.

James added that the scalable design of the IndraDrive allows Serpa to purchase only the features it needs and that overall hardware costs per machine are 40% less than other such systems.

Challenge: Develop a scalable, cost-effective servo-driven balcony case packer with easy access and tight synchronization

Solution by Bosch Rexroth:

• IndraDrive digital intelligent servo drives
• IndraDyn synchronous servo motors
• Linear Ball Rail system
• IndraWorks engineering and programming software suite

Results:

• Efficient, flexible machine with easy accessibility, tight synchronization, and smooth motion
• Reduced installation and startup times by 30 to 35%
• Uses 25% fewer parts than on previous models of the machine
• Internal lube reservoirs in Ball Rail roller block help reduce maintenance costs
• Rexroth drive and control system helps reduce hardware costs by 40%
• Electronic cam shafting allows rapid tool-free changeovers in minutes