Linear motor pallet-transfer systems have been around for many years now. These systems work on the principle of a “smart” track—consisting of multiple linear servomotors—and a “dumb” mover outfitted with powerful magnets. Coordinating the activation of electromagnetic coils in the motors propels the movers around the track.

Linear motor transfer systems offer many advantages for conveyance, including high speeds; precise control of acceleration and deceleration; and independent control over individual pallets. 

On the other hand, like railcars, the movers are still tethered to a track. Since the movers ride on roller bearings, they can only move back and forth on predetermined straight or curved sections.

Now, a variation on the linear motor transfer system does away with that limitation. B&R Industrial Automation, in partnership with Canadian start-up Planar Motor Inc., has introduced a new conveyor system, ACOPOS 6D, based on the principal of magnetic levitation.

Shuttles with integrated permanent magnets float over the surface of electromagnetic motor segments like magic carpets. Bearing systems are unnecessary. The modular motor segments are 240 by 240 millimeters in size and can be arranged freely in any shape. Square, rectangular, L-shaped or annular systems can be created. 

A variety of shuttle sizes carry payloads ranging from 0.6 to 14 kilograms and reach speeds of up to 2 meters per second. The shuttles can move with six degrees of freedom. They can move freely in two-dimensional space, rotate and tilt along three axes, and offer precise control over the height of levitation.

Each motor segment can control four shuttles simultaneously. The shuttles themselves can also be used as axes of motion in processing stations. For example, a shuttle carrying a workpiece could follow a CNC path, allowing the processing tool to be mounted rigidly. Weighing stations can be eliminated entirely, since each shuttle can also serve as a high-precision scale.

The shuttles levitate freely without any contact or friction. With no abrasive wear, there are no parts to be maintained. If a stainless steel cover is placed over the motor segments, ACOPOS 6D offers IP69K protection, so it’s suitable for clean rooms or food and beverage production.

The conveyor is fully compatible with other B&R products, so the shuttles can be synchronized with servo axes, robots, track systems and vision systems with microsecond precision. Path planning for the shuttles occurs in a dedicated controller, connected to the machine network via B&R’s Powerlink system, so it has no impact on the performance of the network or machine control system. For systems with more than 200 segments or 50 shuttles, multiple controllers can be synchronized with each other.

Each shuttle is assigned a globally unique ID. At startup, the controller immediately knows the location of each shuttle on the motor segments, and production can begin without homing sequences or manual input by an operator. Each shuttle can be individually controlled, and the shuttles can be positioned with a repeatability of ±5 microns.

Sophisticated algorithms ensure the shuttles follow an optimal path while avoiding collisions and minimizing energy consumption. With ACOPOS 6D, machines can simultaneously manufacture different product variants or even entirely different products, since each shuttle can navigate its own way through various production processes, amongst a swarm of other shuttles. Each shuttle can take its individual product on a unique path to the stations it needs for customized production.

XPlanar System

The XPlanar conveyor system from Beckhoff Automation is based on the same technology. 

It consists of planar motor tiles that can be arranged in any pattern. Contactless movers float over the tiles and can be positioned quickly, quietly, flexibly and precisely. The tiles are typically laid out horizontally, but they can also be operated vertically and even upside down.

Without a load, movers float over the tiles at a height of 5 millimeters. With a 1-kilogram load, they float at a height of 1 millimeter.

The movers operate jerk-free and can travel at speeds of up to 4 meters per second. They can accelerate at 2 g, and they can be positioned with a repeatability of 50 microns. The movers can be positioned with six degrees of freedom. They can move along the X and Y axes. They can move up and down by up to 5 millimeters. They can tilt by up to 5 degrees. And, they can rotate by up to 15 degrees. (Special planar tiles can rotate movers 360 degrees.)

Since engineers have precise control over acceleration and deceleration of the movers, containers of liquid can be transported without spilling.

The planar motor tiles are 67 millimeters thick and 240 millimeters square. The tile surface can be glass, plastic or stainless steel.

The movers are 12 millimeters thick and come in four sizes. APM1002 is 95 by 95 millimeters and can carry a 0.4-kilogram payload. APM1003 is 155 by 155 millimeters and can carry a 1.5-kilogram payload. APM1005 is 155 by 275 millimeters and can carry a 3-kilogram payload. APM1004 is 275 by 275 millimeters and can carry a 6-kilogram payload.

Engineers interested in testing the technology can order a starter kit, which contains all the components needed to create a conveyor system: planar motor tiles, movers, and an industrial PC with preinstalled software. The planar tiles are preassembled and installed on a carrier frame. The electrical components and the PC are installed in a control cabinet.

Beckhoff offers two starter kits for engineers interested in trying out the technology. The AS9000 kit contains six tiles and two movers. The AS9001 kit contains 12 tiles and four movers.

Conveyor Increases Efficiency of Plasma System

Plasmatreat has introduced a new plasma treatment system that employs Beckhoff’s XPlanar system to precisely move and position workpieces.

Plasma treatment is used to raise the surface energy of plastics to make them more amenable to bonding and printing. Plasmatreat’s new system treats workpieces in a two-stage process. During the first stage, the substrate is moved under a nozzle for cleaning and activation. During the second, a separate nozzle applies a functional coating. The XPlanar conveyor system positions workpieces under the nozzles.

“We wanted a fast, fully programmable, wear-free system to transport the workpieces,” says Jochen Stichling, head of design at Plasmatreat. “There was no real alternative to XPlanar.”

The Plasmatreat machine consists of six planar motor tiles and one mover. By using the XPlanar system, Plasmatreat engineers were able to install the treatment nozzles in fixed positions. The jets are complex, both mechanically and electrically, and the ability to move the workpieces rather than the nozzles reduces wear on the feed lines.

Flexibility was an additional benefit. “We can attach a variety of material samples to the mover for treatment using simple adapters,” says Stichling. “We can easily add processing stations alongside the plasma jets—markers for good parts, for instance, or optical sensing heads to conduct full part inspections—and carry workpieces to them as needed. And, XPlanar’s rapid acceleration also lets us move material samples at high speeds; with thin samples, for instance, this helps minimize treatment time with the fixed jet.”

Another benefit was cost reduction. “Conventional setups use a six-axis robot or linear motors to move a plasma jet around a stationary workpiece,” says Stichling. “From a cost perspective, XPlanar comes in somewhere between linear-axis and robotic systems. With flat parts that don’t require much vertical travel on the Z-axis, where robotic systems are usually ideal, XPlanar offers an excellent alternative to gantry-type systems. XPlanar’s advantages in terms of lack of wear, easy cleaning, and clean-room compatibility also play out here.”

Integrating the XPlanar system into the machine took less than two months. Beckhoff supplied 3D data and electrical connection information, which enabled Plasmatreat to rapidly incorporate the XPlanar starter kit into its machine design. The XPlanar system will enable Plasmatreat to integrate test and inspection processes into its machine.