Almost all modern products require protective packaging for shipment and handling. Paper remains the number one material choice for such packaging. Whether it is in the form of cardboard or corrugated cartons, it allows a multitude of custom options. Prototype models are essential to quickly test a design’s function, however, making the models by hand is expensive and imprecise. A cutting plotter, though, converts CAD data directly into finished cut samples.
Typically, cutting systems are expensive. A specialist in cutting equipment, Lasercomb of Notzingen, has developed a new generation of multifunction plotters to create fast, inexpensive models from paper material. The company’s latest product incorporates reliability, precision and an attractive price. Developing this product, though, required in depth know how of plotter technology and powerful motors for the compact drive. To realize the demanding specifications, Lasercomb’s engineers chose drive supplier, Faulhaber.
Through the use of miniature motors and
drives, this flexible plotter handles cut, print, and scan tasks in an
Compact and maintenance friendly
Initially the demand was for a small, reasonably priced plotter with all the features of its big brother. But a straightforward transfer of the concept into a smaller version was not possible; the cabling costs alone would have taken it out of the price range. Hence, the decision was made to use a compact CNC controller in the top-hat module. A second innovation was to use two CAN-open nodes, cutting cabling costs. One node handles the inputs and outputs as a control bus; the other node cycles at a higher frequency to operate a control bus for the drives. This layout ensures rapid and precise guidance of the tool in the tool head. In the first draft, it reduced the number of trailing cables to the head from 17 to one, including the power supply.
The drive power comes from state-of-the-art dc motors. Depending on the ProDigi plotter model, the tool head traverses work surfaces of 800 x 1,300 mm to 3,100 x 1,700 mm at speeds to 100 m/min (1.66 m/s) with an acceleration of 5 m/s. In full cutting operation, it achieves up to 30 m/min. As a drawing plotter it can reach 50 m/min. A simple change of tools on the head is all that is required to reconfigure the electronics; then adjust the cutting or drawing parameters through the controllable motors. In operation, the low noise levels make the plotter ideal for the office.
The compact tool head uses four motors for two-axis control. The drive is hidden under the cover to save space.
Custom-made dc miniature drives
The Faulhaber motor’s compact dimensions were most important for the tool head. Here, four motors are mounted in a limited space to control the Z-axis (knife stroke movement) and the C-axis (horizontal movement of the head). Each motor pair is responsible for a tool fixture. All motors are pre-configured with connection cables and incremental encoders. The connectors are then simply attached to a “switching panel” that provides connections for the motor, add-on modules, as well as the special plug configuration for the control. The advantage of this layout is that, in an emergency, the customer can easily plug in a new motor. Connections do not need re-soldering. A seal protects the robust motors against the inevitable paper dust, while frictional pairing of brush collectors reduces wear.
Installed in the head of the plotter is a 28 W motor that guides the cutting knife to the precise height. It has a diameter of 35 mm, length of 57 mm, and offers 180 mNm torque. With a lifting spindle functioning as a self-locking gear reduction, the cutting knife can be precisely positioned with zero backlash.
Complete motor gear units that consist of an 80 W motor with 530 mNm and flanged metal planet gears are used for the C-axis. The high dynamics of the dc motors permit precise digital table height compensation (vertical tool tracking) over the entire work surface. This ensures a constant distance between the tool to the vacuum table and, hence, the material to be processed.
Miniature drives can be individually adjusted to desired requirements just like their big brothers. If the drive is matched with the application requirements from the outset, it avoids many problems and compromises. Special characteristics in the type of construction, performance, electromagnetic compatibility, Plug-and-Play or sealing against specific media are easy to implement. Engineers save development time and are quicker on the market with a new product, an advantage that is otherwise difficult to achieve.
Controller and miniature drive are arranged in a top-hat module, and require only one cable for controller and power supply.
Lasercomb of Notzingen
:: Design World ::
Filed Under: Packaging, Motion control • motor controls