Modra Technology, the specialist manufacturer of carpet sample machines, has chosen to base the motion control system for its Mtuft range of machines on Powerlink technology from Baldor Electric Co. The deterministic network for real-time multi-axis synchronization helps the machines produce a tufted carpet sample in 20 min, including setup time — a task that takes at least a day on conventional carpet sample machines or on production machines.
Ethernet based Powerlink helped Modra develop a carpet sample machine that produces carpet samples in 20 minutes.
The need was to come up with a design flexible enough to simulate as wide a range of carpet production machines as possible, so that the samples would accurately represent the finished carpets produced by various manufacturers’ machines.
According to Tim Modra, managing director, Modra Technology, “Complex high speed multi-axis applications such as this traditionally involve a huge amount of wiring — mainly on the control side, and especially for encoder feedback. When Baldor launched its Ethernet-based motion controller and servos, which specifically overcome the real-time data transmission limitations of standard
Ethernet but still use standard Ethernet cable between the controller and the drives, we were keen to try them out.”
Powerlink adds determinism to Ethernet by managing message exchanges in a precise and defined sequence to ensure that only one node communicates at any one time. The protocol guarantees that all time-critical data are transferred within configurable, isochronous bus cycles.
The carpet sample machine uses pneumatic and electrical actuation systems. There are nine axes of electrically operated movement, all controlled by a Baldor NextMove e100 real-time motion controller. Seven axes are driven by Baldor MicroFlex e100 single-phase ac servo drives and Baldor BSM servomotors, using Ethernet Powerlink for all communication between the controller and the drives, and the five axes that use interpolation. The remaining two electrically driven axes use small dc motors.
The host computer is an industry-standard PC running the machine control software and NedGraphics’ Vision Tuft software for carpet sample designs. Each carpet sample design is exported by the Vision Tuft software in OpenTuft format, and downloaded via Ethernet to the NextMove e100 controller line by line.
The machine holds the web — the backing material for the carpet sample — in tension on two backing drums driven in ratio gear mode. Two reciprocating heads, positioned above and below the web, traverse the width of the material. The needle motor sends the reference signal for all interpolated axes, and the top head employs a large servo for needle actuation, using a driven-spline arrangement to save weight on the head itself. Each head is driven synchronously, but can also be moved to simulate production of carpet samples with needle shift ‘zigzag’ patterns.
The machine’s top head uses a large Baldor servo for needle actuation, using a driven-spline arrangement to save weight on the head itself.
High-speed interpolation on the two main head drive servos is an advantage over conventional mechanical systems. “We effectively have a software calibrator that lets us put a variable offset into the system,” said Modra. “So instead of using precision mechanical gears and cams we can now calibrate our machines digitally through Baldor’s Mint programming language. This all-electronic approach has enabled us to create an adaptable, physically compact machine with a small footprint, and helps to reduce machine build time and cost.”
A Mtuft machine can produce 1 m (3.3 ft) or 2 m (6.6 ft) wide samples of cut/loop and cut/multi pile loop carpets of any length in single or multiple colors, as well as samples of servo loop scroll carpets, with servo control of the pile height and up to eight colors. The machine can accommodate yarn gauges from 1.5 to 6.3 mm (0.06 to 0.25 in.) and uses a single needle per color, which means that only one cone of each color yarn is required. The ease of set-up, combined with a high stitching speed of up to 30 per second produces a new carpet sample in just 20 minutes.
Baldor Electric Co.
Filed Under: Machine tool industry + subtractive manufacturing, Electronics • electrical, Motion control • motor controls, Networks • connectivity • fieldbuses