Trimmed to perfection

The drive needed to be specific for the woodworking industry, to avoid high wear and maintenance issues due to wood dust. The E-CUT 200 also incorporates helical bevel geared motors and W22 induction motors from WEG.

The Springer Group, headquartered in Friesach, Austria, is an international manufacturer of machinery and conveying systems for the timber industry. The company's offerings include log yard systems, planning machines, sawn timber sorting machines and production systems for woodworking.

Springer Group's products also include the first electrically operated beltless trimmer, the E-CUT 200. The trimmer represents a revolution in the timber industry in terms of drive type, operation and maintenance.

The E-CUT 200 is equipped with novel crosscut saw arms that are electrically operated, giving them higher efficiency than comparable models powered by a hydraulic or pneumatic drive. The advantages of being electrically operated include a well-defined, precise operating curve that enables optimal control of the crosscut saws, and exact positioning of the saw blades in every sawing process. The E-CUT 200 is equipped with 21 saws in 300 mm modules as standard, and is designed for timber with standard lengths up to six meters and thicknesses up to 100 mm.

Developing a beltless drive

Conventional trimmers operate with belt drive, which results in high belt wear caused by wood dust. In order to reduce this wear and simplify maintenance, Springer sought to develop a beltless geared pivot saw arm. The company also wanted the trimmer to set new standards for precise cutting and resistance to temperature variations.

Our customers expect technologically mature solutions from us that sustainably improve their production processes, explains Egon Eisner, Engineering Manager at Springer. As the first electrically operated beltless trimmer, the E-CUT 200 puts an end to the weaknesses of conventional trimmers. The basis for this innovative solution is the special gear unit from WEG.

Specifically, Springer turned to WEG for the special beltless gear units. Based in Markt Piesting, Austria, WEG specialises in the development and production of gear units and geared motors, and also offers a full range of electric motors and automation products.

To meet Springer's requirements, WEG designed and produced a completely new drive system for each saw. The system consists of an innovative trimmer gear unit, a helical bevel geared motor and one or two W22 motors for the main drive, depending on the configuration.

Geared pivot saw arm

The E-CUT 200's saw blades are turned by centrally positioned, external electric motors through the pivot arms, which are uniquely implemented as beltless gear units. The individual saws are operated by electrically actuated crank mechanisms with pushrods. This electrical operation allows the motion of the individual saws to be controlled precisely, independent of temperature variations.

The sturdy pushrods prevent damage to the mechanism from the motion of the trimmed timber. The trimmed lengths fall freely through a large chute, onto an underlying conveyor belt for removal.

The E-CUT 200's circular saws are driven by one or two four-pole W22 IE2 motors with frame size IEC225. With a rated power of 37 Kilowatts each (kW), the motors drive the input shaft of the special gear units via V-belts. The gear unit cases are made from nodular cast iron, which gives especially high strength and resistance to ambient conditions and is essential for the harsh operating conditions in the timber industry.

With a torque rating of 593 Newton meters (Nm), the special gear units have a gear ratio of 2.42. This boosts the blade speed, giving a circular saw speed of 3,570 revolutions per minute (rpm) with a four-pole motor speed of 1,475 rpm. However, the circular saw speed can also be changed to 4,307 or 4,748 rpm to meet specific customer requirements. This is achieved by a V-belt transmission with various sizes of belt pulley.

The special gear units are designed specifically for high ambient temperatures of up to +50 degrees Celsius, and are especially well-sealed to operate in dusty environments. All the covers are additionally glued in place. Each of the circular saw blades is raised and lowered by a 3 kW helical bevel geared motor equipped with forced-air cooling and a brake, and controlled by a variable-speed drive (VSD). These drive units can be optionally fitted with incremental encoders.

Lower wear, minimal maintenance

The E-CUT 200's new geared pivot arms dramatically reduce machine wear and, therefore, maintenance efforts. That is because the technology eliminates the use of drive belts, which were previously prone to wear due to the high dust burden. The E-CUT 200 therefore scores well for ease of maintenance with the new drive concept, and yields material and cost savings for plant operators.

In addition, all drive components are mounted externally, so they can be accessed easily and safely by service technicians without opening the actual trimmer. The E-CUT 200 is fitted with a newly designed dust enclosure with linear travel, which is especially compact and allows unrestricted access to the maintenance bridge. The machine's blades can be exchanged fast and simply, as a result.

Prior to the definitive product launch of the E-CUT 200, the trimmer was tested for more than 1,000 hours under practical conditions with the new drive system.

We are an innovative family business, comments Timo Springer, CEO of Springer Maschinenfabrik. To be successful internationally in plant engineering for the woodworking industry, we have to constantly evolve. The E-CUT 200, which is a revolutionary product in the trimmer market, is a good example of our innovation strength. We are pleased that WEG played a role in making this technological solution possible."