Robust energy supplies for stone saw systems

Block and bar saws from Kirschner Maschinen- und Metallbau are used for automatic splitting of clearance cairns. These are complex special machines that are configured on-site for the respective stone. If they are used in industrial implementation, as a rule they run in multi-shift operation. Supply of their axes functions via energy feeds from igus. In spite of the extremely harsh operating environments, a service life of 30 years and longer is expected.
 
"In our stone saws, for at least ten years we have been relying on plastic energy chains," explains Mechanical Engineer, Alexander Ritzka, of Kirschner Maschinen- und Metallbau GmbH. "They are stable, resistant to contamination and they absorb high loads. " Today the particularly robust e-chain E4.80 from igus is used in the block and bar saws. It is part of the extensive product line of the E4.1 universal energy supply system offered by igus GmbH in Cologne, Germany. Among other things, E4.1 system is characterised by modularity and easy installation. It protects the lines and ensures a long service life. The chain has been available for more than five years, and it has proven itself in a wide variety of the supplier's saw systems since ever since it was introduced on the market.

The medium-sized company, Kirschner Maschinen- und Metallbau GmbH, has approximately 50 employees. It specialises in mechanical engineering and metal engineering, made-to-order production and series production, as well as agricultural technology. The firm's offering is focused on customer-specific design and manufacturing of the widedly-varied saws for the stone industry.

Saws for shell limestone blocks

In the summer of 2014, the special machine builder installed and commissioned two saw systems at Hemm Stone GmbH Natursteinwerk Kirchheim, an enterprise of Sto AG. With its own quarries, a modern plant, but also manual labour, it offers a variety of products and services associated with natural stone. "Primarily we are mining shell limestone that has proven its advantages as a building material for centuries", explains Manager of Project Business and Authorised Representative, Christian Gruber. Shell limestone is used as a robust floor covering indoors and outdoors, for facade design, and in landscaping.
 
On the block saw the mined stones are cut so that a straight surface is produced, and thus they are either prepared for further processing on the bar saws or the multi-panel saws in the plant. "The advantage of this saw technology is that we can much better utilise the final raw material and cut it more economically," is how Gruber defines the reasons for the investment. Previously a maximum of 2 blocks were processed at the same time, today up to 10 blocks can be placed on the respective system and cut.

Energy chains for saw systems

In addition to shell limestone, sandstone is also processed in the natural stone works. The peripheral speed and the saw blade are matched to the type of stone. Speed-regulated drives ensure a constant cutting speed of the saw blade. Energy is supplied to the x-axis, y-axis, and the z-axis via E4.80 two-side snap-open energy chains with crossbars at every link. They have an inner height of 80 mm and an inner width of 375 mm. The travel of the x-axis is 30 m, the travel of the y-axis 5 m and travel of the x-axis 2.5 m The first 2 axes represent an unsupported application, the advance axis is a standing application.
 
On the block saw the mined stones are cut so that a straight surface is produced, and thus they are either prepared for further processing on the bar saws or the multi-panel saws in the plant. "The advantage of this saw technology is that we can much better utilise the final raw material and cut it more economically," is how Gruber defines the reasons for the investment. Previously a maximum of 2 blocks were processed at the same time, today up to 10 blocks can be placed on the respective system and cut.

There is a high weight load on the chain particularly on the x-axis. In addition to control cables, heavy water hoses, lubricant hoses, and hydraulic hoses are also installed. In this application the interior division possibilities are particularly impressive: They ensure safe guidance of the cables and hoses and extend the service life of the cables in hoses by a multiple factor. Moreover, over the long travel, the energy chain moves in an especially robust steel guide trough. It is a component of the extensive igus modular accessory system.
 
In addition to the issue of sustainable stability, for the stone saw, other priorities include resistance to abrasive substances. When cutting, extreme amounts of dust, as well as smaller and larger stone fragments occur that settle in all areas. In addition there is spray water that follows the course of lease resistance.

Stable and sealed in day-to-day saw operation

The E4.80 e-chain is robust, and due to its structural design it is particularly well-suited for applications with high accumulations of contamination. On the more than 30 meter distance of the x-axis the upper run of the energy chain is placed on the lower run. A high-wear allowance, on one hand, as well as wide placement areas on the other hand, ensure that the forces exerted are distributed over a large area. Permanent stability, and thus functional reliability, are the consequences. In addition, there are very smooth contours. Due to the minimal abrasion, hoses and cables in the interior of the chain are protected over the long term. And in the rarest of cases, crossbars that can be removed on both sides enable easy and fast replacement of cables or hoses.
 
The double rectangular stop system ensures maximum force absorption and thus high stability for the long unsupported lengths. Close tolerances and large bolt/bore connections are responsible for the high load-bearing capacity. Virtually complete absence of play is responsible for long service life. The inner and outer strap principle – inner and outer chain links inter-mesh – ensures straight running, high holding forces and extreme leak tightness. Even the finest dust particles and moisture cannot settle or penetrate into the interior. In addition, there are the advantages of low vibration and low noise. Brakes installed on the radial stop dogs are responsible in this regard.

Convincing trial cuts

"The first trial cuts convinced us," reports Gruber. "We are sure our investment in this technology will pay off. " Alexander Ritzka is counting on it: "We have been using the robust energy chain in our equipment from the first day on. Our experiences are more than good. To this day there have been no complaints whatsoever from customers. There are no downtimes to report. The chains are delivered, we assemble them, fit them with the necessary cables and hoses, and then the saws are commissioned. The collaboration with igus was always running smoothly. “