Optimisation of technology for wood-peeling production systems
The main project objectives are optimizing the technological process for the production of a innovative wood peeling system and launching a new and innovative set of products on to the market.
SIJ Ravne Systems will work with several consortium partners: Systherms, a company with 25 years of experience with heat treatment furnaces, will significantly improve the existing heat treatment technology; Technogenia, a pioneer in additive technologies, particularly tungsten carbide overlays, will contribute advanced technologies to improve the production of pressure bars; and the Maribor Faculty of Mechanical Engineering, will take care of precision monitoring, control and approval of the key characteristics of heat treatment and the laser cladding, as well as monitoring and controlling the effect of these processes on the properties of end products in order to optimize the entire process.
Steel and steel-related industrial processes have significantly transformed the modern world. Steel has not only become an indispensable material in the construction of global infrastructure and industry but has also created new industrial markets and requirements. Today, steel is still one of the materials that will continue to shape the development of products and structures.
Over the years, the company SIJ Ravne Systems has worked together with partners to develop advanced tool steel for the most demanding industrial applications. The aim was to produce high quality value-added tool steel for wood-processing applications that had better mechanical properties than its market competitors.
Wood veneer knives with pressure bars are used to peel different types of wood. Softwoods, such as pine and spruce, are the most difficult woods to peel. After several years of testing in different companies, we have concluded that this is primarily due to old knots in the tree trunks. In conifers, resin accumulates in the lower part of the broken branch, so the branch breaks off some distance away from the trunk itself (usually 10-20 cm). The trunk then continues growing around the dead branch stump for decades, causing the formation of a "floating" knot. When peeling the wood to create veneer, a problem arises when the knife hits the old knot, which is surrounded by brittle, dried-out resin. When the blade hits the knot, a piece of the cutting edge is chipped away. Solid knives can lose up to 1 mm or more. Although removing 0.25-0.5 mm of the knife edge restores its sharpness, it does mean that solid knives wear out up to twice as fast or that their working life is halved.
With the development of our advanced tool steel – compound – inlay and application for veneer knives for softwoods, we can significantly increase the durability of our knives. In addition, our new hardening and straightening process further improves the properties of our knives. This significantly increases a lifespan of knifes and reduces interruptions in the veneer production process. Previously, the knife blade was deformed when it hit a knot, resulting in chipping or shearing of the contact material. In turn, this affected the consistency of the veneer's thickness and reduced the length of veneer that could be cut from the trunk. Other problems associated with this were an increase in the use of glue (plywood), additional corrective measures (sewing veneer) and a higher reject rate. By combining new technologies, we believe we can reduce the frequency of the defects described above and also enable knives to operate in extreme conditions for 50 percent longer than they have previously.
Our new advanced laser cladding technologies have been applied to improve the pressure bars which are a critical element of the peeling system, enabling us to offer our customers a truly "cutting edge" solution.
Basic technical data:
Key features of the tool steel developed for veneer knives:
- Hardness = 61 HRc (or HV30 = 770)
- Tensile strength > 2100 MPa
- Impact toughness > 8 J/mm2
- Working life = 8 hours
- Cutting speed: up to 400 m/min
- Microstructure: residual austenite level < 0.5 %
Key features of the pressure strip:
- Base material - selected structural steel (chemical composition: C, Si, Mn, S, P)
- Welded alloy - special weld-on material grade (chemical composition: Co, Cr, W, C, Fe, Ni, Mn, Si)
- Welded alloy is resistant to wear, tannins and similar elements in wood
- Unique combination of metallurgical and engineering knowledge.
- Ability to offer a wide range of products and services for the steel industry (veneer knives, recycling knives, etc.).
- Professionalism and flexibility, combined with exceptionally high quality.
- Outstanding product quality resulting from a closely integrated, vertical manufacturing chain from steel to the final product, which gives us the best possible control of every process.
- Technical solutions tailored to customer needs, based on more than 70 years of experience in the steel and manufacturing industries.