Cutting (sawing) slats (lamellae)

• In comparison, when sawing the slats (lamellae) with thin-kerf frame saws or thin-kerf band saws, wood yields of only 70% or even less are achieved. This means that 30% or more of the expensive raw material wood converted into sawdust and is only used for thermal purposes.
• These values are based on cutting kerf widths of 1.1 mm and information from the industry. In practice the cutting kerfs are wider.
• The trend in the parquet industry towards thin top layers inevitably leads to even bigger cutting losses and therefore to even lower wood yield.
• Cutting (sawing) does not conserve resources and is counterproductive in terms of increasing raw material costs.

Slicing slats (lamellae)

• With our MARUNAKA slicers, fantastic wood yields of 93-95% are achieved when slicing slats (lamellae).
• The so-called backboard only accounts for 5-7% depending on the remaining thickness (<10 mm) and can be almost completely sliced into slats (lamellae) by placing a spacer board on the backboard.
• Alternatively, the backboard can also be used for other purposes, which means an almost 100% wood yield is possible.
• These values have been proven in practice.
• The trend in the parquet industry towards thin top layers leads to a further increase in wood yield. In addition, resources are also conserved.
• MARUNAKA high-performance slicers are serially manufactured for working widths (slat [lamellae] widths) of 250 mm and 350 mm. There is also the possibility of supplying machines with even larger widths.

Technological lead of MARUNAKA’s slicers

• MARUNAKA is the leader and inventor of the lengthwise slicing technology.
• MARUNAKA is the inventor and the patent holder of the so-called RAND. The RAND makes perfect slicing of lamellae up to ~5.0 mm (6.0 mm) possible. The RAND has significantly reduced the phenomenon of cupping of the slats (lamellae) but dramatically also twisting and bending.
• Due to the RAND of MARUNAKA’s slicers slats (lamellae) come out flat and in addition in axial direction which is most important for handling.
• In conjunction with the RAND and the latest state-of-the-art HIGH-SPEED technology MARUNAKA’s slicer can reach slicing speeds of 120 m/min resp. 200 m/min. This demonstrates not only a performance advantage but also an epochal increase in the production output, in particular for the production of slats (lamellae).
• Based on a special technical modification of MARUNAKA’s lengthwise slicers (option) the final thickness of the remaining flitch (so called backboard) could be reduced to ~6.0 mm. In standard version the backboards thickness is <10 mm. In a separate slicing process, the backboard will be sliced completely down to zero!
• Based on the KNOW-HOW and the long-term experience MARUNAKA decided to make their lengthwise slicers (250 / 350 mm slicing/working width) with 80-degree knife bias angle. Bigger slicers can also be offered. Based on this bias angle the slicing results of MARUNAKA’s slicers are improved especially for the production of slats (lamellae) sliced from all kind of wood species. Bending and twisting are nearly compensated, the thickness tolerances could be dramatically reduced and the surface quality improved seriously. Slicers from other manufacturers with a bias angle below <80 degree creating huge deformations (low quality) of the slats (lamellae) and poor surface quality too.
• At 80-degree bias angle MARUNAKA slicers reach the optimal length of knife with 1,500 / 2,000 mm total length for their 250 / 350 mm lengthwise slicers. This guarantees quick knife changes and much easier and precise knife setting. Based on MARUNAKA’s KNOW-HOW longer knives in conjunction with larger bias angle are not recommended due to the more complicated adjustment of the knife in conjunction with longer maintenance time. Furthermore, expensive knife grinders are required.
• MARUNAKA’s knives are made of high-quality steel (HRC 65 ±2) of highest precision. These knives are made exclusively for MARUNAKA slicers by the most experienced tool manufacturer in Japan Messrs. KANEFUSA. These knives guarantee maximum durability, maximum live time and all the time first class slicing quality. With a total of 6 (six) knives most of our MARUNAKA customers work successfully for more than 2 (two) years. The Japanese knife is of recognized quality which is worldwide well known and legendary too.
• Of course, all MARUNAKA slicers from the T-series (T = thick slicing) are made for the production of slats (lamellae) and veneer. Therefore, the range of slicing thicknesses of these slicers are between 0.5 ~ 5.0 mm (6.0 mm). This wide range of thicknesses provide most flexibility for slicing lamellae and veneer with the same slicer.
• MARUNAKA recommend 18-degree knife angle for slicing slats (lamellae) but 22-degrees for slicing veneer. But the optimal degree depends on various conditions like timber species, thermal treatment of the flitch besides other factors. MARUNAKA like to draw the attention to the fact that various manufacturers of slicers in the world promised max. slicing thickness of up to 10 mm and even thicker this is not only dubious but also technically nonsensical.
• The high-quality feeding belt of our slicers for feeding the flitch smoothly and continuously through the slicer is an endless belt with high tensile strength and only very limited elongation which guarantees long live time for many years. In case of smaller surface damages, the belt can be reconditioned by a very simple method. After reconditioning the belt surface and the belt is in full function again. Depending on the load, experience has shown that our belts will work without any problems for many years.
• Hardwood species up to ~950 kgs/m³ density (green condition) as well as soft wood species of various proveniences can be sliced on MARUNAKA’s lengthwise slicers without difficulty into lamellae and/or veneer. Therefore, MARUNAKA’s slicers are equipped with bigger feed motor in order to ensure considerable higher torque. Other slicers are not strong enough to fulfil such requirements.
• All machine parts of MARUNAKA’s slicers except the knife edge coming into contact with the hot/wet flitch are protected against corrosion. Our special chrome-plated knives are for nearly 100 percent anti-blue-stain. The feed system of the slicer is also protected against corrosion caused by rising aggressive vapors thanks to a special treatment. These protections (except the knife) guarantee that there is no blue-staining of timber with tannic acid like oak (Quercus), false or bastard acacia (Robinia), chestnut (Castanea) etc. possible.
• The height adjustment of the feeding system (thickness adjustment for the flitch) is made by means of high precision spindles. The design of these spindles for MARUNAKA’s slicers needs less power rating and ensures very quick adjustment. The precise adjustment of the feeding system is made by means of an incremental rotary encoder.
• Since the invention of the lengthwise slicing technology in 1970 the world market leader MARUNAKA built some hundreds slicers which are supplied to customers on all six (6) continents. Thus, MARUNAKA has an incredible and unrivalled KNOW-HOW in the construction, design and development of this technology.
• MARUNAKA’s Merry-go-Round Systems are always designed for automatic feeding all flitch dimensions and flitch weights the slicer can process. The layouts are always tailor-made according to customers’ requirements. Only tailor-made solutions are offered. Other manufacturers don’t take care about these most important pre-requisites and mostly offer very light and inefficient conveyors.
• All conveying parts in the Merry-go-Round Systems like rollers, guides etc. made by MARUNAKA guarantee the transport of the flitches without damages. The parts which are in contact to the flitch are always protected against corrosion, thus timber species with tannic acids never can be blue stained.
• MARUNAKA slicers can reach thickness tolerances of ±2.5% for slicing slats (lamellae) and/or veneer. Pre-requisites are optimal thermal treatment (steaming/cooking) of the flitches and final calibration (± 1 mm) right after thermal treatment directly before slicing starts. These extremely low tolerances are not achieved by most competitors! The pre-requisites are the precise sawing of the flitches using log band saws with subsequent thermal treatment or, in case of flitches that are not sawn precisely, the calibration of the flitches (± 1 mm) immediately before slicing. 
• MARUNAKA’s lengthwise slicers are in perfect harmony between machine weight and the working width. The result: high precision during slicing in conjunction with high performance. The torsion-free base of MARUNAKA’s slicers guarantees precise adjustment of the slicing thickness (slats [lamellae]/veneer) as well as the precise and accurate adjustment of the distance between the knife and the nosebar. The upper feeding system is torsion-free too. This feeding system is guided by two large dimensioned cylindrical columns for precise up and down movement. MARUNAKA pay always attention for making steel structures in groove welding and annealing that guarantees high-tensile, stressless and torsion-free structures.
• The PLC from MITSUBISHI is the standard execution of MARUNAKA’s slicer control. Alternatively, the slicer can also be furnished with the PLC from SIEMENS against surcharge.
• The machines from MARUNAKA are CE-certified by TÜV SÜD Germany and therefore in the conformity of the terms of the European Union (DIRECTIVE 2006/42/EC). Therefore, MARUNAKA guarantees highest operating safety for their machines and of course also towards our customers.
• One operator is needed to operate the MARUNAKA slicer line consisting of lengthwise slicer and the Merry-go-Round System. This operator is responsible for the control of the slicer line, for automatic loading the flitches and unloading the backboards. Stacking of the sliced slats (lamellae) resp. veneer is made manually by one person or can be made automatically depending on individual solutions.
• The operation and the adjustment of MARUNAKA’s slicers are really simple to learn and the integration of such slicer line into the production flow is uncomplicated too. Teaching of customers staff including knife grinding is usually made by MARUNAKA’s staff during the installation on site.
• MARUNAKA’s lengthwise slicers only need industrial flooring (thickness ~150mm reinforced and levelled concrete flooring (~4 ton/m² floor load) but no foundation in general!
• Besides necessary changes of the flitch batches, knife changes and machine inspections there are only very short interruptions of the continuous production process. In comparison to traditional crosswise slicers (vertical or horizontal versions) there are no interruptions due to time-consuming loading and unloading the flitch. Therefore, lengthwise slicers guaranteed very high production output because of continuous production process.
• In comparison to cutting process by means of thin-kerf frames or band saws the slicing process does not produce sawdust. Removing sawdust requires high energy consuming dust suction equipment etc.
• Lengthwise slicing technology reduces the costs for heat and electric energy.
• Customers in Far East, Europe and North America slicing already since many years slats (lamellae) by means of MARUNAKA’s lengthwise slicers.
• MARUNAKA also makes precision twin-head automatic wet knife grinding machines guaranteeing the precise rough grinding and lapping (honing) of the knives. This grinding procedure guarantees high durability of the knife edge and therefore first-class slats (lamellae) as well as veneer surfaces. The complete knife is clamped onto the 200 mm wide magnetic table that guarantees vibration-free and precise grinding of the knife.
• This knife grinding machine provides an excellent overall solution in conjunction with the slicer from MARUNAKA. The STELLITE®-equipped pressure beam can be re-grinded several times using a surface grinding machine.