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The study's objective was to assess the particle-size distribution and formulate an empirical model for the content of the finest dust created during the sanding of unmodified and thermally modified pine wood. The experimental design included unmodified and two options of thermally modified pine (Pinus sylvestris L.) wood samples, four feed speeds (3; 6; 9; 12 m·min−1), and three grit sizes of sanding belts (P60; P80; P100). The wood dust samples underwent sieve analysis to determine the particle-size distribution and laser analysis to determine the content of the finest particles. The sanding of thermally modified wood produced a higher amount of fine dust compared to unmodified wood. The content of fine dust increased with decreasing feed speed, while larger grit sizes resulted in increased production of fine dust. The average mass share of dust < 2.5, < 4, and < 10 µm was significantly lower when sanding the unmodified wood than thermally modified wood. The influence of feed speed, grit size, and material type on dust creation suggests that thermal modification is a factor in increasing the content of the potentially harmful finest particles (respirable fraction). The presented empirical model can help minimize health risks during the sanding of thermally modified pine wood by adjusting the sanding parameters. [ABSTRACT FROM AUTHOR]

Reducing harmful emissions from wooden materials is a major challenge for the wood industry. This is particularly important for the particleboard sector, where the use of formaldehyde-based resins can cause substantial pollutant emissions. With the aim of finding a greener alternative to commercial resins, the authors applied four types of liquefied lignocellulosic biomass and two types of nanocellulose-based formulations as a partial replacement of melamine-urea-formaldehyde resin for single-layer particleboard manufacturing and tested: formaldehyde content, formaldehyde and volatile organic compounds (VOC) emissions of the boards. The results revealed reduced formaldehyde content (up to −20%) and a slight decrease (max −13%) in formaldehyde emission in comparison to the panel produced with commercial resin when applying liquefied biomass in the adhesive mass. The values of VOC emissions in the particleboards developed with the alternative adhesive systems were substantially lower in comparison to the commercial panel, especially for γ-methacryloxypropyl-trimethoxysilane nanocellulose, which allowed to achieve a reduction of about 67% of total VOC emissions. Overall, liquefied wood products obtained from softwood bark showed the best performance in decreasing the emissions. The results confirmed the research hypothesis that the use of liquefied lignocellulosic biomass and nanocellulose can reduce the emissions of harmful substances from the wood-based panels. [ABSTRACT FROM AUTHOR]

Milling wood-based materials on CNC devices causes the creation of chips in small sizes that may escape the chip extraction zone to the surrounding environment and pollute the air. The article studied the effect of the feed rate (vf) and the width of cut (ae), transformed into kinematic average chip thickness, on the amounts of chips in respirable sizes <10.0μm created in the cutting zone from particleboards (PB) and medium-density fibreboards (MDF). The amounts of dust-sized chips are discussed and were determined by the sieving analysis. The sizes of potentially respirable chips were estimated by weighting with the laser diffraction method. The highest amounts of chips from PB were of 0.250-0.500 mm (38-41%w), but in MDF, amounts varied depending on cutting conditions. With (ae) 1 mm were in the size range of 0.125-0.250 mm (35-54%w), for (ae) 2 mm (33-35%w), and (ae) 3 mm (36-40%w) with combinations of (vf) 6-8 m·min-1. With a combination of (vf) 10 and 12 m·min-1 distribution moved to a higher size range. Chips in sizes 10.0-4.0 μm were estimated by <1%, for 4.0-2.5 μm <0.5%, in 2.5-0.1 μm <0.3%, and <0.1 μm by <0.05%. Statistically was proven (p<0.05) only in PB, with adjusted (ae) by 1 mm, increasing the value of (vf) from 6 to 12 m·min-1 and also with (vf) at 6 m·min-1, between values of (ae) 1 and 2 mm (hm of 0.025-0.035 mm), will significantly (p<0.05) lower the percentual amounts of chips in sizes 10.0-4.0 and 4.0-2.5 μm. [ABSTRACT FROM AUTHOR]

This article deals with the fractionation of wood dust by sieve after sanding. Dust from untreated beechwood was compared to dust from thermally modified beechwood (at 200 °C for 3 h). The authors hypothesized that the thermal modification changes the particle size distributions of the dust sieve fractions and that all the dust sieve fractions contain the finest particles, which are suspendable in the air and are potentially respirable. To obtain dust for testing, both wood materials were sanded with P120 paper at a belt speed of 14.5 m/s and a pressure of 0.65 N/cm² . A set of sieves with aperture sizes of 25, 80, and 250 µm were used to separate the dust into sieve fractions with grain sizes less than 25 µm, 25 to 80 µm, 80 to 250 µm, and greater than 250 µm. The content of the finest particles in the fractions was measured via a laser particle sizer. Both dusts had similar particle size distributions. In addition, each investigated fraction of both dusts contained the finest particles, i.e., less than 10 µm. It follows that the laser analysis method may be necessary to correctly assess the occupational risk at a sanding. [ABSTRACT FROM AUTHOR]

The aim of the paper is to determine the granulometric composition of chip removed from the beech lumber milling process using a CNC machining center SCM Tech Z5 in the range of commonly used technical and technological parameters under standard conditions of feed speed: vf = 1 ÷ 5 m.min-1 and the thickness of the removed layer: e = 1, 3 and 5 mm. Another goal of the paper was to select a suitable separation technique that would be sufficient to effectively capture the largest possible dispersion of fractions in the beech lumber milling process. Granulometric analysis showed that under the given conditions in the milling process the largest proportion of coarse and medium coarse fraction is formed and particles with a size smaller than 32 µm are not formed. For this reason, it is our recommendation to choose a combination of dry mechanical separators together with fabric filters, as mechanical separators are able to capture mainly larger particle fractions. Fabric filters would serve to trap any finer particles, thus saving the user from greater wear of the coarse and medium coarse fractions, which would increase the wear of the filter cloth to an increased extent. [ABSTRACT FROM AUTHOR]

TechnoPORTA. Intelligent, customized technological line for the automated production of technical doors - selected technical and economic indicators. The development and implementation of innovative production of technical doors in a pilot technological line made it possible to automate the production process. It became possible to manufacture doors with dimensions and weight significantly exceeding the current technological capabilities of the company. An additional benefit resulting from the implementation of the TechnoPORTA line is the improvement of technical and economic indicators related to the consumption of basic materials, additional materials and energy. It relates to annual savings of material in the production line, the unit consumption of electricity and the unit application of the adhesive during postforming. [ABSTRACT FROM AUTHOR]

The present paper provides characteristics of three species of grain straw particles applied in the production of lignocellulose particleboards. For the sake of the investigation, rapeseed, rye, and triticale straw were fragmented to the size of particles used in the wood-based materials industry. The aim of the research was to determine physical properties of particle of rapeseed, rye, and triticale straw and to evaluate their usefulness in the process of manufacturing lignocellulose particleboards purposed for building constructions. Another aspect of the work was to determine the influence of moisture content of straw particles (using rapeseed straw as an example) on properties of the manufactured particleboards made with its use. The conclusion is that each of the investigated materials is characterized by different geometry, poured and tapped bulk density, varied angle of repose, and slippery angle of repose. Differences in sizes and shapes of particles of various grain species and in their moisture content strongly affect properties of particleboards produced with their use. The investigations prove that the best properties are observed for rye straw particleboards. However, due to their physical parameters, difficulties in storage, transport, and particleboards production may happen to be more considerable than in case of other materials. [ABSTRACT FROM AUTHOR]