Disc Mill Research Articles

Influence of the methods of mechanical processing and sterilization on the structural-and-functional condition of the surface layer of bone samples

The authors presented the results of structural-and-functional analysis of the surface layer of bone tissue samples after their mechanical processing and sterilization. Bone samples of the given height were produced on a precision cutting machine using disc cutters. They were made from cylindrical blanks obtained from the fragments of bovine femoral shaft using hollow cutters. In this case, one of the end surfaces of bone samples was processed with a steel cutting disc with teeth, and the second one – using a disc milling cutter with diamond-coated cutting edge. The samples obtained were sterilized by different methods: ozone, radiation and combined ones, based on combined ozone-oxygen exposure at the first stage and radiation exposure – at the second. The elastic-plastic properties (Vickers microhardness index) of the surface layer at the ends of cylindrical bone samples were determined after mechanical and sterilizing physicochemical exposure. Scanning electron microscopy was used when studying the patterns of changes in the structure of sample end surfaces. The advantage of mechanical processing of bone samples using a cutting disc cutter with diamond-coated cutting edge was established compared to using a circular milling cutter with a cutting edge in the form of teeth. The studying of elastic-plastic characteristics of the surface layer of bone samples in mirovolumes demonstrated that the sterilizing physicochemical exposure to ozone-oxygen mixture, to radiation processing using a flow of fast electrons with radiation absorption doses of 10, 15 and 20 kGy, as well as their combined exposure did not have a significant effect on the values of sample microhardness.

Automated Design of Disk Mills for Cutting Helical Channels

Automated Design of Disk Mills for Cutting Helical Channels

Milling force modeling for disc milling cutter of indexable three-sided inserts considering tool runout

Cutting force is essential for studying cutting mechanism and improving cutting process. In order to predict cutting force, the cutting force was measured by experiments; cutter runout was measured by dial indicator; the actual undeformed cutting thickness was obtained in presence of cutter runout. Then a mechanical cutting force model was established. Three kinds of cutting force coefficients, linear, exponential, and polynomial coefficients, are solved and compared. The results show that the exponential model has the highest generality and accuracy. The validation experiment illustrates deviation rates between the predicted values and measured values are mostly <30%, and the deviation rates of the middle inserts are greater than that of the left and right inserts. The mechanical model in this paper can predict the cutting force quickly, which is helpful to select the reasonable cutting parameters and lays a foundation for the research of multi tooth cutting force.

Milling force model prediction considering tool runout with three-teeth alternating disc cutter

Disc cutter has a large diameter and more teeth, and obvious tool runout (δi) is produced during disc milling process, so the irregular distribution of cutting force is generated due to uneven distribution of cutting output per tooth (hi*) caused by tool runout. Therefore, the tool runout (δi) must be considered when milling force model of disc milling is established. In the paper, first, milling force model of disc milling is built with a three-teeth alternating disc cutter considering the tool runout (δi). Second, tool runout (δi) is measured by the dial gauge when the revolving speed of disc cutter is 1 r/min, then cutting output per tooth considering tool runout (hi*) is obtained by the formula between cutting output of each tooth (hi) without considering tool runout (δi) and tool runout (δi). Third, the parameters of frictional angle (βn), normal shear angle (ϕn), and shear yield strength (τs) in model coefficients are calibrated by orthogonal cutting experimental. Then, the predictive model of milling force is obtained. Last, the reliability verification experiment of model is conducted. The experiment results show that the model is with high efficiency and precision and the measured force and predictive force is in good agreement in amplitude and trend, which can be used in the study of milling force of disc milling.

Effect of mechanical activation on terbium dissolution from waste fluorescent powders

Rare earth elements (REEs), independently by the economic value, have a strategic importance and are involved, as critical materials, in the competition for their supply. An innovative process with the introduction of a preliminary physicochemical treatment was proposed. The mechanical activation of waste of fluorescent powders was performed by a vibratory disc mill at different experimental conditions to optimize the process. The mechanical forces induced to the powders cause crystal structure defects with a consequent increase of rare earths leachability. Factorial experimentations and analysis of variance were studied to determine the significant effects of the investigated factors (mechanical activation time, sulfuric acid concentration, pulp density and leaching temperature), especially for terbium dissolution. The preliminary activation allows to increase terbium dissolution of 35%. Then, according to the best conditions the subsequent operations of precipitation and calcination were performed obtaining a purity of 98.3% as rare earth oxides. Based on the experimental results, the flowsheet for rare earths recovery has been proposed and implemented by SuperPro Designer, a simulation software for process analysis and mass-energy balances. Finally, this paper reports a comparison between the present process with the mechanical pre-treatment and the alternative method based on thermal pre-treatment.

Increasing the surface stability of the cutting tool through complex machining

Nowadays, the application of multilayer coatings is widely used to increase the abrasion resistance of cutting tools. Before applying the multilayer coating, the selected cutting tool was purified in a bath with a disc cutting surface from quick-cutting steel and carried out the process of ion-nitriding or chemical-thermal treatment. In this case, nitrogen and argon ions diffuse over the surface of the disc cutter. Ion alloying using low-energy high-precision electron beams followed this process. The processing was carried out on a single-chamber two-system magnetron installation “RITM-SP-M”. Finishing was carried out by disc milling with Swiss Platit π311 ((TiCr)N-(TiAl)N-(CrAlSi)N+ion nitriding, (TiCr)N-(TiAl)N-(CrAlSi)N(nATCRo3)), (TiAl)N+ion nitriding + ion alloying (NbHf), (TiAl)N, (TiAl)N+ion nitriding, diamond-like coatings).Such multilayer coatings were tested at the Navoi mining and metallurgical plant “Navoi machine-building plant”. Machined disc cutters have been tested on 34XH1MA which is difficult to machine.

Reinforcement of bio‐based network polymer with wine pomace

AbstractPolymer materials prepared using renewable resources such as agricultural and food wastes would lead to a sustainable society. Our target was a synthesis of fiber‐reinforced network polymer derived from citrus oil and wine pomace. Lignocellulose nanofiber (LCNF) was successfully prepared from wine pomace by mechanical fibrillation using disk mill grinder under wet condition, followed by freeze‐drying. The resultant LCNF with coarse powder‐like (the untreated LCNF) enabled to reinforce bio‐based network polymer derived from limonene oxide even though heterogeneously dispersed LCNF was observed in the polymer matrix. Polymer/LCNF composite material with almost homogeneously dispersed LCNF was obtained using LCNF prepared from alcohol‐exchange process prior to freeze‐drying (the alcohol‐exchanged LCNF). Tensile strength of the network polymer reinforced by 2% of alcohol‐exchanged LCNF was around 3.2 times higher than that of the polymer without any LCNF. Dynamic mechanical analysis measurement exhibited that cross‐link density of the network polymer reinforced by 2% of alcohol‐exchanged LCNF was around 1.4 times higher than that of the neat polymer. It is noted that the cross‐linker for bio‐based network polymer, branched polyethyleneimine, likely acted as a dispersing agent for LCNF.

Milling method affects the physical properties of black bean flour

AbstractBackground and objectivesDry bean milling has attracted interest due to the increased need for nonwheat ingredients available for food applications. The objective of this study was to examine the physical and flow properties of black bean flour produced using a variety of laboratory mills and mill settings.FindingsFlour from mills which utilized screens (cyclone mill, centrifugal mill, and hammer mill) showed significantly different characteristics than flour from mills without a screen (disk mill and stone mill). Geometric mean size of flour particles was negatively correlated with starch damage (r = −.92), L* (r = −.94), angle of repose (r = −.94), and angle of slide (r = −.80 to −.90, depending on surface material) and positively correlated with moisture content (r = .72) and loose bulk density (r = .72). Finely ground flour resulted in particles that tended to be less circular and more elongated and had high angles of repose and slide.ConclusionsMilling method significantly affected (p &lt; .05) physical and flow properties of black bean flour.Significance and noveltyThese findings can be used by food processors in selecting a milling method that favors the production of black bean flour with the desired physical properties.

Penerapan Disk Mill Pada UMKM Anugerah Produksi Vitamin Unggas di Desa Sekarmojo Kecamatan Purwosari

Poultry vitamins are one of the nutrients needed by breeders. This poultry vitamin serves to accelerate the growth of poultry, maintain the quality of poultry meat, improve the quality of poultry eggs, prolong poultry egg production and accelerate poultry egg production. One of the partners who was worked together with the ITN Malang team is engaged in the field of poultry vitamins production and wants to increase the turnover of poultry vitamin production. All the time, the price of poultry vitamins from factories is considered high enough so that farmers have objections to buying poultry vitamins from the factory. The community service team observed at the quality of poultry vitamins which are produced in the Purwosari area and will transfer technology to apply a disk mill in the production process which will be able to increase the production of poultry vitamins in good prices but with high quality also. In addition, the community service team will improve the packaging by used aluminum foil to avoid moisture and later will be given a logo to facilitate the sales process to breeders. After improved the packaging, it has expected can be freely marketing with the general standardization of poultry vitamins. So that farmers can get cheap and good quality poultry vitamins. From the results of the activities carried out, it was found that a disk mill machine with a capacity of 150 kg / hour. It if the production of 500 kg takes 3 hours with one workers person. So that the partners can save time and production costs. So that the profits obtained now increase 25% from previous profits. Meanwhile the packaging used by the team partners now used aluminum foil so that the product looks more attractive and is able to hold the product dry.

Improving the construction of grinding disk mill for producing fibrous semi-finished products

The article states that grinding is the most important process; it determines the efficiency characteristics of the fibrous semi-finished product and the properties of the products made of it. The effectiveness of this process is influenced by some factors, but a tackle is of the most importance. Recently, the issues of selecting and creating the tackle design for wood fibers preparing, in contrast to cellulose and waste fibers, remain significant. In this regard, a scientific approach to solving the issue of creating the tackle design is required for the effective preparation of high-quality wood fibrous semi-finished product. The article presents theoretical studies for efficient evaluation of the existed structures for grinding wood fibers in disk mills. It has been a basis for developing a new geometry of the tackle and predicting its efficiency along with numerous preliminary studies and investigations carried out by various authors. The results of the experimental studies of the grinding process applying the existing structure and the results of the simulated experiment with the developed geometry of the tackle are presented. A comparative analysis of the influence of the design features of various types of tackles on the dimensional and efficiency characteristics and fractional composition of the semi-finished wood fibers was carried out. It was carried out on the basis of the theoretical and experimental studies, as well as the results of other authors studies concerning a grinding process and the influence of the of the semi-finished product features in the preparation of a fibrous semi-finished product in a disk mill.

Влияние методов измельчения бересты на выход биологически активных веществ

Introduction. Birch bark contains biologically active substances (BAS). In this regard, the search for ways to increase yield of its bioactive agents is relevant. Aim. To study the effect of birch bark grinding methods on the extract of its BAS during extraction. Materials and methods. Samples of birch bark of silver birch (Betula pendula Roth.) and downy birch (Betula pubescens Ehrh.) were ground up on devices with various force effects on plant material — disk (mainly squeezing, shear, tensile and shearing forces), three-roll annular (crushing and abrasive forces) and ball (crushing, abrasive and shock-shear forces) mills. Morphological and microscopic studies were carried out, the content of extractive substances and moisture in the ground up samples was determined. The composition and content of BAS were analyzed. Results. The smallest changes in the morphological and anatomical structure of plant material were observed when using a disk mill (the morphological features of birch bark and its cellular structure are preserved), grinding on three-roll ring and ball mills leads to serious changes in the morphological and anatomical structure of birch bark (the morphological and anatomical structure is lost, cell walls are destroyed). Comparative analysis of the yield of extractive substances from ground up birch bark samples, depending on the grinding method and the extractant used (purified water and ethyl alcohol of different concentrations: 96, 80, 70, 40, 20 and 10%) showed that the best extractant is 80% ethyl alcohol. The highest yield of extractive substances was noted for a sample of birch bark ground up in a ball mill — 36.85%, for ground up in a disc mill — 29.96%, on a three-roll ring mill — 30.88%. When studying the yield of the main groups of BAS (saponins, tannins, coumarins, hydroxycinnamic acids) from ground up birch bark samples, it was found that when using grinding methods that do not lead to the destruction of cell walls, the yield of BAS is limited by the capillary-porous structure of the plant material. Conclusion. When using grinding methods that lead to the destruction of cell walls, the greatest yield of BAS from birch bark is observed in the case of using a more severe impact on it, including not only abrasion, crushing, but also impact (ball mills).

Методика оценки погрешностей автоматизированных измерений длины общей нормали трехкоординатным индикатором на пятикоординатном станке с ЧПУ

The article provides an overview of studies of various errors in the process of measuring parts with three-coordinate probes on CNC machines. The paper considers a method for estimating systematic and random errors in the process of measuring the length of the base tangent using control maps and probabilistic and statistical methods for processing multiple repeated inputs of a three-coordinate indicator to the measured side surfaces of the wheel teeth. The method is designed to assess the acceptability of the measurement process by technologists and adjusters. The data of experimental estimation of random and systematic errors of measurement of the length of the base tangent on a five-coordinate CNC machine with a three-coordinate indicator of Mahr are presented. The obtained error values for the five-axis machine under study allow us to measure the length of the base tangent for the purposes of periodic monitoring and adjustment of the machine when processing oblique cylindrical wheels with universal disk or end mills

Автоматизированное измерение и коррекция длины общей нормали зубчатых колес в операциях зубофрезерования на пятикоординатном станке с ЧПУ

The article discusses a method for automated measurement of the length of the general normal of a helical cylindrical wheel, which allows to obtain its exact value without removing the part after gear processing with disk or end mills. The measurements are carried out by means of an automated supply of a three-coordinate linear measurement indicator to the calculated measurement points. The formulas for calculating the length of the general normal are given, which allow calculating the value of the length of the general normal and the correction value of the CNC gear ring processing program for two and one-point measurement schemes with the indicator. The use of the two-point method of measuring the length of the general normal with a three-coordinate indicator made it possible to measure the length of the general normal without removing the processed gear wheel from the mandrel, the single-point method completely eliminates the possibility of adjustment defects and reduces the complexity of carrying out machine changeovers in the mode of single and small-scale processing of gears. Comparison of gear measurement data with the three-coordinate indicator Mahr and a specialized CNC gear measuring machine give similar values and confirm the possibility of using the developed scheme to measure the length of the common normal

Comparative Analysis of the particle size on the porosity and the tensile properties of aluminium based metal matrix nano-composites

Milling a mixture of aluminium and manganese dioxide (MnO2) powders mixed in ratio of 1:7 by weight and the particle size has been varied by milling in a vibratory disc mill for 450, 600 and 750 min at 700 rpm to obtain Nano-sized alumina particles. Melting commercially pure aluminium followed by addition of different duration of milled powder mix while stirring the melt to synthesis nano-composites. The remaining aluminium powder will melt when the powder mixture will be added to molten Al-Mg alloy during composite processing. The remaining manganese oxide will also react with molten Al-Mg alloy during solidification processing of composite and generate alumina particles (in-situ). The reaction between manganese dioxide and molten alloy releases manganese for alloying with the molten Al-Mg alloy. To enhance wetting of resulting alumina particles by the melt, magnesium is added. It is observed that the porosity in the cast composite increases with increasing addition of particles milled for a given time and it is interesting to observe that for the same amount of addition, powders milled for higher milling time cause higher porosity. There is increasing strength and ductility compared with base alloy and composite prepared with 2wt% addition of different duration milled powder. The tensile properties for AM alloy shows yield strength of 75.9 MPa, tensile strength of 169.8 MPa and elongation of 11.12%. Tensile properties of different composites for addition of 2 wt% powder mix milled for 450, 600 and 750 min shows that 113.3 MPa, 91.8 MPa and 77.3 MPa of yield strength respectively, 250 MPa, 225.2 MPa and 216.8 MPa of tensile strength respectively and 25.65%, 25.68% and 23.91% of elongation respectively. For addition of 2 wt% powder mix milled for 450 min, there is improvement in yield strength by about 25%, tensile strength by about 35% and ductility by more than 120% in the nano-composite over those observed in the base alloy.

Mechanical Impact in Disk Mill for Producing Controlled Rice Husk Particle Size by Changing Impactor Shapes and Disk Rotation Speeds

The purpose of this study was to evaluate regulation of mechanical impact (i.e. impactor sizes and shapes) on triangle, cylinder, and cube as well as disk rotation speed (from 600 to 1500 rpm) in disk mill for controlling size-reduction process. As a model of size-reduced material, rice husk was selected. The study was done by evaluating the final milling product size, which was completed by the measurement of energy impact during the milling process. Experimental results showed that the product size was controllable in the range of between 50 and 1000 μm. The impactor sizes and shapes influenced the contact diameter and area of impactor for making more materials being collided, whereas disk rotation speed led to giving more collision number (between rice husk and impactor) and increasing impact from the collision (due to less time contact during collision). This study provides an important information, which can be further generalized in the use of milling process as a tool for materials size-reduction and mechanochemical process.

Reinforcement Materials in Poly((R)-3-Hydroxybutyrate-co-(R)-3-Hydroxyhexanoate Bionanocomposite

Waste paper is the second-highest municipal solid waste collected in Malaysia and as current practice, it is recycled for further use in the manufacturing of low-grade products. Instead of continuously utilizing waste paper for low-grade products manufacturing, it can be used as a feedstock to produce high bioproducts such as cellulose nanofiber (CNF). Hence, this study explored the potential of waste paper as a feedstock for CNF production. The waste paper was subjected to a different number of cycles of wet disk milling (WDM): 0, 5, 10, 15 and 20 cycles. The presence of nano-sized cellulose was confirmed by FE-SEM micrographs, where CNF with diameter size 20 – 40 nm was formed after 10 cycles of milling. It was also revealed that the obtained CNF possessed appropriate properties as a reinforcement material. The tensile strength and Young’s modulus of poly((R)-3-hydroxybutyrate-co- (R)-3-hydroxyhexanoate (PHBHHx) increased by 19 and 12%, respectively after the reinforcement of 1% CNF. Overall, this study portrays that waste paper could be utilized as a raw material for CNF production, without the need for chemical pretreatment.

THE INFLUENCE OF THE KNIFE METHOD OF GRINDING PULP ON THE PROCESS OF OBTAINING POWDERED CELLULOSE

This article presents the classification of the resulting types of powdered cellulosic materials, their scope, as well as the problems arising during production. The main properties of powder cellulose materials are considered. Analyzed the quality indicators of the pulp, previously ground in a disc mill. The main technological parameters of the experimental setup and the comparative characteristics of the used knife grinding sets are presented. In the course of the experimental research, knife grinding sets with straight and curved knives were used. The data obtained confirmed the previously put forward hypothesis about the predominant fibrillation of cellulose fiber milled using a grinding set with a curved blade shape. This feature of the headset design is especially important when grinding hardwood pulp, which has a lower initial value, compared to softwood pulp. The data obtained in determining the degree of grinding, water retention capacity, fiber length of softwood and hardwood cellulose after knife grinding and the degree of polymerization after hydrolysis are presented. A method for producing powdered cellulose material with characteristics similar to microcrystalline cellulose is considered. The regulated parameters of the hydrolysis process are set and a comparison is made of the degree of polymerization of the considered samples of powdered cellulose.

ТЕОРЕТИЧЕСКОЕ ИССЛЕДОВАНИЕ ПРОЦЕССА ИЗМЕЛЬЧЕНИЯ МАТЕРИАЛА В РАБОЧЕЙ КАМЕРЕ ДИСКОВОЙ МЕЛЬНИЦЫ

This article analyzes the movement of material particles in the central and peripheral parts of the working chamber of a disk mill. A diagram of a disk mill and a diagram of the movement of particles in its working chamber are presented. The cutting elements are blades in the shape of a parabola located on the disks having an inclined surface. An expression is found for determining the time when a particle is located inside the grinding chamber of a mill. It is determined that this time depends on the geometric (x1; y1; x2; y2; ) and technological (ω) parameters. The dependence of the time spent on the change in the angle of deviation of the surface of the curved blade from the radial direction is shown in figure 3. As a result of theoretical research, an analytical expression is obtained that allows to determine the particle size at the output of the grinding chamber. According to the found expression, the final particle size at the output of the grinding chamber depends on such parameters as d0, σ, ω, and . As a result, the dependence (figure 4) of the ratio of the initial particle size to the final one ( 0 ) on the time change is constructed. According to the obtained graphs, as the angle increases, the particle time in the grinding chamber decreases, in result of which the final size of the particle at the output increases.

Mechanochemical and Size Reduction Machines for Biorefining.

In recent years, we have witnessed an increasing interest in the application of mechanochemical methods for processing materials in biomass refining techniques. Grinding and mechanical pretreatment are very popular methods utilized to enhance the reactivity of polymers and plant raw materials; however, the choice of devices and their modes of action is often performed through trial and error. An inadequate choice of equipment often results in inefficient grinding, low reactivity of the product, excess energy expenditure, and significant wear of the equipment. In the present review, modern equipment employing various types of mechanical impacts, which show the highest promise for mechanochemical pretreatment of plant raw materials, is examined and compared—disc mills, attritors and bead mills, ball mills, planetary mills, vibration and vibrocentrifugal mills, roller and centrifugal roller mills, extruders, hammer mills, knife mills, pin mills, disintegrators, and jet mills. The properly chosen type of mechanochemical activation (and equipment) allows an energetically and economically sound enhancement of the reactivity of solid-phase polymers by increasing the effective surface area accessible to reagents, reducing the amount of crystalline regions and the diffusion coefficient, disordering the supramolecular structure of the material, and mechanochemically reacting with the target substances.

Chemical Free Two-Step Hydrothermal Pretreatment to Improve Sugar Yields from Energy Cane

Energy cane is an attractive lignocellulosic feedstock for processing into biofuels and bioproducts. A low-severity two-step hydrothermal pretreatment was investigated on energy cane for the production of monomeric sugar. Pretreatment temperature and time, in addition to the effect of disk milling, were observed for the glucose and xylose yields during hydrolysis. At residence times above 5 min in case of pretreatment at 200 °C, all of the hemicellulose was observed to be solubilized. The pretreatment condition of 200 °C for 10 min with disk milling was observed to provide the highest glucose concentration of 5.4%, and 200 °C for 5 min with disk milling provided the highest xylose concentration of 2.15%. The effect of disk milling in improving the sugar concentrations during hydrolysis was significant, especially at lower pretreatment temperatures and times. Low xylose yields at higher temperatures were attributed to the formation of degradation products at increased severity.