Sawing Machine Research Articles

Improvement of magnetic induction-wire sawing process using a magnetic system

ABSTRACTMagnetic induction-free abrasive wire sawing is a hybrid process that applies a homogeneous magnetic field to transport more abrasives into the sawing channel. This causes the performance of wire sawing significantly improved. Magnetic field strength is a key factor in determining the magnetic force acting on the magnetic abrasives, then affecting the quantity of abrasives adsorbed on the saw wire surface. However, the background magnetic induction strength produced by two permanent magnets is limited in this process. To further investigate the influence of magnetic field strength on the wire sawing performance, a magnetic system, which is based on the magnetic circuit design principle and the structure of single-wire sawing machine, is designed and fabricated. The magnetic field characteristics of the designed magnetic system are investigated both by numerical simulations and experiments. An experimental setup that installs the fabricated magnetic system on the single-wire sawing machine is built to conduct the magnetic induction-wire sawing experiments. The results show that the optimal magnetic induction strength is about B0 = 135 mT. In this case, the kerf loss is decreased by 10% compared to the free abrasive wire sawing technology without a magnetic field.

Совершенствование круглопильных станков

Совершенствование круглопильных станков

Characterization of Sawdust Produced from Circular, Chain and Band Sawing Machines

Particle size distribution (PSD) of sawdust produced from circular, chain and band sawing machines has been carried out in order to study the influence of different saws on sawdust produced and its characterization. The raw materials were collected from the mill sites and screened, then vibrated on mechanical sieves. Four major fractional classification of particle sizes are identified; oversize particles (OS), coarse particle (CPS), pin particle (PSP) and fine (FSP). The particle size distribution in all the three mills shows a similar pattern of distribution on log sieve graph. The proportion of particle size distribution in FPS produced by all the saw showed slight variations with the least (30.0 ± 1.2%) variation in bandsaw, followed in increasing order by chainsaw and circular saw (37.2 ± 1.3%). Analysis of variance revealed that blade type, particle size, wood density, and particle density are significantly affected by porosity.

PROSES MANUFAKTUR MESIN GERGAJI KAYU UNTUK PENGRAJIN PALET KAYU

Wood saws are hand machines that small industries need. Almost all work processes through a saw machine with good results. Circular saws are not only used in timber industry, but also in the carbuery industry, by plumbing, construction experts, loggers or gardenists. In any hobby there are wearing it. For manufacturing process of making wood sawing machine in allotment for wooden pallet craftsman. The formulation of the problem in making this saw machine is how to manufacture wood saw process for wooden pallet craftsman and howmuch budget cost in manufacturing process of saw machine for wooden pallet craftsman. The components of the saw machine are frame, table mat, bearing, shaft, pulley transmission and V belt, while the tools and machinery used in the manufacturing process are electric welding tools, electric grinding wheels, grinding wheels, lathes, and frais machines.

Large eddy simulation of turbulent heat transfer from a rotating disk subjected to a forced parallel air stream

Nowadays, rotating disks are an important part of most industries such as turbo machines, heat exchangers, braking systems, rotating sawing machines, and computer disk drives. Working temperature and consequently heat transfer have a profound effect on performance and lifetime of rotating disks. There is a noticeable difference between numerical and experimental results in the studies of turbulent heat transfer from a rotating disk subjected to parallel air stream. The main objective of this study is numerical simulation of turbulent convective heat transfer from a rotating disk subjected to parallel air stream. In this study, the 2nd order finite volume scheme and large eddy simulation (LES) with the dynamic Smagorinsky procedure in sub-grid-scale is used. Two limit cases called rotating disk in still air (von Karman's swirling flow), stationary disk subjected to parallel air stream are investigated as well. The mean Nusselt number of the disk surface is obtained at statistical steady state for a wide range of rotational and cross flow Reynolds numbers. The influence of flow separation and finite disk thickness on heat transfer is investigated and followed by a detailed discussion. The effect of convection and diffusion on temperature field is illustrated. Comparison with experimental data shows that the LES dynamic Smagorinsky results are by far better than available numerical results. It is discussed in detail that there is a critical value for ratio of crossflow Reynolds number to rotational Reynolds number which above that the influence of disk rotation on mean Nusselt number is negligible.

Effect of Spindle Parameters of Woodworking Band Saw on the AE Value of Crack Band Saw Blade in Compound Material Processing (1)

Taking the MJ3210A motion band saw as the research object, the AE value of the band saw blade vibration was obtained by analyzing the VIBSYS vibration signal acquisition and analysis software system in Beijing, and the change of the AE value of the band saw and the crack was found out. The experimental results show that in the MJ3210A sports car sawing machine, the band saw blade with width of 130 mm is used, and the AE value of the cracked band saw blade is well in the high band saw blade AE value. Under the best working condition of the band saw, the band saw blade AE If the value exceeds 104.7 dB (A) above, it means that the band saw blade has at least one crack length greater than 1.38 mm for the crack defect and the need to replace the band saw blade in time. Different species with saw blade of the AE value is different, white pine wood minimum, the largest oak wood; according to a variety of wood processing AE instrument value to determine the band saw blade crack to the situation; so as to fully rational use of band saw blade, The failure and the degree of development to find a new method.

A newly-developed model for predicting cutting power during wood sawing with circular saw blades

In the classical approach, cutting forces and cutting power in sawing processes of orthotropic materials such as wood are generally calculated on the basis of the specific cutting resistance kc (cutting force per unit area of cut). For every type of sawing kinematics (frame saws, band saws and circular sawing machines) different empirical values of specific cutting resistance kc have to be applied. It should be emphasised that sources in the scientific literature and handbooks do not provide any information about wood provenance, nor about cutting conditions in which cutting resistance had been determined. In analyses of sawing processes in which the offcut is formed by shear, Atkins’s ideas that all cutting forms a branch of elastoplastic fracture mechanics can be applied. Thanks to this modern approach it was possible to reveal, using experimental results data of fracture toughness and shear yield stresses of Polish pine (Pinus sylvestris), the significant effect of the raw material provenance (source of wood) on cutting power. In the common model for circular sawing machine kinematics, which is similar to metal milling, the sum of all uncut chip thicknesses of the all the teeth simultaneously engaged represented the mean uncut chip thickness. In this work predictions of the newly-developed model for the circular sawing machine are presented. In the model, beside uncut chip thicknesses changes, appropriate changes in shear yield stress and toughness with tooth/grain orientation have been taken into account. The conducted analyses have demonstrated that values of RMS of cutting power obtained with the new developed model are slightly larger than experimental values. On the other hand computed values of cutting power with the use of the mean uncut chip thicknesses in the model are a bit lower from the empirical one.

Wear of Monolayer Brazed Diamond Beads in Wire Sawing of Granite

The wear behavior of monolayer brazed diamond beads was investigated during wire sawing of granite. Diamonds were bounded onto the beads by brazing in vacuum. Brazed beads were abrasive sawed on a wire sawing machine and the wear of the brazed diamond beads were traced and observed by using a digital microscope. The results reveal that the wear of root fractured, characterized by breaking off grit at its bonding level, was the fatal failure of the cutting ability of grit as well as the main wear behavior of brazed grits on brazed bead.

Effects of magnetic field distributions on wire sawing performance

To transport more abrasive grains into the cutting zone, the method of magnetic-induction free-abrasive wire sawing is proposed. A uniform magnetic field is used to magnetize a steel wire and forms a high gradient magnetic field around the wire. The magnetic abrasive grains are adsorbed on the magnetized wire and are transported into the cutting zone, which improves the wire sawing performance. The adsorption of the magnetic abrasive grains is observed using an experimental setup along the wire cross-sectional direction. The results suggest that magnetic abrasive grains are increasingly adsorbed in the paramagnetic region of the wire with increasing magnetic field intensity. Single-wire sawing experiments are conducted on a WXD170 reciprocating wire sawing machine at variable magnetic field intensity and distribution. The results suggest that the change in magnetic field intensity strongly affects the cutting efficiency, kerf loss, and surface roughness. The performance of the magnetic-induction free-abrasive wire sawing under different magnetic field intensities and distributions are compared. The wire sawing performance improves when the uniform magnetic field is evenly distributed in the cutting zone and at the top of cutting zone.

Estimation of the Ampere Consumption of Dimension Stone Sawing Machine Using of Artificial Neural Networks

Nowadays, estimating the ampere consumption and achieve to the optimum condition from the perspective of energy consumption is one of the most important steps to reduce the production costs. In this research it is tried to develop an accurate model for estimating the ampere consumption by using the artificial neural networks (ANN).In the first step, experimental studies were carried out on 7 carbonate rock samples in different conditions at particular feed rates (100, 200, 300and 400) and depth of cuts (15, 22, 30and 35mm) using a fully instrumented laboratory rig that is enable to change the machine parameters and measure the ampere consumption. In next step, a back propagation neural network was designed for modelling the sawing process for predicting the ampere consumption. The input network consisting of two parts: machine, work piece characteristics and the output of neural network was ampere consumption. This research evaluated the competencies of neural networks to estimate the ampere consumption in sawing process. The correlation coefficient between measured and predicted data in training and testing data is 0.95 and 0.97 respectively. The root mean square error (RMSE) for train and test data is 1.2 and 0.7 respectively. The results of this study showed that the ANNs can be used to estimate the ampere consumption with high ability and low error for industrial applications. Moreover, the cost of sawing machine ampere consumption can be accurately estimated using this neural model from some important physical and mechanical properties of rock.

Study on the formation mechanism of saw-tooth chip in high-speed cutting process

The 080A15 and 30CrMnMo steels were cut by precision sawing machine. The microscopic characteristic of the chip surface and the chip failure microscopic mechanism have been studied. The studies show that the formation of saw-tooth chip is mainly a function of the strength and thermal conductivity. For 080A15 steel, the strength is low and the thermal conductivity is high, the plastic work was absorbed continuously by the process of plastic deformation, and the heat was dissipated at any moment. The heat energy did not reach the critical value causing thermal softening. The chip is more prone to ductile fracture. For 30CrMnMo steel, the bonding ability is stronger among atoms, and thermal conductivity is smaller. The plastic deformation is extremely fast and the instantaneous temperature rise was very high because the heat energy reached the critical value causing thermal softening. Therefore, the chip is more prone to adiabatic shear failure to form the saw-tooth chip divided uniformly by adiabatic shear band. The research results help to provide the basis for selecting materials with different adiabatic shearing sensitivities in the process of high-speed cutting by studying the energy barrier on the influence of chip failure mechanism.

Design and Development of Billet Sawing Machine for Improving Productivity

Background/Objectives : The objective of our research work is to increase the productivity of the billet sawing machine. Methods/Statistical Analysis : In this research work we suggest some modification to the existing machine by redesigning the some parts of the auto loader, main and shuttle vice. The rod resting area and feeder area of the auto loader has been modified by raising the height of the rod resting area and also designed the feeder to hold two rods vertically. And also the dimensions of the main vice and the shuttle vice have been redesigned to hold the two rods vertically. Findings : The proposed billet sawing machine thus enables to cut two rods at the same time in order to reduce the cutting time and also could be improved 50 to 75 % (approx.) of the productivity in modern manufacturing environment than the existing machine.

Attenuation of blast vibration in tunneling using a pre-cut discontinuity

A pre-cut discontinuity, similar to the pre-splitting around a tunnel periphery, is introduced to investigate the attenuation of the wave propagation due to tunnel blasting. For this, two empty holes were drilled to support the sawing jigs and a wire sawing machine with embedded industrial diamond wire was used to cut an artificial discontinuity near the initial blasting holes at the tunnel face. The peak particle velocity with/without pre-cut was measured during tunnel blasting and the effect of the pre-cut method was quantitatively accounted for, although, due to limited time and unfavorable field conditions, the cutting depth was not able to reach the initial design depth. Numerical analysis was also performed in order to model the tunnel geometry and blasting procedure. For this, a commercial package called UDEC was used and the accuracy of UDEC was initially proven by an analytical solution of the reflection and transmission of the incident wave. Various parametric studies including sequential detonations were performed and the reduction factor of attenuation with ideal cut-off discontinuity was shown to be 50%. Future work will concentrate on the improvement of the wire sawing machine to reduce the cutting time and three dimensional modeling of the blasting effect will also be performed.

Investigation on diamond wire break-in and its effects on cutting performance in multi-wire sawing

Multi-wire sawing with diamond wire is used to slice hard and brittle materials such as sapphire, silicon carbide, or silicon into thin wafers. Compared to traditional slicing methods, multi-wire sawing with diamond wire has many advantages, including reduced kerf loss, efficient machining, and improved form accuracy. However, the process is associated with several unexpected problems, including considerable kerf loss and inefficient cutting during the initial cutting step. Thus, materials cannot be constantly removed due to the instability of the cutting performance of the diamond wire. These phenomena are defined as the break-in characteristics of diamond wire. This paper focused on the break-in characteristics of diamond wire and the effects of these characteristics on the cutting performance. In an experiment, a single-wire sawing machine equipped with a monitoring system was used to analyze the horizontal and vertical cutting forces which arose during the cutting process. The cutting performance was evaluated by means of cutting profile measurements. The wires used were analyzed by the newly developed vision measurement system and through scanning electron microscope (SEM) imagery. On the basis of results, it was found that the break-in characteristics of diamond wire are strongly correlated with the wear behaviors of the diamond wire.

Sawing Processes as a Way of Determining Fracture Toughness and Shear Yield Stresses of Wood

A new computational model, based on fracture mechanics, was used to determine cutting forces. Unlike traditional computing methods, which depend on many coefficients reflecting the machining of solid wood, the new model uses two main parameters: fracture toughness and shear yield stresses. The aim of this study was to apply this new method to determine these parameters for the tooth cutting edge principal positions and longitudinal and perpendicular cutting speed directions. Samples of beech wood (Fagus sylvatica L.) were sawn. The measurements of energetic effects (cutting power and cutting force) while sawing wood were carried out on two laboratory stands: the sash gang saw and the circular sawing machine. The basic relationships between different sawing methods, such as cutting on a frame sawing machine (sash gang saw) and a circular sawing machine, and the fracture toughness and shear yield stresses were recognizable. The data obtained could be applied to the computation of the energetic effects on other wood cutting methods.

Determining optimal primary sawing and ripping machine settings in the wood manufacturing chain

for wood manufacturers around the world, the single biggest cost factor is known to be its raw material. Maximum volume recovery of this raw material is, therefore, of key importance for the industry. The wood products industry consists of several interrelated manufacturing steps for converting trees into logs and logs into finished lumber. Each operation usually optimises its functionality in isolation from the preceding and following operations. It is a well documented fact that the optimisation of decisions through the whole chain of operations is considerably more profitable than the optimisation of individual operations. The objective of this study was to determine the optimal machine settings for two interrelated operations, namely the sawing and ripping operations which have tradition‑ ally been optimised individually. A model, having two decision variables, was developed which aims to satisfy market demand at a minimal cost. The first decision was how to saw the log supply into different thicknesses by choosing specific sawing patterns. The second was to decide on a rip saw's priority value settings, which determines how the products from the primary sawing operation are ripped into products of a certain thickness and width. The techniques used to determine the machine settings included static simulation with the SIMSAW software to represent the sawing operation and mixed integer programming to model the ripping operation. A metaheuristic, namely the Population Based Incremental Learning algorithm, was used to link the simulation and mixed integer models and to determine the optimal settings for the combined process. The model's objective function was to minimise the cost of production. This cost included the raw material waste cost and the over or under production cost. The over production cost included the stock keeping costs and the under production cost was estimated as the buy‑in cost of under supplied products from another wood supplier. The model performed well against current decision software available, namely the Sawmill Production Planning System package, which combines simulation and mixed integer programming techniques to maximise profit. The model added further value by modelling and determining the ripping priority settings in addition to the primary sawing patterns.

The Study of Band Sawing Vibration and Cutting Performance

Band saws machine is the most efficient metal cutting machine. By losing less material, material qualitative, having big saw range and having low cutting costs are superiority of band saws. Band saws are acting with most long route and more limited support point in all cutting tools. In band sawing machine, band saws and structure are easy to produce vibration. Affect cutting life, costs of band saws and material surface topography. So this study focuses on analyzing what is vibration cause of band saws by vibration source and establishes the relationship between band saws natural frequency along and change cutting condition. In this research use the C-430GNC band saws machine, and use S45C material for cutting test. Accelerometers are used with a measurement system to capture sawing vibration data. By the fast Fourier transform to analyze spectrogram transform in order to identified characteristic spectrums, and find out vibration feature with band sawing operating conditions and unusual evens came from wear of blade. Minimum cutting vibration and best surface topography were compared to find out the best cutting condition.

Совершенствование круглопильных станков

Совершенствование круглопильных станков

Design and experimental characterization of thin film heaters on glass substrate for Lab-on-Chip applications

This paper presents a comprehensive procedure for the design and implementation of thin film heaters manufactured on glass substrates. The thermal and electrical behavior of the heaters have first been simulated and proper design solutions have been adopted for increasing the thermal resistance of the heaters, thus decreasing their power consumption. Trenches were adopted in order to thermally isolate the heater from the glass substrate. The presence of four different layouts of trenches on the back and the front side of the glass slide with different geometries was extensively simulated. The simulated geometries were manufactured and an automatic sawing machine was exploited to dig 240μm wide trenches in the glass substrate. The trenches were typically stopped at about 80μm from the opposite surface. Techniques commonly adopted for measuring the temperature coefficient of resistance, the thermal resistance and thermal capacitance in the case of Si-based microheaters have conveniently been modified to take into account the fundamentally different thermal parameters of a heater manufactured on glass. An experimental improvement of the thermal resistance up to 217% on a heat sink and 30% in air has been obtained when a large part of the thermal mass under the microheater was removed. The thermal capacitance was also considerably decreased, thus improving the dynamic thermal behavior.

산업용 기계 제조자와 사용자 대상 직접규제의 균형과 실효성 분석

This study first addresses the ineffectiveness of indirect regulation on industrial machines. Analysis of causes of industrial accidents associated with industrial machines further reveals the fact that technical causes need to be resolved at the manufacturing stage to reduce the frequency and strength of industrial accidents. Balanced safety certification on manufacturers and safety inspection on users of industrial machines are then suggested to effectively resolve such technical causes. The effectiveness of such safety certification and safety inspection can be justified by cost-benefit analysis. Particularly, balance in expected benefits of safety certification and safety inspection is a key issue for validity of such analysis. The accumulated benefit-costs for press brake and portable sawing machine confirm the effectiveness of such safety system.