Cut-off Wheel Research Articles

Unusual Penetrating Mandibular Injury By A Cut-Off Wheel

Penetration wounds on the face caused by foreign bodies other than bullets are rare in today’s life. Most of the adult penetrating injuries reported in the literature were due to industrial accidents, criminal assaults or self-injury. We present an unusual case of a man who suffered a fracture of his lower jaw due to a broken cut- off wheel. This kind of injuries was rare in todays life because of the Poor workplace safety still existing in our country.

Robotic Disassembly of Electric Vehicles’ Battery Modules for Recycling

Manual disassembly of the lithium-ion battery (LIB) modules of electric vehicles (EVs) for recycling is time-consuming, expensive, and dangerous for technicians or workers. Dangers associated with high voltage and thermal runaway make a robotic system suitable for the automated or semi-automated disassembly of EV batteries. In this paper, we explore battery disassembly using industrial robots. To understand the disassembly process, human workers were monitored, and the operations were analyzed and broken down into gripping and cutting operations. These operations were selected for automation, and path planning was performed offline. For the gripper, a linear quadratic regulator (LQR) control system was implemented. A system identification method was also implemented in the form of a batch least squares estimator to form the state space representation of the planar linkages used in the control strategy of the gripper. A high-speed rotary cut-off wheel was adapted for the robot to perform precise cutting at various points in the battery module case. The simulation results were used to program an industrial robot for experimental validation. The precision of the rotary cutter allowed for a more direct disassembly method as opposed to the standard manual method. It was shown that the robot was almost twice as fast in cutting but slower in pick and place operations. It has been shown that the best option for disassembly of a LIB pack is a human–robot collaboration, where the robot could make efficient cuts on the battery pack and the technician could quickly sort the battery components and remove connectors or fasteners with which the robot would struggle. This collaboration also reduces the danger encountered by the technician because the risk of shorting battery cells while cutting would be eliminated, but the time efficiency would be significantly improved. This paper demonstrates that a robot offers both safety and time improvements to the current manual disassembly process for EV LIBs.

Increasing the effectiveness of cut-off wheels on a bakelite bond

The composition of the molding mixture for the manufacture of cut-off wheels on a bakelite bond with the content of surfactants in the form of fine powders of molybdenum disulfide and chromium diiodide is proposed. The performance indicators of these cut-off wheels are investigated. Keywords: cut-off wheel, bakelite bond, thermomechanical destruction, surfactants, cutting coefficient. safoklovbb@mail.ru

Modelling and Multi-objective Optimization of Elastic Abrasive Cutting of C45 and 42Cr4 Steels

Elastic abrasive cutting is a new high-performance method to produce workpieces made of materials of different hardness, which ensures lower wear of cut-off wheels and higher quality machined surfaces. However, the literature referring to elastic abrasive cutting is scarce; additional studies are thus needed. This paper proposes a new approach for modelling and optimizing the elastic abrasive cutting process, reflecting the specifics of its particular implementation. A generalized utility function has been chosen as an optimization parameter. It appears as a complex indicator characterizing the response variables of the elastic abrasive cutting process. The proposed approach has been applied to determine the optimum conditions of elastic abrasive cutting of С45 and 42Cr4 steels. To solve the optimization problem, a model of the generalized utility function reflecting the complex influence of the elastic abrasive cutting conditions has been developed. It is based on the findings of the complex study and modelling of the response variables of the elastic abrasive cutting process (cut-off wheel wear, time per cut, cut piece temperature, cut off wheel temperature and workpiece temperature) depending on the conditions of its implementation (compression force F exerted by the cut-off wheel on the workpiece, workpiece rotational frequency nw, cut off wheel diameter ds). By applying a genetic algorithm, the optimal conditions of elastic abrasive cutting of С45 and 42Cr4 steels: ds = 120 mm; F = 1 daN; nw = 63.7 min–1 and nw = 49.9 min–1, respectively for С45 and 42Cr4 steels, have been determined. They provide the best match between the response variables of the elastic abrasive cutting process.

Prediction of Tool Forces in Manual Grinding Using Consumer-Grade Sensors and Machine Learning.

Tool forces are a decisive parameter for manual grinding with hand-held power tools, which can be used to determine the productivity, quality of the work result, vibration exposition, and tool lifetime. One approach to tool force determination is the prediction of tool forces via measured operating parameters of a hand-held power tool. The problem is that the accuracy of tool force prediction with consumer-grade sensors remains unclear in manual grinding. Therefore, the accuracy of tool force prediction using Gaussian process regression is examined in a study for two hand-held angle grinders in four different applications in three directions using measurement data from an inertial measurement unit, a current sensor, and a voltage sensor. The prediction of the grinding normal force (rMAE = 11.44% and r = 0.84) and the grinding tangential force (rMAE = 18.21% and r = 0.82) for three tested applications, as well as the radial force for the application cutting with a cut-off wheel (rMAE = 19.67% and r = 0.80) is shown to be feasible. The prediction of the guiding force (rMAE = 87.02% and r = 0.37) for three tested applications is only possible to a limited extent. This study supports data acquisition and evaluation of hand-held power tools using consumer-grade sensors, such as an inertial measurement unit, in real-world applications, resulting in new potentials for product use and product development.

Justification of the parameters and operating modes of the disinfecting system

Increasing yields is an important task for our country. This is possible due to removing the tip of the shoot, which stimulates the potential of the plant itself, and such products can be sold as organic since no other chemicals are used to increase yields. When the shoot tip is removed, a wound is formed through which pathogens can enter. To reduce the likelihood of plant contamination, the device provides a system for applying a disinfectant solution (hydrogen peroxide) to the knife blade. The settings of the injector are taken into account. When choosing a spray gun, it is necessary to take into account the average working pressure, equal to P = 0.28 MPa, which provides a solution flow rate щa Q = 0.8 l • min-1 with a nozzle diameter of 0.1 mm. These requirements can be met by spray guns of caliber 04 or 05. At a spray angle of 800, the recommended spray angle is 300; the mounting distance is 0.3 m below the plane of rotation of the cut-off wheel. The initial flow rate of the liquid of 17.33 m • s-1 will provide stable droplet formation, providing the recommended dispersion of the solution of 150-200 microns.

A novel, rapid, and low cost method for preparing tissues with metallic stents for routine histology.

Coronary artery stenting has become a common procedure and cardiovascular pathology specimens containing these metallic stents are accordingly becoming common. Histologic examination of stented vessels is imperative, but special techniques are needed due to the presence of metal within the tissue. We describe a rapid and inexpensive method for preparing stented vascular specimens for routine histology suitable for use in almost any histology laboratory. After formalin fixation and decalcification, stented vascular segments were freeze-embedded and sectioned using a handheld power micro cutoff wheel tool into ~1mm slices. Sections were allowed to thaw and the strut shards removed with fine forceps. No longer containing metal, the sections were processed for routine paraffin embedding, microtomy and staining. Histologic sections showed only minor tissue disruption around the stent struts. In our experience with 25 stented arteries (mean interval from implantation 5.6 years), the mean subjective section quality score was 4.1 out of 5. The position of each strut could easily be determined, along with neointimal in-stent restenosis and thrombosis. Local reaction to each strut could be surmised even if minor tissue disruption occurred. The entire process was completed in 2-3 days. The incremental cost over that of routine histology is nominal. This method for examining stented vascular segments histologically could readily be applied in most pathology laboratories and serves as a highly practical solution to dilemma of examining stents histologically.

Performance of Cut-Off Wheels during Elastic Abrasive Cutting of Rotating Workpieces

Performance of Cut-Off Wheels during Elastic Abrasive Cutting of Rotating Workpieces

Infrared Thermography for Elastic Abrasive Cutting Process Monitoring

This paper presents the features of infrared thermography (IRT) for contactless study of elastic abrasive cutting process of rotating workpieces. IRT monitoring specifics along with the experimental procedures and techniques for data analysis are discussed. IRT measurement results of the influence of workpiece rotational speed, during the processing of various materials, on heat release and heat distribution at the workpiece surface, on the cut-off wheel, the cut piece and the cutting time period are presented. The operational methodology and the results obtained can be used for optimizing the abrasive cutting of rotating workpieces.

Development of a Process Data-based Strategy for Conditioning Position-controlled ID Cut-off Grinding Wheels in Silicon Wafer Manufacturing

Manufacturing technologies in the semiconductor industry put high demands on accuracy, especially for the initial steps of wafering. ID grinding has established itself as a cost-effective manufacturing method for the production of wafers with a diameter of up to 150mm. Methods for improving the quality parameters of the wafer, resulted in the integration of a magnetic position control for the ID grinding wheel to control its axial position. For this, a new conditioning strategy had to be developed in consideration of tool life of the grinding wheel, process automation and wafer quality.

Analysis and Modeling of Heat Flux into the Tool in Abrasive Circular Cutting of Unidirectional CFRP

For edge trimming of slightly curved thin walled CFRP parts dry circular cutting is a promising alternative. However, a high fraction of the cutting energy is converted into heat. The study focuses on the determination of the amount of heat dissipated by the tool in circular cutting of unidirectional CFRP with epoxy matrix. An inverse heat conduction model is developed and solved for a set of temperature profiles measured on the tool surface with an infrared camera. It was found, how the heat dissipation by the diamond abrasive cut-off wheel is affected by fiber orientation, cutting speed, feed velocity and immersion depth of the wheel. The projected cutting area normal to the fiber direction turned out to be crucial for heat dissipation. The results of numerical simulations and experiments indicate, that tool temperatures in dry circular cutting do not exceed temperature limits of CFRP present in dry end milling. The developed heat flux model allows for optimization of dry CFRP abrasive circular cutting processes. It forms a module for future workpiece temperature assessment and thermo-mechanical process simulation.

The In-Depth Stress Distribution for 1H13 Specimen after Cutting

Abstract Measuring the in-depth stress state is of vital importance for materials scientists. Strain gauges methods are capable of yielding information only about the surface stress state. Diffraction methods using synchrotron or neutron radiation, which allow totally non-destructive stress measurements inside the material, are not widely available. In this context, the best widely available method combines the X-ray diffraction stress measurements and gradual removal of the outer layer by means of electropolishing. Here, this method was applied to the specimen made of 1H13 stainless steel cut with under water on a corundum cut-off wheel. The idea was to investigate how deeply an additional stress state resulting from cutting was introduced and whether the technique of combining of X-ray diffractometry and electropolishing can be used widely for determining the stress state inside the specimen.

Modelowanie konstrukcji przecinaków ściernych diamentowych ze spoiwem żywicznym

Modelowanie konstrukcji przecinaków ściernych diamentowych ze spoiwem żywicznym

Wpływ przyspieszenia kątowego ściernic do przecinania na ich wytrzymałość na rozerwanie

Wpływ przyspieszenia kątowego ściernic do przecinania na ich wytrzymałość na rozerwanie

Study on Machining Characteristics of Sawing Al<sub>2</sub>O<sub>3</sub> Ceramic with Diamond Cut-Off Wheel

In the present study, sawing forces of Al2O3 ceramic and wear of metal-bonded diamond cut-off wheel were examined by counting the statistical data of diamond wear and analyzing the force signals under different sawing conditions. The experimental results demonstrated that normal grinding force reduced with the increasing of sawing speed, and rose with the increasing of workpiece feed rate and grinding depth. In all of the variables, sawing depth made the greatest effects on normal grinding froce. The percentage of whole crystal or pull-out crystal decreased and fractured crystal increased as the sawing depth increased or the sawing speed decreased. Among machining factors, sawing speed was the greatest effectors on the wear of diamond cut-off wheel.

Exposure Assessment in Auto Collision Repair Shops

Workers in auto collision shops are exposed to a variety of chemical and physical hazards. Previous studies have focused on measuring levels of isocyanates, but little is known about exposures to dust, noise, and solvents. In preparation for an intervention effectiveness study in small collision repair businesses, sampling was conducted on 3 consecutive days in four representative businesses with three to seven employees. Full-shift and task-specific exposures were measured for dust and solvents (for operations other than painting and spray gun cleaning). Full-shift personal exposures and tool-specific noise levels were also evaluated. Samples of banded earplugs were distributed to employees and feedback was collected after 1 week of wear time. Dust and solvent exposures did not exceed the OSHA PELs. Noise exposure doses were below the OSHA PEL; however, 4 of the 18 measurements were in excess of the ACGIH® threshold limit value. The majority of tools generated noise levels above 85 dBA. Air guns, wrenches, cutoff wheels, and air drills generated noise levels with the 5th percentile above 90 dBA. Mean noise levels generated by hammers, grinders, and ratchets were also above 95 dBA. Three pairs of banded earplugs had the best reviews in terms of comfort of use. This study was conducted during a time when all shops reported relatively low production levels. Noise exposure results suggest that it is likely that technicians’ 8-hr time-weighted average exposures may be in excess of 85 dBA during periods of higher production, but exposures to dust and solvents are unlikely to approach OSHA exposure limits. These pilot test results will be useful when developing recommendations and technical assistance materials for health and safety interventions in auto collision repair businesses. [Supplementary materials are available for this article. Go to the publisher's online edition of the Journal of Occupational and Environmental Hygiene for the following free supplemental resource: a PDF containing a table on employee feedback on seven hearing band models, an example of an HP feedback card, a table showing a tool for selecting the solvents to be analyzed for area samples, a table containing MSDS and sample information for degreasing compounds, additional information for degreasing operations, an excerpt from the discussion with the AssayTech lab manager, and an image from the paint mixing room that returned the highest styrene and acetone concentrations.]

Slot Grinding of Advanced Ceramics with Brazed Diamond Cut-Off Wheels

Based on the analysis of problems of diamond cut-off wheels used in slot grinding of ceramics at present, a brazed diamond cut-off wheel was produced and analyzed. Two typical advanced ceramics, alumina and silicon nitride, were used as the workpiece materials. In the experiments of slot grinding of ceramics, grinding ratio, wear process of the wheel and grinding quality of the work were studied. Experimental results showed that the brazed diamond cut-off wheel obtained good grinding ratio and abrasive resistance. The surface roughness of ground silicon nitride was better than that of alumina.

Machining of reinforced concrete using grinding wheels with defined grain pattern

By means of single grain scratch experiments, the material removal mechanisms of reinforced concrete have been investigated. On the basis of these experiments, the removal factors kw and kd have been introduced. These removal factors enable the design of different adapted, deterministic and stochastic cut-off grinding wheels. With three different prototypic tools, real cut-off grinding experiments have been conducted. The performance of these prototypic tools has been evaluated by process force and wear investigations. The results show that with regard to process efficiency and stability, the cut-off grinding wheel with higher diamond grain concentration and deterministic distribution performs best in the given field of application.

Extending the technological potential of machines and devices with annular movable operating elements

The paper demonstrates the possibility of designing technological machines and devices with operating elements in the form of a wide flat ring that has no mechanical supports or electrical contacts, is rotated, maintained in space, and driven to take technological loads by the magnetic field forces generated by induction coils. A criterion for the stable rotation of a free annular rotor is theoretically derived and experimentally verified. The technological and economic benefits of new constructions are shown by the examples of a diamond cutting machine and a centrifugal pump. The web site http://www.elmache.com/ illustrates a through-feed diamond cutting with a free-rotating cutoff wheel and rotation of a centrifugal pump impeller without any shaft or bearings; computer models of machines for slicing semiconductor monocrystals are presented there as well.

The effect of axial stiffness of cutoff diamond wheels on nonflatness of cut wafers

An analytical expression has been derived to relate the axial component of the cutting force and the axial stiffness of a diamond cutoff wheel with an inner cutting edge to the nonflatness of cut wafers. The adequacy of the proposed mathematical model is analyzed qualitatively and quantitatively. The verification results are in agreement with the available experimental data on geometrical errors of cut wafers.