Machining Burr Research Articles

Applications of lasers in industries and laser welding: A review

Laser can be focused up to 1/1000 of a millimeter. Laser machining is clean, and free from post machining burrs. Laser technologies are highly effective and efficient in industries which has created a massive impact in manufacturing. Laser is versatile, it can be performed efficiently on a large range of materials, High precision, speed, and quality of laser machining are a few advantages of this technology. The compatibility of this technology makes it extremely convenient to incorporate into industrial lines. The utilization of Laser Technology to improve precision in production, increased automation substituting the conventional methods, which would have various drawbacks in reflected through this review paper. This review paper compiles the impact of various laser sources, industrial applications of laser on industries over conventional methods. It also summarizes the Laser Welding being used in the industries for précised manufacturing. The precision and quality of laser welding is also demonstrated by performing bead-on-plate weld on steel.

Design optimization and experimental performance test of dynamic flow balance valve

This paper considers a solution to the serious problem of hydraulic maladjustment in a dynamic flow balance valve for small diameter and low-pressure drop working conditions. The pressure drop compensation coefficient revising method was proposed to optimize the profile line of the valve core variable opening area. The flow rates of the valve before and after optimization under different displacements were simulated using Computational Fluid Dynamics (CFD) methods. The flow control accuracy of the balance valve before and after the optimization is compared and analyzed to the test values. At the same time, the influence of three key parameters: spring stiffness, the shell structure of the valve core, and geometry imperfections change due to machining burrs on the surface of the valve core for flow control accuracy was discussed. The results show that flow control accuracy after optimization satisfies the requirements of 5% flow rate control. Spring stiffness, the shell structure of the valve core and machining burrs on the surface of the valve core are shown to have an influence on the flow rate of the balance valve. This is especially true for machining burrs which has a larger effect with an average error of 10.1.

A numerical insight on machining burr formation: A comprehension to optimization approach

An insight into comprehension and optimization of exit burr formation in orthogonal machining case is presented in the work. Formation of exit burr has been simulated using a three dimensional FE based machining model. Variation of “pivot-point” (point of maximum bending stress, appearing at workpiece exit edge) location on workpiece end and its appearance with respect to tool position during cutting process has been correlated with burr formation process. To minimize the burr formation, machining process variables (including speed, feed and tool rake angle) optimization have been realized employing Abaqus®. Burr lengths at exit end along workpiece depth of cut (ap) are quantified and optimum machining parameters generating less burrs for dry machining of AA2024 are identified. Simulated results pertaining to chip and cutting forces are fairly matched with related experimental results in the published literature.

The appearance of machining burr as a cracking failure on twistlock pin

The failure analysis of the twist lock pin made of alloy steel is presented. The pin was visually observed to have a cracking character at curvature area after 45,000 cycles. Some non-destructive inspections were previously done. However it failed to detect any crack defect. The twist lock pin sample was further macro and microscopic analysis. The analysis found that the surface discontinuities that were previously presumed as a cracking morphology was actually a machining burr and improper machining marks. There were some micro- and nano-sized pinholes dispersed over the metal matrix of the twistlock pin sample. The microstructure of the twistlock pin was tempered martensite structure.

Burr edge occupancy: edge finishing index for milling machined parts

Machining burrs are formed at all machined workpiece edges. One useful solution to decrease machining time and cost, in particular for milling parts, is to generate machined parts edges with minimum burr. This article proposes burr edge occupancy ηs as an index to evaluate deburring difficulty and, consequently, adequate selection of suitable deburring methods. Initially the sensitivity of ηs to cutting parameters must be evaluated. We investigated the main governing factors on ηs when slot milling two types of aluminium alloys (from different families) that are used in the automotive and aerospace industries. The cutting parameters that led to edges with minimum ηs are presented. It was found that, unlike most burr size attributes, ηs is sensitive to variation of the cutting parameters used: cutting speed, family of material, and cutting tools. Lower ηs means less time and effort for deburring and edge finishing of machined parts. Furthermore, ηs measurement is more convenient than the procedures used to measure other burr size attributes, including burr height (bh) and burr thickness (bt).

Parametric analysis of magnetic abrasive deburring process

Machining burrs have been the most troublesome obstruction to high productivity and automation of manufacturing processes. A study of new cost-effective deburring processes has always been an area of keen interest for production engineers. This paper investigates the effectiveness of magnetic abrasive deburring (MADe) method for deburring burrs formed by drilling operation on brass workpieces. An experimental investigation has been conducted using in-house fabricated set-up to identify the effectiveness of process parameters and hole-edge quality before and after deburring. On the basis of the results, in general, the percent reduction in burr height depends mainly on the abrasive mesh size, working gap, deburring time and rotational speed of magnet. The effect of deburring time is found to be the most significant parameter amongst all parameters. This study concludes that the significant burr reduction and the effective improvement in hole-edge quality can be obtained by MADe method.

Ultra-precision machining of reflector array for laser diode beam shaping

Ultra-precision machining is an effective approach to achieve high dimension accuracy and surface finish required in optical and laser components. An extensive study using a two-axis diamond turning machine is conducted to machine the reflector arrays used for laser diode beam shaping. To position the workpiece precisely, theoretical analysis is made so that the dimensional accuracy can be achieved. Investigations into machining burr reduction are carried out. With the process developed, reflectors with optical surface finish of 8 nm in Ra and minimized burr size of less than 0.5 μm have been achieved.

Quality of Surgical Instruments

Many surgeons will have encountered the scissors that would not cut, and the artery clip that comes off in a deep difficult location, but it would be reasonable to assume that new instruments should be of assured quality. This study reports the surprising findings of a local quality control exercise for new instruments supplied to a single trust. Between January 2004 and June 2004, all batches of new surgical instruments ordered by the Central Sterile Supplies Department of St Bartholomew's and the Royal London Hospitals were assessed by three clinical engineers, with reference to British Standards (BS) requirements. Of 4800 instruments examined, 15% had potential problems. These included 116 with machining burrs and debris in the teeth of the tissue-holding regions, 71 defects of ratcheted instruments, 34 scissors with deficient cutting action, and 35 tissue forceps protruding guide pins. In addition, 254 instruments did not have a visible manufacturer's mark. This study demonstrates the value of local quality control for surgical instruments. This is of importance in an increasingly hazard-conscious environment, where there are concerns over instrument sterilisation, surgical glove puncture and the potential for transmission of blood-borne and prion diseases.

An experimental study of micromachining step-mirrors for laser-diode beam shaping

Micro and ultra-precision machining is an effective approach to achieve the high-dimensional accuracy and surface finish required in optical and laser components. In this paper, an extensive study using a two-axis diamond turning machine is conducted to machine the step-mirrors used for laser-diode beam shaping. To position the workpiece precisely, theoretical analysis is made so that dimensional accuracy can be achieved. Investigations into machining burr reduction are carried out. With the process developed, step-mirrors with an optical surface finish of 8 nm in Ra and a minimized burr size of less than 0.5 µm are achieved.

Possibility of Metal Processing Using Ultrasonic Cavitation Jet

Utilizing a high-intensity ultrasonic cavitation, a processing experiment was conducted with the aim of performing volumetric flow adjustment of a fuel jet nozzle to be used for a small engine, which cannot be carried out by a method such as machining. At the bottom of the nozzle used for the experiment, which is in the shape of a cup, a nozzle hole with a diameter of 0.15 mm is drilled. In this experiment, we make adjustments in the volumetric flow by grinding and removing the machining burr with the aid of the processing power of ultrasonic cavitation. The processing effect is highly dependent on the ultrasonic cavitation intensity. In the experiment, the processing reservoir was filled with pressurized highly deaerated water to increase the processing force by allowing cavitation with high intensity to be generated. The processing principle is to utilize the effect of a cavitation jet flow passing through the nozzle hole. To restrain the intake of the bubbles into the flow circuits during the pressure reduction cycle of the vibrator, the water flow was discharged into a pressure reduction reservoir. By allowing the horn tip with a diameter of 6 mm at a frequency of 28 kHz to approach the sample, followed by high-intensity ultrasonic irradiation, powerful cavitation was generated. As a result of the evaluation of the processing efficiency made based on the volumetric flow increase and microscopic observation of the nozzle, burrs smaller than 10 µm were almost entirely removed within 15 min of initial irradiation, resulting in a volumetric flow increase of more than 0.4%/min. However, in the case of burrs of more than 10 µm, no force that could remove the burrs was found. It was surprising for the burrs to generate deformation rather than to be removed.

Burr Formation in Metal Cutting

Machining burrs formed in various cutting operations are rationally designated by the combination of two systems of classification: (1) by cutting edge directly concerned and (2) by the mode and direction of burr formation. The size of burr is shown to be reduced by (1) reducing the undeformed chip thickness, (2) selecting the cutting conditions so as to reduce the shear strain undergone by the chip and (3) designing the tool and workpiece geometry so as to strengthen the edge of workpiece and also to turn the direction of cutting force toward the workpiece.

The Formation and Properties of Machining Burrs

The mechanisms causing machining burrs and four analytical models that predict burr properties are presented. The study indicates that three basic mechanisms are involved. They are lateral deformation, chip rollover, and material tearing. Both the theory and experimental results indicate that machining burrs cannot be prevented by changing machining parameters alone.