A study on laser touch dressing of electroplated diamond wheels using pulsed picosecond laser sources
Introduction
Touch dressing of superabrasive wheels is usually applied to electroplated bond material, where an accurate profile and defined grain protrusion is necessary. Touch dressing of diamond or CBN wheels can be conventionally done using a diamond roll or wheel as truer and/or dresser. In the case of touch dressing, both the wheel and truer are diamond plated, and have almost the same hardness resulting in a time consuming and relatively expensive process. That is why an alternative method to reduce process time as well as cost is a matter of high interest in industry.
Upon discovering the benefit of lasers in the machining industry, laser conditioning has always been an interesting alternative to conventional mechanical dressing. However, due to certain drawbacks and technological problems, its use in industrial applications was limited. In the case of touch dressing of electroplated diamond wheels, it is much more difficult to reach the realized target because the laser beam must cut the diamond grains with high accuracy, without any kind of thermal damage either to the diamond grain (graphitization, residual stress, etc.) or to the nickel bond material. This research is an important step forward to the realized target using a pulsed ps-laser. This paper presents a successful attempt on touch dressing of an electroplated diamond wheel using a ps-laser source.
Section snippets
Laser dressing, state of the art
Laser technology for conditioning of superabrasives was first proposed by Westkaemper [1] for dressing and truing of resin bonded CBN grinding wheels. The results show a topography with sufficient chip clearance compared with conventional dressing methods. It also illustrated approximately the same values for grinding force and roughness after grinding. Timmer [2] utilized a Nd:YAG laser to differently bonded diamond and CBN grinding wheels both radially and tangentially to the wheel surface.
Laser system
The experimental setup (Fig. 1) consists of the laser system (1) producing laser pulses with a pulse width tP < 10 ps and a maximum pulse energy of eP = 125 μJ at a maximum repetition rate of fP = 400 kHz. The experimental wavelength is λ = 1030 nm in the near infrared. The setup consists of multiple mirrors, a beam expansion unit (4.5) and a two-dimensional scanning system (8). The beam expansion unit itself consists of a concave and a convex lens.
This increases the beam diameter dB = 5 mm to dB = 8.5 mm prior
Experimental results
Evaluation of multiple validation samples in terms of raman-spectroscopy (Fig. 3) reveals that within the cut kerf, there is no presence of a graphite layer. Even after irradiation with ten repetitions and multiple pulses per area, the measured peak position value is 1332.49 cm−1 compared to the expected value which is 1332.5 cm−1. This is in good agreement to the quality of natural or High-Pressure High-Temperature (HPHT) synthetic diamond [10]. There is no evidence of a second peak around the
Conclusions and next steps
Using ps-laser sources, a great potential for high precision and a highly reliable method for touch dressing of the diamond grinding wheels is observed. Diamond grains can be cut without remarkable graphitization effects. Comparison of wheel topography before and after mechanical and laser touch dressing shows a very similar form within Abbott-Firestone-Curves as conventional roughness values (Ra and Rz). The lower dressing forces after dressing of SiC grinding wheels with diamond toch dressed
Acknowledgments
The authors wish to gratefully acknowledge the financial support which was granted by the Swiss Innovation Promotion Agency as well as the technical support provided by Faessler AG, Dubendorf and Trumpf Laser AG, Baar, both located in Switzerland.
References (10)
- et al.
Dressing of Resin-bonded Superabrasive Grinding Wheels by Means of Acousto-optic Q-switched Pulsed Nd:YAG Laser
Optics & Laser Technology
(2004) - et al.
Laser Dressing of Metal Bonded Diamond Wheel
Annals of the CIRP
(2006) - et al.
Experiment and Numerical Simulation Study on Laser Truing and Dressing of Bronze-bonded Diamond Wheel
Optics and Lasers in Engineering
(2010) Grinding Assisted by Nd:YAG Laser
Annals of the CIRP
(1995)- Timmer JH (2001) Laserkonditionieren von CBN- und Diamant-Schleifscheiben. Dissertation, Braunschweig...
Cited by (67)
Laser dressing of fine-grained metal-bonded diamond grinding wheels with concave surface
2024, Optics and Laser TechnologyTrajectory planning of deep-cutting laser profiling of superabrasive profile grinding wheels
2023, Engineering Science and Technology, an International JournalPrecision truing of electroplated diamond grinding wheels via spray-mist-assisted laser technology
2022, Materials and DesignLaser precision profiling of small-angle bevel-edge contour grinding wheels
2022, Journal of Materials Processing TechnologyDual-laser dressing concave rectangular bronze-bonded diamond grinding wheels
2022, Diamond and Related MaterialsCitation Excerpt :It is almost difficult to achieve accurate dressing because of the inhomogeneity of the cross-sectional distribution of laser energy. In terms of laser tangential dressing, Dold et al. [15] used a Yb:YAG pulsed picosecond laser to perform tangential incidence dressing experiments on electroplated diamond wheels, comparing the surface morphology and grinding performance of mechanical method dressings and demonstrating the possibility of tangential truing with high accuracy and high reliability of dressings. Christian et al. [16] used pulsed nanosecond lasers with tangential incidence to shape the concave surfaces of small metal-ceramic hybrid bond CBN grinding wheels and obtained rectangular, V-shaped, and circular groove profiles.
Optimization of the processing parameters in laser sharpening of bronze-bonded diamond grinding wheels
2021, Diamond and Related Materials