Experimental studies on material removal mechanisms in ultrasonic assisted grinding of SiC ceramics with a defined grain distribution brazed grinding wheel

Abstract

Ultrasonic assisted grinding (UAG) is one of the most suitable methods for the processing of hard and brittle materials such as silicon carbide (SiC). During UAG of SiC, the machining quality is directly determined by the material removal mechanism. However, the research on the material removal mechanism for UAG of SiC is still not sufficiently developed. To achieve better comprehension of the material removal mechanism in UAG of SiC, this study conducted both UAG and conventional grinding (CG) tests with a brazed grinding wheel with defined grain distribution. The material removal mechanism in UAG of SiC was studied by comparing the ground surface/subsurface micro-morphology, surface roughness, grinding force, and specific grinding energy between both processes. The results showed that the material removal mechanism experienced a transition from ductile removal to brittle fracture with increasing undeformed chip thickness in both UAG and CG. In addition, the ground surface roughness, grinding force, and subsurface breakage size increased with increasing undeformed chip thickness, while the specific grinding energy first decreased rapidly and then stabilised. Compared with conventional grinding, UAG always resulted in lower surface/subsurface breakage, surface roughness grinding force, and specific grinding energy under identical operating conditions.

Precision Grinding Technology of Silicon Carbide (SiC) Ceramics by Longitudinal Torsional Ultrasonic Vibrations

“…The pulse waveform during the actual machining can be approximated by a triangular waveform, as shown in Figure 6. According to the momentum theorem, in one vibration cycle, the impulse size of the average cutting force on the grinding head is equal to the impulse value of the maximum impact force, and the relationship between the cutting force 𝐹 applied to the grinding head as a whole and the cutting force 𝐹 applied to a single abrasive grain on the grinding head is shown in Equation (11). During the longitudinal torsional compound ultrasonic vibration grinding process, the head and the workpiece are in an intermittent processing state, so that the force exerted by the head is actually pulsed.…”

“…Ding et al designed a wheel with fixed structure to conduct a comparative test study on ultrasonic vibration grinding of SiC ceramics and ordinary grinding, and mainly studied the removal mechanism of SiC ceramics in the grinding process. The results show that the removal pattern of SiC ceramic materials changes from plastic removal to brittle fracture removal as the cut depth increases [ 11 ]. Zhou et al carried out ultrasound-assisted scratching tests on BK7 and JGS1 glass with a diamond indenting head, and the results showed that ultrasonic vibration could significantly increase the critical cutting depth of the brittle–plastic transition of the glass material, so ultrasound-assisted grinding is easier to achieve plastic-domain grinding [ 12 ].…”

Investigation of the equivalent circuit and performance of an ultrasonic transducer under a force load

“…Ultrasonic processing technology has the advantages of reducing cutting forces and heat, decreasing tool wear, optimizing chip morphology, improving surface quality, reducing subsurface damage, improving machining efficiency, etc. It has been widely applied to titanium alloys [1][2][3][4], high-temperature alloys [5][6][7][8], semiconductor wafers [9][10][11][12], engineering ceramics [13][14][15], ceramic matrix * Author to whom any correspondence should be addressed. composites [16,17], and honeycomb composites [18][19][20][21] and other difficult-to-process materials.…”