High Speed Deep Grinding Research Articles

Повышение эффективности плоского глубинного шлифования

There is considered a possibility of effectiveness increase of machinery billet flat deep grinding at the expense of high-speed machining use and also grinding on an automatic cycle of grinding mode changes. The application of high-speed deep grinding, for instance, slots or profiles of turbine blade locks allows rejecting their preliminary milling, carrying out single position machining on one machine which increases machining accuracy and its capacity.

Surface roughness of sintered yttria stabilised zirconia (YSZ) using high speed moderate depth super-abrasive grinding

An experiment was carried out to understand the surface characteristics and removal mechanism in high speed deep grinding of yttria stabilized zirconia (YSZ). The grinding wheels used in the present study are single layer electroplated diamond grinding wheels of 151 μm grit size having grits of grade PDA878 (Element six). Most of the previous studies have employed resin bonded and single layer vacuum bonded diamond grinding wheels. Previous investigators also do not reveal the morphology of the grit used, which is very important for high speed grinding of ceramics. The diameters of the wheels used in high-speed grinding (up to 200 m/sec) are 125 mm, with a width of 10 mm. Surface roughness were measured and morphological features of ground surfaces were examined. The grinding forces and specific grinding energies are very less compared to grinding of metals and metallic alloys because of the mechanism of ceramic grinding which is by micro brittle fracture, whereas the mechanism of grinding in metals and metallic alloys is by shear deformation. Smooth, fractured, smeared and ploughing striation on ground surface of YSZ was observed using scanning electron microscopy.

Experimental investigation of grinding temperature and burn in high speed deep camshaft grinding

Camshaft grinding is more complex comparing with the ordinary cylindrical grinding. To improve grinding efficiency and quality, high speed deep grinding with CBN wheel has been shown great advantages. This paper presents an experimental investigation of grinding temperature and depth of maximum un-burn (DMUB) in high speed deep camshaft grinding. A series of experiments have been accomplished by CNC8325 NC camshaft grinder. The results show that the grinding temperature increases with the peripheral wheel speed rises from 60 m/s to 130 m/s. Grinding burn occurs when bigger depth of cutting is applied. The higher peripheral wheel speed has a positive effect on improving depth of maximum un-burn.

Study on Grinding Burn in High Efficiency Deep Grinding

The high efficiency deep grinding is widely used in manufacturing. The experiments were carried out to study on the high speed deep grinding force and grinding burn and cracks in grinding 40Cr steel specimen with Al2O3 wheel. The experimental studies demonstrate that the grinding force increases with the grinding layer depth. The trail of grinding on space surface is blurred progressively, the surface topography deteriorates gradually. When the depth of grinding increases to the certain value, grinding burn appears, and micro-cracks emerge. Selecting the optimization parameter in high speed deep grinding can avoid the grinding burn and grinding cracks.

High efficiency axial deep creep-feed grinding machining technology of engineering ceramics materials

Axial deep creep-feed grinding machining technology is a high efficiency process method of engineering ceramics materials, which is an original method to process the cylindrical ceramics materials or hole along its axis. The analysis of axial force and edge fracture proved the cutting thickness and feed rate could be more than 5–10 mm and 200 mm/min respectively in once process, and realized high efficiency, low-cost process of engineering ceramics materials. Compared with high speed-deep grinding machining, this method is also a high efficiency machining technology of engineering ceramics materials as well as with low cost. In addition, removal mechanism analyses showed that both median/radial cracks and lateral cracks appeared in the part to be removed, and the processed part is seldom destroyed, only by adjusting the axial force to control the length of transverse cracks.

The Grinding Temperature of Alumina Ceramic in High Speed Deep Grinding (HSDG)

The grinding temperature in wheel-workpiece contact zone in HSDG of alumina ceramic was measured using the grindable K type thermocouple. Effects of the grinding conditions, including wheel velocity, feed rate and depth of cut, on the temperature were investigated. The results indicate that the grinding temperatures measured under different grinding conditions varied from 100 to 300 °C. The grinding zone temperature exhibits a reasonably linear relationship with the average energy flux, i.e. the higher the energy flux, the higher the corresponding grinding zone temperature will be.

Experimental Research of Grinding Force and Specific Grinding Energy of TC4 Titanium Alloy in High Speed Deep Grinding

Focusing on the characteristic of hard-to-grind for titanium alloy, experiments were conducted about grinding TC4 titanium alloy under high speed deep grinding (HSDG) condition. The changing of grinding force per unit area with maximum undeformed chip thickness hmax and equivalent cutting thickness aeq are analyzed in this paper. The effect of maximum undeformed chip thickness hmax and specific material removal rate Zw' on specific grinding energy es, material removal mechanism and consumption of grinding power in HSDG process are also discussed. The experiment results reveal that application of HSDG can improve machining efficiency of grinding TC4.

Grinding temperature in high speed deep grinding of engineering ceramics

The paper presents an investigation of the thermal behaviour of high speed deep grinding (HSDG) for engineering ceramics, yttria partially stabilised zirconium (PSZ) and Al2O3, using the grindable thermocouple technique. Effects of the grinding conditions, including wheel velocity, feed rate and depth of cut, on the temperature were investigated. It was found that the grinding temperature measured under different grinding conditions varied from 100°C to 300°C when the wheel velocity was smaller than 160 m/s. The temperature could rise to about 800°C at the wheel velocity of 160 m/s. The enhanced resistance of the air barrier formed around the wheel periphery at the higher velocity to the coolant supply was mainly responsible for the temperature rise. When the grinding forces and temperatures are considered comprehensively, high wheel speed and large depth of cut are preferable for the wet HSDG of engineering ceramics under low workpiece feed rate.

An experimental investigation of temperature in high speed deep grinding of partially stabilized zirconia

The grinding temperature in the high speed deep grinding of yttria partially stabilized zirconia was measured using the grindable thermocouple technique. Effects of the grinding conditions, including wheel velocity, feed rate and depth of cut, on the temperature were investigated. It was found that the grinding temperature measured under different grinding conditions varied from 100 to 300 °C when the wheel velocity was smaller than 160 m/s. The temperature could rise to about 800 °C at the wheel velocity of 160 m/s. The enhanced resistance of the air barrier formed around the wheel periphery at the higher velocity to the coolant supply was mainly responsible for the temperature rise.

Coolant effect on grinding performance in high-speed deep grinding of 40Cr Steel

High-speed deep grinding (HSDG) technology was developed based on high-speed and creep-feed grinding techniques. What mainly distinguishes HSDG from creep-feed grinding is its employment of a significantly higher wheel speed. Because the higher wheel speed results in a decrease in the undeformed chip thickness, HSDG is thus capable of achieving high stock removal rates and producing a high surface quality throughout the workpiece. However, the increase in wheel speed leads to the formation of a strengthened air barrier around the grinding wheel periphery, which is a great obstacle to the impinging of coolant into the grinding zone. Additionally, the higher wheel speed will also generate greater grinding heat in the grinding zone, thus resulting in a higher temperature.'This increases the risk of thermal damage on the workpiece, such as burns and cracks, especially when grinding metals and alloys. In order to take advantage of the full potential of HSDG technology, effective cooling must be employed. Great research efforts have been directed toward investigating effective coolant supply technologies for the HSDG process. 71° Previous works focused on the development of coolant nozzles for high-speed grinding, which could block the air barrier formation and help smoothly guide the coolant entering the grinding zone. There are several drawbacks regarding these nozzles. First, a gap between the wheel and the air-wiper in the nozzle still exists, which affects the coolant supply when operating at an extremely high speed. Second, the air blocking alters the coolant flow direction, thus resulting in an increase of 30-50% in spindle power. Third, special grinding wheels are required if there is direct contact between the wheel and the air wiper. This article will report on the development of a closed coolant shoe, which can overcome the limitations of previous coolant nozzles, and the effect of the new nozzle on the grinding performance in HSDG of 40Cr steel.

Experimental investigations of machining characteristics and removal mechanisms of advanced ceramics in high speed deep grinding

Machining characteristics and surface integrity of advanced ceramics, including alumina, alumina–titania, and yttria partially stabilized tetragonal zirconia, were studied under high speed deep grinding conditions. Material removal mechanisms involved in the grinding processes were explored. The material removal in the grinding of alumina and alumina–titania was dominated by grain dislodgement or lateral cracking along grain boundaries. The removal for zirconia was via both local micro fracture and ductile cutting. It was found that under a feed rate of 500 mm/min and for all the wheel speeds used, an increase in the wheel depth of cut (DOC) from 0.1–2 mm slightly improved the ground surface finish, but greatly prolonged the wheel life. This increase did not deepen the subsurface damage layer for the alumina and alumina–titania, but resulted in a slightly deeper damage layer for the zirconia.

Machining characteristics and surface integrity of yttria stabilized tetragonal zirconia in high speed deep grinding

High speed deep grinding has been studied to explore its effects on machining characteristics and surface integrity of yttria partially stabilized tetragonal zirconia. A grinding depth of cut of up to 1.5 mm, which is significant for ceramics grinding, was used to grind this ceramic material under a normal creep feed rate of 500 mm min(-1) using a resin bond diamond wheel. It was found that the increase in the grinding depth of cut from 0.1 to 1.5 mm greatly reduced the wheel wear and slightly improved the surface finish, but resulted in a slightly deeper subsurface damage layer. High wheel speeds reduced subsurface damage, but shortened wheel life. (C) 2002 Elsevier Science B.V. All rights reserved.