China
Africa
Explore chapters and articles related to this topic
Abrasive Finishing Machining Operations
Published in Zainul Huda, Machining Processes and Machines, 2020
Honing is an abrasive finishing operation that produces functional surface finish by use of a honing tool. The honing tool consists of a set of bonded abrasive sticks that are equally spaced around the tool’s periphery. The grit numbers of abrasive sticks in a honing tool lie in the range of 300–600. In honing, the honing tool is moved through the cylinder bore, while the abrasive sticks are highly pressed outwards (usually exercised by small springs) against the bore surface (see Figure 12.1). The honing tool is given a complex rotational and reciprocating axial motions, which combine to produce a crosshatched pattern with topographic form of the surface roughness (see Figure 12.2). This crosshatched pattern may either be a smooth surface or a rough topography with defined oil pockets to retain the lubrication. A cutting fluid must be used in honing for cooling, lubrication, and the removal of chip.
Electrochemical Machining
Published in Madhav Datta, Electrodissolution Processes, 2020
A schematic diagram of the ECH process is shown in Figure 8.13 [64]. It consists of a tooling system loaded with honing stones, a tool motion system, a machining chamber with the properly held workpiece, an electrolyte supply system, and a power supply system. The tooling system is enclosed in a machining chamber, which includes provisions for supply and removal of the electrolyte, and for the escape of gases generated during the ECH process. The electrolyte supply system supplies supply the filtered electrolyte with a controlled flow rate and pressure to the machining zone. The power supply system consists has provision for operating at both continuous and pulsating condition. During ECH operation the tool rotates and reciprocates while the workpiece is stationary fixed in the machine chamber. This rotary and reciprocation movement of the ECH tool is the critical parameter in achieving the closer tolerances desired surface finish. Honing stones are embedded abrasive particles (Al2O3, SiC, CBN) bonded in vitreous bonding material with particular grit size honing stones. The choice of the abrasive type and size of the honing stones depends on the type of workpiece and the desired rate of surface finish. The honing stones are mounted on a stainless steel tool holder which is simultaneously given a rotary motion as well as reciprocating (or oscillatory) motion to perform a complete cycle. The reciprocating motion is along the axis of the workpiece to bring the entire work surface in contact with the honing stone.
Design for Machining
Published in Helmi Youssef, Hassan El-Hofy, Non-Traditional and Advanced Machining Technologies, 2020
The main purpose of honing is to generate an accurate surface configuration and an improved surface finish. It is used primarily for inside diameters and flat surfaces. The bore diameter ranges from 2.4 mm to 1.2 m, and the length of bore varies between 1.6 mm and 9.1 m. External cylindrical honing can tackle parts of 6.3 mm diameter by 14.7 m long to 450 mm in diameter by 9.1 m long. Flat surfaces of area less than 645 mm2 and spherical diameters ranging from 3 to 300 mm can also be honed. The nature of a cross-hatched honed surface finish is efficient in moving bearing applications, such as automotive-cylinder bore or a valve body bore. In such applications, the peaks carry the load of the mating parts and valleys provide reservoirs for the lubricating oil. The absence of surface damage by heat is another process advantage. Gear teeth, races of ball and roller bearings, crank-pin bores, drill bushings, gun barrels, piston pins, and hydraulic cylinders are often finished by honing. Honing can be used economically; manual honing suits one-of-a-kind or very limited quantity. When honing is applied in mass production, millions of parts are produced per year using the general-purpose horizontal or vertical honing machines. The most common materials to be honed are steel, CI, and aluminum. Other materials such as bronze, stainless steel, and plastics can be honed at lower speeds.
Advanced abrasive-based nano-finishing processes: challenges, principles and recent applications
Published in Materials and Manufacturing Processes, 2022
Manjesh Kumar, Anupam Alok, Vikash Kumar, Manas Das
Surface polishing is an absolutely vital, ridiculously priced stage of the complete manufacturing process. This stage is the more time-consuming and unmanageable field in the manufacture of precise components since it often consumes up to 15% of total manufacturing costs.[1] The conventional finishing methods are less suited to finishing material due to less force control[2] and create a defect on the material surface.[3,4] A huge quantity of heat produced throughout the grinding process creates many dangerous surface impacts, including micro-crack and residual thermal stresses. In the lapping method, the two layers are squeezed along with abrasives (Al2O3, SiC or B4C).[5] Honing is often the most useful technique for polishing the inner faces of cylinders. The honing method is also used where geometric and shape-accuracy specifications are keen to get the best surface finish.[6] The component’s fatigue life is more influenced by a lower surface finish.[7] Finishing 3D complex freeform components, including different angle projections, sleeve structures and freeform shapes occupy a significant position in terms of technological advancements. Uses with 3D complex freeform shapes can be considered most fitting in producing dies and molds, automobiles, semiconductors, electronics, optical glasses or mirrors and aerospace industry.[8] Numerous studies created specialized finishing processes, including grinding,[9] honing,[10] flexible abrasive tools,[11] and ball burnishing[12] for the polishing of freeform structures. The larger cutting forces generated in such methods can not achieve optimum surface roughness values. To addressing such disadvantages, several innovative micro/nano finishing processes were established to give better quality textures.[13,14] These nano polishing techniques were well-known to attain the high surface precision requirement by resolving several basic restrictions of conventional polishing methods.