Honing Process is not only a special form of grinding, but also a machining method in finishing machining.  This process can not only remove large machining allowance, but also is an effective machining method to improve the dimension accuracy, geometric shape accuracy and surface roughness of parts. It is widely used in automobile parts manufacturing.  

Honing process principle

Honing is to use one or more oil stones installed on the circumference of the honing head, and expand the oil stones radially by the expansion mechanism (including rotary and propelling) to press the oil stones towards the hole wall of the workpiece, so as to produce a certain surface contact.  At the same time, make the honing head rotate and reciprocate, and the parts do not move.  Or the honing head only rotates and the workpiece reciprocates, so as to realize honing.  

In most cases, the honing head is floating between the machine tool spindle or between the honing head and the workpiece fixture.  In this way, the honing head is guided by the hole wall of the workpiece during machining.  Therefore, the machining accuracy is less affected by the precision of the machine tool itself, and the formation of the hole surface basically has the characteristics of the creation process.  The so-called creation process is the grinding and dressing of the pore wall and the surface of the whetstone.  The principle is similar to that of two flat plates moving in plane.  

Honing is to use one or more oil stones installed on the circumference of the honing head, and expand the oil stones radially by the expansion mechanism (including rotary and propelling) to press the oil stones towards the hole wall of the workpiece, so as to produce a certain surface contact.  At the same time, make the honing head rotate and reciprocate, and the parts do not move.  or the honing head only rotates and the workpiece reciprocates, so as to realize honing.  In the honing process, as the honing head rotates and reciprocates or the workpiece rotates and reciprocates, the cutting track of the machining surface fork helix is caused, and the number of revolutions of the honing head within each reciprocating stroke time is not an integer. 

 Therefore, between two strokes, the honing head diverges a certain Angle in the circumferential direction relative to the workpiece, so that the movement track of each abrasive particle on the honing head on the hole wall will not repeat.  In addition, for each turn of honing head, there is an overlap length on the axis between the cutting track of the oil stone and the previous one, which makes the connection between the grinding track before and after more smooth and even.  In this way, each point of the hole wall and the stone surface will interfere with each other almost equally throughout the honing process.  As honing hole surface and, therefore, oil stone surface continuously produce interference point, to put these interference point grinding and generate new interference of more points, and continuous grinding, make the hole and sharpening stone surface contact area is increased, the degree of mutual interference and cutting effect weakening, holes and oil-stone roundness and cylindricity also constantly improve, after completing the process of initiative on the surface of the hole.  In order to obtain better cylindricity, it is often possible to turn around parts or change the axial position of the honing head and the workpiece.  

As abrasive materials such as diamond and cubic boron nitride are used in honing oilstone, the wear of oilstone is very small in machining, that is, the amount of dressing of oilstone by workpiece is very small.  Therefore, the precision of the hole depends to some extent on the original precision of the oil stone on the honing head.  So when diamond and cubic boron nitride whetstone are used, the whetstone should be well trimmed before honing to ensure the accuracy of the hole.  

---EDITOR: Doris Hu

---POST: Doris Hu