Application areas of honing
Honing technology came into being with the birth and development of automobiles. In order to improve the performance of engines and extend the life of automobiles, honing technology was invented. At present, honing technology has become one of the key manufacturing technologies in the automotive industry.Honing is the most important precision manufacturing technique for cylinder working surface. Honing technology not only can be used in automobile, motorcycle, tractor, crankshaft, cylinder manufacturing, and can be widely used in aircraft, missiles, tanks, tanks, artillery, ships, industrial sewing machine, air machine, hydraulic pneumatic, radar, radio and television equipment, machine tools, dies, brake oil pump, nozzle, bearings, engineering machinery, pipe and other manufacturing areas.

Modern honing techniques
Modern honing technologies such as flat top honing, extrusion honing, composite electrolytic honing, CNC honing, ultrasonic honing, ultrasonic honing and laser honing
1) CNC laser honing technology is a key technology for the engine manufacturing of modern automobiles, motorcycles, tractors, ships, etc., and belongs to the field of optical and mechanical integration technology.
2) Ultrasonic honing has many advantages, such as small honing force, low honing temperature, oil stone not easy to block, high processing efficiency, good processing quality, high wear resistance of parts sliding surface, etc. It can solve the problems of ordinary honing, especially the steel thin-walled cylinder liner substrate , Honing problems of tough materials such as aluminum alloy cylinder liners, chrome-plated steel thin-wall cylinder liners, cast iron hardened cylinder liners and ceramic engines.


 Simple feed honing
Single feed honing is a precision machining method that uses a set of whetstone assembled on the honing head, applies a certain pressure to the workpiece along the radial direction, and performs rotational and reciprocating motions. Honing can be used not only for precision machining of inner hole, but also for precision machining of outer circle, plane and surface.


Honing has the following characteristics:
(1) Good surface quality characteristics. Honing can get lower surface roughness, Ra can be 0.8 ~ 0.2 m, even lower than Ra 0.025 m. At the same time, the honing surface has even cross mesh, which is good for oil storage and lubrication .Hole shape error corrected by honing (a) ripple (b) taper (c) drum or convex
(2) High machining accuracy.The honing technology can not only achieve higher dimensional accuracy, but also correct holes (minor shape errors, such as roundness, cylindricity, and surface ripples, etc.). When honing holes, roundness and cylindricity can be up to 0.5 m, and axis straightness can be less than 1 m.Honing medium aperture, roundness up to 5 m, cylindricity up to 10 m.When honing short holes, the perpendicularity of the axis of the short hole and the end face can be improved if the honing head is rigidly connected with the flat floating fixture.Intermittent hole honing can improve coaxiality.

(3) High honing efficiency.Multiple honing stones or super hard abrasive stones can be used, and the reciprocating speed of honing head can also be increased to increase the cross Angle of the net, which can quickly remove the honing margin and hole shape error.Strong honing technique can also be applied to improve the honing efficiency effectively.

(4) The honing process is more economical.For thin wall holes and hard workpieces or hard workpieces, honing is easy to finish without complex equipment and equipment.

Honing clamp
Commonly used honing clamp can be fixed or floating. The floating type includes flat float (two degrees of freedom on the plane) and spherical float (two rotational degrees of freedom).Fixed types are used for honing large and heavy parts, while floating types are used for honing short holes, small holes and nesting parts.

Honing clamp	Equipped with the honing head connection type	Scope of application	Error of centralization（mm）
Fixed fixture	Floating connection	Large and medium holes, long holes in complex and irregular parts, Such as a variety of cylinder hole and cylinder sleeve hole, can get better results.	＜0.08
	Semi-floating connection	Blind hole and short hole are processed with short whetstone, but the error caused by honing fixture and spindle is easy to be affected, Stable alignment accuracy is needed to ensure the honing quality	＜0.05
	Rigid connection	Precision honing of small holes and workpiece holes with regular shape in mass production requires high accuracy in alignment.	≤0.01
Flat floating	Rigid connection	Honing short holes (L < D), such as connecting holes, gear holes, etc. The perpendicularity error between the axis and the end surface of the hole can be properly corrected, and the honing accuracy is high	＜0.02
	Semi-floating connection	When the honing spindle is not too high and the float of the honing fixture is less than 1.0mm, the honing hole can get high precision	＜0.05
Spherical floating fixture	Rigid connection	It is suitable for honing all kinds of small holes. In good alignment, holes with high straightness and uniform surface roughness can be obtained	＜0.02
	Semi-floating connection	It is suitable for honing middle hole and small hole, and can obtain higher honing precision under longer whetstone or guiding condition	＜0.05

Honing Stones
The specifications, quantities and properties of honing stones must be selected correctly according to the material, aperture and machining requirements of the honing stones.
The specification of whetstone mainly refers to the shape and size of whetstone (length × width × height). The cross section size is generally wider than the height (i.e. B >h), so as to make the whetstone installation stable.
But when honing large-diameter holes, you can also choose stone with a square section to extend the stone's life.

 

Table 2-3 Selection of section size and quantity of honing stones
Honing aperture	Quantity of whetstone/ piece	Size of whetstone section (B X H)	Diamond whetstone section size （B X H ）
5~10	1~2	—	1.5 X 2.5
10~13	2	2 X 1.5	2 X 1.5
13~16	3	3 X 2.5	2 X 1.5
16~24	3	4 X 3.0	3 X 3.0
24~37	4	6 X 4.0	4 X 4.0
37~46	3~4	9 X 6.0	4 X 4.0
46~75	4~6	9 X 8.0	5 X 6.0
75~110	6~8	10 X 9.12 X 10	5 X 6.0
110~190	6~8	12 X 10.14 X 12	6 X 6.0
190~310	8~10	16 X 13.20 X 20	—
＞300	＞10	20 X 20.25 X 25	—

1）Abrasive selection. See Table 2-4 for details
 

Table 2-4 Selection of honing stone abrasives
Name of abrasive	Code name	Suitable materials for processing	Application range
Brown fused alumina	A	Unquenched carbon steel, alloy steel, etc	Rough honing
white fused alumina	WA	Heat-treated carbon steel, alloy steel, etc	Fine honing、 Half fine honing
single crystal corundum	SA	Good toughness bearing steel, stainless steel, heat resistant steel, etc	Rough honing、Fine honing
monocrystalline fused alumina	PA	All kinds of hardened and unhardened steel parts	Fine honing
chrome corundum	C	Cast iron, copper, aluminum and other non-metallic materials	Fine honing
Black silicon carbide	GC	Cast iron, copper, aluminum, etc. It is mainly used for quenching steel and all kinds of brittle metal and non-metallic materials	Fine honing
synthetic diamond	MBD6~8	All kinds of steel, cast iron and brittle, hard metal and non-metallic materials, such as hard alloy	Rough honing、Half fine honing
Cubic Boron Nitride	CBN	Alloy steels with good toughness and high hardness and strength	Rough honing、Fine honing

 

Table 2-6 Selection of honing stone hardness
Whetstone grit size	Honing allowance (diameter /mm)	Whetstone  hardness
		Steel parts	castings
100#~150#	0.05~0.5 0.01~0.1	L~Q N~T	N~T Q~Y
180#~280#	0.05~0.5 0.01~0.1	J~P L~S	L~R Q~T
W40~W20	0.05~0.15 0.01~0.05	E~M M~R	K~Q M~T
Note :(1) under normal honing conditions, the hardness of whetstone should be soft within the demonstration area. (2) When the hardness of the workpiece material changes, the hardness of whetstone should change 1~2 small steps in the opposite direction

Honing head
Honing head is a kind of precision machining tool with complicated structure.
General honing head with medium aperture .The honing head has a front guide and no guide bar. It is used for honing the inner hole without active measurement.

(2) Small hole honing head. For honing holes larger than 5, single stone honing head as shown in FIG. 2-5 is generally used.
(3) Short hole honing head. The honing head and connecting rod can be made into one, rigid connection.
(4) Large hole honing head. The outer diameter of convex rings is close to the honing aperture to support the stone base and withstand the honing cutting force.

7.2 The connecting rod of the honing head is connected to the main shaft of the honing machine by connecting rod. The connecting rod generally has three forms: floating connecting rod, semi-floating connecting rod and rigid connecting rod.