CIRP Encyclopedia of Production Engineering

Living Edition
| Editors: The International Academy for Production Engineering, Sami Chatti, Tullio Tolio

Honing

  • Hans-Werner HoffmeisterEmail author
Living reference work entry
DOI: https://doi.org/10.1007/978-3-642-35950-7_6430-5

Synonyms

Definition

Honing is abrasive machining with bonded geometrically undefined abrasive cutting edges whereby the multi-cutting point honing stones describe at least two components of motion with at least one of them not rotational (CIRP Dictionary of Production Engineering 2004). Honing serves to improve the shape, size, subsurface, and surface quality of the workpiece.

Theory and Application

The application focus of honing is the internal honing, for example, in automotive engineering such as finishing cylinder bores, crankshaft bores, fuel injection pump housings, etc. Another field of application is hydraulics and pneumatics.

Depending on the geometry of the workpiece and the process kinematics, different process variants are classified, for example (CIRP Dictionary of Production Engineering 2004):
  • External honing

  • Internal honing/bore honing

  • Short stroke honing/superfinishing

  • Longitudinal stroke honing

  • Face honing

  • Gear honing

  • Form honing.

The variants of external, internal, and face honing and their kinematics are shown in Fig. 1.
Fig. 1

External, internal, and face honing

In Addition, honing can also be classified by the topography of the machined surface, e.g. plateau honing, spiral slide honing, or laser honing.

Kinematics and Forces

The kinematic of cylindrical honing is determined by a superposition of permanent rotation and oscillating axial strokes. The infeed is performed in radial direction. For the finishing of cylinder bores in combustion engines, the internal longitudinal stroke honing is used. Therefore, all motions are accomplished by the honing tool while the workpiece stands still. The velocities and forces at internal honing are described in Fig. 2 and below (Mushardt 1986; Von See 1989).
Fig. 2

Velocities and forces at honing

The cutting speed results of the axial and tangential cutting speed. The radial infeed speed can be neglected.
$$ \overrightarrow{v_c}=\overrightarrow{v_a}+\overrightarrow{v_t} $$
(1)
According to this, the magnitude of the cutting speed vector can be calculated by using the diameter of the honing tool dw with
$$ {v}_c=\sqrt{v_a^2+{\left(\pi \cdot {d}_w\cdot n\right)}^2} $$
(2)
The cross hatch angle α is defined as the angle between the cutting speeds +vc and −vc with a horizontal bisecting line. Figure 3 shows the cross hatch angle and the speed components.
Fig. 3

Cross hatch angle (According to Flores 1992)

So, the cross hatch angle can be calculated by
$$ \alpha =2\arctan \frac{v_a}{v_t} $$
(3)
Analogically to the cutting speed, the cutting force is determined by the sum of the axial and tangential force. And thus, the magnitude of the cutting force vector can be written as
$$ {F}_c=\sqrt{F_a^2+{F}_t^2} $$
(4)
The contact pressure of the honing stones against the workpiece is realized by the axial feed force Fz. This force is distributed by the tool internal double cone to the single honing stones and therefore is redirected to the radial acting normal force Fn. As a consequence, the normal force can be calculated with
$$ {F}_n=\frac{F_z}{m\cdot \tan \gamma } $$
(5)
where m is the number of honing stones and γ is the cone angle.
The resultant force is calculated by the magnitude of the sum vector of axial, tangential, and normal force.
$$ {F}_{\mathrm{res}}=\sqrt{F_a^2+{F}_t^2+{F}_n^2} $$
(6)
The honing pressure pn results from the distribution of the normal force on the contact surface of the honing stones:
$$ {p}_n=\frac{F_z}{m\cdot {l}_h\cdot {b}_h\cdot \tan \gamma } $$
(7)
with the honing stone length lh and width bh. In general, the honing stone length should be about 2/3 of the bore length and the overshot length should be about 1/3 of the honing stone length.

Machines

The design of honing machines depends on the workpiece to be machined. For the internal honing of large parts with diameters up to 1,100 mm and bore lengths up to 12,000 mm, “horizontal honing machines” with horizontally arranged spindles are used.

Internal honing of smaller workpieces with diameters from about 0.6–350 mm is often performed on “vertical honing machines.” These most prevalent machines have (often multiple) vertically arranged spindles and are used, for example, to machine cylinder crankcases.

For the honing of flat surfaces, so-called flat honing or fine grinding machines are used. The kinematic of flat honing can be described by a planetary gear, with the workpiece carriers as planet wheels rotating around a central driven sun wheel. The workpiece carriers are running on a flat honing wheel, which contains the abrasive grains and is driven in the opposite direction of rotation. To machine parallel faces of a workpiece, often two-wheel flat honing machines are used. Examples for parts being machined on a flat honing machine are bearing rings or cutting inserts.

External honing of cylindrically or eccentrically shaped parts like camshafts, pins, and printing rolls is performed on superfinishing machines to improve the surface quality after a grinding process. While the workpiece rotates, the honing tool is permanently pressed on the lateral surface and oscillates in axial direction. The honing tool can be either a stone or an abrasive tape (Rao 2000).

Feed Systems for Cylindrical Honing

In cylindrical honing, basically two feed devices are used – the hydraulic and the mechanical feed device (Flores 1992; Grote and Antonsson 2009). At the hydraulic feed device, a constantly pressurized piston provides a constant advancing force Fz. Thus, the hydraulic feed device can also be called “force dependent.”

At the mechanical feeding, a feed moment Mz is converted to a defined displacement by a threaded gear or a step motor, whereby the honing pressure of the honing stones against the workpiece builds up. So, the mechanical feed device can also be called “path dependent.”

The principles of the hydraulic and mechanical feed devices are presented in Fig. 4.
Fig. 4

Hydraulic and mechanical feed system for cylindrical honing

Tools

Cylindrical honing tools can be divided into the groups of expandable and nonexpandable honing tools, as seen on Fig. 5.
Fig. 5

Overview of cylindrical honing tools

Single Stone Honing Tools

At the expandable honing tools, the honing stone is fed constantly against the workpiece during the honing operation. When using single stone honing tools, support bars for the tool guidance in the processed bore are necessary. On the other hand, single stone honing tools allow to process very small bores up to about 5 mm diameter.

Multistone Honing Tools

For bores from about 5–1,000 mm diameter, multistone honing tools can be used. Figure 6 shows the principle design of a multistone honing tool.
Fig. 6

Principle design of a multi stone honing tool (According to WBK)

Honing Mandrels

Honing mandrels are electroplated abrasive tools with a single layer of diamond or CBN grains in a metallic bond. Thus, their diameter is pre-adjusted and not expanded during the honing process; honing mandrels are assigned to non-expandable honing tools even if they can be expanded in a small amount to compensate for wear. As another consequence of the pre-adjustment, only small stock removal capacities are possible. Higher stock allowances often require a multi-step process. Honing mandrels are used to process small bores with diameters from about 0.6–16 mm.

Honing Rings

For gear honing (also called shave grinding), a precisely trued, internal gear shaped ring, the honing ring, consisting entirely of abrasive ceramics (aluminum oxide or silicon carbide) with resinoid or vitrified bond, is used. The honing ring and the gear wheel have non-coaxial rotational axes (Fig. 7). By this besides the gearing movement, which introduces relative speeds in the contact area between the honing ring and the gear wheel in the profile direction an axial relative speed is introduced. Because on the pitch circle no relative movement in profile direction between honing ring and gear wheel flank occurs, the gear honing pattern is fishbone-like.
Fig. 7

Honing ring for gear honing

Gear honing enhances the flank and the pitch. In normal gear honing, only the honing ring is driven. Gear power honing introduces also a second synchronous and prestressed drive of the work wheel.

Honing rings are comparable to grinding wheels and therefore must be dressed at regular intervals using a diamond dressing wheel, which itself has helical or spur gear shape, but plated with diamonds.

Honing Disks/Wheels

Honing wheels consist of a disk-shaped steel body with an abrasive cutting layer, comparable to grinding wheels. According to this, the same cutting materials (ceramics, diamond, CBN) and bonds are used. For the improvement of the chip transport, the cutting layers are available with different patterns of grooves or can be assembled of multiple hexagonally shaped segments.

Application Examples

Form Honing of Cylinder Bores

As mentioned in the definition of honing, this process serves among others to improve the cylindrical shape of bores, e.g., engine blocks. In this special case, the assembly of the cylinder head and the temperature load at the engine run cause static and thermal deformations of the cylinder running surface. As a consequence, the blow-by and oil consumption increases. Currently, deck plates are mounted on the crankcase while honing to simulate the static deformation of the cylinder head assembly. A new approach to anticipate the static and thermal deformations without using deck plates is form honing. At this approach, a honing tool with one or several piezoelectric driven honing stones is used to produce a free form that represents the negative of the static and thermal deformation (Wiens et al. 2009). The required free form can be determined by experiments or by way of calculation (Fig. 8).
Fig. 8

Radial deformation of cylinder bores (Wiens et al. 2009)

Cross-References

References

  1. CIRP Dictionary of Production Engineering (2004) Material removal processes, vol 2, 1st edn. Springer, BerlinGoogle Scholar
  2. Flores G (1992) Grundlagen und Anwendungen des Honens. Vulkan-Verlag, EssenGoogle Scholar
  3. Grote K-H, Antonsson EK (2009) Springer handbook of mechanical engineering, vol 10. Springer, New YorkCrossRefGoogle Scholar
  4. Mushardt H (1986) Modellbetrachtungen und Grundlagen zum Innenrundhonen. VDI-Verlag, DüsseldorfGoogle Scholar
  5. Rao PN (2000) Manufacturing technology: metal cutting and machine tools. Tata McGraw-Hill Education, NoidaGoogle Scholar
  6. Von See M (1989) Optimierung von Honprozessen auf der Basis von Modellversuchen und -betrachtungen. VDI-Verlag, DüsseldorfGoogle Scholar
  7. Wiens A, Lahres M, Hans-Werner H, Flores G (2009) Formhonen von Zylinderlaufbahnen in Kurbelgehäusen mittels eines piezoelektrischen Formhonwerkzeuges, Jahrbuch Schleifen, Honen, Läppen und Polieren. Vulkan Verlag, Essen, pp 265–280Google Scholar

Copyright information

© CIRP 2018

Authors and Affiliations

  1. 1.Institute of Machine Tools and Production TechnologyTU BraunschweigBraunschweigGermany

Section editors and affiliations

  • Konrad Wegener
    • 1
  1. 1.Institute of Machine Tools and ManufacturingETH ZürichZürichSwitzerland