Page 19 - MMI_MarApr 2021 (high-singles)
P. 19
Source: Sunnen
Honing oils are available in many different formulations and have various levels of viscosity.
angle. The depth or roughness of ventional piston ring ‘break-in’ of abrasive honing stones avail- Honing
the crosshatch pattern depends processes are not required and able as there are types of milling improves
on the relative size of the abra- the microscopic peaks that are or turning cutters, differentiat- the bore
sive grit in the honing stone. The honed off before the engine is ed by grit material, grit size and diameter
larger the grit, the rougher the assembled do not end up in the bonding agent. size and
finish. A mirror finish with al- engine oil upon startup. surface
most imperceptible surface tex- 5 How does lubrication finish of
ture can be achieved with very 4 What is involved in gun barrels
fine grit abrasives. affect honing? prior to
As mentioned earlier, the cross- establishing an effective, Honing oils and water-based the rifling
hatch pattern created during consistent honing process? coolants provide needed lubri- opera-
honing is beneficial for appli- Like CNC machining, a number cation, washing away cut mate- tion. This
cations such as engine cylinder of questions must be answered rial and bringing new abrasive ensures
bores to ensure some oil is re- when developing an optimized grit to the surface of the stones uniform
tained on the bore surface for honing process. What is the part to maintain optimum cutting ac- rifling for a
proper piston ring lubrication material, size and shape? What tion. Quality oils, saturated with better shot.
and piston ring sealing. Oil will is the production volume? How surface active agents, provide the
not adhere well to a smooth or much material needs to be re- necessary lubricity to increase
glazed cylinder bore surface, moved? What are the finished honing pressure and use harder
leading to premature wear and workpiece bore tolerances and abrasives at faster cutting rates.
possible engine failure. If desired, surface finish requirements? An- Similarly, lubricity agents com-
a second honing operation us- swers to those and other ques- bined with sulfur extreme-pres-
ing specialized tools can follow tions determine the proper ma- sure additives prevent workpiece
initial honing to create a plateau chine, fixtures, tooling, abrasives welding and tearing while keep-
finish in which the peaks are and honing oils or coolants, as ing stones clean, resulting in a
uniformly clipped at a consistent well as honing process parame- very consistent surface finish.
level while leaving the valleys ters such as spindle and stroking Specially formulated honing flu-
untouched. Most engine cylin- speeds and feed rate. The hon- ids are also available for use in se-
ders today are honed with this ing stone is selected based upon vere applications in which prob-
plateau surface finish, which in- the type of material to be honed, lems such as galling can occur.
creases the bearing area of the tolerances to be achieved and Honing oils are available in many
bore surface. This means con- the amount of material to be re- different formulations with vari-
moved. There are as many types ous levels of viscosity.
www.mmindia.co.in | 19March-April 2021
