Title of Invention	AN EXTRUSION HONING COMPOSITION
Abstract	An extrusion honing composition comprising polydimethyl slloxane homogeneously mixed with silicon carbide particles selected £rom grit size 36, 54, 100, the said particles being present in the composition in the range 25% to 55% by volume of the said polydimethyl siloxane.

Full Text

This invention relates to an extrusion honing composition. Extrusion honing, a flexible honing method, is a versatile method for finishing internal features of metal objects, such as manifolds in IC engines. It has also been found useful for correction of form error and imparting finish to pre-honed surfaces. Extrusion honing is limited in use owing to lack of ready availability of extrusion hone medium which is proprietory and is imported. The present invention has for its object to propose an extrusion honing composition which can be prepared indigenously, quickly and easily, with locally available raw materials. The extrusion honing composition, according to this invention, comprises polydimethyl siloxane homogeneously mixed with silicon carbide particles selected from grit size 36, 54, 100, the said particles being present in the composition in the range 25% to 55% by volume of the said polydimethyl siloxane present in the said composition. This invention will now be described with reference to Figs. 1 and 2 of the accompanying drawings which illustrate, by way of example, and not by way of limitation, the morphology of the extrusion medium without abrasives. The medium proposed herein, which is polydimethyl siloxane, is highly viscous and translucent at room temperature. It has good bonding strength, both cohesive and adhesive, that facilitates holding of abrasives and ease in extrusion through restricted openings without significant tear at room temperature. This makes the medium suitable for extrusion honing. Some of the characteristics/ features of this medium of the proposed honing composition is summarised below. Appearance Translucent Mechanical Properties Tensile Strength 8.4 MPa Tear Strength 24 N-m Durometer hardness 40 JIS A The effectiveness of the proposed composition was tried in a hydraullcally controlled setup for carrying out the extrusion honing method. Trials were conducted under different conditions to assess the parametric influence on desired output (surface finish). Details of the experimental conditions used are summarised below. Abrasive SiC size 36 mesh Volume Fraction (Abrasive) 25% Pressure 1-2 MPa Velocity 0.4 - 1.2 m/min Work Material S6 Cast Iron/AISI 4419 To assess the in-service characteristics of the medium, rheological study was conducted with different input conditions. EXAMPLE To polydimethyl slloxane, silicon carbide of volume which is 25% of the said polydlemethyl slloxane, is added and thoroughly mixed to obtain a homogeneous consistency. The particles of silicon carbide, thus added, are of 54 grit size. Homogeneity is obtained by using an appropriate polymeric mixer. It is preferred to use Grade 4U of commercially available polydimethyl slloxane since this is found to give optimum results. The terms and expressions herein are of description and not of limitation, as these terms and expressions do not exclude any equivalents of the features described,having regard to the scope and ambit of this invention. We Claim: 1. An extrusion honing composition comprising polydimethyl siloxane homogeneously mixed with silicon carbide particles selected from grit size 36/ 54, 100/ the said particles being present in the composition in the range 25% to 55% by volume of the said polydimethyl siloxane. 2. An extrusion honing composition wherein the polydimethyl siloxane conforms to 4U commercial grade. 3. An extrusion honing composition substantially as herein described and illustrated. 4. A method of manufacture of an extrusion honing composition comprising the steps of homogeneously mixing polydimethyl siloxane with silicon carbide particles selected from grit size 36, 54, 100, the said particles being present In the composition In the range 25% to 55% by volume of the said polydlmethyl siloxane present In the said composition. 5. A method as claimed In Claim 4 wherein the said homogeneous mixing Is carried out by a polymeric mixer. 6. A method of manufacture of an extrusion honing composition substantially as herein described and Illustrated by the Example.

Documents:

0133-che-2003 abstract-duplicate.pdf

0133-che-2003 abstract.jpg

0133-che-2003 abstract.pdf

0133-che-2003 claims-duplicate.pdf

0133-che-2003 claims.pdf

0133-che-2003 correspondence-others.pdf

0133-che-2003 correspondence-po.pdf

0133-che-2003 description (complete)-duplicate.pdf

0133-che-2003 description (complete).pdf

0133-che-2003 drawings-duplicate.pdf

0133-che-2003 drawings.pdf

0133-che-2003 form-1.pdf

0133-che-2003 form-19.pdf

0133-che-2003 form-26.pdf