EP1884316B1

EP1884316B1 - Method for making abrasive discs and the abrasive discs made thereby

Info

Publication number: EP1884316B1
Application number: EP07014584A
Authority: EP
Inventors: Fabrizio Cortese
Original assignee: TAF Abrasivi SpA
Current assignee: TAF Abrasivi SpA
Priority date: 2006-07-31
Filing date: 2007-07-25
Publication date: 2009-09-23
Anticipated expiration: 2027-07-25
Also published as: SI1884316T1; ATE443599T1; PL1884316T3; ITMI20061516A1; EP1884316A1; ES2334396T3; DE602007002528D1

Abstract

The present invention relates to a method for making abrasive discs, comprising the steps of coupling a vulcanized fiber or fiber paperboard or paperboard supporting layer (1) to a further layer (2) having at least a glass fiber net, hot pressing, in a pressing mold, the two coupled layers, thereby forming a central bulged portion (4), fixing a central ring nut (5), spreading on the concave face a binding resin, applying fabric blade elements (11) coated by an abrading material and pressing the assembly in a heated oven.

Description

BACKGROUND OF THE INVENTION

The present invention relates to a method for making abrading or abrasive discs, and the abrasive disc made thereby.
An example of such an abrasive disc is disclosed in DE 9216621 U1 where a grinding tool to be coupled to a driving spindle has a substantially disc-like carrier (10), the front side thereof bearing a ring of abrasive material (11) comprising numerous overlapping arranged grinding lamellas (12) glued on the flange (19) and the overlapping portion of the ring part (14). The carrier (10) is made of two parts comprising a metal plate-shaped central hub portion (13) and an annular wearable ring portion made of pressed natural fibers (14) radially overlapping the hub portion (13). The hub portion (13) comprises a flange (19) extending through an opening (16) of the ring portion (14), on whose back the ring part (14) is attached. The ring part (14), made of a hardboard plate comprising humic acid or urea resin-bound cellulose fibers, is centered through its opening (16) over the rising hub portion (13).
As is known, lamellar or blade-like abrasive discs are generally made by molding a plastics material, such as nylon, polycarbonate and the like, or said abrasive discs are made starting from a fiberglass material, by using fiberglass net layers, impregnated or embedded with synthetic resins, and then pressed and polymerized or cross-linked.
Other prior methods provide to make the supporting construction starting from a metal, such as stainless steel, aluminium and the like.
Thus, all the above prior abrasive discs are made starting from a single type of supporting element which must be constructed so as to resist against mechanical efforts applied as the abrasive discs are used, thereby it is necessary to provide complex sized arrangement, and to make specifically designed template, to resist against the generated efforts or stress.
It should be apparent that the above prior methods and constructions would involve a very high operating cost, negatively affecting the cost of the finished abrasive disc product.

SUMMARY OF THE INVENTION

Accordingly, the aim of the present invention is to overcome the above mentioned drawbacks, by providing a method for making abrading or abrasive discs, allowing to easily provide constructionally very simple abrasive discs and, in which, they are achieved as individual finished products, of a comparatively low cost.
Within the scope of the above mentioned aim, a main object of the invention is to provide such a method allowing to make abrasive discs which, while being greatly resistant from a mere mechanic standpoint, also have a small weight, and can be used in a very safe and efficient manner.
Another object of the present invention is to provide a method for making abrasive discs, and the related made abrasive discs, which, owing to their specifically designed constructional features, are very reliable and safe in operation.
Another object of the present invention is to provide abrasive discs which can be easily constructed and which, moreover, are very competitive from a maintenance, servicing and operating standpoint.
According to the present invention, the above mentioned aim and objects, are achieved by a method for making abrasive discs, according to claim 1.

BRIEF DESCRIPTION OF THE DRAWINGS

Further characteristics and advantages of the present invention will become more apparent hereinafter from the following detailed disclosure of a preferred embodiment of a method for making abrasive discs, according to the invention, which is illustrated, by an example, in the accompanying drawings, where:

Figure 1 is a schematic exploded view showing the supporting layer and fiberglass net arrangement;
Figure 2 is a further exploded view showing the supporting layer and fiberglass material, as seen in elevation;
Figure 3 shows the coupling of a fiberglass layer and a supporting layer;
Figure 4 is a side elevation view showing the obtained coupling;
Figure 5 is a front view showing the forming of the supporting layer and fiberglass layer, as coupled to one another, and seen in plan;
Figure 6 is an elevation view showing a contoured coupled or laminated arrangement;
Figure 7 shows the laminated arrangement as seen from its convex face;
Figure 8 is a cross-sectional view showing the laminated or coupled arrangement;
Figure 9 shows an applying step for applying a binding resin layer;
Figure 10 shows a further operating step for initially partially applying fabric material blade elements, as coated by an abrasive material;
Figure 11 shows the laminated construction and the abrasive fabric material blade elements coupled thereto; and
Figure 12 is a schematic cross-sectional view showing an end pressing step, for pressing the laminated construction in a heated pressing oven.

DESCRIPTION OF THE PREFERRED EMBODIMENT

With reference to the number references of the above mentioned figures, the method for making abrasive discs, according to the invention, provides the step of coupling a supporting layer 1 to a fiberglass net layer, generally indicated by the reference number 2.
The support layer 1 is advantageously made starting from a vulcanized or cured fiber material, or a fibrized paperboard material, or a simple paperboard material, made starting from a regenerated paper material, and with a thickness varying from 0.8 to 3 mm.
More specifically, said support or supporting layer can be advantageously impregnated or embedded with synthetic resins or animal glue materials.
The fiberglass layer 2 is made of a fiberglass net construction, having a weight varying from 200 to 500 g/m².
The layer 2 can be impregnated by phenolic resins, Novolac, epoxydic resins, polyurethane resins or other like synthetic resins.
The thus obtained laminated construction, generally indicated by the reference number 3, is made by molding operation in a mold designed for binding or coupling the layer 1 and layer 2 through a combined use of pressure and at a temperature of about 100-130°C.
In this laminating or coupling step, performed by a pressing operation, in the central portion a bulging or bulged portion is obtained, generally indicated by the reference number 4, where a central hole for receiving a ring nut 5 anchored to the laminated construction is formed.
After having made the laminated construction 3, is applied a binding or coupling resin, including preferably a single component epoxydic resin material.
More specifically, said resin is applied by a spreading operation, thereby providing circular region 10 affecting the concave surface or face, where fabric blade elements 11, coated by an abrasive material, are applied.
The thus made assembly is pressed, and the made disc elements are in turn pressed and conveyed, as supported on a rod element 15, to a heated oven, which is heated to a temperature from 110°C to 130°C.
The disc elements are held in the oven 11 from about one to three hours, thereby causing the resin materials used for making the abrasive discs to be perfectly cured or polymerized.
According to a different embodiment of the method, it is possible to provide a supporting layer, of the above disclosed type, derived from a web or strip material, and a fiberglass layer, also obtained from a web or strip material, which are coupled to one another by causing them to pass through a calander, including calandering heated rollers, at a temperature from 100°C to 120°C; and, after having been subjected to a heating and cooling step, said coupled or laminated layer being rolled on.
The thus made web is cut through to provide desired diameter disc elements.
Then, by causing said disc element to pass through a hot pressing apparatus, heated to about 100°C, the desired depressed center shape is achieved, to connect with the central metal ring nut element.
The thus obtained disc product has a very small cost.
In particular, the product made by the first making method can be produced in a single making line, starting from component elements to fully achieve a finished abrading disc.
The above disclosed method allows to eliminate the comparatively long and complex operations of the prior art, thereby allowing to achieve a saving of 30% with respect to conventional like products.
The invention, as disclosed, is susceptible to several modifications and variations, all of which will come within the scope of the claims.
In practicing the invention, the used materials, provided that they are compatible to the intended application, as well as the contingent size and shapes, can be any, depending on requirements.

Claims

A method for making abrasive discs comprising the steps of providing a laminated web made by coupling a vulcanized fiber paperboard material, or a regenerated paper material supporting first layer (1), to a second fiberglass net layer (2), cutting said laminated web to provide disc elements, hot pressing, in a hot pressing mold, each said disc element to form a central bulged portion (4) defining a central hole, fixing in said central hole a central ring-nut (5), spreading on the concave face of said central bulged portion a binding resin, adhering fabric material blade elements coated by an abrasive material to said binding resin, and further pressing said disc elements in a heated pressing oven (11), wherein said supporting layer (1) has a thickness varying from 0.8 to 3 mm, wherein said fiberglass net layer (2) has a weight variable from 200 to 500 g/m², and wherein said first and second layers (1, 2) are coupled at a temperature from 100°C to 130°C.
A method, according to claim 1, characterized in that said supporting layer (1) is impregnated by synthetic resins or animal glue materials.
A method, according to claim 1, characterized in that said fiberglass layer (2) is impregnated by phenolic resins, Novolac resins, epoxydic resins, polyurethane resins, ureic resins and the like.
A method, according to claim 1, characterized in that said binding resin is applied by spreading it in substantially circular regions.
A method, according to claim 1, characterized in that said pressing heated oven (11) is heated to a temperature from 110°C to 130°C.
A method, according to claim 1, characterized in that said method further comprises the step of applying, in said heated oven, said disc elements to a supporting rod (15).
A method, according to claim 1, characterized in that said disc elements are held in said heated oven for a period from 1 to 3 hours.
An abrasive disc, characterized in that said abrasive disc made by a method according to claims 1 to 7.