WO2006013598A1 - Procedure for the construction of diamond wheels for the processing of stone and resulting wheels - Google Patents

Abstract

The present invention relates to a method for the construction of abrasive diamond wheels and to abrasive diamond wheels obtainable by injection moulding material between a diamond canvas (1) and a support (5) .

Description

Procedure for the construction of diamond wheels for the processing of

stone and resulting wheels

Technical field

The present invention provides o method for the production of rigid

wheels boasting continuity of the abrasive surface on machinery that

manage to exceed 12,000 r/m; these wheels do not present "swelling"

problems, do not produce deformations and do not cause rips and

blows between the abrasive and the processed piece thanks to rubber

supports that especially provide a geometric abrasion well over grains of

400 and up to 3000; the second objective of the present invention is the

production of a series of wheels with variable geometry based on the

function of the granulometry for the abrasive utilized.

Description of the Related Art

Diamond wheels for the processing of stone material, such as marble,

have been on the market for some time. They are generally composed

of a metal support, usually in steel, with an integral industrial diamond

whose grain must not be greater than 400 for. technical reasons.

Therefore the wheels constructed in this briefly-described manner may

only be used for roughing and grinding the profiles being processed, but

not for the buffing of the same. In recent times, wheels have been manufactured in an agglomerated

resin and abrasive material, also with a diamond composition and

integral with its central body in metal. This construction method allows

for the execution of wheels with an abrasive grain ranging from 800 up to

2000 and with fair dimensional precision. Its main flaw is represented by

its low wear-resistance, which decreases the harder the material to be

processed is. Therefore making it impossible for the wheel to revolve at

more than 1000 r/m since these wheels might explode at greater speeds.

A further and not least important problem is the compatibility of such

wheels with modern machinery since machines with numeric control are

not capable of managing wheel consumption, to the detriment of the

resulting quality and production time.

Further improvement has been obtained through the use of diamond

canvas sections glued onto vulcanized rubber around a metal body; this

technology has allowed an increase in the limits of the abrasive grain,

but is not efficient in avoiding the canvas to become detached at a

high number of revolutions. It also possesses dimensional precision

problems while increasing the number of revolutions due to its centrifugal

force; continuity problems for the presence of the abrasive on the

vulcanized surface, which proves to be discontinuous on this type of tool.

Finally, thermoplastic material has been used for the construction of the

wheel, with certain and repetitive Shore hardness, that allows for a

considerable reduction in production costs and a method for the

complete coating of the exterior wheel profile with diamond canvas. This provides abrasive continuity on the entire surface that comes in

touch with the material to be processed. But this type of wheel is not

compatible with some present-day sophisticated and rapid machinery.

Description of the invention

The present invention provides a method for the production of rigid

wheels boasting continuity of the abrasive surface on machinery that

manage to exceed 12,000 r/m. These wheels do not present "swelling"

problems, do not produce deformations and do not cause rips and

blows between the abrasive and the processed piece thanks to rubber

supports that especially provide a geometric abrasion well over grains of

400 and up to 3000.

The second objective of the present invention is the production of a

series of wheels with variable geometry based on the function of the

granulometry for the abrasive utilized.

According to the present invention, the wheel is made up of a main

support constructed in aluminium or other material that is not necessarily

metallic. It possesses a central canal set up in axis with the central axle

support and in communication to this same axle through orthogonal

holes. They are in turn connected through radial canals allowing for the

distribution of plastic thermoset material between the support and the

diamond canvas, previously fixed to the support extremities via common

means such as glue, for example. In order to obtain the distribution and

monolithicity of the whole made up of! support, thermoset and diamond

canvas on the central body on which the modelled diamond canvas has been mounted, it is placed in a mould for injectable thermoplastics.

Upon injection, the axle channel is first filled to the assembly hole; the

plastic material is arranged between the support and the diamond

canvas in a homogeneous and constant manner through the radial

holes in communication with the distribution canals.

Upon its removal from the mould, the tool already presents a high

dimensional precision and cylindricity of the exterior surface with respect

to the axis, which has never been reached beforehand. Therefore tools

with established profiles may be produced, theoretically with an

approximation of only a few hundredths of a millimetre.

This method produces wheels with highly-precise profiles and joints. For

example, for the processing of a determined piece it can produce a

series of wheels with variable geometry in function of the granulometry.

This wheel, compared to the previous one, has a profile and therefore a

geometry that takes into consideration the modification of the profile of

the processed item produced by the previous wheel and subsequently

for a whole series of wheels involved in the processing.

The invention will now be described in reference to the attached plans,

which illustrate the preferential but not exclusive production solution, in

particular for that which regards the profile of the wheel obtained.

Brief description of the drawings

Table 1 shows the diamond canvas, on the left with a front orthogonal

view. Table I a shows a tri-dimensional view of Table 1 , a cross-section of the

canvas relative to the surface to be enveloped and connected to the

extremities.

Table 2 shows an orthogonal front view of the central body of the wheel,

preferably in metal.

Table 2a shows a tri-dimensional view of Table 2..,

Table 3 shows a front orthogonal view of the thermoset support.

Table 3a shows a tri-dimensional view of the injected thermoset as it

penetrates into the canvas, rendering it solid and concentric to the

Table 2 support.

Table 4 shows the Table 2 support wrapped up in the Table I canvas that

is joined to the extremities, before being mounted in the mould shown at

a cross-section and frontal view.

Table 5 shows another section of the Table 4 support, with thermoset

injected into the special cavities.

Table 6 shows a cross-section of the Table 5 support.

Table όa shows a front view of the Table 5 support, finished at the lathe

and ready for use.

Table 7 shows a schematic section of the mould used for producing the

wheel.

Table 8 shows the Table 7 mould with its appropriate parts for

accommodating thermoset injections full of such material.

Table 9 shows a cross-section of the stone modelled by a series of wheels

whose profiles are calculated on the basis of their granulometry. Detailed description of the preferred embodiment

With reference to the above Tables, the wheels produced according to

the present invention procedure are hereby described.

The diamond canvas is cut according to the procedure described in the

patent request No. Rm 2000 A 000665 belonging to the same owner. For

example, if the wheel has the shape indicated in the attached plans, the

development of the surface allows for the union of the two extremities (2

and 3) of the strip in order to obtain the shape (1 ) of Table 1 and Ia:

similar results may be obtained by cutting them into thin modelled strips

according to the line (4) and then either gluing them together or placing

them into the mould in correspondence with the air suction holes.

Then the support (5) is produced, as shown in Tables 2 and 2a. This

support is made with well-known techniques, preferably in metal, but

may be produced in non-metallic material such as for example plastics;

the support (5) has an opening (6) that is aligned on the central axle of

the support (5). This opening (6) communicates with the canals (8a)

through the radial holes (8), that allow for the distribution of injected

thermoset material (8b) . between the diamond canvas (1 ) and the

support (5).

The whole made up of a support (5) and the diamond canvas (1 ) is

placed inside a mould, for example such as the one illustrated in Table 7,

where a match setting (1 1 ) should preferably be present for its correct

positioning; the mould has a certain n'umber of holes (13) connected by

suction ducts (14) and a suction pump; then the mould is closed by joining the two mobile semi-moulds (12); suction is activated to ensure

the correct positioning of the diamond canvas (1 ); the upper part of the

mould that runs along the vertical axles (17) is then closed (16); the

operator activates the injector so that the material may be injected, with

a great pressure, along the hole (18), going through the canal (19), the

opening (6) and the radial holes (8) and is distributed thanks to the

canals (8a) located in the empty space (20) between the diamond

canvas (1 ) and the support (5); the injection pressure of the mould and

the heat of the material injected allow the plastic material to become

one with the canvas (I ) and the support (5), thus producing a monolithic

tool whose canvas cannot be detached during its use, even at high

revolutions and temperatures.

Following the removal of the wheel from the mould, attachments to the

tool machinery will be manufactured as follows: the holes will be

opened up once again (6) and the connections will be finished off (22,

23, 24) so that the wheel can be centred on the toolpost support.

As previously mentioned, it is evident that such a procedure can create

wheel profiles different from those illustrated, practically depending on

the- profile conformation of the support (5) and the consequent mould

conformation.

In a more accurate production, between the internal part of the canvas

(1 ) and the upper part of the support (5) in contact with the canvas, a

primer that improves resistance is distributed when the canvas support is

made of synthetic or similar material. To best comprehend the advantages produced by the procedure and

the resulting wheels, it must be kept in mind that one of the problems

that afflict commercial wheels is the one regarding excessive wear in the

areas most converging between the wheel and the piece being

processed; the present wheel avoids this problem by manufacturing a

profile for a series of wheels with various geometries that compensates

the different passages going from grinding to buffing. It ensures

continuous contact and therefore the progressive uniform wear solely of

the abrasive part on the entire profile to be processed, both with the

new wheel and once it is worn out.

Commercial wheels do not only wear out their abrasive parts, but also

their wheel profile. So as the processing takes place, the successive

wheel adapts itself to the profile created by the previous wheel and

practically carries out with the subsequent processing steps, therefore

altering the original wheel profile. This implies, in the case of wheel

substitution, its rapid wear and the necessity to also substitute the other

wheels of the set because otherwise the substituting wheel would be

operating on a profile mismatching the programmed one, at least in a

few points. Therefore should even only one wheel in a set be substituted

during processing, it will be necessary for the wheel to be worn out until it

perfectly matches the profile created by the previous wheels before

obtaining the expected results.

Wheels made according to the present procedure possess, as previously

stated and as illustrated by Table 9, a progressive geometry. This means that from its planning the geometry of a wheel is calculated by taking

into consideration the profile that the previous wheel has created on the

piece so that the following wheel need not adapt itself in order to

continue with the processing and therefore avoids being worn out in

some points of the profile created by the previous wheel. It is already in

the condition to adhere completely to the processed piece in its entire

surface.

This characteristic also allows the substitution of one wheel of the set

necessary for processing, without major inconveniences and, as already

mentioned, without the necessity for the new wheel profile to adapt itself

to the profile created by previous processing.

Another advantage of this invention is that it will no longer be necessary

to make corrections to the positioning of the substituting wheel on the

tool machinery, nor will it^" be necessary to alter the scheduled paths

according to axles Z and Y.

Claims

1. Procedure for the production of diamond wheels for the processing

of stone, metal, marble, granite and glass material compounds and

other hard material and the resulting wheels characterized by the

fact that the previously modelled diamond canvas (1 ) becomes one

with the support (5) via the gluing of its edges so as to create an

empty space (20) between the internal side of the canvas and the

support and that the support (5) on which this diamond canvas is

applied hosts a canal centred on the rotation axle of the wheel. The

aforesaid canal, since it communicates with the outside via an

opening (6) subsequently in communication through a series of radial

canals (8a) capable of distributing injected material (8b) through the

external hole in the space (20) existing between the diamond canvas

(1 ) and the support (5).

2. Procedure for the production of diamond wheels for the processing

of stone, metal, marble, granite and glass material compounds and

other hard material and the resulting wheels according to the

previous claim characterized by the fact that the whole is made up

of a support (5) and diamond canvas (1 ) that is placed in a mould

compatible with the wheel to be processed, in which a matching

notch (1 1 ) is present for its correct positioning; the mould hosts a

certain number of holes (13) connected via suction ducts (14) and a

suction pump; after the mould hds been closed by joining the two

mobile semi-moulds (12) together, suction is activated so as to ensure the correct positioning of the diamond canvas (1 ); therefore the

upper part of the mould (16) that runs along the vertical axles (17) is

closed; thermoplast material is injected through the hole (18) and

passes through the canal (19), the opening (6), the radial holes (8)

and is distributed thanks to the canals (8a) located in the empty

space (20) between the diamond canvas (1 ) and the support (5).

The mould pressure and its heat activate a monolithic cohesion

between the support (5), the thermoplast material (8b) and the

diamond canvas (1 ).

Procedure for the production of diamond wheels for the processing

of stone, metal, marble, granite and glass compound material and

other hard material and the resulting wheels according to the

previous claims characterized by the fact that the support (5) is in

non-metallic material.

Procedure for the production of diamond wheels for the processing

of stone, metal, marble, granite and glass compound material and

other hard material and the resulting wheels according to the

previous claims characterized by the fact that following the

extraction of the wheel from the mould (5), through the following

processes, connections to the tool machinery are created by

opening up the openings (6) once again and finishing off the

connections in points (22, 23, 24) so as the wheel can be centred on

the toolpost support. 5. Procedure for the production of diamond wheels for the processing

of stone, metal, marble, granite and glass compound material and

other hard material and the resulting wheels according to the

previous claims characterized by the fact that through a most

accurate execution between the internal side of the canvas (1 ) and

the part of the support (5) in contact with the canvas, a primer is

distributed to improve the adherence should the canvas support be

produced in synthetic and similar material.

6. Wheels produced according to the said procedures and the previous

claims characterized by the fact that the geometry of each

successive wheel in a set hosting different grains is calculated

according to the modified profile that the previous wheel executed

on the piece being processed.