WO1994026450A1

WO1994026450A1 - Circular saw blades

Info

Publication number: WO1994026450A1
Application number: PCT/EP1994/001515
Authority: WO
Inventors: Otto Katz
Original assignee: Ledermann Gmbh
Priority date: 1993-05-15
Filing date: 1994-05-11
Publication date: 1994-11-24
Also published as: DE9307394U1

Abstract

Circular saw blades for cutting non-ferrous or materials without a homogenous structure are fitted with hard-metal tips. These tips are coated on their face sides (4) with polycrystalline diamond, titanium nitride or a material with similar properties. On two side edges together forming an angle the tip (2) forms attachment areas for bonding to the saw blade (1). To avoid the cost-intensive repair of damaged saw blades, they are fitted with tips (2) of rhomboid shape, the coating (6) of polycrystalline diamond or the like is provided on the narrow front surface.

Description

Circular saw blade

The invention relates to a circular saw blade, which is equipped with cutting plates made of hard metal or the like, which have a coating of polycrystalline diamond, ceramic or a material with similar properties on their end face, arranged uniformly distributed over the circumference of the circular saw blade and with two contact surfaces enclosing an angle are connected to corresponding surfaces in the circular saw blade by an adhesive layer.

Circular saw blades of this type are used for separating non-ferrous metals or materials with an inhomogeneous structure, for example wood-based materials, polymers, etc. Such materials usually have inclusions of a mineral or metallic type which make up the expensive PCD layer wear or damage unevenly, so that the circular saw blade must be reground and repaired prematurely. If these circular saw blades are worn almost uniformly, they can be resharpened several times, but this changes the mass and the geometry of the cutting tips equipped with polycrystalline diamond (hereinafter abbreviated to "PCD"). As a result, the dynamic and mechanical behavior of the circular saw blades also changes in an unforeseeable and uncontrollable manner, in particular with regard to their natural frequencies and the noise level. The material of the master sheet also loses the tension given to it during manufacture; the consequences of this are deteriorated plan and concentricity values. At the same time, the cutting properties of the circular saw blade and thus the achievable cutting quality deteriorate.

As a result of the high surface hardness, the cutting edge is very wear-resistant in the case of thin, hard cutting plates coated with PCD, but on the other hand extremely sensitive to impact. The inclusions, such as metal particles, minerals, stones, etc., which are inevitably present in the materials to be machined, penetrate the PCD cover layer, which can flake off as a result. A cutting blade damaged in this way can no longer be equalized by repair and must be replaced. The exchange is relatively complicated, complex and expensive. The damaged cutting tip is first unsoldered, after which the seat of the cutting tip is reworked. A new cutting blank is then soldered in, the starting material for the blank being a rectangular, relatively long hard metal cutting tip, which has a flat surface with polycrystalline diamond, ceramic, titanium nitride or a 94.2 * 450 -.

- 3 -

Material with similar properties is coated. The required cutting edge geometry, in particular the circumferential and radial free surfaces, is then attached to this blank and the cutting flight circle of the circular saw blade is then leveled.

In the known circular saw blades with cutting plates made of hard metal or a similar material and a coating with polycrystalline diamond, titanium nitride, ceramic or the like, so-called alternate tooth shapes are used, the corner angle of approximately 15 ° being attached to the blank. They require time-consuming and costly processing, parts of the expensive cutting material still having to be cut off. In addition, in the known circular saw blades, the long side of the cutting tip is fixed approximately radially to the center of the main blade, which requires a relatively long soldering surface and an even longer coating surface with expensive PCD material. A further disadvantage of these known circular saw blades is that the repair of damaged cutting tips can only be carried out where there is a suitable, relatively expensive machine park and the corresponding special experience. In practice, this means that generally only the manufacturer of the circular saw blades can carry out such repairs themselves. This, in turn, causes uneconomical downtimes for the circular saw blade to be repaired because of the transport and repair times, especially since no replacement circular saw blade is often available due to the high acquisition costs.

Based on this prior art, the invention has for its object to provide a circular saw blade, the Cost-intensive cover layer of the hard metal cutting tips made of PCD, ceramic, titanium nitride or the like is reduced to a minimum size in comparison to the known PCD-coated cutting tips and it has to be designed such that the cutting tip coated with PCD or the like has a predetermined, time-limited period of use at least approximately maintains a constant cutting quality as well as constant dynamic and mechanical properties, without the need for re-sharpening.

According to the invention, this object is achieved in the case of a circular saw blade with the features of the preamble of claim 1 in that the cutting tips are rhomboid-shaped and their cover layers made of polycrystalline diamond, ceramic, titanium nitride or the like are provided on their narrow end faces.

In a further embodiment of the invention, the cutting tips designed in this way are advantageously arranged with their coated end faces at least approximately tangentially to the circumferential circle of the circular saw blade of the master blade. A further embodiment is that the cutting tips with their coated end faces are arranged approximately radially to the axis of the circular saw blade. According to a further feature, the contact surfaces of the cutting tips and the seating and adhesive surfaces assigned to them form an angle that is less than 90 °. The cutting tips advantageously already have their final tooth shape or their final circumferential clearance angle before being introduced into their adhesive seat on the base sheet, which is achieved in that the cutting tips are cut out of a PCD-coated blank corresponding to their geometric shape. Because the expensive covering layer of the cutting tips is reduced to a minimum in the embodiment according to the invention, so that regrinding is no longer necessary, all disadvantages associated with the removal of a damaged circular saw blade, the shipping and repair of the same are eliminated. As a result of the deliberately reduced overall service life of the circular saw blade according to the invention, there is no fatigue in its base body, that is to say in the master blade. This results in optimal plan and concentricity values over the entire, reduced service life of the circular saw blade, so that the user can count on a constant cutting quality, because overall the cutting edges remain virtually unchanged over the entire service life.

In the production of such circular saw blades, this makes it possible to optimize the concentricity and runout values by changing the parameters accordingly and to reduce the noise level to a minimum, with special noise insulation coatings, sandwich designs, CFRP blades etc. being provided in individual cases can be. Above all, in the new design, new material adhesion connections for fastening the cutting blade in the base blade, in particular suitable adhesives, can be used instead of the previously complicated and expensive soldering. The use of such adhesives for connecting the cutting tips to the basic body of the circular saw blade represents a considerable simplification, since the technically complex soldering devices or soldering devices can be dispensed with.

The improvement with regard to the application of a new material liability, for example by glue, is therefore from This is particularly advantageous because when cutting wood-based materials, work is carried out at high cutting speeds. The centrifugal forces occurring here must counteract the material adhesion forces (solder or adhesive connection). This means that the size of the cutting tip is not primarily determined by the geometry that is required to separate the material, but by the adhesive connection, in particular by the connecting surface, which is required, for example, for soldering or an adhesive is.

These requirements are met by cutting discs with rhomboid shapes, the end faces of which are coated with a hard cover layer, preferably made of PCD, ceramic, etc. In comparison to the known cutting tips, such cutting tips have a large soldering or adhesive area with a relatively small cover layer area. These cutting tips can be used either radially or tangentially on the base sheet in accordance with the respective geometric requirements. The contact surfaces of the cutting tips are preferably designed such that they are at an angle to one another which is less than 90 °. This results in an optimal support of the cutting tip in relation to the master blade, which counteracts the cutting force component. This advantageous support effect has a particular effect in the case of a tangential arrangement of the cutting tips, since in such an arrangement the distance between the point of application of the cutting force to the support point of the cutting tip in the main blade is smaller than in the case of a radial arrangement and is considerably smaller than the known ra ¬ dial arrangement of long and regrindable cutting tips. Further advantageous embodiments are explained below with the aid of a few exemplary embodiments shown in the drawing.

1 to 5 all show partial views of a circular saw blade with the tooth shapes assigned to them. All of the cutting tips of the illustrated exemplary embodiments are rhomboid-shaped and have on their narrow end face 4 a cover layer 6 made of polycrystalline diamond, titanium nitride, ceramic or a similar hard cutting material. In the exemplary embodiments in FIGS. 1 and 2, the cutting tips 2 with their coated end face 4 are arranged approximately tangentially to the circumferential circle of the circular saw blade. To the right of the partial views of the circular saw blade cutouts are the front views of the cutting tips of the embodiments according to FIGS. 1 to 5.

It can be seen from the illustration la of FIG. 1 that when the cutting tip 2 is installed tangentially, the end face 4 coated with PCD may have a trapezoidal shape, while, for example, a rectangular shape can be provided for the tooth behind it (see FIG. 1b).

2, the cutting tips 2 are arranged tangentially as in FIG. 1. As FIG. 2a shows, the PCD-coated end face of the leading cutting tooth 2a is roof-shaped, while the trailing cutting tooth 2b has a substantially square end face, but the free corners can be rounded or beveled. Seen in the direction of rotation of the circular saw blade, the individual cutting tips 2 can advantageously be either the same either tangential or assume radial position, as shown in the exemplary embodiments of FIGS. 1, 2, 4 and 5. However, it is also conceivable that, viewed in the direction of rotation, successive cutting tips 2 are arranged alternately approximately tangentially with coating 3 of end faces 4 or radially with coating of free surface 7, as shown in FIG. 3. There, the tangentially arranged cutting tips 2 are provided with the PCD layer on the end face 4, while the respectively following cutting tip 2 carries the PCD coating on the free surface 7. 3, the front, tangentially arranged tooth 3a is a so-called roof tooth and the rear tooth 3b is a tooth in which the end face or free surface 7 is concavely ground, as can be seen from the illustration 3c is.

In the embodiments of FIGS. 1 and 2, in which the cutting tips 2 are preferably arranged tangentially, the angle is Cx ^; between the contact surfaces 5, 5 'and also the angle between the assigned seating and adhesive surfaces on the master blade 1 is less than 90 °, which provides advantageous support by accommodating the cutting force components in the circular saw blade. In the case of a radial arrangement of the cutting tips, as can be seen from FIGS. 4 and 5, the angle between the contact surfaces 5, 5 '(see FIG. 4) can be 90 °. In this embodiment according to FIG. 4, the radially arranged cutting tips are provided with sloping roof surfaces. Examples 4a and 4b show mutually inclined roof surfaces which are provided with a PCD layer 6. The representation 4c shows the position of the cutting teeth one behind the other according to FIGS. 4a and 4b. In the embodiment according to FIG. 5, the cutting teeth provided with inclined surfaces are not approximately congruently one behind the other as shown in FIG. 4, but laterally offset from one another in such a way that they partially overlap, as can be seen from FIGS. 5, 5c .

According to the invention, the circular saw blade is thus designed and designed as a disposable blade such that, without regrinding, cutting values and means for noise reduction provided on the master blade, for example, have constant optimum values at least approximately over the entire service life of the disposable circular saw blade. The disposable design of the circular saw blade makes it possible to reduce the PCD portion by 50% in the case of tangentially arranged cutting tips and by approximately 70% to 80% in the case of radially arranged cutting tips according to FIGS. 4 and 5. This is particularly due to the fact that the blank from which the cutting plates are cut out has the basic shape of the cutting plate and therefore the previous cutting away of parts of the PCD layer can be omitted.

The cutting tips 2, as can also be seen from FIGS. 1 to 3, are formed parallelogram-like when viewed tangentially in the side view, while they have a trapezoidal shape when viewed in side view in the approximately radial arrangement (cf. in particular FIGS. 4 and 5). Compared to known circular saw blades with long, radially arranged cutting tips and correspondingly long, front, PCD-coated end face, there is also an advantage in the illustrated exemplary embodiments, particularly in the case of a tangential arrangement, that the point of application of the cutting force has no or only a small cutting moment on that Exercises cutting plate, so that the forces acting on the adhesive connection are lower than in a conventional design and thereby the adhesive connection can be made in addition to soldering, in particular by glue.

In summary, the disposable circular saw blade described has the advantage that - because it can no longer be resharpened - the size of the cutting edge is retained over its entire service life and the same cutting conditions therefore exist. If, on the other hand, resharpening several times, as in the prior art, this also makes regrinding or re-eroding necessary, as a result of which different mass ratios on the cutting tip and thus on the circumference of the entire circular saw blade and, as a result, changed physical and mechanical properties, such as changed cutting action , Noise formation etc. occur. In addition, with conventional circular saw blades, it is necessary to significantly increase the inherent stability of the master blade under dynamic loading, for example by introducing internal stresses into the master blade itself in order to make it particularly rigid for use at higher speeds. In the case of conventional circular saw blades, these rolled-in internal stresses decrease as a function of time and through resharpening and regrinding, which is not the case with a disposable tool designed according to the invention, so that the master blade has the same stress ratios over the entire service life and avoids the previous material fatigue is. The advantage of the disposable circular saw blade is therefore primarily that the mechanical and physical properties given to it in a targeted manner are retained over the entire service life and, accordingly, that in comparison with conventional circular saw blades it also has better concentricity and runout values over the entire service life. The one-way solution also makes it possible to design the base sheet with special properties, for example by arranging or introducing insulating foils for noise reduction, which can also be glued on or applied in layers or Teflon layers and are retained over the entire term. In the case of known circular saw blades, on the other hand, due to the longer operating time, there are considerable signs of wear, particularly on the insulating layers, which can therefore be ineffective after two or three repairs and, for example, by milling grooves and gluing layers to achieve one at least approximately satisfactory noise reduction must be worked up cost-intensively.

Claims

Expectations

With saw blades made of hard metal or the like. Circular saw blade (1), the cutting tips (2) made of hard metal which are provided with a coating of polycrystalline diamond, titanium nitride, ceramic or a material with similar properties on their end face (4) and which are provided with two contact surfaces (5, 5 ') enclosing an angle are evenly distributed over the circumference of the circular saw blade and are connected to it by an adhesive layer, characterized in that the cutting plates (2) have a rhomboid shape and the cover layer (6) is made of polycrystalline Diamond or the like. Is provided on the narrow end face (4). 2. Circular saw blade according to claim 1, characterized in that the cutting tips (2) with their coated end faces (4) are arranged at least approximately tangentially to the circumferential circle of the circular saw blade (Fig. 1,

2).

3. Circular saw blade according to claim 1, characterized in that the cutting tips (2) with their coated end face (4) are arranged at least approximately radially to the axis of the circular saw blade (1).

4. Circular saw blade according to one of claims 1 to 3, characterized in that the contact surfaces (5, 5 ') of the cutting tip (2) and the seating and adhesive surfaces assigned to them include an angle od of - 90 °.

5. Circular saw blade according to one of claims 1 to 4, characterized in that the cutting tips (2) have their approximately final tooth shape or their final circumferential clearance angle before being introduced into their adhesive seat.

6. Circular saw blade according to one of claims 1 to 5, characterized in that the cutting tips (2) are fastened in their adhesive seat by an adhesive, for example made of epoxy resin.

7. Circular saw blade according to one of claims 1 to 6, characterized in that it has a design as a disposable circular saw blade, such that cutting values, concentricity and runout values as well as means provided on the master blade for noise reduction provided at least approximately over its lifespan without regrinding are constant.

8. Circular saw blade according to one of claims 1 to 7, characterized in that the PCD coating of the end face (4) is trapezoidal or roof-shaped in an approximately tangential installation position of the cutting tip (2) (Fig. 1, 2).

9. Circular saw blade according to one of claims 1 to 7, characterized in that viewed in the circumferential direction, the successive cutting tip (2) each occupy tangential positions or the same radial positions (Fig. 1, 2; Fig. 4, 5).

10. Circular saw blade according to one of claims 1 to 8, characterized in that, viewed in the circumferential direction, one behind the other, cutting plates (2) alternately assume tangential and radial positions, the end faces (4) being coated in a tangential arrangement and the open surfaces (7) being coated in a radial arrangement (Fig. 3).

11. Circular saw blade according to one of claims 1 to 7, characterized in that in the radial position, the free surfaces (7) of the cutting tips (2) are formed obliquely, preferably in such a way that the inclined surfaces of the cutting tips (2) lying one behind the other are mutually oblique run (Fig. 4, 5).

12. Circular saw blade according to one of claims 1 to 11, characterized in that the radially arranged cutting tips (2) with inclined, coated free surfaces (7) are laterally offset in the direction of the circular saw blade axis such that they are mutually seen in the circumferential direction overlap a given dimension.