This invention relates to a method for forming grooved panels faced with thermodefor abie -material , and a panel obtained by the method.

Grooved panels faced with thermodeformabie material are known, for use generally for doors and/or front sections of furniture. They generally comprise a chipboard or MDF substrate in which grooves of the desired ornamental cross- section motif are formed generally by copy milling.

A sheet of thermoplas ic material is then applied to the thus prepared substrate, generally with a hot press, to cover at least the front surface and possibly the edges of the panel, and adhere to the walls of the previously prepared grooves.

The traditional method of forming the grooves by copy milling means that at the corner joints between two straight lengths of groove, the connection between the outer walls must be rounded, with a radius not less than the radius of the cutter, in contrast to the connection between the inner walls, which can be of sharp or rounded corner according to requirements- An object of the invention is to provide grooved panels faced with thermodeformabie material , in which the grooves are of sharp corner also at the joints between the outer walls.

A further object of the invention is to provide grooved panels faced with thermodeformabie material, in which the groove can be surrounded externally by a fascia raised from the plane of the panel- A further object of the invention is to provide grooved panels of the aforesaid type using conventional equipment both to prepare the substrate and to effect the facing with the sheet of plastic thermodeformabie material -

These and further objects which will be apparent from the ensuing description are attained according to the invention by a method for forming grovved panels faced with thermodeformabie material , characterised by forming in a substrate grooves having at least their outer wall flat, then to said wall applying separately-prepared portions of profiled sections chamfered at their ends to form sharp-edged joints in the corners, and finally applying a facing sheet to the thus treated substrate.

According to the invention the panel obtained is formed of a substrate comprising grooves which join together with a sharp edge at the corners, and faced with a sheet of plastic thermodeformabie material.

Four preferred embodiments of the present invention are further described hereinafter with reference to the

accompanying drawings, in which:

Figure 1 is a plan view of a panel portion in an intermediate working stage; Figure 2 is a cross-section therethrough on the line II-II of Figure 1;

Figure 3 shows it in the same view as Figure 1 on termination of facing stage; Figure 4 is a cross-section therethrough on the line IV-IV of Figure 3; Figure 5 shows it in the same view as Figure 1 but in a different embodiment of the method; Figure 6 is a cross-section on the line VI-V1 of Figure 5; Figure 7 shows it in the same view as figure 5, on termination of the facing stage; Figure 8 is a cross- section therethrough on the line VIII- VIII of Figure 7; Figure 9 shows it in the same view as Figure 1 but in a third embodiment of the method; Figure 10 is a cross-section therethrough on the line X-X of Figure 9;

Figure 11 shows it in the same view as Figure 9 , on termination of the facing stage; Figure 12 is a cross-sec ion therethrough on the line XII-XII

of Figure 11 ^' ; Figure 13 shows it in the same view as Figure 1 but in a fourth embodiment of the method; Figure 14 is a cross-section therethrough on the line XIV-XIV of Figure 13 ;

Figure 15 shows it in the same view as Figure 13, on termination of the facing stage; and Figure 16 is a cross-section therethrough on the line XVI-XVI of Figure 15. As can be seen from the figures, the method according to the invention is used, in the embodiment shown in Figures 1 to 4, to obtain panels with a groove the outer edge of which is not raised from the exposed surface of the panel .

According to the method, a substrate 1 is subjected to copy milling, to form in it one or more grooves 2 having the desired ornamental motif.

Each groove 2 is formed by two milling passes using two different tools 3, 4. The first tool, which forms the inner wall 5 of each groove, consists of a cutter 3 shaped to correspond to the particular design of said wall 5. The second tool, which forms the flat outer wall 6 inclined to the upper surface of the substrate 1 , consists of a conical cutter with its angle corresponding to this inclination.

At the corners the movement of the profiled tool 3 relative to the inner wall 5 of the groove 2 enables the sharp-edged joint to be formed directly. The conical cutter 4 can also form a sharp-edged joint between the two outer wall portions 6 provided it is removed from the groove 2 with an outward and upward translational movement (see arrow in Figures 1 and 2) with an inclination equal to that of the tool generators-

In practice, after this operation the groove or grovves 2 in the substrate 1 have their inner wall 5 of finished form and their outer wall 6 flat and inclined. A separately prepared profiled frame 8 chamfered at its corners to form a sharp-edged joint is then appied to the outer wall 6.

The panel is then subjected to conventional facing with a. sheet of plastic thermodeformabie material 9, which covers the entire surface to give the panel its final shape, with the grooves forming a sharp-edged joint at the corners.

If panels are required with grooves having an outer edge raised from the panel surface, it is necessary only to form the profiled sections 8 with a flange 10 which defines this raised edge when the profiled section 8 is applied to the groove 2 (see dashed lines in ^" Figure 4).

To obtain this latter type of panel it is however

possible to use the method illustrated in Figures 5 to 8, ie to effect a first milling pass with a profiled cutter 3 to form the inner wall 5 of the groove 2 in traditional manner, and a second pass with a cylindrical cutter 4', which forms the outer wall 6' . At each corner the cylindrical tool 4' is moved slightly outwards to form a cylindrical recess 11 suitable for housing the ends of the two subsequently applied profiled section 8, which join in a sharp edge. This recess is then covered by the flange 10 of said profiled section, forming the raised edge of the groove.

Again in this case the final stage of the method is the traditional facing of the substrate 1 of a sheet 9 of suitable thermodeformabie material .

Figures 9 to 12 illustrate a third embodiment of the method, which while comprising the formation of a recess 11' for receiving the ends of the two angle-chamfered sections 8, can use sections of a lower height than the depth of the grooves 2. In this case, the inner wall 5 of the groove 2 is formed by a traditional profiled cutter 3, the outer wall 6' is formed by two passes at different height with a cylindrical cutter 4" of height less than the depth of the groove 2, so that the recess 11' formed in this manner does not reach the upper surface of the panel, but instead stops

at a lower level . The recess thus formed can then house the chamfered ends of the two outer sections 8 and the entire surface finally be faced with the sheet of plasti thermodeformabie material 9 which covers all joints. If the thin diaphgram 12 which covers the recess 11' , and which is curved in plan view at the corner, represents a obstacle to obtaining a sharp-edged joint between the tw profiled sections -8, it can be removed with a conical cutter, used as indicated in relation to Figures 1 to 4. In all the embodiments heretofore described, the inne wall 5 of the groove 2 and the base are formed by milling th panel 1, the groove outer wall being obtained by means of separately formed profiled section 8 applied to the flat wall 6 or 6' of the groove- For this, the starting panel 1 must be formed of goo quality material which can be milled without producing an irregularity or disintegration of the worked surface- However, as chipboard panels of poor quality may sometime have to be used in which it is not possible to form a groov with perfectly finished walls, the invention provides th embodiment shown in Figures 13 to 16, by which a groove 2' o rectangular cross-section is formed in the panel 1, to the house a profiled section 13 formed of better quality materia

and reproducing the ornamental motif of the complete groove. In this case if a fascia projecting beyond the upper surface of the panel is required, there is no problem in using a cutter to form a recess 11' in the aforesaid manner at the corners of the groove 2' to house the outer sharp-edged corners of the frame by the profiled sections 13. This projecting fascia can cover the recess 11* in the aforedesσribed manner.

If the heigth of the section 13 is less than the depth of the rectangular groove 2' , it is preferable to use a cutter 14 with a conical tip 15 and an overlying cylindrical portion 16 of height less than the height of the groove 2' .

In this manner a first groove with rounded outer corners can be made with a first pass of the cutter 14, followed by a _ pass using a deeper cutter to complete the groove - and also form the corner recesses 11' , which are covered by a thin corner diaphgra 12-

This can finally be removed by extracting the cutter 14 inclined outwards, as already described in relation to the o embodiment shown in Figure 1 to 4.

The ability to remove the diaphgram 12 is due essentially to the lower conical tip 15 of the cutter 14, this tip forming a triangular groove 17 in the base of the

groove 2. The triangular groove 17 is completely hidden from view by the fact of totally covering the groove 2' with the separately formed profiled section 13.

When the section 13 has been applied, the panel can be covered in the traditional manner with a sheet of plastic thermodeformabie material 9- It is also possible to face the grooved panel 1 before applying the section 13, which can be finished and possibly covered separately with a sheet of thermodeformabie material of different characteristics. This latter embodiment is particularly advantageous _, i that besides allowing the use of panels which in themselves would not allow profiled grooves to be directly formed i them, it enables the base grooves to be formed without changing the tool.