AN IMPROVED HIGH-PRECISION, HIGH-PRODUCTIVE MACHINING CENTER FOR MACHINING WOOD COMPONENTS

Abstract

Machining center (4) for machining wooden workpieces or wooden parts (8) with a parallelepiped or cuboid geometry with a predominant extent and a quadrilateral cross-section with respect to the predominant longitudinal extent, in order to identify pairs of mutually parallel surfaces, - wherein the machining center (4) comprises a first and a second machining line (12, 16) which are parallel to each other along a predominant longitudinal direction (XX) and are at least partially connected to each other by at least one portal (20) which is arranged in a transverse direction (YY) perpendicular to said longitudinal direction (XX), - wherein the machining center (4) comprises: - a first area or a first station (24) for drilling / milling, which includes the means (28) for drilling and / or milling the said wooden parts (8), - a second area or a second station (32) for tenon joint production orTenon cutting / drilling / milling with means (36) for tenon joint production or tenon cutting and / or drilling and / or milling of the aforementioned wooden parts (8),- a third area or a third station (40) for drilling / milling and profile production with means (44) for drilling and / or milling and / or profile production of the aforementioned wooden parts (8),- wherein the aforementioned processing areas or stations (24, 32, 40) are located on the aforementioned processing lines one and two (12, 16), wherein the aforementioned portals (20) provide at least one mechanical interruption (64) between the aforementioned processing lines (12, 16), which divides each portal (20) into two stubs (68, 72) which are at least partially cantilevered or projecting along the transverse direction (YY).

Description

APPLICATION AREAThe present invention relates to an improved, high-precision and high-productivity machining center for machining wood parts.PRIOR ARTAs is known, machining centers are used to perform a series of drilling, milling, pin joint manufacturing and profile manufacturing operations on elongated wood parts used and assembled, for example, in the manufacture of wood frames. These machining centers must ensure flexibility in machining the parts, but also speed and precision in machining them.In order to obtain these advantages, solutions of machining lines are known in which the parts are passed through a plurality of series-connected machining stations. However, these solutions do not provide the necessary flexibility or machining accuracy. Moreover, these solutions have considerable overall dimensions and, owing to their excessive expansion, are subject to inaccuracies due to the unavoidable irregularities of the floor on which the working line lies.Moreover, the known solutions do not guarantee high machining precision and quality of finishing, since the presence of several simultaneously operating motors, manipulators and appliances determines an uncontrolled propagation of vibrations between the various components, which deteriorates the quality of the machining of wood parts.DE 197 52 685 A1 discloses a machine with machining units for the machining profiling first of all of the two front ends and then of at least one longitudinal side of the starting edge timber, which is transported on a workpiece carrier towards the individual machining units. In order not to have to respan the edge timber, the workpiece carrier can be moved as a carriage on a longitudinal guide, above which a cross member extends with the machining units movable thereon within a working space above and next to the longitudinal guide. The longitudinal guide has guide sections on both sides of the cross member which are substantially of the same length and are adapted to the greatest length of the edge timbers to be machined, wherein the carriage is moved back and forth between these two guide sections in such a way that the front ends of the edge timber are machined in a stationary manner in the working space under the cross member and the longitudinal profiling is then carried out in a continuous manner.EP 2 067 586 A2 describes a wood processing machine which is intended in particular for the processing of wood bars as are used in the production of door and window frames.IT PC 0020110018 A discloses a machining centre for machining wood comprising a first locking means configured to receive a semi-machined profile and transfer it to a machining area to perform first machining operations, a second locking means configured to receive the profile from the first locking means and transfer it to the machining area to perform further machining operations, and gripping and moving means configured to move the profile from the first locking means to the second locking means and vice versa, wherein the gripping and moving means are configured to rotate the profile about an axis substantially parallel to a main axis of the machine.DE 10 2014 222 422 A1 relates to a processing device for workpieces, in particular made of wood, plastic or the like, having a first workpiece table that can be displaced along a longitudinal direction and having a second workpiece table that can be displaced in the longitudinal direction, wherein the two workpiece tables are arranged at a distance perpendicular to the longitudinal direction, wherein each of the two workpiece tables has clamping elements for clamping a workpiece, wherein the clamping elements are designed such that they have two clamping positions that are opposite one another with respect to the longitudinal direction for clamping a workpiece, such that a workpiece can be clamped in both clamping positions, and wherein a guide element is furthermore provided, which is arranged aligned perpendicular to the longitudinal direction and serves for displaceably guiding a tool element, having a first tool element, which is arranged displaceably on the guide element, for processing the workpiece, having a first manipulating device for gripping and positioning a workpiece in at least one clamping element of one of the workpiece tables or for carrying a workpiece out of at least one clamping element of one of the workpiece tables.DE 10 2015 218 814 A1 relates to a processing device, in particular for processing workpieces made of wood, wood materials, plastic or the like, having at least one workpiece table with a first workpiece holder for holding at least one workpiece and with a second workpiece holder for holding at least one workpiece, wherein the workpiece can be positioned in at least two dimensions, advantageously in three dimensions, when remounting from the first workpiece holder into the second workpiece holder.DE 10 2016 009 430 A1 discloses a system for machining workpieces made of wood, plastic and the like and has at least one machining unit for end machining and longitudinal machining of the workpieces. It also has at least two feed units, each of which has at least one table with clamping elements for clamping the workpieces. They are located next to one another, viewed in the X direction, and can be moved along guides in the X direction. The two feed units each have at least two tables which are adjustable relative to one another in the X direction and in the Y direction.EP 3 560 654 A1 describes a machine for machining at least one workpiece, wherein a first side and a second side opposite to the first side are defined. The machine comprises at least a first gripping unit having a first gripping system and a second gripping system oriented parallel to a first axis and opposing each other with respect to a second axis.EP 3 639 971 A1 discloses a method for machining elongated workpieces made of wood, plastic or the like. In the method, the workpieces are clamped between at least one upper and one lower clamping jaw of a first clamping unit such that at least one side can be machined. A second clamping unit, which has at least one upper and one lower clamping jaw, is supplied with the first workpiece by the first clamping unit, which is clamped by the second clamping unit in such a way that a further machining can be carried out on the workpiece. During the transfer between the two clamping units, the workpieces are clamped horizontally, wherein they are still clamped vertically by the clamping jaws of at least one clamping unit until they are clamped horizontally. With horizontal clamping and released vertical clamping transversely to the longitudinal direction, the workpieces are displaced and then vertically clamped by the clamping jaws of the same clamping unit or the clamping unit receiving the workpieces. The horizontal clamping is then released. As a result, the workpiece is always clamped during the transfer from the first clamping unit to the second clamping unit, so that the risk of bending or twisting of the workpiece, for example due to internal stresses, is prevented in itself.PRESENTATION OF THE INVENTIONThere is therefore the object of solving the drawbacks and limitations mentioned in connection with the known art.Therefore, there is an object to provide a machining center that enables high flexibility, machining speed, reduced dimensions, precision, and high machining quality.This object is fulfilled by a machining centre for machining wood parts according to claim 1.DESCRIPTION OF THE FIGURESOther features and advantages of the present invention will be more fully understood from the following description of preferred and non-limiting embodiments thereof, wherein:FIG. 1 is a general perspective view of a machining center according to the invention;FIG. 2 is a general perspective view of the machining center of FIG. 1 without a cover cabin;FIG. 3 is a top view of the machining center of FIG. 1 ;FIG. 4 is a top view of the machining center of FIG. 2;FIG. 5a is a top view of a central part, without a cab, of the machining centre according to an embodiment of the invention;FIGS. 5b-5c show top views of enlarged details of connecting cross-pieces connecting the machining lines according to the invention of the machining center according to the invention;FIGS. 6 to 7 are perspective views from different perspectives of a central part, without a cab, of the machining center according to an embodiment of the present invention;FIG. 8a is a perspective view of the machining center on one side of the wooden component load;FIGS. 8 b- 13 show a partial perspective view, a lateral view or a top view of the machining center from FIG. 1 in a sequence of machining phases of a piece of wood according to an embodiment of the present invention, as described in more detail below.The elements or parts of elements common to the embodiments described below are denoted by the same reference numerals.DETAILED DESCRIPTIONWith reference to the above figures, 4 denotes the overall schematic view of a machining centre according to the invention for machining wood parts 8.Before working, i.e. in the raw state, the wood pieces 8 have a parallelepiped geometry with a predominant dimension and a quadrangular cross-section with respect to said predominant longitudinal dimension, in order to identify pairs of mutually parallel surfaces.It will be appreciated that the square cross-section may, as is known, be either square or rectangular.From the point of view of its general architecture, the machining centre 4 comprises a first and a second machining line 12, 16 which run parallel to one another along a prevailing longitudinal direction X-X.It should be noted that by "machining line" we mean a substantially linear geometric arrangement, thus having a predominant longitudinal extent along which a plurality of tools, machine tools, work heads, racks, units, regions and machining stations are arranged, as will be better described below.According to the invention, the first processing line 12 and the second processing line 16 are at least partially connected to one another by at least one portal 20 which is arranged in a transverse direction Y-Y perpendicular to the said longitudinal direction X-X.The machining center 4 includes:a first drilling / milling area or station 24 comprising means 28 for drilling and / or milling said wood parts 8,a second area or station 32 for producing pin connections / drilling / milling with means 36 for pin connection production and / or for drilling and / or milling said wood parts 8,a third area or station 40 for drilling and / or milling and profile production with means 44 for drilling and / or milling and / or profile production in said wood parts 8.Said machining areas or stations 24, 32, 40 are located on said machining lines one and two 12, 16.In other words, as described in detail below, each processing line 12, 16 includes at least one of the processing areas or stations 24, 32, 40 that can operate on wood parts simultaneously, andThis is independent of each other in order to increase the productivity of the machining center.For this purpose, said machining areas or stations 24, 32, 40 preferably simultaneously perform their respective machining by means of independent motors and drives of the respective means 28, 36, 44 for drilling, spigot joint production, milling and profile production.Preferably, the first machining line 12 comprises the first area or station 24 for drilling / milling and the second area or station 32 for pin connection making / drilling / milling, which / s are arranged in a row or one behind the other along said prevailing longitudinal direction X-X.Preferably, the second machining line 16 comprises the third area or station 40 for drilling / milling and profile productions that extends along the same predominant X-X longitudinal direction.Preferably, the machining centre 4 comprises manipulators 48 with two types of handling, and machining lines 12, 16 with three types of clamping of pieces of wood 8, which are independent of each other and complementary to each other, so that the piece or piece 8 is never released, and which is connected within a single structure, which is connected with respect to the movements of passing the piece between the different areas or stations 24, 32, 40 by means of said manipulators 48.For example, the manipulators 48 include grippers 52 having a pair of jaws 56 with gripping surfaces movable perpendicular to and along the transverse direction Y-Y.In addition, the manipulators 48 comprise grippers 52 having a pair of jaws 56 with gripping surfaces perpendicular to and movable along a vertical direction Z-Z perpendicular to said longitudinal direction X-X and to said transverse direction Y-Y.Preferably, the manipulators 48 also include grippers 52 having a pair of jaws 56 with gripping surfaces perpendicular to and movable along the longitudinal direction X-X.The use of different types of manipulators makes it possible to remove the piece of wood after each working operation and to transport it from one station to the other without ever releasing it: that is, the manipulators can replace the part with one another or with the blocks of each station without having to release the piece of wood 8 per time.In this way, the precision of machining is ensured because the "zero point" of the workpiece is never lost and is fixed at the time of loading it into the machining center 4.Preferably, said portals 20 carry intermediate manipulators 60 of the wood parts 8 from the first processing line 12 to the second processing line 16 and / or vice versa along the transverse direction Y-Y.According to the invention, said portals 20 provide at least one mechanical break 64 between said first and second processing lines 12, 16, which divides each portal 20 into two stubs 68, 72 which are at least partially cantilevered along the transverse direction Y-Y.According to one embodiment, a cross member 76 with a rail 80 is arranged parallel to the aforementioned stubs 68, 72 in order to guide at least one manipulator 48 of the wood parts 8.Preferably, said manipulator 48 is an intermediate manipulator 60 adapted to move the parts from the first machining line 12 to the second machining line 16.According to one embodiment, said rail 80 is fixed to a pair of bases 84 each arranged in the region of one of the machining lines 12, 16.Thanks to the mechanical break 64, there may be no direct transmission of vibrations from the first machining line 12 to the second machining line 16 and vice versa.The use of a mechanical interruption is of fundamental importance for reducing vibrations and allows an extremely compact design of the machining center architecture, which at the same time ensures a high precision and quality of the machined parts.A machining cycle carried out by a machining centre according to the invention will now be described, in particular with reference to the accompanying figures.In particular, the piece of wood enters from the loading side (FIG. 8 a ) and is gripped by a loading manipulator 48 on side surfaces perpendicular to the transverse direction Y-Y.In a / a pre-loading area or station 140, the piece 8 is thus placed on a loading carriage 88 provided with opposing locking catches 92 along said transverse direction Y-Y. In practice, the locking catches 92 lock the piece 8 on the loading carriage 88 in the same way as the jaws 56 from which they receive said piece 8, which is therefore never released so as not to lose the reference points, i.e. the "zero point", of the machining centre 4.According to a possible embodiment, it is possible to provide, in the area of the loading carriage 88, a drilling and milling area 130, which makes it possible to carry out some drilling and milling operations on the part 8 immediately, even before it is subsequently transported via the loading carriage 88 to the area or to the station 32 for establishing / drilling / milling pins.Then, the part 8 blocked by the blocking locks 92 moves forwards on the loading carriage 88 (Fig. 8e) along the longitudinal direction X-X until the bank (Italian: bancata) of the loading carriage 88 is completely filled (Fig. 8f).A manipulator 48 equipped with several grippers 52 then receives the parts previously blocked on the loading carriage by means of the blocking locks 92 (FIG. 9 a). In this phase, the manipulator 48 preferably moves in the transverse direction Y-Y, guided by the rail 80 of a stump 68 of the cross member 76.The grippers 52 of the manipulator 48 join one another in grooves 96, parallel to the transverse direction Y-Y, which are formed specifically on the support surface of the loading slide 88 in such a way that the parts 8 can be gripped on surfaces perpendicular to the vertical direction Z-Z (FIGS. 9 a- 9 b ).In this way, it is possible to feed all the parts into the area or station 32 for making / drilling / milling tenons (FIG. 9 b ) and it is possible to perform, for example, tenon operations (FIG. 9 c ). The part is blocked in the corresponding position by first pin connection slides 100 (FIGS. 9 b- 9 c ).Then, the part 8 is removed by the manipulator 48 and moved from a first pin connecting line, on which it has been blocked by the first pin connecting slides 100, to a second profile production line (FIG. 9 d).The discharge of the parts from the first pin junction line is illustrated in Figure 9e.After completion of the pin connection making operations (Fig. 9f), the parts are then loaded into the next area (Fig. 9g).At this point, the part 8 is ready for profile-manufacturing operations in the profile-manufacturing area 40; for this purpose, the part 8 is picked up by the intermediate manipulator 60, which takes it in the pin connection area and delivers it into the profile-manufacturing area 40 (FIGS. 10, 11 a, 11 b ).In particular, the parts 8 are loaded onto special carriages 108 for external profile production, which hold them in position with jaw pairs 56 counter to the vertical direction Z-Z (Fig. 11a).When the external profiling is completed by the profile-making means 44 (Fig. 11b), the parts 8 are picked up by a profile-making manipulator 112 which grips them with special jaws 56 facing each other in the vertical direction Z-Z (Figs. 11c-11d) and which brings them into the vicinity of a slide 116 by which they are blocked with jaw pairs 56 facing each other in the vertical direction Z-Z (Fig. 11e). The inner profile production of the parts 8 is then carried out with the profile production tools 44 (FIG. 11 f).After completion of the outer and inner profile production, an unloading manipulator 120 receives the now finished parts (FIG. 11 g) and places them on an unloading roller conveyor 124 (FIG. 11 h).Finally, Fig. 12 shows a profile production tool changer 44, while Fig. 13 shows a pin connection production tool changer 28.It is clear that the sequence described above represents a possible sequence of processing phases and can be varied as desired by the user.As will be apparent from the foregoing, the present invention enables the disadvantages of the prior art to be overcome.In fact, the machining center is extremely flexible, since it allows the simultaneous machining of several parts and the simultaneous execution of different machinings, i.e. drilling, making of tenon joints, milling and making of profiles, in an extremely versatile manner.The machining center is extremely versatile because it enables machining of extremely short and extremely long wood parts in real time on a single, extremely compact area.It is possible to load several parts simultaneously, also in different lengths and sizes, thus reducing idle times. In the machining center according to the invention, up to 40 parts can be simultaneously machined in one cycle.Furthermore, the space requirement of the machining center is very limited overall, since the various stations are not arranged in series or one behind the other, but the part follows a ring or S-path, in any case not linearly overall, in order to reduce the longitudinal extent of the machining center.The plurality of blocking systems provided in the machining centre allows, by means of suitable manipulators, the transfer of the part from one station to the other without the need to release the part: in this way, the "zero point" of the machine, which is determined when the part is first loaded, is never lost in the first station of the machining centre.The manipulators are further arranged such that at least one drilling and / or milling operation and / or a pin connection manufacturing and / or profile manufacturing operation can be performed at any time.In particular, in all provided types of blocking of the parts, it is possible at any time to carry out drilling and milling operations.The machining operations are extremely precise, since the part is moved from one machining station to the other as shown without ever being released by the grippers and / or carriages, in order never to lose the reference of the machine or "zero point".Moreover, the machining center is capable of ensuring high productivity and extreme machining precision in the range of tenths of a millimeter and high quality of finish machining.The high productivity is ensured by the fact that many machine tools and their heads operate simultaneously on several parts and perform simultaneously drilling, milling, pin connection manufacturing and profile manufacturing operations.The simultaneous use of several driving means or motors and tools, due to the fact that these motors operate at different machining frequencies, produces a high degree of vibrations which could affect the parts, which would limit the quality level of the final machining and the precision thereof. However, due to the mechanical separation of the portals, it is possible to interrupt the transmission of vibrations, which effectively prevents the transmission of vibrations between the two processing lines.In this way, the machine tools and drive means of a first line cannot adversely affect the machine tools, drive means and wood parts of the second line, and vice versa. The separation of the portals between the machining lines makes it possible to machine more parts simultaneously and with more tools in a compacted and reduced space without adversely affecting the precision of the machining by the vibrations of one and the other machining line. Therefore, the separation of the portals enables the creation of a compacted and compact machining center, which, as an alternative to the known solutions consisting of a single machining line, consists of two machining lines connected to each other, and with machining precision and productivity higher than the known solutions.Despite the proximity of the machining lines, the mechanical separation de facto prevents or at least drastically limits the transmission of vibrations so that the machining on one line cannot impair that on the other.In order to meet practical and specific requirements, a person skilled in the art can make numerous modifications and variations of the solutions described above, all of which are included within the scope of the invention in the sense of the following claims.

Claims

Machining centre (4) for machining wood pieces (8) having a parallelepiped geometry with a predominant dimension and a quadrangular cross-section with respect to the predominant longitudinal dimension, in order to identify pairs of mutually parallel surfaces, - wherein the machining centre (4) comprises a first and a second machining line (12, 16) which are connected to each other along a predominant longitudinal direction (X-X) parallel to each other and at least partially by at least one portal (20) arranged in a transverse direction (Y-Y) perpendicular to said longitudinal direction (X-X), - wherein the machining centre (4) comprises: - a first area or station (24) for drilling / milling, which / or station comprises means (28) for drilling and / or milling said wood pieces (8), a second area or station (32) for pin connection or pin cutting / drilling / milling with means (36) for pin connection or pin cutting and / or drilling and / or milling said wood parts (8), a third area or station (40) for drilling / milling and profile production with means (44) for drilling and / or milling and / or profile production in said wood parts (8), wherein said machining areas or stations (24, 32, 40) are located on said machining lines one and two (12, 16), wherein said portals (20) provide at least one mechanical break (64) between said machining lines (12, 16), which divides each portal (20) into two stubs (68, 72), which are cantilevered at least partially along the transverse direction (Y-Y).Machining centre (4) for machining wood parts (8) according to claim 1, wherein said areas or machining stations (24, 32, 40) perform their respective machinings simultaneously, by means of motors and drives independent of the respective means for drilling, spigot joint making, milling, profile making (28, 36, 44).Machining centre (4) for machining wood parts (8) according to any of the preceding claims, wherein the first machining line (12) comprises the first area or station (24) for drilling / milling and the second area or station (32) for pin connection making / drilling / milling, which are arranged in series.Machining centre (4) for machining wood parts (8) according to any of claims 1 to 3, wherein the second machining line (16) includes the third area or station (40) for drilling / milling and profile making.A machining centre (4) for machining wood pieces (8) according to any one of claims 1 to 4, wherein the machining centre (4) includes manipulators (48) with three ways of blocking wood pieces (8) which are independent and complementary to each other in order to never release the wood piece (8) within a unitary structure which is related to the movements of passing the piece by means of the manipulators (48) between the different machining areas or stations (24, 32, 40).Machining centre (4) for machining wood parts (8) according to any of the preceding claims, wherein the manipulators (48) comprise grippers (52) having a jaw pair (56) with gripping surfaces perpendicular to and movable along the transverse direction (Y-Y).Machining centre (4) for machining wood parts (8) according to any of the preceding claims, wherein the manipulators (48) comprise grippers (52) having a jaw pair (56) with gripping surfaces perpendicular to and movable along a vertical direction (Z-Z) perpendicular to the transverse direction (Y-Y) and to the longitudinal direction (X-X).Machining centre (4) for machining wood parts (8) according to any of the preceding claims, wherein the manipulators (48) comprise grippers (52) having a jaw pair (56) with gripping surfaces perpendicular to and movable along said longitudinal direction (X-X).The machining centre (4) for machining wood parts (8) according to any of the preceding claims, wherein said portals (20) support intermediate manipulators (60) of the parts (8) along said transverse direction (Y-Y) from the first line (12) to the second line (16) and / or vice versa.Machining centre (4) for machining wood parts (8) according to any one of the preceding claims, wherein parallel to said stubs (68, 72) a cross member (76) with a rail (80) for guiding at least one parts manipulator (48) is arranged.Machining centre (4) for machining wood parts (8) according to any one of the preceding claims, wherein said rail (80) is fixed to a pair of bases (84), each located in the area of one of the machining lines (12, 16).Machining centre (4) for machining wood parts (8) according to any one of the preceding claims, wherein corresponding to a loading carriage (88) of the parts in the machining centre (8) a drilling and milling area (130) is provided which allows to perform certain drilling and milling operations on the part (8) after it has been loaded into the centre.

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