Pneumatic automatic tool coupling device for a three-dimensional printing machine with tool changing

Abstract

The invention relates to an automatic coupling device (100) for at least one tool for a three-dimensional printing machine, said coupling device (100) comprising at least one main body (110) and a tool-gripping member (120), characterized in that the main body (110) has a female receiving zone (111) having at least one conical portion (112), the tool-gripping member (120) has a male connector (121) having at least one conical portion (122) with the same conicity as the conical portion (112) of said female receiving zone (111), and a suction channel (130) opening into the female receiving zone (111) is connected to a vacuum source so as to create a vacuum between the female receiving zone (111) of the main body (110) and the male connector (121) of the member (120) tool gripping mechanism to hold them together. Figure for the abbreviation: Fig. 7

Description

Title of the invention: Pneumatic automatic tool coupling device for a three-dimensional printing machine with tool change Technical field of the invention

[0001] The present invention relates to the field of three-dimensional printing machines with tool change and more specifically that of gripping and holding in position a 3D printing tool, in particular the pneumatic coupling of tools. Prior art

[0002] In the field of material transformation machines, such as three-dimensional printers, also called 3D printers or additive manufacturing machines (Fused Deposit Material / Fused Filament Fabrication printer), there are different ways of connecting the printing tools (fusion head) to their support.

[0003] The automatic tool coupling function is generally divided into two specific sub-functions. On the one hand, the automatic gripping function corresponds to the machine's ability to perform operations of securing and detaching a tool on a machine coupling mechanism. This is to ensure that the tool is properly attached or detached at the desired times (machine use or rest phases). On the other hand, the positioning and rigidity function ensures that during each of the successive coupling and decoupling operations, the tool is positioned in a quasi-identical manner relative to a reference frame of the machine coupling mechanism. This is to ensure the precision of the coupling and its repeatability over time. However, a certain number of technological locks can prevent these two functions from being carried out in an optimized manner.

[0004] Mechanical gripping systems are mainly based on elements that provide mechanical locking by a traction or clamping force of the tool / tool ​​holder. The force applied to hold the load is most often done by a pneumatic cylinder but can also rely on conventional electric motorized elements for lower loads. Thus, gripping pliers for moving objects by applying a clamping force on either side of the object to be gripped are an example of this type of machine. We can cite articulated systems with a deformable parallelogram (pantograph) of the “ice gripper” type. We can also cite jaw type systems (mobile / static or mobile / mobile).

[0005] Pneumatic gripper systems rely on depressurization of a volume of air between the part to be gripped and the gripper. This depressurization assumes hermetic contact between the part and the gripper. The best-known system consists of a suction cup (with or without bellows), most often used to lift plates with a perfectly flat surface.

[0006] Finally, magnetic systems necessarily require that the gripper and the object themselves be magnetic, which excludes a large number of objects designed in incompatible materials (non-magnetic metal, plastic materials, composites, natural materials, etc.). Moreover, the magnetic attraction force decreases sharply with increasing temperature, the use of a magnetic system is therefore little or not compatible with a heated enclosure of a three-dimensional printer.

[0007] These different gripping methods, each based on a distinct type of force (they are rarely used together), of course each have their advantages but also various disadvantages. Apart from the gripping force (and the source of the energy necessary to provide this force) provided by each system and the constraints linked for example to the shape of the object and / or the material constituting it, other problems can be raised which these systems do not resolve.

[0008] Indeed, to obtain a satisfactory, repeatable and durable coupling over time between the tool and the machine, it is also necessary to consider the problems of positioning and rigidity of the coupling system, as indicated previously.

[0009] In the more specific field of 3D printing, a coupling system is most often made up of a tool plate and a machine plate. It is then a question of securing the two plates by positioning them relative to each other in the most repeatable and precise way possible. Without this repeatability, it is impossible for the machine to precisely locate (down to a hundredth of a millimeter or even less) the position of the working end of its tool. Poor repeatability or excessive mounting clearance therefore has disastrous consequences on the surface conditions and / or geometry of the parts obtained.

[0010] There are currently a large number of additive manufacturing machines on the market that are based on the concept of tool change, whether to offer multi-material (or multi-color) printing processes and / or hybrid processes.

[0011] Various solutions have already been attempted to resolve this problem. Examples include the Prusa XL machine, based on a mechanical sliding locking system, or the "Toolchanger E3D" from the company E3D-Online Ltd, based on a machine plate system with three pairs of cylinders oriented at 120° and centered around a central orifice and a tool plate with three balls. distributed in the same way so that each one is housed between pairs of cylinders of the machine plate to perform the positioning function, the balls being organized around a central ramp acting as a surface for applying the gripping force. A motor attached to the machine coupler assembly then ensures locking by controlling the rotation of a camshaft which slides on the central ramp of the tool plate. During this sliding, the shaft moves in translation by a few millimeters, which causes the compression of a spring in the coupling mechanism. It is from this compression that results the mechanical gripping force which is distributed uniformly between the three ball / cylinder contacts. However, this system, which also includes a PM type stepper motor to control the locking, cannot withstand an environment whose temperature is higher than approximately 80°C.

[0012] However, the problem of the working environment in which the tool coupling device operates is particularly important, so that the criteria of temperature resistance and size greatly reduce the possibilities offered in terms of gripping technology.

[0013] Indeed, most mechanical, electronic or even pneumatic elements are not designed to withstand thermal conditions exceeding 60-80°C. It is therefore easy to understand that resisting close to 180 - 200°C quickly becomes problematic with the solutions of the prior art.

[0014] To summarize, mechanical connection systems are highly dependent on the temperature of the environment in which the tools / tool ​​holders operate, on issues of mechanical clearances and elasticity, and on the orientation of the load, while pneumatic systems require a dedicated pneumatic circuit leading to issues of sealing / leakage control, weight and size.

[0015] It results from the study of tool-machine connection technologies, in particular in the field of multi-tool 3D printers, that current systems are not optimized and do not sufficiently take into account the problems of positioning and rigidity so that improvements can be made. Furthermore, these systems also do not take into account possible problems of high-frequency vibration, damping, tool trajectory (in particular for the locking / unlocking phases), miniaturization (weight / volume, number of constituent parts) or durability of the connection over time. Presentation of the invention

[0016] The present invention aims to remedy these drawbacks with a completely innovative approach ensuring rapid, efficient, versatile and secure coupling.

[0017] To this end, according to a first aspect, the present invention relates to a device for automatic coupling of at least one tool for a three-dimensional printing machine with tool change, said coupling device comprising at least one main body and a tool gripping member, characterized in that: - the main body comprises a female receiving area having at least one conical-shaped portion, - the tool gripping member comprises a male connector having at least one conical portion of the same conicity as that of the conical portion of said female receiving zone so as to cooperate with the latter in the assembled position of use of the tool gripping member and the main body, and - a suction channel terminating in the female receiving zone is connected to a source of depression so as to create a vacuum between the female receiving zone of the main body and the male connector of the tool gripping member to hold them together.

[0018] Thanks to this solution, the tool holder can retrieve a tool very easily from a tool magazine integrated into the machine, ensure its coupling (positioning and gripping) precisely and firmly, in a high temperature environment, and safely carry out printing operations (use phase) before, if necessary, storing or changing the tool (storage phase at rest or replacement phase).

[0019] The pneumatic coupler of the present invention thus makes it possible to carry out the coupling / decoupling operations almost instantly. The speed of the coupling operation then depends only on the machine trajectories and the duration of the movements during the manufacture of the part and not on a phase of 3-4 seconds each time one wishes to couple a tool with mechanical systems of the prior art which often rely on a fairly slow movement of a mechanical part performing the clamping.

[0020] The invention is implemented according to the embodiments and variants set out below, which are to be considered individually or in any technically effective combination.

[0021] Advantageously, the female receiving zone of the main body comprises a bottom wall in which the suction channel ends, and the male connector comprises a suction face having the same dimensions as said bottom wall, so that the depression causes the suction face to be brought closer by suction against the bottom wall so as to maintain the male connector in the female receiving zone throughout the suction.

[0022] This solution makes it possible to obtain a firm hold of the tool on the tool holder thanks to the depression which acts on the rear part of the male part connector (therefore located opposite the tool and therefore away from the hot zones).

[0023] According to an additional characteristic, each of the female receiving zone and of the male connector comprises a front cone portion extended by a rear cylindrical portion provided respectively with a bottom wall and the suction face.

[0024] This solution allows for rapid, reliable and very precise coupling of the male connector in the female connection area.

[0025] Preferably, the cylindrical portion of the female receiving zone or of the male connector comprises an annular groove for receiving a sealing gasket.

[0026] This solution makes it possible to avoid losses of depression between the male connector and the female receiving zone, and therefore a possible partial decoupling of the tool (which would have significant consequences on the precision of the manufacturing process), or even a much more damaging total decoupling.

[0027] According to a complementary aspect, the seal is of the four-lobe type in a material resistant to high temperatures greater than or equal to approximately 150°C, with a hardness of approximately 70 Shore A.

[0028] Advantageously, a pneumatic connector is connected to the suction channel to be connected to the vacuum source.

[0029] According to a preferred embodiment of the present invention, the suction channel ends in the center of the bottom wall.

[0030] This solution makes it possible to optimize the suction and distribution of the vacuum created between the male connector and the female receiving area.

[0031] According to a particular embodiment of the present invention, the male connector further comprises a front end plate for supporting the tool, one of said plate and a front edge of the main body is equipped with a lateral tenon while the other of said plate and the front edge of the main body comprises a slot receiving the lateral tenon so as to block the relative axial rotation of the main body and the gripping member.

[0032] This solution allows for optimized positioning of the tool and prevents untimely rotation of the male connector inside the female receiving area.

[0033] Preferably, the bottom wall and the suction face respectively have flat surfaces.

[0034] According to an alternative embodiment, the bottom wall and the suction face respectively have corrugated surfaces of complementary shapes cooperating with each other.

[0035] This solution makes it possible to slightly increase the contact surface between the male connector and the female receiving area, which improves coupling.

[0036] Advantageously, the main body is connected to a rear rotation shaft.

[0037] According to a particularly interesting aspect of the present invention, the bottom wall and the suction face have an identical surface area greater than or equal to approximately 1200 mm2, and preferably greater than or equal to 1500 mm2.

[0038] Similarly, the conical contact surface between the male connector and the female receiving area is greater than or equal to 1500 mm2, and preferably approximately equal to 1800 mm2.

[0039] With the same aim of ensuring an optimized coupling without unnecessary expenditure of energy, the absolute value of the vacuum / depression is greater than or equal to 0.45 bar (i.e. -0.45 bar of negative pressure), and preferably substantially equal to approximately 0.9 bar to 1 bar (i.e. -0.9 bar of negative pressure).

[0040] Similarly, the device has a gripping force greater than or equal to approximately 75 N for a low depression, and preferably greater than or equal to 140 N for a high depression.

[0041] The present invention also relates to a three-dimensional printing machine comprising at least one enclosure, a tool support(s), a tool coupling device as described previously and a movable plate.

[0042] Finally, the present invention also relates to a method for producing a part by additive manufacturing using the machine as described above and comprising at least the following series of steps: a) gripping a first tool on the tool holder(s) using the coupling device as described previously, b) carry out a first phase of additive manufacturing of a first portion of the part to be produced, c) rest the first tool on the tool support(s), d) gripping a second tool on the tool holder(s) using the coupling device, e) carry out a second phase of manufacturing a second portion of the part to be produced.

[0043] Advantageously, the second tool is a three-dimensional printing head and the second manufacturing phase is an additive manufacturing phase adding material to the first portion of the part to be produced.

[0044] According to an alternative embodiment, the second tool is a machining tool, for example a milling cutter, and the second manufacturing phase is a subtractive manufacturing phase removing material from the first portion of the part to be produced.

[0045] Preferably, steps a) to e) are repeated as many times as necessary to obtain the final part, with alternation (regular or not) of additive manufacturing and subtractive manufacturing. Brief description of the figures

[0046] Other advantages, aims and characteristics of the present invention emerge from the following description given, for explanatory and non-limiting purposes, with regard to the attached drawings, in which:

[0047] [Fig.l] [Fig.l] is a perspective view of a three-dimensional printing machine equipped with an automatic tool coupling device according to the present invention,

[0048] [Fig.2] [Fig.2] is a front view of [Fig.l],

[0049] [Fig.3] [Fig.3] is a perspective view similar to [Fig.l] but in which a tool is coupled to the coupling device

[0050] [Fig.4] [Fig.4] is a front view of [Fig.3],

[0051] [Fig.5] [Fig.5] is a detailed perspective view of the device of [Fig.l] on which a tool is coupled,

[0052] [Fig.6] [Fig.6] is a side view of [Fig.5],

[0053] [Fig.7] [Fig.7] is an exploded perspective view of the coupling device alone,

[0054] [Fig.8] [Fig.8] is a view similar to [Fig.7] but taken from another angle,

[0055] [Fig.9] [Fig.9] is a perspective view of the coupling device alone assembled,

[0056] [Fig. 10] [Fig. 10] is a view similar to [Fig.9] but taken from another angle,

[0057] [Fig. 11] [Fig. 11] is a side view of Figures 9 and 10, and

[0058] [Fig.12] [Fig.12] is a longitudinal sectional view of [Fig.11]. Description of the embodiments

[0059] Figures 1 to 4 schematically represent a three-dimensional printing machine 10, also called an additive manufacturing machine (Fused Deposit Material or Fused Filament Fabrication), equipped with a device 100 for automatic coupling of tool 20 in accordance with the present invention and presented in more detail in Figures 5 and following.

[0060] The present description is given without limitation, each characteristic of an embodiment being able to be combined with any other characteristic of any other embodiment.

[0061] It should be noted, from now on, that the figures are not necessarily to scale, without this hindering their understanding.

[0062] Typically, the 3D printing machine 10 comprises an enclosure 11 (preferably at least partly transparent) which can be closed for the manufacture of a part and opened to recover it, a plate 12 (also called a “bed”), most often heated, on which the part being manufactured rests, a support 13 (commonly called a magazine) of the rail or rack type on which various tools 20 are stored, available and interchangeable depending on the uses, and the device 100 according to the present invention mounted on a mobile support.

[0063] During 3D printing, the molten material (plastic material in this case), generally stored in the form of a filament spool, passes through the head 20 and exits the latter via a heated end nozzle 22, while the plate 12 and / or said filament deposition head 20 mounted on a carriage 50 is / are motorized and can thus move in a synchronized manner along rails 30, 40 and 60 at least in the three directions X, Y and Z of an orthonormal reference frame to manufacture the part progressively by vertical superposition of layers.

[0064] The print head 20, which is not the subject of the present invention, is heated to a high temperature so as to reach at least the melting temperature of the filament of material used, often beyond 160-200°C in the case of the most common materials which are PLA (polylactic acid) and ABS (Acrylonitrile butadiene styrene), so that it can melt and be deposited on the plate 12 then on the previously deposited and solidified material.

[0065] The object of the present invention is thus to provide an automatic coupling device 100 which can withstand the various constraints mentioned above of positioning and rigidity, high frequency vibration, damping, tool trajectory (in particular for the locking / unlocking phases), miniaturization (weight / volume, number of constituent parts) and resistance of the connection over time (in tens or hundreds of thousands of cycles).

[0066] Thus, as can be seen in Figures 5 to 12, the coupling device 100 comprises at least one main body 110 and a tool gripping member 120 20. The main body 110 comprises a female receiving zone (i.e. hollow) 111 having at least one portion 112 of conical shape. The tool gripping member 120 comprises a male connector 121 having at least one portion 122 of conical shape with the same conicity as that of the conical portion 112 of said female receiving zone 111 so that these two cones can cooperate in the assembled position of use of the tool gripping member 120 inside the main body 120.

[0067] According to the invention, a suction channel 130 passes laterally through the main body 110 to end in the female receiving zone 111, and is connected to a vacuum source (of the pump type, not shown) so as to create a vacuum between the female receiving zone 111 of the main body 110 and the male connector 121 of the tool gripping member 120. This makes it possible, as will be described below, to firmly and precisely hold the gripping member 120 in the main body 110. A pneumatic connector 131 is connected to the suction channel 130 to be connected to the vacuum source (vacuum pump).

[0068] As is clear from Figures 8, 8 and 12, the front cone portion 112 of the female receiving area 111 is extended by a rear cylindrical portion 113 provided with a bottom wall 115, while the front cone portion 122 of the male connector 121 is extended by a rear cylindrical portion 123 provided of a suction face 125.

[0069] The conical contact surface (developed surface of each of the conical portions 113 and 123) between the male connector 121 and the female receiving zone 111 is in the present case greater than or equal to 1500 mm2, and preferably close to 1800 mm2, for example 1771 mm2.

[0070] The contact surface between the bottom wall 115 of the female receiving zone 111 and the suction face 125 of the male connector 121 is in the present case greater than or equal to approximately 1200 mm2, and preferably greater than or equal to 1500 mm2, for example equal to 1548 mm2 for a diameter of 44.4 mm, to which can be added the chamfered surface which is 200 mm2. If we base ourselves on a cylindrical section of 46.5 mm in diameter, the suction surface is thus 1698 mm2. This surface is the reference surface for the suction force calculations.

[0071] The suction channel 130 preferably ends in the center of the bottom wall 115 for a homogeneous distribution of the depression exerted on the suction face 125, but other solutions are conceivable to meet the same constraints.

[0072] Thus, the depression prevailing in the coupling device 100, that is to say between the bottom wall 115 and the suction face 125, can drop to approximately -0.86 bar (relative to atmospheric pressure, that is to say approximately 0.14 bar in absolute).

[0073] In order to limit the quantity of air used to maintain the vacuum, this is controlled between the terminals of -0.8 bar (lower terminal which causes the inlet valve to close) and the upper terminal of -0.45 bar (at which the machine reactivates the depressurization to avoid decoupling of the male connector 121).

[0074] At the maximum pressure of -0.86 bar, the vacuum force (coupling force) caused is approximately 146 N while at the low pressure of -0.45 bar, the vacuum force (coupling force) is 76 N. This low limit could be increased since it is only a datum making it possible to limit the activation of a depressurization sequence to maintain the male connector 121 in position.

[0075] The cylindrical portion 123 of the male connector 121 comprises an annular groove 124 for receiving a seal 150. This seal 150 is typically of the four-lobe type, made of a material resistant to high temperatures greater than or equal to approximately 150°C, and has, for example, a hardness of approximately 70 Shore A. It makes it possible to prevent air leaks and to maintain the depression between the male connector 121 and the female receiving zone 111 throughout the coupling phase and use of the tool 20, as will be explained later.

[0076] The male connector 121 further comprises a front end plate 127 for supporting the tool (which is not shown in Figures 7 to 12 but visible in Figures 1 to 6). This plate 127 is provided with a radial slot 128 in which, in the assembled position of the device 100, a corresponding radial tenon is housed. 118 arranged in a front rim 117 of the female receiving zone 111 so as to block the relative axial rotation of the main body 110 relative to the gripping member 120 once the assembly has been carried out.

[0077] The main body 110 is connected to a rear shaft 140 provided with a welded plate 142 which can be fixed using screws 145 to the rear of the main body 110, allowing, if necessary, the rotation of the coupling device 100 along a longitudinal axis.

[0078] The operation of the coupling device 100 according to the present invention is as follows:

[0079] Once the spool of plastic filament is installed, the three-dimensional printer 10 is powered on, and the manufacturing program is loaded, the device 100 is put into operation.

[0080] For this, the coupling device 100 connected to the carriage 50 moves in the X and Y directions along the rails 30 and 40 to retrieve a tool 20 already mounted on the gripping member 120 and attached to the support 13. The conical portion 112 of the female receiving zone 111 of the main body 110 is positioned facing the conical portion 122 of the male connector 121 of the gripping member 120 so that the tenon 118 is inserted into the radial slot 128 and the bottom wall 115 is against the suction face 125.

[0081] The vacuum pump (not shown), for example with the Venturi effect, is then activated so that the air is sucked in through the conduit 130, which creates a depression between said bottom wall 115 and said suction face 25 with a suction force such that the male connector 121 of the gripping member 120 firmly attaches to the female receiving zone 111 of the main body 110, which makes it possible to release the tool 20 from its support 13.

[0082] The three-dimensional printing machine 10 then follows its additive manufacturing program for the part to be manufactured by moving the coupling device 100 equipped with its tool 20 along the X, Y and Z axes along the rails 30, 40 and 60 (more precisely, the movable plate 12 moves longitudinally along the Z axis, while the coupling device 100 moves in an XY plane) until the end of the planned manufacturing cycle. During this entire phase, the tool 20 is firmly held on the coupling device 100 because the pump maintains sufficient vacuum to create a vacuum force (coupling force) of the tool greater than 76 N. An integrated control system makes it possible to increase the vacuum in order to maintain it above this minimum gripping value.

[0083] Once the manufacture of the part is finished, the coupling device 100 is brought back facing the support 13 of the tool 20 in order to reposition the latter on said support 13 by ceasing the depression created by the vacuum pump which makes it possible to separate the male connector 121 from the female receiving zone 111. A small pressure of the pump can even improve the decoupling of the main body 110 and the gripping member 120 so that the latter allows the tool 20 to be attached to its support 13.

[0084] Of course, a change of tool 20 is entirely possible during the manufacture of the part, in which case the first tool 20 is first connected to the coupling device 100, it is used to carry out a certain manufacturing phase, it is then placed back on its support 13 as explained above, then another tool 20 is connected to the coupling device 100 as already described in order to carry out another manufacturing step of the part, and so on until the completion of the additive manufacturing.

[0085] It is also entirely possible to imagine a more complex solution, called “hybrid manufacturing”, in which a first three-dimensional printing tool 20 is gripped on the tool support 13 using the coupling device 100, a first additive manufacturing phase is carried out to produce a first portion of the part on the plate 12, the first tool 20 is placed back on the tool support 13, a second subtractive manufacturing tool 20, for example a milling cutter, is gripped on the tool support 13 using the coupling device 100, and a second subtractive manufacturing phase (machining such as a chamfer, drilling, finishing by local polishing of the surface, etc.) is carried out on the part to be produced.

[0086] This hybrid process can also comprise more generally the sequence one after the other and several times of several additive and / or subtractive phases, with for example a first additive manufacturing phase to produce a first portion of the part with a first three-dimensional printing head, a second different additive manufacturing phase with a second three-dimensional printing head to produce a second portion of the part (change of plastic material and / or color for example), a third subtractive manufacturing phase (for example drilling, chamfering) working on at least one of the portions of the part produced during the two previous additive phases, then a fourth very localized additive manufacturing phase with a third three-dimensional printing head, followed by a fifth and final subtractive manufacturing phase of general polishing of the entire part.All phase combinations are possible as long as the tools are available.

[0087] The present invention thus makes it possible to propose a solution adapted to the following constraints:

[0088] - Compatibility with an operation of the coupling device evolving from dynamically inside a high temperature enclosure, typically above 150°C and even beyond 200°C, (mainly depending on the material used and its melting temperature), - Reduced size to be able to mount the coupling device at the end of 5-axis kinematic chain, - Significant rigidity of the system, - Coupling accuracy less than 20qm, - Vibration resistance, - Long service life (several hundred thousand hours of use), - High coupling force (close to 150 N in certain circumstances), - Automation (no user intervention during the phases of gripping, use, changing and storing the tool, from the moment the printing program is launched until the part is removed from the machine plate).

[0089] It should be clearly understood that the detailed description of the subject of the Invention, given solely by way of illustration, does not constitute in any way a limitation, the technical equivalents also being included in the scope of the present invention.

[0090] Thus, there could be several suction orifices 130 ending at the bottom 115 of the female receiving zone 111 in order to distribute the depression and the vacuum created more evenly.

[0091] The bottom wall 115 and the suction face 125 may respectively have corrugated surfaces of complementary shapes cooperating with each other so as to increase the contact surface between the male connector and the female receiving zone.

[0092] The annular groove 124 for receiving the seal 150 can be arranged in the cylindrical portion 112 of the female receiving zone 111.

[0093] The seal 150 used may be different in its shape, its construction material and its Shore A hardness as long as it provides the same functions and resists the same imposed constraints.

[0094] The plate 127 of the male connector 110 may comprise a tenon 118 which is inserted into a slot 128 formed in the front edge 117 of the female receiving zone 111 so as to block the relative axial rotation of the main body 110 and the gripping member 120 once the coupling device 100 is assembled.

[0095] The coupling device of the present invention can also be used for gripping parts, for robocasting, machining, milling, or tapping.

[0096] Thus, the three-dimensional printing head can be replaced by a drilling / tapping head equipped with a drill or a tap, a milling head, a marking head, a control tool (dimensions, surface conditions) or even a coating tool.

[0097] The different dimensions and values ​​of depression (vacuum) and attraction force, given for information purposes only, can of course be modified as soon as the principle of the invention is retained, namely on the one hand the cones of complementary shapes for the female receiving area and the male connector and on the other hand the suction. The increase in the suction face and the bottom wall would for example make it possible to increase the gripping force.

[0098] The cylindrical portions 113 and 123 are not obligatory so that, in this configuration, there would only be the two cones 112 and 122 and no sealing gasket 150.

Claims

Claims

1. Device (100) for automatically coupling at least one tool (20) for a three-dimensional printing machine (10) with tool change (20), said coupling device (100) comprising at least one main body (110) and a tool gripping member (120) (20), in which: - the main body (110) comprises a female receiving zone (111) having at least one portion (112) of conical shape, - the tool gripping member (120) comprises a male connector (121) having at least one portion (122) of conical shape with the same conicity as that of the conical portion (112) of said female receiving zone (111) so as to cooperate with the latter in the assembled position of use of the tool gripping member (120) (20) and the main body (110), and - a suction channel (130) ending in the female receiving zone (111) is connected to a source of depression so as to create a vacuum between the female receiving zone (111) of the main body (110) and the male connector (121) of the tool gripping member (120) (20) to hold them together, - each of the female receiving zone (111) and the male connector (121) comprises a front cone portion (112; 122) extended by a rear cylindrical portion (113; 123) provided respectively with a bottom wall (1215) and the suction face (125), characterized in that - the female receiving area (111) of the main body comprises a bottom wall (115) in which the suction channel (130) ends and the male connector (121) comprises a suction face (125) having the same dimensions as said bottom wall (115), so that the depression causes the suction face (125) to be brought together by suction against the bottom wall (115) so as to maintain the male connector (121) in the female receiving area (111) throughout the suction, and - the cylindrical portion (113; 123) of the female receiving zone (111) or of the male connector (121) comprises an annular groove (124) for receiving a sealing gasket (150).

2. Tool coupling device (100) according to claim 1, characterized in that the seal (150) is of the four-lobe type in a material resistant to high temperatures greater than or equal to approximately 150°C, with a hardness of approximately 70 Shore A.

3. Tool coupling device (100) according to any one of the preceding claims, characterized in that a pneumatic connector (131) is connected to the suction channel (130) for connection to the vacuum source.

4. Tool coupling device (100) according to any one of the preceding claims, characterized in that the suction channel (130) ends in the center of the bottom wall (115).

5. Tool coupling device (100) according to any one of the preceding claims, characterized in that the male connector (121) further comprises a front end plate (127) for supporting the tool, one of said plate (127) and a front edge (117) of the main body (110) is equipped with a lateral tenon (118) while the other of said plate (127) and the front edge (117) of the main body (110) comprises a slot (128) receiving the lateral tenon (118) so as to block the relative axial rotation of the main body (110) and the gripping member (120).

6. Tool coupling device (100) according to any one of the preceding claims, characterized in that the bottom wall (115) and the suction face (125) respectively have flat surfaces.

7. Tool coupling device (100) according to any one of claims 1 to 5, characterized in that the bottom wall (115) and the suction face (125) respectively have corrugated surfaces of complementary shapes cooperating with each other.

8. A tool coupling device (100) according to any preceding claim, characterized in that the main body (110) is connected to a rear rotation shaft (140).

9. Tool coupling device (100) according to any one of the preceding claims, characterized in that the bottom wall (115) and the suction face (125) have an identical surface area greater than or equal to approximately 1200 mm2, and preferably greater than or equal to 1500

10. Tool coupling device (100) according to any one of the preceding claims, characterized in that the conical contact surface between the male connector (121) and the female receiving area (111) is greater than or equal to 1500 mm2, and preferably approximately equal to 1800 mm2.

11. A tool coupling device (100) according to any preceding claim, characterized in that the absolute value of the vacuum / depression is greater than or equal to 0.45 bar, and preferably substantially equal to approximately 0.9 bar to 1 bar.

12. Tool coupling device (100) according to any one of the preceding claims, characterized in that it has a gripping force greater than or equal to approximately 75 N for a low depression, and preferably greater than or equal to 140 N for a high depression.

13. Three-dimensional printing machine (10) comprising at least one enclosure (11), a tool support(s), a tool coupling device (100) according to any one of the preceding claims and a movable plate (12)

14. Method for producing a part by additive manufacturing using the machine according to claim 13 and comprising at least the following series of steps: a) gripping a first tool on the tool support(s) using the coupling device (100) according to any one of claims 1 to 12, b) carrying out a first phase of additive manufacturing of a first portion of the part to be produced, c) resting the first tool on the tool support(s), d) gripping a second tool on the tool support(s) using the coupling device (100) according to any one of claims 1 to 12, e) carrying out a second phase of manufacturing a second portion of the part to be produced.

15. Method according to claim 14, characterized in that the second tool is a three-dimensional printing head and the second manufacturing phase is an additive manufacturing phase adding material to the first portion of the part to be produced.

16. Method according to claim 14, characterized in that the second tool is a machining tool, for example a milling cutter, and the second manufacturing phase is a subtractive manufacturing phase removing material from the first portion of the part to be produced.

17. Method according to any one of claims 15 or 16 in which steps a) to e) are repeated as many times as necessary to obtain the final part.

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