WO2018087488A1

WO2018087488A1 - Tool-holder device for selective additive manufacturing equipment

Info

Publication number: WO2018087488A1
Application number: PCT/FR2017/053071
Authority: WO
Inventors: Jean-Pierre Nicaise
Original assignee: Addup
Priority date: 2016-11-10
Filing date: 2017-11-10
Publication date: 2018-05-17
Also published as: FR3058354B1; FR3058354A1

Abstract

The invention relates to a tool-holder device for additive manufacturing equipment, characterised in that it comprises: a tool-holder spindle (1) mounted such that it can rotate about an axis and designed to hold multiple working blades (2); and a drive means (4) designed to rotate the tool-holder spindle (1) for the angular positioning of a selected blade (2) in its working position relative to the powder bed.

Description

TOOL HOLDER DEVICE FOR APPARATUS

OF SELECTIVE ADDITIVE MANUFACTURING

GENERAL TECHNICAL FIELD AND PRIOR ART

The present invention relates to the general field of selective additive manufacturing.

More particularly, it relates to the tools used in additive manufacturing enclosures to intervene on a bed of powder, for example during the layering of the additive manufacturing powder.

Selective additive manufacturing consists in producing three-dimensional objects by consolidating selected areas on successive layers of powder material (metal powder, ceramic powder, etc.). The consolidated areas correspond to successive sections of the three-dimensional object. The consolidation is done for example layer by layer, by a total or partial selective melting carried out with a source of consolidation (high power laser beam, electron beam, etc.).

Conventionally, an additive manufacturing apparatus comprises in a manufacturing enclosure:

a support on which are deposited successively the different layers of additive manufacturing powder,

one or more sources of energy beams controlled to selectively scan the bed of powder,

a powder supply tank,

- A tool, such as a squeegee or a roller, which moves in translation on the bed of powder to spread the powder.

The configurations proposed so far for such tools are not fully satisfactory.

In particular, when a tool is considered defective, it is necessary to stop the additive manufacturing device to intervene on the tool or change it. The downtimes that result are a significant cost. In addition, the current configurations can only provide inside the enclosure a limited number of tools, if only for issues of space. GENERAL PRESENTATION OF THE INVENTION

A general object of the invention is to overcome the disadvantages of the configurations proposed so far.

In particular, an object of the invention is to propose a solution that makes it possible to reduce downtime.

Another more specific object of the invention is to propose a solution that does not need to immobilize the entire additive manufacturing apparatus when it is considered that a tool inside the enclosure must be changed or maintained and can no longer be used.

Another object of the invention is to propose a solution that allows the use of several tools inside the enclosure, while being of a small footprint.

Thus, according to a first aspect, the invention proposes a tool-holder device for an additive manufacturing apparatus, characterized in that it comprises:

- A tool shaft which is rotatably mounted about an axis and which is adapted to carry a plurality of working blades, a motor adapted to rotate the tool shaft to angularly position a selected blade in its working position. compared to the bed of powder.

This device is advantageously completed by the following different characteristics taken alone or according to their different possible combinations:

for mounting a working blade, the tool-carrying shaft comprises at least one row of grippers distributed along the same length of said shaft and adapted for clamping and locking said working blade in the shaft toolholders. a clamp comprises a tilting piece which comprises a jaw portion and a lever portion, and a spring exerting on the lever portion a force tending to tilt the jaw portion on a blade when positioning it in the clamp to tighten said blade against a wall forming a stop of the tool-holder shaft.

a clip further includes a cone-shaped piece adapted to cooperate with a clamping screw to clamp the jaw portion and lock the blade in the clamp once said blade is in place and adjusted in position.

The device comprises at least two rows of diametrically opposed clamps for receiving working blades of the same type.

the tool shaft is configured to receive working blades for working in different directions of movement of the tool shaft relative to the powder bed. The device comprises a gearbox at the motor output and a pulley-belt assembly which is driven by the gearbox and which rotates the tool-holding shaft, the motor and said gearbox being superimposed on the tool-holding shaft, pulley-belt assembly extending laterally with respect to the tool-carrier shaft and the gearbox,

the blades comprise blades intended to function as squeegees for spreading the powder and / or blades intended to serve as a planer for interventions after melting of the material,

the device carries the working blades,

the blades are removably mounted on the tool shaft,

the blades are adapted to be changed,

for mounting a working blade, the tool-carrying shaft comprises removable holding means, for example removable fixing means, of the blade in the bearing shaft; tool, for example for clamping and / or locking the working blade in the tool shaft,

the removable fastening means are adapted to lock the blade in a fixed position with respect to the tool-carrying shaft, the removable fixing means comprise for example at least one row of grippers distributed along the same length of said shaft and adapted for clamping and locking said working blade in the tool shaft, the removable holding means and / or removable fixing are configured on the shaft so that the blades they receive extend radially in the tree once in place,

the device is adapted to allow spreading of the additive manufacturing powder, for example on the support (plate), for example on the support (plate) on which the various additive manufacturing layers are successively constituted,

the motor is adapted to maintain the tool-holder shaft in a position, for example an angular position, where at least one of the blades is in its working position with respect to the powder bed,

each blade is provided for working in a given direction on the bed of powder, the removable holding means and / or removable fixing being for example configured to support the face of a blade which is opposite to that which is intended to work on an abutment wall of the shaft, for example while the working face of the blade is disengaged on a part, for example a major part, of its height,

two successive blades on the shaft are for example intended to work in different directions,

the shaft can be rotated, for example 180 °, for one of the blades, for example when a blade failing or to be changed or no longer usable, replaced by a similar blade already in place on the tool shaft,

the holding and / or fixing means comprise diametrically opposite means carrying the same type of blade, for example blades intended to function as a scraper for spreading the powder and / or blades intended to serve as a planer for interventions after melting of matter,

the device is adapted to allow the use of working blades acting on the powder bed in two directions of passage of the device, for example a block, for example with respect to a window and / or the bed of powder, the window being for example formed in a bottom to the right of a powder support of an additive manufacturing apparatus, the bottom forming for example a work plane, for example a work plan of the manufacturing enclosure, the block comprising, for example, the shaft and / or the blades and / or the motor and / or a motor and / or a gearbox and / or a pulley-belt system,

the motorization is for example controlled by a controller, for example to maintain the tool-holder shaft in an angular position which allows the selected blade to be in its working position with respect to the powder bed, for example when moving the tool tree in front of the powder bed,

during layering (for example the spreading of powder), the controller of the motorization is able to detect an increase in torque, for example an increase beyond a given threshold, for example a large increase, for example due to a "gratton" (agglomerate of powder), and for example to unlock the tool holder (for example by a small movement shifting the tray), for example to avoid damaging the blade and / or the piece manufacturing course. The invention also proposes an assembly comprising a device of the aforementioned type and a plurality of working blades mounted on the tool-carrying shaft of said device, these blades being able to be working blades of different types.

In particular, the invention proposes an assembly of this type, characterized in that it comprises a tool-holder device movable in translation on a laying carriage of an additive manufacturing apparatus.

Finally, the invention further provides an additive manufacturing apparatus, characterized in that it comprises such an assembly in a manufacturing chamber.

PRESENTATION OF FIGURES

Other characteristics and advantages of the invention will emerge from the description which follows, which is purely illustrative and nonlimiting, and should be read with reference to the appended figures in which:

- Figure 1 is a block diagram representation of a device according to a possible embodiment of the invention;

FIGS. 2a and 2b illustrate a squeegee block of a device of the type of that of FIG. 1;

FIG. 3 also illustrates such a scraper block and the intervention thereon in order to put in place new blades therein;

FIG. 4 illustrates the tool-holder shaft of the block of FIGS. 2a, 2b and 3;

- Figure 5 shows schematically in sectional view the tool-holder shaft of Figure 4, the section being formed at the tool locking clamps of said shaft;

- Figure 6 is a representation of a detail of the sectional view of Figure 5;

FIG. 7 and FIG. 8 are a perspective view of the positioning of the device of FIGS. 2a and following on a layering carriage. DESCRIPTION OF ONE OR MORE MODES OF IMPLEMENTATION AND REALIZATION

The device illustrated in FIG. 1 comprises, in an enclosure E of an additive manufacturing apparatus, a tool-carrying shaft 1 on which a plurality of working blades 2 are mounted, as well as a motor 4 and a gearbox 5 which make it possible to driving said shaft in rotation through a belt-pulley system 6 (rotation around the axis of the shaft 1 or an off-axis axis).

The shaft 1 and its blades 2, the motor 4, the gearbox 5 and the pulley-belt system 6 together form a block B intended to be mounted on a support 3a which is movable in the bottom of the enclosure. Block B and the mobile support 3a together form a layering carriage 3.

In operation, during additive manufacturing, this carriage 3 is moved above the working surface of the enclosure E of the additive manufacturing apparatus. It is mainly intended to allow spreading the additive manufacturing powder on the support (plate) on which the various additive manufacturing layers are successively constituted.

The displacement is for example a displacement in translation. During such a movement, the shaft 1 holder is held by the motor 4 in an angular position where a given blade 2 is in its working position relative to the powder bed.

More particularly, as illustrated in FIGS. 2a and 2b, the motor 4 and the gearbox 5 are superimposed on the shaft 1 in the block B. For this purpose, the axis of the motor 4 and the axes of entry and output of the gearbox 5 are parallel to the axis of the shaft 1.

The pulley-belt assembly 6 extends meanwhile in a lateral housing 10, at one end of the tool-holding shaft 1 and the gearbox 5.

As illustrated in Figures 3 to 5, the tool shaft 1 comprises several rows 7 of clamps 7a which ensure the maintenance of the blades 2 on the body of said shaft.

In the example illustrated in the figures, there are four rows 7, each having five identical clamps 7a. The four rows 7 of clamps are distributed in pairs on either side of a diametral plane P of the shaft 1 (Figure 5).

The clamps 7a are themselves two to two symmetrical with respect to the axis A of the shaft 1, two axially symmetrical clamps 7a receiving identical blades 2.

These clamps 7a are further configured on the shaft 1 so that the blades 2 they receive extend radially in the shaft 1 once in place.

Each blade 2 is provided to work in a given direction on the bed of powder. For this purpose, the clamps 7a are configured to support the face of a blade 2 which is opposed to that which is intended to work on an abutment wall BT of the shaft 1 (FIG. 5), whereas the working face of FIG. the blade 2 is disengaged over a major part of its height.

Also, two successive blades 2 on the shaft 1 are intended to work in different directions, the clamps 7a being configured so that the blades 2 extend at an angle of the order of 15 to 25 °, and preferably 20 °, relative to the diametral plane P of the shaft 1. The angular space between two successive blades 2 on the same side of the diametrical plane P is clear to allow the work of said blades, while the space between two blades 2 successive on either side of said plane P is occupied by the material which defines their abutment walls BT.

More precisely (FIG. 6), a gripper 7a is in the form of a part which is pivotably mounted around an axis A1 parallel to the axis of the tool-holder shaft 1. This part comprises a portion 8 forming jaw (part farthest from the axis A) and a lever portion 9 biased by a spring R (compressed coil spring). In the absence of other effort, the force exerted by the spring R is intended to tilt said clamp member to close the jaw 8 on the blade 2 and thus clamp it against the abutment wall BT facing.

Typically, the spring 9 of a clamp 7a produces a clamping force of 5 kg (25 kg of holding force per blade 2).

This effort is intended to be only temporary. It allows the sliding of the blades 2 when they are placed in the clamps 7a.

Note that the blades 2 are placed in the clamps 7a with an overhang, without being wedged to the bottom thereof to allow their adjustment in position in a second time as is described in detail below.

The locking of the blades 2 in position is for example by means of torque screwdrivers.

On its face opposite to its face intended to close on a blade 2, the jaw portion 8 is engaged with a conical bearing surface 11 whose clamping on said jaw portion 8 serves to lock the blades 2 in the bearing shaft. tool 1.

The tightening of said conical bearing surface 11 is achieved by a screw 12 whose head itself bears in a housing formed in said bearing surface 11.

The tightening of said screw 12 is for example carried out by means of a torque screwdriver (screwdriver T in FIG. 3).

The locking achieved by a conical bearing surface 11 can be up to 100 kg per gripper 7a.

The shaft 1 and the block B are respectively represented in FIG. 7 and in FIG. 8 in position relative to the working plane 17 of the manufacturing enclosure.

It comprises two lateral flanges 13 which guide the carriage 3 in its movement relative to the bottom 17 which constitutes said work plane.

A window F is formed in said bottom 17 to the right of the powder support of the additive manufacturing apparatus (in this case a plate 14 which descends gradually, layer after layer).

An actuator 15 associated with pulley / belt assemblies 16 drives the block B and thus the carriage 3 moving above said window F, which makes it possible to spread a new layer of powder with a blade 2 or to perform a planing operation with a blade 2 adapted. The tool-holder device 1 which has just been described has the advantage, when a blade 2 of work is defective or that it is desired to change the type of working blade, to allow, by simple rotation of the shaft tool holder 1 on itself, to use a new working blade among those carried by the tool shaft 1.

For example, given the symmetrical configuration with respect to the axis A of the clamps 7a of the tool holder 1, it can be provided that two diametrically opposite clamps carry the same type of blade. When one of these blades must be changed, or is no longer usable, simply order a 180 ° rotation of the tool shaft 1 so that the faulty blade is replaced by the similar blade already in place on the tool shaft 1.

Also, this device allows a saving of operating time by making it possible to use working blades intervening on the bed of powder during the two directions of passage of the block B with respect to the window F and to the bed of powder.

Also, several types of blades can be used for blades 2.

In particular, it can be provided on the tool holder blades intended to operate as a squeegee to spread the powder and at the same time blades for use as a planer for interventions after melting of the material.

The motor 4 is controlled by a controller (not shown). During the movement of the tool shaft 1 in front of the powder bed, said motor 4 is controlled to hold the tool shaft 1 in its angular position which allows the selected blade 2 to be in its working position. compared to the bed of powder.

A resolver or angular encoder (also not shown) may be provided at the shaft 1 to allow to control this angular position with great accuracy.

In particular, it may be provided that the blades are slightly inclined relative to the plane of the powder bed during a passage thereon. In addition, blades adapted to different types of powder granulometry can be envisaged on the same tool holder 1 (especially for the squeegee function).

Moreover, during layering (powder spreading) the controller of the motorization 4 is able to detect a strong increase in torque due to a "gratton" (powder agglomerate) and to unblock the tool holder 1 ( for example by a small movement shifting the plate 14) to avoid damaging the blade or the part being manufactured.

Note also that the change of the block B on the carriage 3 or intervention on the block B to change blades 2 is particularly easy.

An intervention process for changing a blade 2 is for example of the type described below.

Block B is moved to be placed in a side position towards the side door of enclosure E.

The following steps are then performed:

1- Opening of the side door of the enclosure E,

2- Positioning of the tool holder 1 in secure mode,

3- Loosening of the five tool clamps 7a,

4- Engaging two assembly / disassembly tools on the blade 2 to change and removal of said used blade,

5- Cleaning the clamps 7a and the abutment wall BT with a clean cloth,

6- Turning the blade 2 and checking the condition of the unused generator. If both generators have been used, change the blade 2.

7- Engagement of the two assembly / disassembly tools on the new blade 2,

8- Engagement of the blade 2 in the clamps 7a of the tool holder and abutting of the assembly / disassembly tools on the tool holder 1,

9- Positioning the tool holder in secure mode, 10- Resumption of steps 3 to 8 for a new blade 2,

11- once the set of blades 2 changed and put in place in the clamps, launching the automatic blade adjustment cycle:

• Door 14 door piece in reference position 0,

· Moving the layering carriage 3 in the center of the tray 14,

• Rotation of the tool shaft 1 to the working position of the blade 2. Counterclockwise direction of rotation,

• Vertical movement of the plate 14 to the desired adjustment position for the blade,

• Lowering the plate 14 to the reference position 0,

• Rotating the tool shaft 1 to the working position of another blade 2. Clockwise rotation direction,

• Moving the plate 14 to the desired adjustment position of the blade 2,

• Lowering the plate 14 to the reference position 0,

• Set access position of block B in safe mode and side door position (Simultaneous operation).

12- Tightening to the locking torque of the five clamps 7a of the blade 2.

13- Setting access position of block B in secure mode.

14- Resumption of the steps 12 and 13 for the tightening to the locking torque of the five clamps 7a of another blade 2.

Claims

Tool holder device for additive manufacturing apparatus, characterized in that it comprises:

a tool shaft (1) rotatably mounted about an axis and adapted to carry a plurality of working blades (2), a motor (4) adapted to rotate the tool shaft (1) to angularly positioning a blade (2) selected in its working position relative to the powder bed.

Device according to claim 1, characterized in that for the assembly of a blade (2) of work, the tool-holder shaft comprises at least one row of grippers (7a) distributed along the same length of said shaft and adapted for clamping and locking said working blade (2) in the tool shaft.

Device according to claim 2, characterized in that a clamp comprises a rocker part which comprises a jaw part and a lever part, and a spring exerting on the lever part a force tending to tilt the jaw part on a blade (2 ) during the positioning thereof in the clamp to clamp said blade (2) against a wall forming a stop of the tool shaft.

Device according to claim 3, characterized in that a clip further comprises a conical bearing part adapted to cooperate with a clamping screw in order to clamp the jaw part and lock the blade (2) in the clamp once said blade ( 2) set up and adjusted in position.

Device according to one of claims 2 to 4, characterized in that it comprises at least two rows of clamps (7a) diametrically opposed for receiving working blades of the same type.

6. Device according to claim 1, characterized in that the tool shaft is configured to receive working blades for working in different directions of movement of the tool shaft relative to the bed of powder.

7. Device according to claim 1, characterized in that it comprises a reducer at the output of the motor and a pulley-belt assembly which is driven by the reducer and which rotates the tool shaft, the motor and said reducer. being superimposed on the tool shaft, the belt-pulley assembly extending laterally with respect to the tool shaft and the gearbox.

8. Device according to any one of the preceding claims, wherein the blades comprise blades intended to operate as a squeegee to spread the powder.

9. Device according to any one of the preceding claims, wherein the blades are removably mounted on the tool shaft.

10. Device according to any one of the preceding claims, wherein the motor is adapted to maintain the tool shaft in an angular position where at least one of the blades is in its working position relative to the powder bed.

11. An assembly comprising a device according to one of the preceding claims and a plurality of working blades mounted on the tool-holder shaft of said device.

12. The assembly of claim 11, characterized in that it comprises working blades of different types.

13. Assembly according to one of claims 11 or 12, characterized in that it comprises a tool holder device according to one of claims 1 to 7 mounted movably in translation inside the manufacturing chamber of an additive manufacturing apparatus.