Patent Description:
A typical 3D printing application in the so-called fused filament fabrication (FFF) in which a thermoplastic filament is melted and applied to a printing bed uses plastics materials. The filament may contain additives or reinforcements. The filament cools down and re-solidifies on the printing bed.

An additive manufacturing machine which uses profile bars instead of filament is known from the not previously published German patent application <CIT>. The manufacturing machine disclosed therein uses a conventional gear wheel drive for conveying the profile bars.

<CIT> and <CIT> disclose a feeding device having a conveyor belt for feeding a filament.

<CIT> and <CIT> disclose a feeding device having two rollers for transporting filament.

<CIT> and <CIT> disclose rotating mechanisms.

<CIT> discloses a printing head, printing apparatus and printing method, where the printer comprises a nozzle with a texturing member that forms the printing layer with protrusions.

<CIT> discloses a robot 3D printing system with six degrees of freedom.

The invention is based on the object of improving the production rate of additive manufacturing machines and the quality of components generated by additive manufacturing machines.

The object is achieved by the subject matter of the independent claims. Preferred design embodiments are the subject matter of the dependent claims.

The invention achieves a conveying device for an additive manufacturing machine, wherein the conveying device is configured for conveying a semi-finished product which is composed of a manufacturing material that is to be processed by the additive manufacturing machine and has a semi-finished product longitudinal axis, wherein the conveying device comprises a longitudinal conveying mechanism which is configured for conveying the semi-finished product along a conveying direction parallel to the semi-finished product longitudinal axis, wherein the longitudinal conveying mechanism has at least one running conveying means which extends along the conveying direction and which has a conveying portion that is configured for engage a semi-finished product portion of the semi-finished product in such a manner that the semi-finished product is able to be moved in the conveying direction. The longitudinal conveying device has a contact pressure device which is configured for pushing the conveying means against the semi-finished product so as to move the semi-finished product. The contact pressure device has a fluid chamber which is able to be supplied with a fluid pressure. The fluid chamber is able to be deformed by the fluid pressure and which in an supplied state is configured for urging the conveying means in the direction toward the semi-finished product so as to move the semi-finished product. The fluid chamber is able to be deformed by the fluid pressure and which in a non-supplied state is configured for not exerting on the conveying means a force which is sufficient for moving the semi-finished product.

It is preferable for the conveying means to be configured as a continuously revolving conveying means.

It is preferable for the semi-finished product to be a filament and/or a profile bar.

It is preferable for the running conveying means to be a conveying belt or a conveyor belt.

It is preferable for the conveying portion to be disposed on a load strand of the running conveying means.

It is preferable for the longitudinal conveying mechanism to have a deflection roller which deflects the conveying means.

It is preferable for the longitudinal conveying mechanism to have a drive roller which engages the conveying means so as to drive the conveying means.

It is preferable for the longitudinal conveying mechanism to have a tensioning device which keeps the conveying means under tension.

Additionally, the contact pressure device may have at least one contact pressure roller and one elastic element which is configured for urging the contact pressure roller in the direction toward the semi-finished product such that the conveying means engages the semi-finished product.

It is preferable for the conveying means to be configured in such a manner that the conveying means when pushing on the semi-finished product clings to the semi-finished product and in any case partially encompasses, particularly engages in any case to an extent of one fifth, more particularly in any case to an extent of one third, the circumferential face of said semi-finished product.

It is preferable for the deflection roller and/or the drive roller and/or the contact pressure roller to have a profiled feature which corresponds to the contour of the semi-finished product.

The conveying device preferably comprises a first running conveying means and a second running conveying means which conjointly define a conveying duct through which the semi-finished product by virtue of the movement of the conveying means is able to be conveyed in the conveying direction.

The conveying device preferably comprises a rotating mechanism which for driving the longitudinal conveying mechanism is configured in such a manner that the semi-finished product is able to be rotated about the semi-finished product longitudinal axis thereof.

It is preferable for the rotating mechanism to have at least one turntable which is able to be driven and on which the longitudinal conveying mechanism is supported such that the longitudinal conveying mechanism when driving the turntable carries out a rotating movement.

It is preferable for the rotating mechanism, in particular the turntable, to have an infeed opening for the semi-finished product so as to feed the semi-finished product to the conveying means.

The invention achieves a tool head for assembly and use in an additive manufacturing machine, wherein the tool head comprises an input portion for a semi-finished product, which is composed of a manufacturing material that is to be processed by the additive manufacturing machine and has a semi-finished product longitudinal axis, an exit region, which is configured for depositing molten manufacturing material on a printing bed so as to manufacture a component, as well as a preferred conveying device that is configured for conveying the semi-finished product from the input portion to the output portion and for holding said semi-finished product on the tool head.

The invention achieves an additive manufacturing machine which is configured for carrying out a fused deposition modeling method for manufacturing a component, in particular for an aircraft, wherein the manufacturing machine is configured for processing manufacturing material tailored so as to form profile bars, wherein the manufacturing machine comprises a preferred conveying device for conveying the semi-finished product and/or a preferred tool head for processing the semi-finished product.

The most prevalent 3D printing application in the so-called fused filament fabrication (FFF) in which a thermoplastic filament is melted and applied to a printing bed uses plastics materials. The filament may contain additives or reinforcements. The filament cools down and re-solidifies on the printing bed.

The filament is typically provided as a coil which is assembled close to the printing head or on an immovable location of the 3D printer. The filament herein is fed to the printing head by way of an adequate guide system, for example by means of a Bowden cable. This enables the use of comparatively long filaments but is associated with certain limitations in terms of the filaments used.

It can thus be a limitation that the filaments used have a rather small diameter (typically between <NUM> and less than <NUM>) so as to permit the winding and guiding by way of acceptable bending radii. The achievable deposition rates may be limited by virtue of the small diameter. Alternative methods such as, for example, the use of added yarns or in-situ impregnation, in particular by virtue of the additional complexity of the method, can be significantly more complex in terms of the parts quality obtainable.

By virtue of the continuous configuration of the filaments it may additionally be necessary to carry out a cutting operation for fiber-reinforced filaments, for example when a part cannot be generated in a single uninterrupted fiber path or filament path, respectively. While cutting devices of this type do exist, this approach may be less desirable because the cutting of the fibers may pose a limitation in terms of the continuous operation of the 3D printer. This applies in particular when materials such as carbon fibers are used.

In another case, the accumulation of degraded thermoplastic material at the exit of the printer nozzle may represent an issue.

Furthermore, the thicker the filament the longer the latter has to be heated (or the method has to be decelerated) so as to guarantee complete melting of the filament. The risk and the prevalence of degradation may increase on account thereof. The degradation modifies the viscosity of the material, for example, such that said material can accumulate on the nozzle or be pushed into the component, this being undesirable and potentially compromising the printing quality. This is typically more critical in so-called "(endless) fiber reinforced printing" in which the cleaning of the nozzle is more complicated than in the case of an endless filament which cannot be cut directly at the nozzle.

A printing device for layered melting with and without fiber reinforcements is known per se and comprises a printing head which is disposed so as to be able to move relative to a printing bed. The printing head can contain a filament driving installation so as to by means of a plurality of drive wheels move a filament wound on a coil toward the hot end. A cutting device by which the filament can be chopped can be provided at a location which in the direction of material flow is ahead of the hot end. If required, a filament guide can be additionally interposed between the filament driving device and the hot end. A heating element which heats the filament to melting temperature and deposits said filament on the printing bed by way of an exit nozzle is located at the hot end.

The sequence and the functioning principle of said components may be different. The cutting device can also be dispensed with when no endless fiber reinforcement is used.

The profile bar can presently be conveyed by two belts. A drive roller of the belt mechanism is preferably configured as the rotor of an external-rotor motor such that no gearbox is necessary for driving the belt. The rollers can additionally have a groove which is in particular disposed so as to be centric and/or corresponds to the cross section of the (reinforced) profile bar.

The belt mechanism can additionally be disposed on a rotatable ring mount. A rotation of the profile bar can therefore take place, on account of which the profile bar by virtue of fiber length compensation can better be placed about curves.

The concepts described herein relate to the field of 3D printing. The particular focus is on different types of 3D printing such as fused filament fabrication (FFF), additive layer manufacturing (ALM), or selective laser sintering (SLS). The concepts described herein are in particular focused on increasing the deposition rate, or the positioning rate, respectively, in the printing process using non-reinforced and reinforced materials. This can in particular also relate to the so-called endless fiber reinforcements in which the length of the fiber corresponds substantially to the extent of the semi-finished product to be processed, or to the component made therefrom, respectively. The measures discussed herein are particularly suitable for the measures of the not previously published German patent application <CIT>.

Exemplary embodiments will be explained in more detail by means of the appended schematic drawings in which:.

Reference is made to <FIG> which schematically shows an exemplary embodiment of an additive manufacturing machine <NUM>. The additive manufacturing machine <NUM> has a tool head <NUM> which is disposed so as to be able to move relative to a printing bed <NUM>. The relative movement between the tool head <NUM> and the printing bed <NUM> herein can result from a movement of the tool head as well as from a movement of the printing bed.

The tool head <NUM>, by means of a conveying device <NUM>, is configured for conveying a semi-finished product <NUM> which is composed of a manufacturing material and has a semi-finished product longitudinal axis, for example a profile bar <NUM> having a profile bar longitudinal axis, from an input portion <NUM> to an output portion <NUM>.

The input portion <NUM> is configured for receiving the profile bar <NUM> and for feeding the latter to the conveying device <NUM>. The conveying device <NUM>, by virtue of control commands, conveys the profile bar <NUM> to the output portion <NUM> where the profile bar <NUM> by means of a heating installation <NUM> is heated so as to melt, and thereafter is deposited on the printing bed <NUM> or on an already existing component layer <NUM> by an exit nozzle <NUM>, so as to thereafter form a further component layer <NUM> and successively form the desired component <NUM>.

Reference is in particular made to <FIG> which illustrates in more detail the tool head <NUM>, or the conveying device <NUM>, respectively.

The conveying device <NUM> has a longitudinal conveying mechanism <NUM>. The longitudinal conveying mechanism <NUM> is configured for conveying the profile bar <NUM> along a conveying direction F from the input portion <NUM> to the output portion <NUM>.

The longitudinal conveying mechanism <NUM> for conveying the profile bar <NUM> comprises at least one conveying means <NUM> which extends so as to be parallel to the conveying direction F. The conveying means <NUM> is configured as a conveying belt or a conveyor belt <NUM>, for example. The conveying means <NUM> is in particular provided as a continuously revolving conveying means <NUM>.

The longitudinal conveying mechanism <NUM> comprises at least one drive roller <NUM> which engages the conveying means <NUM> so as to drive the latter. Besides the at least one drive roller <NUM>, the longitudinal conveying mechanism <NUM> comprises at least one deflection roller <NUM> which deflects the conveying means <NUM> back onto the drive roller <NUM>. The deflection roller <NUM> can moreover be configured as a drive roller <NUM>.

The drive roller <NUM> and the deflection roller <NUM> are provided on the longitudinal conveying mechanism <NUM> so as to be mutually spaced apart in the conveying direction F.

The longitudinal conveying mechanism <NUM> can moreover have a tensioning device <NUM> which keeps the conveying means <NUM> under tension. The tensioning device <NUM>, on account of an adjustable spacing of the drive roller <NUM> from the deflection roller <NUM>, can tension the conveying means <NUM>, on the one hand. Alternatively or additionally, the tensioning device <NUM> can have at least one tension roller which effects the tensioning of the conveying means <NUM> on the side that faces away from the profile bar <NUM>.

The conveying device <NUM> can furthermore comprise a rotating mechanism <NUM>. The rotating mechanism <NUM> is configured for rotating the profile bar <NUM> about the profile bar longitudinal axis of the latter in that the force is transmitted to the profile bar <NUM> by way of the conveying means <NUM>.

The rotating mechanism <NUM> has a rotary drive actuator <NUM>, for example a motor. The driving power of the rotary drive actuator <NUM> is transmitted to a turntable <NUM> by means of a rotary drive gearbox <NUM>.

The longitudinal conveying mechanism <NUM> is preferably supported on the turntable <NUM>. The drive roller <NUM> and/or the deflection roller <NUM> are/is in particular disposed on the turntable <NUM>.

The rotating mechanism <NUM> can furthermore have a further turntable <NUM> which in the conveying direction F is spaced apart from the turntable <NUM> and on which a drive roller <NUM> and/or a deflection roller <NUM> are/is likewise disposed.

The input portion <NUM> is furthermore provided on the turntable <NUM>, while the output portion <NUM> can be disposed on the further turntable <NUM>.

As can in particular be seen from <FIG>, the longitudinal conveying mechanism <NUM> preferably comprises a first conveying means <NUM> and a second conveying means <NUM>. The first conveying means <NUM> comprises a first conveying portion <NUM>, and the second conveying means <NUM> comprises a second conveying portion <NUM>. The first conveying portion <NUM> and the second conveying portion <NUM> are disposed so as to face one another and conjointly define a conveying duct <NUM> in which the profile bar <NUM> can be received for conveying. Each conveying portion <NUM>, <NUM> is preferably provided on a load strand <NUM> of the conveying means <NUM>.

The functioning mode of the conveying device <NUM> will be explained in more detail by means of <FIG>.

First, the profile bar <NUM> is inserted into the input portion <NUM>. The profile bar <NUM> thereafter is preferably engaged by a pair of conveying rollers <NUM>, such as, for example, the drive roller <NUM> and/or the deflection roller <NUM>, and introduced into the conveying duct <NUM>. The conveying means <NUM> can hug the circumferential face of the profile bar and thus engage a large part of the circumferential face of the profile bar. The conveying means <NUM> conveys the profile bar in the direction toward the output portion <NUM>. In the proximity of the output portion <NUM>, the profile bar <NUM> passes a second pair of conveying rollers <NUM>, for example a drive roller <NUM> and/or a deflection roller <NUM>, and thereafter enters the output portion <NUM> through the further turntable <NUM>.

In the output portion <NUM>, the profile bar <NUM> is melted by the heating installation <NUM> and by means of the exit nozzle <NUM> ejected in the direction toward the printing bed <NUM>.

The profile bar <NUM> is thus engaged by each conveying portion <NUM>, <NUM> along the entire conveying duct <NUM>. Each conveying portion <NUM>, <NUM> accordingly extends from the conveying roller <NUM> on the turntable <NUM> up to the conveying roller <NUM> on the further turntable <NUM>.

On account of the force-transmitting connection between the conveying means <NUM> and the profile bar <NUM>, the torque can be transmitted to the profile bar <NUM> by activating the rotating mechanism <NUM> such that said profile bar <NUM> can be rotated about the profile bar longitudinal axis of the latter.

Reference is made to <FIG> which shows a cross section along the line VI-VI from <FIG>. As can be seen in <FIG>, the conveying rollers <NUM> are configured as profiled rollers <NUM>. Each profiled roller <NUM> comprises a profile groove <NUM> which is adapted to the cross-sectional shape of the profile bar <NUM>. The profile bar <NUM> in the present example has a circular cross section so that the profile groove <NUM> has a semicircular shape. However, other cross-sectional shapes of the profile bar, for example elliptic, rectangular, or square, are also conceivable. The profile groove <NUM> in this instance has the correspondingly complementary shape which is adapted to the cross section of the profile bar <NUM>.

Reference is made to <FIG> which show further exemplary embodiments of the tool head <NUM>. Each tool head <NUM> is described only to the extent to which said tool head <NUM> differs from the tool head <NUM> from <FIG>. The conveying device <NUM> comprises a contact pressure device <NUM> which is configured for pushing the conveying means <NUM> against the profile bar <NUM>.

As is illustrated in more detail in <FIG> and <FIG>, the contact pressure device <NUM> can have a fluid chamber <NUM> which is able to be deformed by a fluid pressure. The fluid chamber <NUM> in a non-supplied state (<FIG>) is released from the conveying means such that a configuration as in the tool head <NUM> from <FIG> results. In order to improve the transmission of force from the conveying means <NUM> to the profile bar <NUM>, the fluid chamber <NUM> can be supplied with a fluid pressure (<FIG>) such that the fluid chamber <NUM> urges the conveying means <NUM> against the profile bar. The fluid chamber <NUM> is preferably configured as a deformable fluid cushion <NUM>.

Alternatively or additionally, the contact pressure device <NUM> can have a plurality of contact pressure rollers <NUM> which by virtue of an elastic element <NUM>, for example a spring <NUM>, urge the conveying means <NUM> in the direction toward the profile bar <NUM>, as is illustrated in more detail in <FIG>.

Claim 1:
A conveying device (<NUM>) for an additive manufacturing machine (<NUM>), wherein the conveying device (<NUM>) is configured for conveying a semi-finished product (<NUM>) which is composed of a manufacturing material that is to be processed by the additive manufacturing machine (<NUM>) and has a semi-finished product longitudinal axis, wherein the conveying device (<NUM>) comprises a longitudinal conveying mechanism (<NUM>) which is configured for conveying the semi-finished product (<NUM>) along a conveying direction parallel to the semi-finished product longitudinal axis, wherein the longitudinal conveying mechanism (<NUM>) has at least one running conveying means (<NUM>, <NUM>, <NUM>) which extends along the conveying direction and which has a conveying portion (<NUM>, <NUM>) that is configured for engage a semi-finished product portion of the semi-finished product (<NUM>) in such a manner that the semi-finished product (<NUM>) is able to be moved in the conveying direction, wherein the longitudinal conveying device (<NUM>) has a contact pressure device (<NUM>) which is configured for pushing the conveying means (<NUM>, <NUM>, <NUM>) against the semi-finished product (<NUM>) so as to move the semi-finished product (<NUM>) characterized in that
the contact pressure device (<NUM>) has a fluid chamber (<NUM>) which is able to be supplied with a fluid pressure, wherein the fluid chamber (<NUM>) which is able to be deformed by the fluid pressure and which in a supplied state is configured for urging the conveying means (<NUM>, <NUM>, <NUM>) in the direction toward the semi-finished product (<NUM>) so as to move the semi-finished product (<NUM>), and in particular in a non-supplied state for not exerting on the conveying means (<NUM>, <NUM>, <NUM>) a force which is sufficient for moving the semi-finished product (<NUM>).