HK1162405A - Device and method for generative manufacturing of a three dimensional object with construction area limit - Google Patents

Description

The present invention relates to a device and a process for generative manufacture of a three-dimensional object.

DE 199 37 260 B4 describes a device, known as a laser system, for the generative manufacture of a three-dimensional object, with a frame, the upper part of which encloses a construction field; a support which is arranged in the frame and which is moved vertically by a lifting mechanism at least below the construction field; a fixing device which produces an energy beam, which is focused by a deflector device at any point in the construction field in order to selectively sinter or melt the powder material in the construction field; and a coating for the application of a layer of powder material to the bearing or a layer of powder material to be applied to the bearing. The process of this fabrication shall be as follows:

In the upper part of the frame, a two-dimensional maximum construction area with a maximum length and width is defined in which the powder material can be applied and irradiated. In the vertical direction, the height of the largest object determines the minimum height per construction process. The three dimensions, namely the maximum length, maximum width and minimum height per construction process, give the minimum construction volume, and the powder bed and construction layers allow the amount of powder material required to be calculated.

If there is only a small amount of powder material or the use of material must be kept low for cost reasons, a very small height of the construction process is possible with a large area of the support. The situation is exacerbated in particular by the fact that the non-solid powder material can only be partially or sometimes not reused. A construction process with a large vertical height then leads to large amounts of waste, especially if the objects cannot be conveniently arranged in the frame or construction containers.

The present invention is intended to provide a device and a process for generative manufacture of a three-dimensional object, which will allow greater flexibility in the use of the device and an economical use of the powder in small objects and in the processing of costly and non-recyclable powder materials.

The advantage of the invention is that even small objects can be produced economically in a large laser sintering plant, since only the minimum amount of powder is used. In addition, it is possible to study the construction process under the thermal conditions of a large laser sintering plant with little powder material. In particular, the invention can be used for PAEK powders, such as PEEK, PEKK, etc., as a building material.

Further features and usefulness of the invention are shown by the description of examples of embodiments in the accompanying drawings. Figure 1a schematic view of a device for producing a three-dimensional object;Figure 2a schematic view of the maximum area and the reduced area contained therein according to an embodiment of the present invention; andFigure 3a schematic cross-sectional view of the device for producing a three-dimensional object with reduced area.

Figure 1 shows a schematic view of a device for producing a three-dimensional object 3 exemplified by a laser interpolation device.

The laser interlayer has a frame 1 open upwards with a vertical support 5 located in it, which can be moved in the direction of the three-dimensional object 3 to be manufactured. The upper section 2 of the frame includes a mounting field 6. Preferably, the frame 1 and the support 5 form an interchangeable interchangeable frame which can be removed from the laser interlayer. The support 5 is connected to a lifting mechanism 4 which moves it vertically at least below the level of the mounting field 6 so that the top of a powder layer to be solidified is in the level of the mounting field 6.

In addition, a coating 10 is provided for the application of a layer of a powder material 11. All laser sintering powders, such as plastic, metal, ceramic, sand and composite powders, may be used as powder materials 11. In particular, the powder may contain a PAEK polymer powder. Any metallic powder material may be any metal and alloys thereof, or mixtures with metallic or non-metallic components.

The coating 10 shall be applied at a predetermined height above the construction site 6 so that the layer of powder material 11 is above the support 5 or the last layer solidified at a defined height.

The device also has a solidification device in the form of a laser 7 which produces an 8.8' laser beam which is focused by a deflector 9 at any point in the field 6 and allows the 8.8' laser beam to selectively melt and solidify or sinter the powder material 11 at the points corresponding to the cross-section of the object 3 to be manufactured.

The laser sinter device may have a heater (not shown) above the construction site 6 to preheat a freshly applied powder layer to a temperature close to the process temperature of the powder material 11 required for solidification.

The reference number 100 is a housing containing frame 1, support 5 and coating 10. Preferably the housing is gas-tight and has an inlet at the top to introduce the laser beam 8, 8'. Preferably a protective gas is introduced into the housing 100. There is also a control unit 40 which controls the device in a coordinated manner to carry out the construction process and control the energy input by the laser 7. The control unit 40 uses 3 data sets of object 3 to produce the object, which define the geometry of the object 3, such as CAD data.

The side view of the coating is shown in Figure 1 and Figure 2 shows a schematic view of the coating 6 which is hereinafter referred to as the maximum coating 6 and has a maximum length L and a maximum width B in which the powder material 11 can be applied and irradiated.

If small objects 3 are to be manufactured and the maximum width B of the construction site 6 is not to be used, the coating layer 10 may be provided with a mechanical insert 12 which is only schematically indicated in Fig. 2 and which limits the application of powder material 11 to less than the maximum width B of the maximum construction site 6. Preferably, the mechanical insert 12 has an opening 15 for application of powder material 11 whose length in y direction is smaller than the maximum width B of the maximum construction site 6. This defines a y direction reduced construction site 13 as shown in the example in Fig. 2. Preferably, the mechanical insert 12 is provided with interchangeable coatings 10.

In the first step of operation of the device, the support 5 is lowered by the lifting mechanism 4 until its upper side is about the desired thickness of a first powder layer below the plane of the site 6 and then a first layer of powder material 11 is applied to the support 5 by the coating 10 and smoothed.

The method of the invention has a normal operation in which the powder material 11 is applied and irradiated within the maximum construction area 6. The method of the invention also has a special operation in which the powder material 11 is applied and irradiated in a region of less than the maximum length L and, when using the method 12, also of less than the maximum width B of the maximum construction area 6.

Thus, if small objects 3 are produced and the maximum length L of the construction site 6 is not to be used, the coater 10 can apply the powder material 11 in the x direction in an area with a reduced length compared to the maximum length L of the construction site 6, i.e. the coater 10 reverses its direction of motion before reaching the maximum length L of the construction site 6. This reduces the reduced construction site 13 in the x direction, as shown in Fig. 2 as an example. Structurally, the limitation of the cutting site 13 in the x direction is achieved, for example, by the control unit 40, which serves as a base limitation device and is programmed so that the coater 10 is not moved over the full distance L in the x direction, but only in the x direction of the reduced edge of the construction site 13.

Surprisingly, the adhesion forces commonly present between the powder particles have led to the realization of even angles of inclination of approximately 90°, so that objects of any three-dimensional shape can be realized despite the absence of boundary walls. Figures 2 and 3 show a particular embodiment of the invention. In addition to the three-dimensional object 3 being produced during the laser support process, the object 3 is produced in order to prevent the object from moving and to prevent the object 3 from moving on the powder field produced by the cut-out of the powder.

Preferably, the reduced site 13 is essentially bounded by the side of the maximum site 6 where the coating 10 enters site 6 because the coating process cannot start in the middle of site 6 if it is continuously carried out from a coating filling station outside site 6.

A construction operation using the special operation method with reduced construction area shall be carried out as follows: After application, the powder material 11 can be solidified at the desired points. If the heating device is provided, the heating device can bring the temperature of the top powder material 11 globally to a few °C below the process temperature necessary for solidification. The control unit 40 then controls the deflector 9 so that the deflected laser beam 8, 8' selectively reaches the points of the layer of powder material 11 to be solidified. This results in the powder material 11 being solidified or sintered at these points, thus producing the three-dimensional object 3 and, if necessary, the support 14 forcing.

In a next step, the support 5 is lowered by the lifting mechanism 4 to the desired thickness of the next layer. A second layer of powder material is applied through the coating 10, smoothed and selectively hardened by the laser steel 8.8'. These steps are repeated until the desired object 3 and, if necessary, the support walls 14 are produced.

Since the control unit 40 uses, for example, CAD data sets of object 3 defining the geometry of object 3 to produce object 3, the data sets should be supplemented, if necessary, by the CAD data of the support walls 14 by first generating, in the conventional way, a data set defining the geometry or dimensions of the finished three-dimensional object 3 and then by supplementing the data set with data defining the geometry or dimensions of the support walls 14 so that the support walls 14 can be produced simultaneously with the actual object 3 by the laser system.

The scope of protection is not limited to the examples of embodiments shown, but includes further modifications and alterations, provided that they fall within the scope defined by the enclosed claims.

The illustration described in this example describes a rectangular maximum construction block 6 and a rectangular reduced construction block 13. However, the invention is not limited to these shapes, since the building blocks 6, 13 can take a wide variety of shapes, for example, the building block 6 can be rectangular with rounded corners. The building blocks 6, 13 can also be circular, in which case the maximum length and maximum width of the building block correspond to the diameter of the circle. Oval building blocks 6 are also possible. Generally, the shape of the reduced upper building block 13 is not bound to the shape of the maximum construction block 6 or to the shapes of section 2 of frame 1. Depending on the different types of coating of the building block, the coating of a building block 13 can also be reduced in a number of ways, for example, by reducing the shape of the frame 1 by a rotating circle.

In the example shown, the support walls 14 are manufactured simultaneously with object 3 by the same manufacturing process. The device in question is applicable not only to the laser core but to all powder-based generative processes in which a material or powder material is used per layer to be applied, for example, which is solidified by the energetic radiation. The energetic radiation need not necessarily be an 8' laser beam, but it may also be, for example, an electron beam or a particle beam. Also, a full-surface irradiation, for example through a mask, is possible. Instead of the energetic radiation, an adhesive or binder can be applied at the desired places, selectively adhering the powder material.

Claims (6)

1. a width of not more than 50 mm, Other

   a frame (1) whose upper section (2) encloses a construction site (6);

   a support (5) placed in the frame (1) and capable of being moved vertically by a lifting mechanism (4) at least below the construction site (6);

   a coating (10) to apply a layer of powder material (11) to the support (5) or a previously applied layer of powder material (11) to the construction site (6);

   a strengthening device (7) capable of selectively strengthening powder material (11) in the site (6) at points corresponding to the cross-section of the object (3) in the applied layer, where:

   the construction site (6) is a two-dimensional maximum construction site (6) with a maximum length (L) that the coating (10) of the construction site (6) can travel and a maximum width (B) that the coating (10) can apply the powder material (11); and

   the coating (10) has a mechanical insert (12) that limits the application of the powder material (11) to less than the maximum width (B) of the maximum construction area (6), and/or the device has a construction area limitation device (40) that limits the travel of the coating (10) to less than the maximum length (L) of the maximum construction area (6), so that a reduced construction area (13) is defined.
2. Device according to claim 1, where the mechanical input (12) has an opening (15) the width of which in the direction of the maximum width (B) of the construction site (6) is less than the maximum width (B) of the maximum construction site (6).
3. Device according to one of the above claims, with the mechanical insert (12) being interchangeable on the coating (10).
4. A process for generatively producing a three-dimensional object in a device, using the following steps: Other

   (a) layered application of a powder material (11) on a support (5) of the device or a previously applied layer;

   (b) selective solidification of the powder material (11) at points corresponding to the cross-section of the object (3) in the applied layer;

   (c) Repeat steps (a) and (b) until object (3) is complete, wherein

   Other The device defines a two-dimensional maximum construction area (6) with a maximum length (L) and width (B) within which the powder material (11) can be applied; and The method consists of a normal operation where the powder material (11) is applied to the maximum surface area (6), and a special operation with a reduced surface area (13), where the powder material (11) is applied to a surface area less than the maximum length (L) and/or the maximum width (B) of the maximum surface area (6).
5. The method described in claim 4 whereby one length and one width of the three-dimensional object (3) are reduced upwards.
6. The method described in claim 4 or 5 whereby, in addition to the three-dimensional object (3), support walls (14) are produced that run around the object (3) in the reduced area (13) and prevent the applied powder (11) from escaping from the reduced area (13).