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1. WO2020141099 - TRAY SYSTEM FOR A 3D-PRINTER

Note: Text based on automatic Optical Character Recognition processes. Please use the PDF version for legal matters

[ EN ]

Title: TRAY SYSTEM FOR A 3D-PRINTER

FIELD

[0001 ] The present invention relates to additive manufacturing. In particular, the present invention relates to a tray system for an additive manufacturing apparatus or 3D-printer.

BACKGROUND

[0002] In the field of additive manufacturing an additive manufacturing apparatus is commonly referred to as a“3D-printer”. There are known 3D-printers that build workpieces by irradiating material in a tray. This material may be any suitable material e.g. metal or plastic powder or radiation curing liquid. The trays are usually containers that have a movable bottom or workpiece support such that the layers of the workpiece(s) are irradiated on the top of the tray and the bottom moves subsequently downwards in order to build up the workpiece(s). The material in the tray can be irradiated by a radiation source that passes over the tray and irradiates the areas of the tray where the respective layer of the workpiece(s) should be.

SUMMARY

[0003] Known 3D-printers of the above kind usually comprise only one tray and are thus not flexible in view of the size of workpiece(s) being built with the 3D-printer. Further, it is impossible to build different workpieces in different stages (e.g. one almost finished and another right at the beginning of the build). Further, with known 3D-printers of the above kind it is not possible to use different tray sizes. Flence, there is the need to provide for a tray system that is flexible.

[0004] It is thus the object of the present application to provide a tray system and 3D-printing method according to the appended independent claims to overcome the above inconveniences. Selected embodiments are comprised in the dependent claims. Each of which, alone or in any combination with the other dependent claims, can represent an embodiment of the present application.

[0005] According to one aspect of the present application a tray system for a 3D-printer comprises at least one tray and a modular receiving system. The modular receiving system has a modular receiving space with multiple tray slots. The at least one tray fits in at least one of the tray slots. This has the advantage that the 3D-printer can be flexibly equipped with trays of different size and flexible position(s) of the tray(s) in the modular receiving space. There can be only one tray and one tray slot.

[0006] According to a further aspect of the present application the tray system may further comprise a central material supply system. The central material supply system can supply material each of the tray slots from one point. This has the advantage that all tray slots can be supplied with material from one point.

[0007] According to a further aspect of the present application the multiple tray system may further comprise an individual material supply system for each tray slot. Each individual material supply system can supply material to the respective tray slot independent from the other material supply systems. This has the advantage that e.g. in case there is no tray at one of the tray slots the material supply can for example be deactivated for this tray without affecting the material supply for the other trays. Further, it is possible to use different materials with different trays.

[0008] According to a further aspect of the present application a bottom or workpiece support of each tray may be movable parallel to a build direction. The build direction is essentially parallel to the vertical axis of the 3D-printer. In other words, a bottom of each tray can move up and down, parallel to the build direction. This has the advantage that the inside of the tray can be used to produce workpieces.

[0009] According to a further aspect of the present application the modular receiving system may further comprises a conveying system. This conveying system can move a tray being located in a tray slot between a build area and an extraction area. This has the advantage that each individual tray can be moved out

of the build area to e.g. bring the tray to another processing machine and/or take out the workpiece(s) independent from the other trays.

[0010] According to a further aspect of the present application the multiple tray system may further comprises at least one material spreader per tray slot. This has the advantage that the material for each tray in the respective tray slot can be spread independent from the other tray slots, rendering the production process of the 3D-printer more flexible.

[0011 ] According to a further aspect of the present application the multiple tray system may further comprises one material spreader for the modular receiving space. This has the advantage that the multiple tray system may be kept simple in its design and maintenance for example is simplified.

[0012] According to a further aspect of the present application one tray may fit into one or more tray slots. In other words, the modular receiving space has a maximum number of tray slots and thus a maximum number of trays that can be put into the tray slots of the modular receiving space. However, a tray may fit into more than one tray slot and hence be lager as each individual tray that in case of said maximal number of trays. There are two opposing maximum scenarios: One in which there is said maximum number of trays and thus each tray is smallest in size and the other, where only one tray occupies all tray slots of the modular receiving space and thus this tray is largest in size. All other different configurations between these maximum scenarios are possible and disclosed. This has the advantage, that modular receiving space may be occupied with trays of different sizes such that the size of the tray can be matched with e.g. the size of the workpiece and further the 3D-printer having the multiple tray system may be operated with increased efficiency.

[0013] According to a further aspect of the present application each tray may comprise an identification system. This has the advantage that information regarding a print-job related to the regarding tray can be stored on the identification system and be of use in the entire production process.

[0014] According to another aspect of the present application a 3D-printing method for multiple trays is disclosed. According to this method a radiation source passes subsequently over the multiple tray slots of the above mentioned multiple tray system in a predetermined sequence (e.g. one by one starting from either side of the modular receiving space). This has the advantage that different workpieces having for example different dimensions, materials and quantities can be produced simultaneously.

[0015] According to another aspect of the present application the tray slots that are not irradiated are recoated or pre-heated or scanned or moved. Recoating has the meaning that a tray that was just irradiated is brought into a state in which the radiation source can pass a subsequent time and build up another layer of the workpiece(s). Recoating thus may comprise moving the bottom of the tray parallel to said build direction, supplying material to the tray, spreading the material, etc. This has the advantage that the tray is prepared for a further pass of the radiation source while said radiation source is irradiation another tray. Hence the efficiency of the printing method is increased.

[0016] Pre-heating has the meaning that the material, preferably after recoating and prior to a pass of the radiation source is heated up to a predetermined temperature. This temperature may inter alia depend on the material, the size of the tray, the radiation source and other parameters. Pre-heating has the advantage that the radiation source does not have to add a lot of energy into the material or tray or workpiece to add another layer and bring the material into a plastic state, but only a small amount to bridge the gap between the predetermined temperature and the temperature that renders the material into the plastic state. Hence the predetermined temperature is lower than the temperature that renders the material into the plastic state.

[0017] Scanning has the meaning that a scanning system scans the freshly irradiated tray prior to e.g. recoating in order to check if the material was irradiated according to the program controlling the 3D-printer to build the respective

workpiece. Scanning is thus a solution to control and ensure the quality of the workpiece while still in production. The scanning is not dependent on the modular receiving space or the multiple tray slots. The scanning can be performed on any kind or number of tray(s) or buildspace. This has the advantage that while the workpiece is still produced, the method or process can be controlled and if necessary altered or stopped to ensure the desired quality of the workpiece.

[0018] Each of the above aspects is to be considered an invention on its own. The aspects can be combined freely with each other. The aspects regarding the tray system are also aspects of the printing method and vice versa.

BRIEF DESCRIPTION OF THE FIGURES

[0019] Further advantages and features of the present disclosure will be apparent from the appended figure. The figure is of merely informing purpose and not of limiting character. The figure schematically describes an embodiment of the present application.

[0020] Figure 1 shows a schematic view of a tray system according to the present application.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0021 ] Referring to figure 1 a tray system 10 is depicted. The tray system 10 comprises a modular receiving system 30. The modular receiving system 30 comprises four equally sized trays 20 (any other number of trays starting from one tray is possible). The modular receiving system 30 further comprises a modular receiving space 40 having tray slots 50 in which the trays 20 can be positioned. The modular receiving system 30 further comprises a conveying system 60.

[0022] The tray system 10 further comprises a radiation source 90 and a scanner 80 that can move above the trays 20 parallel to a direction B. The scanner 80 is optional. The radiation source 90 and the scanner 80 can move independently from each other. The radiation source irradiates the trays 20. The scanner 80 scans the trays 20 after each pass of the radiation source 90 and prior to a recoating of the respective tray. There can be a central material supply that supplies all four trays 20 with material (not shown). There alternatively can be an individual material supply for each of the trays 20 (not shown). The tray system 10 may further comprise either one material spreader for all trays or individual material spreader for each of the trays 20 (both not shown). In case of one material spreader, the single material spreader can also move parallel to the direction B and spread material supplied to the trays 20 from either a central material supply or an individual material supply for each tray 20. The options of single or individual material spreader and central or individual material supply can freely be combined: central material supply with single material spreader, individual material supply with single material spreader, central material supply with individual material spreader and individual material supply with individual material spreader.

[0023] The conveying system 60 can move a tray 20 from its tray slot 50 and thus a build area to an extraction area. In figure 1 tray 20a is shown in the extraction area. Here, one or more workpieces may be taken from the tray 20a or the entire tray 20a can be replaced with another tray. The conveying system 60 then conveys the tray 20a back to the respective tray slot 50. In figure 1 only one conveying system 60 is shown, however, all or any desired number of tray slots 50 may be equipped with a conveying system 60. The conveying system 60 can move the tray 20a parallel to the direction C indicated with the arrow in figure 1.

[0024] The tray 20a comprises an identification system 70. The identification system 70 may be a transponder device such as an RFID device or the like. Information regarding the workpiece(s) in the tray 20a may be stored in the identification system 70. This information may be the material information, number of workpieces, customer information, etc. In case of an individual material supply for each tray 20 or tray slot 50, the information system 70 may communicate with the material supply such that the material supply supplies the material stored on the identification system 70.

[0025] In figure 1 the trays 20 have a movable bottom 25 (only one shown in figure 1 ). The movable bottom 25 is movable parallel to a build direction A as indicated with the arrow in figure 1.

[0026] In figure 1 four equally sized trays 20 and tray slots 50 are shown. It is however possible that a tray occupies more than one tray slot. In the depicted example a tray may have the size of two, three or even all four tray slots. In other words, the trays 20 have a minimum size to fit into the tray slot 50 but can be larger by a multiple of the size of the tray slot up to the size of the entire modular receiving space 30.

[0027] The radiation source 90 passes over the trays 20 in the modular receiving space 30 one by one and irradiates the trays 20 to form a layer of the workpiece(s). Subsequently the scanner 80 follows and scans the areas within the trays 20 that just had been irradiated by the radiation source 90 in order to make sure the layer of the workpiece(s) have correctly been irradiated. After the scanner scanned a respective tray this tray may be recoated. For this the bottom of the tray 25 moves downwards parallel to the build direction A by a predetermined way (a layer thickness). Subsequently material is supplied to the tray by either the central or the individual material supply. Subsequently and in case there are individual material spreader, the individual material spreader spreads the material of the tray that is being recoated. In case there is a single material spreader, the radiation source 90 and the scanner 80 pass all trays 20 and all bottoms or workpiece supports 25 of the trays 20 move downwards and material is supplied to all trays, corresponding to the proceeding described above. After all trays were irradiated, scanned and filled with new material the single material spreader passes over all trays 20 parallel to the direction B and spreads the material.