Abstract
A 3D printed fixture (100) for a luminaire is provided. The 3D printed fixture comprises at least one meshed wall part (110) and at least one solid wall part, wherein the meshed wall part further comprises a plurality of wall segments (112) defining a plurality of apertures (114) extending through the meshed wall part. The solid wall part and the meshed wall part are formed by a plurality of layers (130) stacked on each other in a stacking direction. Each layer forms cross sectional portions (116) of the plurality of wall segments of the meshed wall part and a cross-sectional portion (126) of the solid wall part. For each layer, the sum of the perimeters of the cross-sectional portions of the plurality of wall segments exceeds the perimeter of the cross-sectional portion of the solid wall part.
Claims
1. A 3D printed fixture for a luminaire, comprising: at least one meshed wall part having a plurality of wall segments defining a plurality of apertures extending through the meshed wall part, and at least one solid wall part, wherein the solid wall part and the meshed wall part are formed by a plurality of layers stacked on each other in a stacking direction, such that each layer forms cross-sectional portions of the plurality of wall segments of the meshed wall part and a cross-sectional portion of the solid wall part, wherein, for each layer, the sum of the perimeters of the cross-sectional portions of the plurality of wall segments exceeds the perimeter of the cross-sectional portion of the solid wall part, wherein each layer is formed by a material added in a plurality of lines arranged adjacent to each other in a main plane of extension of the layer, and wherein each of the plurality of wall segments is formed by more than two and less than ten lines adjoining each other in the direction orthogonal to the stacking direction, and further by more than one and less than ten lines adjoining each other in the stacking direction.
2. The fixture according to claim 1, wherein each of the plurality of wall segments is elongated and interconnected to each other at interconnection points to form the meshed wall part.
3. The fixture according to claim 2, wherein for each of the plurality of wall segments a spacing between two neighboring interconnection points is formed by more than one and less than ten lines adjoining each other in the length direction.
4. The fixture according to claim 1, wherein the fixture is elongated.
5. The fixture according to claim 4, wherein the fixture has a length to width ratio exceeding two, such as exceeding five, such as exceeding ten.
6. The fixture according to claim 1, wherein the fixture forms a housing comprising at least two side walls, wherein a first one of the side walls is formed of the solid wall part and the other one of the side walls is formed of the meshed wall part.
7. The fixture according to claim 6, wherein the fixture is elongated, and wherein the two side walls extend along a length direction of the fixture.
8. A method for 3D printing of a fixture for a luminaire, comprising: forming at least one meshed wall part having a plurality of wall segments defining a plurality of apertures extending through meshed wall part, and forming at least one solid wall part, wherein forming the solid wall part and the meshed wall part comprises adding a plurality of layers stacked on each other in a stacking direction, such that each layer forms cross-sectional portions of the plurality of wall segments of the meshed wall part and a cross-sectional portion of the solid wall part, wherein, for each layer, the sum of the perimeters of the cross-sectional portions of the plurality of wall segments exceeds the perimeter of the cross-sectional portion of the solid wall part, wherein each layer is formed by adding a material in a plurality of lines arranged adjacent to each other in a main plane of extension of the layer, and wherein each of the plurality of wall segments is formed by more than two and less than ten lines adjoining each other in the direction orthogonal to the stacking direction, and further by more than one and less than ten lines adjoining each other in the stacking direction.
9. The method according to claim 8, wherein the solid wall part and the meshed wall part are formed by means of fused deposition modelling, FDM.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) This and other aspects of the present invention will now be described in more detail with reference to the appended drawings showing embodiment(s) of the invention.
(2) FIG. 1 shows a fixture comprising at least one meshed wall part and at least one solid wall part according to an exemplifying embodiment of the present invention,
(3) FIG. 2 shows a fixture according an exemplifying embodiment of the present invention,
(4) FIG. 3 schematically shows cross-sectional portions of a meshed wall part and a solid wall part according to an exemplifying embodiment of the present invention,
(5) FIG. 4 shows the formation of a part of a fixture according to an exemplifying embodiment of the present invention,
(6) FIG. 5 a fixture according to an exemplifying embodiment of the present invention, and
(7) FIG. 6 shows a fixture for a linear luminaire according to an exemplifying embodiment of the present invention.
DETAILED DESCRIPTION
(8) Referring to FIG. 1, there is shown a 3D printed fixture 100 according to an exemplifying embodiment of the present invention. The fixture in FIG. 1 comprises at least one meshed wall part 110 and at least one solid wall part 120. The at least one meshed wall part 110 comprises a plurality of wall segments 112 arranged in a mesh-like structure, thereby defining a plurality of apertures 114 extending through the meshed wall part 110. In contrast to the meshed wall part 110, the solid wall part 120 has a continuous or connected surface without any apertures.
(9) The fixture 100 may be formed in an additive manufacturing process, such as a fused filament fabrication (FFF), or fused deposition modelling (FDM) process, in which raw material is added in a layer-by-layer fashion as will be discussed in further detail in connection with e.g. FIG. 4. The meshed wall part 110 and solid wall part 120 may be formed of the same material or by different materials. Examples of materials commonly used for 3D printing include a thermoplastic materials, such as acrylonitrile butadiene styrene (ABS), polylactic acid (PLA), polyethylene terephthalate (PET), high-impact polystyrene (HIPS), thermoplastic polyurethane (TPU) and aliphatic polyamides (nylon).
(10) The fixture 100 illustrated in FIG. 1 forms part of a linear luminaire, and is more specifically arranged to form a frame holding functional elements of the luminaire. In the present example, the fixture 100 is configured to receive printed circuit boards (PCBs) 160. The PCBs holds a plurality of light sources, such as LEDs, as well as electronic circuits for controlling and operating the light sources (not shown in present figure). The fixture 100 may be arranged to allow the PCBs 160 to slide into the fixture. In the present example, the fixture 100 may be considered to form an elongated housing at least partly enclosing the functional elements of the luminaire. It will be appreciated that this luminaire design requires the fixture 100 to have a relatively high mechanical stability and form integrity, as it otherwise may be difficult to fit the PCBs 160 into the fixture 100. Warping may for instance cause the PCBs 160 to get stuck as they are being slid into the fixture 100. Further, if PCB's are slid into a curved guidance, stresses may arise in the PCBs because of bending, which risks resulting in non-functioning PCBs in terms of light beam generation and life-time reductions.
(11) In FIG. 1 this issue is addressed by combining the solid wall part 120 with a meshed wall part 110 according to a design rule that will be discussed below with reference to FIGS. 3-5. While solid print designs such as the one represented by the solid wall part 120 may provide objects having a relatively high mechanical strength, they also tend to suffer from stress-induced damages originating from internal stresses at the interface between adjoining material lines and adjoining layers. The internal stresses may accumulate and propagate through solid parts of the 3D printed object. Beneficially, the internal stresses may be reduced by introducing meshed wall parts 110, comprising apertures 114 breaking the accumulation and propagation of internal stresses through the material forming the wall part. The meshed wall parts 110 may, as shown in FIG. 1, form entire sidewalls of the fixture 100. Thus, the fixture 100 may comprise a first elongated wall part 120 formed by a solid print design and a second elongated wall part 110, parallel to the first one, formed by a meshed print design.
(12) FIG. 2 schematically illustrates a fixture 100 according to an exemplifying embodiment of the present invention, comprising a meshed wall part 110 and a solid wall part 120 similar to the ones discussed above in connection with FIG. 1. Thus, the meshed wall part 110 and the solid wall part 120 may be manufactured in a layer-by-layer fashion, wherein each layer defines a cross-sectional portion of both the solid wall part 120 and the segments 112 forming the meshed layout of the meshed wall part 110. Each layer may extend in the x-y plane illustrated in the present figure, and be stacked on top of each other in the z-direction.
(13) In contrast to the meshed wall part 110 in FIG. 1, the present meshed wall part 110 comprises a regular pattern of rectangular apertures 114. The plurality of wall segments 112 are in FIG. 2 elongated and interconnected to each other at interconnection points 118 to form the mesh. For each individual wall segment 112, two neighboring interconnection points 118 are separated by a spacing 119.
(14) A design rule determining the balance between the meshed wall part 110 and the solid wall part 120 for each layer will now be exemplified with reference to FIG. 3, showing a cross section taken along one of the layers forming the fixture 100 shown in FIG. 2. The cross section is hence taken orthogonal to the stacking direction z. The layer comprises a plurality of cross-sectional portions 116 of the plurality of wall segments 112 of the mesh wall part 110 as well as a cross-sectional portion 126 of the solid wall part 120 of the fixture 100. As already mentioned, each layer (such as the one coinciding with the cross section in FIG. 3) comprises cross sectional portions of both the plurality of wall segments 112 of the meshed wall part 110 and the solid wall part 120. Each of cross-sectional portions 116 of the plurality of wall segments 112 of the meshed wall part 110 has perimeter P1, defining the outer boundary of each segment in the particular layer shown in FIG. 3. Similarly, the cross-sectional portion 126 of the solid wall part 120 has perimeter P2, defining the outer boundary of the solid wall part in the layer illustrated in the present figure.
(15) The design rule may be expressed as an inequality which may be applied for each layer of the fixture 100. According to this inequality, the sum of the perimeters P1 of the cross-sectional portions 116 should exceed the perimeter P2 of the cross-sectional portion 126 of the solid wall part 120. Thus, if there are n wall segments 112 in a layer, the perimeter P2 of the solid wall part 120 may not exceed n times P1, i.e., nP1>P2. It will be appreciated that the sum of the perimeters P1 of the meshed wall part 110 may vary between different layer, as long as the sum exceeds the perimeter P2 of the solid wall part 120 in the same layer. Should the perimeter P2 of the solid wall part exceed this value, the number of segment 112 in the meshed wall part 110 may be increased to balance the distribution between the solid wall part 120 and the meshed wall part 110.
(16) In FIG. 3 the cross-sectional portions 116 of the plurality of wall segments 112 and the cross-section portion 126 of the solid wall part 120 have a regular shape, for example, a rectangular shape. This is merely for illustrative purposes, and it will therefore be appreciated that other shapes also are possible, as illustrated below in connection with FIG. 6. The cross sections 116, 126 may for example conform to circles, ellipses, hexagons, and the like, as well as irregular shapes and patterns.
(17) FIG. 4 shows an example of a 3D printing technique employed for forming a wall part, such as a meshed wall part 110 and or a solid wall part 120, of a fixture 110 according to an embodiment. The fixture 100 may be similarly configured as any of the fixtures discussed above with reference to FIGS. 1-3. The material may be added in a stack of consecutive layers 130, wherein each layer has a main plane of extension along the x-y plane illustrated in the present figure and a thickness in the z-direction. The layers may be added one-by-one in a sequential manner along the stacking direction (in the present example coinciding with the z-direction). Each layer may be formed of a plurality of lines, or material strings, added next to each other in an adjoining manner. Beneficially, the material is added in a melted or at least softened state to promote adhesion to underlying layers and neighboring lines.
(18) The 3D printing technique may be a fused filament fabrication process in which a raw material, such as a filament material, is extruded through a nozzle 150 moving in the x-y plane to deposit the material in a plurality of lines or strings 132. The number of lines 132 touching each other in each plane, and also in the stacking direction, may be determined by a design rule according to an exemplary embodiment of the present invention. This is based on the insight that the strength and stability of the meshed wall part 110, well as the internal stresses accumulated in the same, depend on the number of adjoining lines 132 used to form the cross-sectional portions 116 of the segments in each layer 130. With too few adjoining lines 132 it may be difficult to provide a sufficient mechanical strength, and with too many adjoining lines 132 stress may be induced in the material.
(19) In an exemplary embodiment, each of the plurality of wall segments 112 may be formed by more than two and less than ten lines 132 adjoining each other in the direction orthogonal to the stacking direction, and further by more than one and less than ten lines 132 adjoining each other in the stacking direction. When the plurality of lines 132 of melted or softened printing material are arranged adjacent to each other and starts to cool down, an internal stress is introduced because of the material shrinking. By limiting the number of touching lines 132 when forming the meshed wall part 110, the stress in the material may be reduced and potential problems with delamination and warpage mitigated.
(20) FIG. 5 shows a meshed wall part 110 of a fixture 100 according to an embodiment, which may be similarly configured as the fixtures disclosed in FIGS. 1-4. Thus, the segments 112 of the meshed wall part 110 may be formed by adding material in a plurality of layers 130 similar to what is described above in connection with FIG. 4. The segments 112 are interconnected at interconnection points 118, which may be spaced apart by a spacing 119 corresponding to more than one and less than ten lines 132 adjoining each other in the length direction of the segment 112. It will be appreciated that the lines may adjoin each other in the plane coinciding with the layer 130, in the stacking direction substantially orthogonal to the plane, or a combination of both, depending on the orientation of the particular segment 112. The length of a segment 112 may thus be defined by the number of lines 132 touching each other in the length direction of the segment. As shown in FIG. 5, the segment 112 may not necessarily extend along a straight line. It may as well have a curved or bent shape. In such case, the length of the segment 112 may still be defined by the number of lines adjoining each other along the curved line.
(21) FIG. 6 shows an exemplary embodiment of a fixture 100 which may be similar to the one in FIG. 1. The fixture 100 forms an elongated housing comprising at least two side walls 140 extending in parallel along the length direction of the housing, as well as two end walls 142 arranged at opposite end portions of the elongated housing 100. A first one of the side walls 140 is formed of a solid wall part 120 and the other one of the side walls 140 is formed of a meshed wall part 110. Similar to the above-mentioned fixtures, the fixture 100 may be formed by a 3D printing process in which a stack of consecutive layers are arranged on top of each other. In the present example, the stacking direction may coincide with the length direction of the housing 100. Hence, for each cross section through the sidewalls 140, a sum of the perimeters of the cross-sectional portions of meshed wall part 110 exceeds the perimeter of the cross-section portion(s) of the solid wall part(s). The housing may for example form part of a linear luminaire, having a length l exceeding the width w by a factor two or more. In some examples, the length to width ratio exceeds 5, or even 10.
(22) The housing 100 may allow at least one light source, for example, a LED, a light bulb, a light tube and/or a series of light sources, such as a strip of LEDs to be accommodated in the fixture 100. In the present example the LEDs are attached to a PCB 160 which can be slid into a receiving structure in the housing 100.
(23) The person skilled in the art realizes that the present invention by no means is limited to the preferred embodiments described above. On the contrary, many modifications and variations are possible within the scope of the appended claims. For example, the fixture 100 may be configured to form part of, or form, other types of luminaries than the linear ones.
