Selective laser sintering printing system

Abstract

The selective laser sintering printing system comprises a laser (10) with a laser spot diameter of 0.3mm to 0.35mm. The selective laser sintering printing system is capable of clearly presenting the detailed features of a 3D printed part. The invention also provides the use of the selective laser sintering printing system as described above in the selective laser sintering printing of polymer powder to produce a 3D printed product.

Description

Technical Field

[0001] This invention relates to the field of 3D printing additive manufacturing, and in particular to a selective laser sintering printing system. Background Technology

[0002] Selective Laser Sintering (SLS) is an additive manufacturing technology based on the discrete-stacking principle. It uses a laser beam as the heat source and powdered materials (such as nylon powder) as the raw material. During processing, a thin layer of powder material is uniformly laid in a powder-laying space. Under computer control, the laser beam selectively scans and sinterstens the powder layer according to the two-dimensional cross-sectional contour information of the part, causing the powder particles to bond together and form a layer of the part. After one layer is sintered, the stage lowers by one layer thickness to empty the powder-laying space, and a new layer of powder is laid. This sintering process is repeated layer by layer until a three-dimensional solid part is formed. The unsintered powder plays a supporting role during the forming process and can be recycled after forming.

[0003] In current laser applications, 10.6 μm wavelength carbon dioxide lasers are widely used. For polymer materials, especially nylon powder, the absorption rate of 10.6 μm wavelength laser light is as high as 96%. However, because the temperature absorption effect cannot achieve an instantaneous change, a heat-affected zone inevitably forms at the edge of the actual focused laser spot. The existence of this heat-affected zone makes the actual diameter of the laser spot acting on the nylon powder significantly larger than the actual laser spot diameter.

[0004] In selective laser sintering (SLS) printing applications, the heat-affected zone of the focused spot of a 10.6μm wavelength carbon dioxide laser can cause a series of problems when manufacturing small parts or integrally molded mating parts. For example, the detailed features of the parts are not clearly presented, affecting the quality and performance of the parts. Summary of the Invention

[0005] The purpose of this invention is to provide a selective laser sintering printing system that can clearly present the detailed features of 3D printed parts.

[0006] Another object of the present invention is to provide the application of the above-described selective laser sintering printing system in selective laser sintering printing polymer powder to prepare 3D printed products, so as to prepare 3D printed parts with clear detailed features.

[0007] The selective laser sintering printing system provided by the present invention includes a laser with an output laser spot diameter of 0.3 mm to 0.35 mm.

[0008] By selecting a smaller laser spot diameter, selective laser sintering printing systems can clearly present the detailed features of 3D printed parts.

[0009] In another illustrative embodiment of the selective laser sintering printing system, the laser is a carbon dioxide laser with an output wavelength of 9.0 μm to 9.8 μm. Choosing a carbon dioxide laser helps reduce processing costs.

[0010] In another illustrative embodiment of the selective laser sintering printing system, the laser is a carbon dioxide laser with an output wavelength of 9.3 μm. This type of laser is technologically mature and inexpensive.

[0011] In another illustrative embodiment of the selective laser sintering printing system, an optical assembly is also included. The optical assembly includes a base plate and a beam expander, a reflector, a dynamic focusing module, and a galvanometer module disposed on the base plate. The laser emitted by the laser can sequentially pass through the beam expander, the reflector, the dynamic focusing module, and the galvanometer module before illuminating the processing surface.

[0012] In another illustrative embodiment of the selective laser sintering printing system, the laser's scanning speed for the printed data border is 1320 mm / s, the power of the printed data border is 19 W, and the laser energy density for the printed data border is 0.12 J / mm². 2 The print data filling scanning speed is 7640 mm / s, the print data filling power is 62 W, ​​and the print data filling laser energy density is 0.26 J / mm². 3 .

[0013] The selective laser sintering (SLS) printing system provided by this invention is applied in the selective laser sintering printing process. The SLS process uses polymer powder as raw material to prepare 3D printed products; the polymer powder is nylon powder. The selective laser sintering printing process includes: S10: The polymer powder is laid in the powder-laying space of the selective laser sintering printing system to obtain a thin powder layer; S20: A construction is completed by melting a selected region within the powder thin layer using laser scanning; and S30: Move the constructed portion down to make room for toner, then return to S10 until printing is complete. Attached Figure Description

[0014] The following figures are for illustrative purposes only and do not limit the scope of the invention.

[0015] Figure 1 This is a schematic diagram illustrating one embodiment of a selective laser sintering printing system.

[0016] Figure 2 A flowchart illustrating one embodiment of selective laser sintering (SLS) for preparing 3D printed products.

[0017] Figure 3 This is a comparison chart used to illustrate the printing effect of a selective laser sintering system.

[0018] Label Explanation 10 Lasers 20 Optical Components 21 Base Plate 22 Beam expander 23. Reflector 24 Dynamic Focusing Module 25. Galvanometer module. Detailed Implementation

[0019] To provide a clearer understanding of the technical features, objectives, and effects of the invention, specific embodiments of the invention are now described with reference to the accompanying drawings, in which the same reference numerals denote the same parts.

[0020] In this document, “illustrative” means “serving as an example, illustration or description”, and any illustration or implementation described herein as “illustrative” should not be construed as a more preferred or advantageous technical solution.

[0021] Figure 1 This is a schematic diagram illustrating the structure of a selective laser sintering printing system. See also... Figure 1 In an illustrative embodiment, the selective laser sintering printing system includes a laser 10 that outputs a laser spot with a diameter of 0.3 mm to 0.35 mm.

[0022] By selecting a smaller laser spot diameter, selective laser sintering printing systems can clearly present the detailed features of 3D printed parts.

[0023] Laser 10 is, for example, a carbon dioxide laser, which outputs a laser wavelength of 9.0 μm to 9.8 μm, preferably 9.3 μm. This type of laser is technologically mature and inexpensive, which helps to reduce processing costs.

[0024] The selective laser sintering printing system also includes an optical assembly 20. The optical assembly 20 includes a base plate 21 and a beam expander 22, a reflector 23, a dynamic focusing module 24, and a galvanometer module 25 disposed on the base plate 21. The laser emitted by the laser 10 (such as...) Figure 1 As shown by the red line (and the arrow indicating the direction of laser propagation), the laser beam passes sequentially through the beam expander 22, the reflector 23, the dynamic focusing module 24, and the galvanometer module 25 before illuminating the processing area. In an illustrative embodiment, the processing area is, for example, polymer powder laid in the powder-laying space of the selective laser sintering printing system.

[0025] During selective laser sintering printing, the operating parameters of the laser 10 include: a scanning speed of 1320 mm / s for the printing data border, a power of 19 W for the printing data border, and a laser energy density of 0.12 J / mm² for the printing data border. 2 The print data filling scanning speed is 7640 mm / s, the print data filling power is 62 W, ​​and the print data filling laser energy density is 0.26 J / mm². 3 .

[0026] The selective laser sintering (SLS) printing system provided by this invention can be applied to the selective laser sintering (SLS) printing process. The SLS process uses polymer powder as a raw material to prepare 3D printed products, such as nylon powder. The SLS process includes steps S10 to S30, as follows: Figure 2 As shown.

[0027] S10: The polymer powder is laid in the powder-laying space of the selective laser sintering printing system to obtain a thin powder layer.

[0028] S20: Selected areas in the powder layer are melted by laser scanning to complete a build.

[0029] S30: Move the constructed portion down to make room for toner, then return to S10 until printing is complete.

[0030] The following examples illustrate the application of the selective laser sintering printing system provided by the present invention in the selective laser sintering printing process, and compare it with comparative examples. Example

[0031] S10: Polymer powder (brand name: 1172Pro BLK) is laid in the powder-laying space of the selective laser sintering printing system to obtain a thin powder layer. The laser output wavelength of the selective laser sintering printing system is 9.3μm.

[0032] S20: A construction is completed by melting a selected region in the powder thin layer using laser scanning, wherein the laser scanning mode is border-fill, and the border laser energy density is 0.12 J / mm². 2 The border scanning speed is 1320 mm / s, the border power is 19 W, and the fill laser energy density is 0.26 J / mm². 3 The fill scanning speed is 7640mm / s, the fill power is 62W, the fill spacing is 0.26mm, the spot fill is 0.3mm, and the distance from the border to the fill is 0.08mm.

[0033] S30: Move the constructed part down to make room for powder spreading, then return to S10 until printing is complete, and obtain the 3D printed part.

[0034] Measure the laser scan width used for this 3D printed part, such as Figure 3 The white bar region A is shown in Figure 'a'. A black rectangular measuring bar is inserted into this white bar region A (located in...). Figure 3 The width of the left side of 'a' is 0.20mm, therefore, the laser scan width is approximately 0.24mm. Measuring the dimensions of the 3D printed part with calipers, the minimum build size is 0.44mm. Figure 3 As shown in c.

[0035] Comparative Example S10: Polymer powder (brand name: 1172Pro BLK) is laid in the powder-laying space of the selective laser sintering printing system to obtain a thin powder layer. The laser output wavelength of the selective laser sintering printing system is 10.6μm.

[0036] S20: A construction is completed by melting a selected region in the powder thin layer using laser scanning, wherein the laser scanning mode is border-fill, and the border laser energy density is 0.12 J / mm². 2 The border scanning speed is 1320 mm / s, the border power is 19 W, and the fill laser energy density is 0.26 J / mm². 3 The fill scanning speed is 7640mm / s, the fill power is 62W, the fill spacing is 0.26mm, the spot fill is 0.3mm, and the distance from the edge to the fill is 0.08mm.

[0037] S30: Move the constructed part down to make room for powder spreading, then return to S10 until printing is complete, and obtain the 3D printed part.

[0038] Measure the laser scan width used for this 3D printed part, such as Figure 3 The white bar region B shown in Figure b. Insert the black rectangular measurement bar (located in...) into this white bar region B. Figure 3 The width of the left side of 'b' is 0.20mm, therefore, the laser scan width is approximately 0.28mm. Measuring the dimensions of the 3D printed part with calipers, the minimum build size is 0.55mm. Figure 3 As shown in d.

[0039] like Figure 3As shown, this selective laser sintering printing system uses a laser with an output wavelength of 9.3 μm, which has a smaller laser scanning width and minimum forming size than a laser with an output wavelength of 10.6 μm. Therefore, in the actual printing process, using a laser with an output wavelength of 9.3 μm can more accurately render the fine features of the parts, reducing surface adhesion problems at the edges of the parts caused by an excessively wide laser scanning width, and reducing adhesion problems at the mating parts of the assemblies.

[0040] It should be understood that although this specification is described according to various embodiments, not every embodiment contains only one independent technical solution. This way of describing the specification is only for clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

[0041] The detailed descriptions listed above are merely specific descriptions of feasible embodiments of the present invention and are not intended to limit the scope of protection of the present invention. All equivalent implementation schemes or modifications made without departing from the spirit of the present invention, such as combinations, divisions or repetitions of features, should be included within the scope of protection of the present invention.

Claims

1. A selective laser sintering printing system, characterized in that, It includes a laser (10) whose output laser spot diameter is 0.3 mm to 0.35 mm.

2. The selective laser sintering printing system as described in claim 1, characterized in that, The laser (10) is a carbon dioxide laser with an output laser wavelength of 9.0 μm to 9.8 μm.

3. The selective laser sintering printing system as described in claim 2, characterized in that, The laser (10) outputs a laser wavelength of 9.3 μm.

4. The selective laser sintering printing system as described in claim 1, characterized in that, It also includes an optical component (20), which includes a base plate (21) and a beam expander (22), a reflector (23), a dynamic focusing module (24) and a galvanometer module (25) disposed on the base plate (21). The laser emitted by the laser (10) can pass through the beam expander (22), the reflector (23), the dynamic focusing module (24) and the galvanometer module (25) in sequence and then irradiate the processing area.

5. The selective laser sintering printing system as described in claim 1, characterized in that, The laser (10) has a printing data border scanning speed of 1320 mm / s, and / or a printing data border power of 19 W, and / or a printing data border laser energy density of 0.12 J / mm², and / or a printing data fill scanning speed of 7640 mm / s, and / or a printing data fill power of 62 W, ​​and / or a printing data fill laser energy density of 0.26 J / mm². 3 .

6. The application of the selective laser sintering printing system as described in any one of claims 1 to 5 in the selective laser sintering printing process, wherein the selective laser sintering printing process uses polymer powder as raw material to prepare 3D printed products, the polymer powder being nylon powder, and the selective laser sintering printing process includes: S10: The polymer powder is laid in the powder-laying space of the selective laser sintering printing system to obtain a thin powder layer; S20: A construction is completed by melting a selected region within the powder thin layer using laser scanning; and S30: Move the constructed portion down to make room for toner, then return to S10 until printing is complete.

Images