A method for additive manufacturing of highly transparent molten salt pump impellers based on photocuring technology

Abstract

The invention relates to the technical field of photocuring additive manufacturing, and in particular to an additive manufacturing method for a high-transparency molten salt pump impeller based on photocuring technology. The method can directly manufacture products with high transparency through additive manufacturing, and the implementation process is simple. There is no need to use polishing and varnish spraying to achieve a high transparency effect, thereby improving the manufacturing efficiency of transparent parts. The method comprises the following steps: a first step, determining the size of a metal substrate and a photosensitive resin material for additive manufacturing according to the size of a molten salt pump impeller; a second step, using slicing software to slice and layer components to be printed; a third step, determining a support scheme and a laser spot scanning scheme; and a fourth step, performing additive manufacturing of a high-transparency molten salt pump impeller.

Description

Technical Field

[0001] The present invention relates to the technical field of photocuring additive manufacturing, and in particular to a method for additive manufacturing a highly transparent molten salt pump impeller based on photocuring technology. Background Art

[0002] Additive manufacturing is a technology that uses digital model files as the basis, and uses adhesive materials such as resin plastics or powdered metals to construct objects by printing layer by layer. 3D printing, as a popular name, belongs to rapid prototyping in terms of molding methods, and its essence is additive manufacturing technology. It is an emerging technology that is rapidly developing in the manufacturing field and is called "manufacturing technology with industrial revolutionary significance". It has been widely promoted because it has the advantages of saving cost and time and being more environmentally friendly than traditional manufacturing models. Photocuring technology is the earliest rapid prototyping additive manufacturing technology. It is highly mature, and the appearance of photocuring technology molding is delicate. The support structure is a mesh support, and the material utilization rate is relatively high. The characteristics of manufacturing using this technology are: using computer software to design a three-dimensional data model, and then using a specific molding device (commonly known as a "3D printer") to "print" the product layer by layer with liquid resin materials.

[0003] However, currently, products additively manufactured using liquid resin materials based on photocuring technology are mainly white and black. Even products additively manufactured using transparent resin materials are mostly translucent, and later on, they are processed manually, such as polishing and spraying varnish, to achieve a transparent effect, which is a cumbersome process.

[0004] Invention patent CN201811633861.8 discloses a method for preparing a highly transparent bionic vascular model for fluid mechanics observation experiments. The positive mold of the bionic vascular model is made using FDM-type 3D printing technology. It belongs to the fused deposition model (FDM) additive manufacturing technology and uses thermoplastic materials. It is completely different from the photo-curing (SLA) additive manufacturing technology used in the method of the present invention. The method of the present invention uses photosensitive resin materials instead of thermoplastics.

[0005] No other related patents were found regarding the additive manufacturing method for highly transparent parts using photocuring technology. Summary of the invention

[0006] In order to solve the above technical problems, the present invention provides a high-transparency molten salt pump impeller additive manufacturing method based on photocuring technology, which can directly manufacture high-transparency products. The implementation process is simple and there is no need to use polishing and spraying varnish to achieve high transparency, thereby improving the manufacturing efficiency of transparent parts.

[0007] The invention discloses a method for additive manufacturing of a highly transparent molten salt pump impeller based on photocuring technology, comprising the following steps:

[0008] The first step is to determine the size of the metal substrate and the photosensitive resin material used for additive manufacturing based on the size of the molten salt pump impeller. The second step is to use slicing software to slice and layer the components to be printed. The third step is to determine the support plan and laser spot scanning plan. The fourth step is to perform additive manufacturing of the highly transparent molten salt pump impeller.

[0009] Furthermore, the size of the molten salt pump impeller needs to be smaller than the size of the metal substrate. The shape of the metal substrate is square, and the outer diameter of the impeller is more than 5 mm smaller than the side length of the metal substrate.

[0010] Furthermore, the high-transparency molten salt pump impeller slices are layered, each layer is 0.05 mm high, and a fill line vector staggered arrangement method is adopted, which changes alternately with different layers.

[0011] Furthermore, the design support height of the high-transparency molten salt pump impeller is between 8-12 mm.

[0012] Furthermore, the radius of a single internal support point of the high-transparency molten salt pump impeller in the same layer is 3 mm, the support tip point penetrates the printing build depth of 0.5 mm, and the support point radius is 0.6 mm.

[0013] Further, the laser scans the high-transparency molten salt pump impeller in a continuous X-direction or Y-direction propagation mode, and the light spot jumps back and forth on the hole or column, which is different from the traditional one-side surrounding scanning and then returns to the second side surrounding scanning.

[0014] Furthermore, the number of compensation layers of the high-transparency molten salt pump impeller along the Z-axis height direction is 6 layers, that is, the number of initial printing layers is reduced by 6 layers.

[0015] Furthermore, the photosensitive resin material is a plastic that simulates the performance and appearance of polycarbonate and ABS, with a density of 1.1g / cm 3 , the color is highly transparent.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: first, the additive manufacturing method of a highly transparent molten salt pump impeller based on light-curing technology proposed by the present invention can replace the traditional mechanical processing and manufacturing of organic glass, and greatly improve the manufacturing efficiency of transparent components;

[0017] Second, the transparent component manufactured by the method of the present invention has high transparency, with a light transmittance of more than 97%, and can be directly used in visualization experiments that are beneficial to the internal flow field of the molten salt pump impeller;

[0018] Third, the present invention is applicable to the additive manufacturing of transparent components, which is conducive to promoting the technological progress of additive manufacturing of transparent materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1Schematic diagram of the overall solution for additive manufacturing of high-transparency molten salt pump impellers;

[0020] Figure 2 Support height for additive manufacturing of high transparency molten salt pump impellers;

[0021] Figure 3 Schematic diagram of support point distribution for additive manufacturing of high-transparency molten salt pump impeller;

[0022] Figure 4 Schematic diagram of support point penetration depth and support point for additive manufacturing of high-transparency molten salt pump impeller;

[0023] Figure 5 Schematic diagram of the layer height distribution of the additive manufacturing of the high-transparency molten salt pump impeller;

[0024] Figure 6 This is a real picture of the highly transparent molten salt pump impeller based on light curing technology ( Figure 6 Left) and the actual picture of the transparent molten salt pump impeller made by traditional additive manufacturing ( Figure 6 Right) Comparison. DETAILED DESCRIPTION

[0025] The specific implementation of the present invention is further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0026] The technical principle of the present invention is the additive manufacturing of molten salt pump impeller based on photocuring technology. In the construction of additive manufacturing, due to excessive layer height, insufficient support height and unreasonable support scheme design, as well as unscientific scanning scheme, the transparency of the molten salt pump impeller will be affected. Therefore, if you want to obtain a highly transparent molten salt pump impeller by additive manufacturing, the most effective way is to use the additive manufacturing method of the highly transparent molten salt pump impeller of the present invention.

[0027] The invention discloses a method for additive manufacturing of a highly transparent molten salt pump impeller based on photocuring technology, comprising the following steps:

[0028] The first step is to determine the size of the metal substrate and the photosensitive resin material used for additive manufacturing based on the size of the molten salt pump impeller. The second step is to use slicing software to slice and layer the components to be printed. The third step is to determine the support plan and laser spot scanning plan. The fourth step is to perform additive manufacturing of the highly transparent molten salt pump impeller.

[0029] Furthermore, the size of the molten salt pump impeller needs to be smaller than the size of the metal substrate. The metal substrate is square in shape, and the outer diameter of the impeller is more than 5 mm smaller than the side length of the metal substrate, ensuring that the outer support point of the molten salt pump impeller is inside the substrate.

[0030] Furthermore, the high-transparency molten salt pump impeller slices are layered, with each layer height of 0.05 mm. The filling line vector staggered arrangement method is adopted, which changes alternately with the different layers, which can effectively reduce the layer depth.

[0031] Furthermore, the design support height of the high-transparency molten salt pump impeller is between 8-12 mm, that is, the distance between the bottom of the molten salt pump impeller and the metal substrate is 8-12 mm. Both too large and too small heights will affect the stability of the component.

[0032] Furthermore, the radius of a single internal support point of the high-transparency molten salt pump impeller in the same layer is 3mm, ensuring that there is no sagging on the suspended surface. The support tip penetrates the printing build depth of 0.5mm, and the support point radius is 0.6mm, preventing the scraper from affecting the stability of the component during the additive manufacturing process, thereby producing local obvious layer patterns and affecting the transmittance.

[0033] Furthermore, the laser scans the high-transparency molten salt pump impeller in a continuous X-direction or Y-direction propagation mode, and the light spot jumps back and forth on the hole or column, which is different from the traditional scanning around one side and then returning to the second side to scan around, thereby maximizing the surface finish.

[0034] Furthermore, based on the laser intensity, the properties of transparent materials and the structural characteristics of the molten salt pump, the first layer of the highly transparent molten salt pump impeller molding is a laser penetrating layer, which causes over-curing. The method of the present invention compensates the layer thickness value along the Z-axis height direction by 6 layers, that is, the number of starting printing layers is reduced by 6 layers to ensure the accuracy of the geometric dimensions of the molten salt pump.

[0035] Furthermore, the photosensitive resin material is a plastic that simulates the performance and appearance of polycarbonate and ABS, with a density of 1.1g / cm 3 The color is highly transparent, which ensures the light transmittance inside the body from the material perspective.

[0036] Example:

[0037] This embodiment is based on the light curing technology to additively manufacture the 100MW-level molten salt pump high-transparent impeller experimental piece. The specific process is as follows:

[0038] (1) 100MW molten salt pump impeller 3D image and high transparency material preparation:

[0039] The 3D image of the molten salt pump impeller to be manufactured is saved in .stp format or .x_t format, ready to be imported into 3DSprint software. The outer diameter of the molten salt pump impeller is 320mm, the metal substrate is square in shape, and the size is 380mm×380mm. The outer diameter of the impeller is smaller than the side length of the metal substrate by 60mm. Ensure that the outer support point of the molten salt pump impeller is inside the substrate (such as Figure 1 ). SL Clear photosensitive resin material is a plastic that simulates the performance and appearance of polycarbonate and ABS, with a density of 1.1g / cm 3 At a temperature of 30 degrees Celsius, the viscosity is 250cps, the tensile strength is 52Mpa, and the material transmittance is 95%.

[0040] (2) 100MW molten salt pump impeller support design:

[0041] The distance between the bottom of the molten salt pump impeller and the metal substrate is 10 mm, that is, the support height is 10 mm. This improves the efficiency of additive manufacturing while ensuring the stability of the molten salt pump manufacturing process (such as Figure 2 As shown). The radius that a single internal support point of the molten salt pump impeller can support in the same layer is 3mm. A smaller radius value will result in a higher point density, and a larger value will result in a sparser point density. The distribution diagram of the support points is shown in Figure 3 , the support tip penetration printing build depth is 0.5mm, and the support point radius is 0.6mm (such as Figure 4 shown).

[0042] (3) Determination of basic process parameters for photo-curing additive manufacturing:

[0043] like Figure 5 As shown in the figure, the high-transparency molten salt pump impeller is sliced ​​and layered, with each layer height of 0.05mm. The filling line vector is staggered and arranged alternately with the different layers, which can effectively reduce the layer depth. The laser scans the high-transparency molten salt pump impeller in a continuous X-direction or Y-direction propagation mode, jumping back and forth on the hole or column, which is different from the traditional one-side surrounding scanning and then returning to the second side surrounding scanning, thereby maximizing the surface finish. Based on the laser intensity and laser power of 300W The properties of SL Clear transparent material and the structural characteristics of the 100MW molten salt pump. The first layer of the molten salt pump impeller molding is a laser penetrating layer, which causes over-curing. Therefore, the compensation layer thickness along the Z-axis height direction is 6 layers.

[0044] In this embodiment, the laser power is set to 300W. Too high a power will cause the component to turn yellow and reduce transparency, while too low a power will lead to insufficient photocuring and thus affect the strength of the component.

[0045] In this embodiment, the large and small line width compensation amounts used to compensate for the width of the boundary vector are: the large line width is 0.12 mm, and the small line width is 0.05 mm. This parameter helps to maintain the overall dimensional accuracy of the stereolithography part.

[0046] In this embodiment, Figure 6As shown, the method of the present invention can solve the problem of opacity or translucency of the molten salt pump impeller caused by the traditional impeller additive manufacturing method. The 100MW-level molten salt pump high-transparency impeller experimental piece manufactured by this method can be directly used for PIV (particle imaging test) technology to visualize the internal flow field of the pump impeller.

[0047] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for additive manufacturing of a highly transparent molten salt pump impeller based on photocuring technology, characterized in that: The following steps are involved: The first step is to determine the size of the metal substrate and the photosensitive resin material used for additive manufacturing according to the size of the molten salt pump impeller; The second step is to use the slicing software to slice and layer the printed components; the third step is to determine the support scheme and laser spot scanning scheme; the fourth step is to perform additive manufacturing of the highly transparent molten salt pump impeller; The size of the molten salt pump impeller must be smaller than that of the metal substrate. The shape of the metal substrate is square, and the outer diameter of the impeller is at least 5mm smaller than the side length of the metal substrate. The high-transparency molten salt pump impeller is sliced ​​and layered, with each layer height of 0.05mm. The filling line vector is arranged in an interlaced manner, alternating with the different layers; The design support height of the impeller of the high-transparency molten salt pump is between 8-12mm; The radius of a single internal support point of a high-transparent molten salt pump impeller in the same layer is 3mm, the support tip point penetrates the printing build depth of 0.5mm, and the support point radius is 0.6mm; The laser scans the high-transparency molten salt pump impeller in a continuous X-direction or Y-direction propagation mode, and the light spot jumps back and forth on the hole or column and then returns to scan around the second side.

2. The additive manufacturing method for a highly transparent molten salt pump impeller based on photocuring technology as claimed in claim 1, characterized in that: The high-transparency molten salt pump impeller has 6 compensation layers along the Z-axis height direction.

3. The additive manufacturing method for a highly transparent molten salt pump impeller based on photocuring technology as claimed in claim 2, characterized in that: Photosensitive resin material is a plastic that simulates the performance and appearance of polycarbonate and ABS, with a density of 1.1g / cm 3 , the color is highly transparent.

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