CN103962556A - Pure titanium powder forming method based on selected area laser melting technology - Google Patents

Abstract

The invention discloses a pure titanium powder molding method based on selective laser melting technology, comprising: A, adopting an optimization comparison method to obtain the optimal processing parameters for pure titanium powder molding; B, constructing a three-dimensional model of the required part structure; C 1. Perform layered preprocessing on the constructed 3D model; D. Using the obtained optimal processing parameters as 3D printing parameters, perform layered processing on the layered 3D model after layered preprocessing, thereby generating the print files required for 3D printing; E. Import the generated printing file into the 3D printing equipment, and use pure titanium powder as the molding material for 3D printing. The invention is based on the selective laser melting technology, and can accurately manufacture metal parts of various structures according to actual requirements; the optimal processing parameters of pure titanium powder molding can be obtained by using the optimization comparison method, and different settings can be made according to the actual required mechanical properties. The optimal processing parameters, high flexibility and good dynamic performance. The invention can be widely used in the field of automatic control.

Description

A pure titanium powder molding method based on selective laser melting technology

technical field

The invention relates to the field of automatic control, in particular to a method for forming pure titanium powder based on selective laser melting technology.

Background technique

Due to their excellent mechanical properties and biocompatibility, titanium and its alloys are widely used in the fields of clinical bone repair, bone implantation and corresponding processing and manufacturing. However, the traditional titanium and titanium alloy processing technology generally has problems such as many influencing factors, complicated process, difficult to accurately process the internal structure, difficult to clean the shape at one time, and difficult to obtain a uniform treatment effect. The selective laser melting technology can better overcome the above problems, and it has flexible manufacturing characteristics that cannot be matched by any other processing method. However, most of the processing parameters of the current powder molding process based on selective laser melting technology are fixed processing parameters provided by the manufacturer, which has low flexibility and poor dynamic performance, making it difficult for the final parts to be consistent with the actual use environment. Sometimes it will even affect the life of parts.

Contents of the invention

In order to solve the above technical problems, the object of the present invention is to provide a pure titanium powder forming method based on selective laser melting technology with high flexibility and good dynamic performance.

The technical solution adopted by the present invention to solve the technical problem is: a pure titanium powder molding method based on selective laser melting technology, including:

A. Obtain the optimal processing parameters for pure titanium powder molding by using the optimization comparison method;

B. Construct a three-dimensional model of the required part structure;

C. Perform layered preprocessing on the constructed 3D model;

D. Using the obtained optimal processing parameters as 3D printing parameters, perform layered processing on the 3D model after layered preprocessing, so as to generate the printing files required for 3D printing;

E. Import the generated printing file into the 3D printing equipment, and use pure titanium powder as the molding material for 3D printing.

Further, the optimal processing parameters for titanium powder forming include optimal processing power, optimal scanning speed, optimal scanning distance and optimal layer thickness.

Further, said step A, which includes:

A1, build a cube model with a side length of 10 mm;

A2. Process one by one according to the set processing power node, scanning speed node, scanning distance node, scanning layer thickness node and the constructed cube model, so as to obtain the corresponding part model of each node;

A3. Use the coordinate measuring instrument to collect the surface scanning track images of the corresponding part models of each node, and then preliminarily determine the node range corresponding to the optimal processing parameters for pure titanium powder molding according to the collected images;

A4. Calculate the density and density of the corresponding part model of each node within the initially determined node range according to the Archimedes principle, and then determine the optimal processing parameters for pure titanium powder molding according to the calculated density and density.

Further, the set processing power nodes are 50W power nodes, 60W power nodes, 70W power nodes, 80W power nodes, 90W power nodes and 100W power nodes.

Further, the set scanning speed nodes are 100mm/s speed node, 200mm/s speed node, 300mm/s speed node, 400mm/s speed node, 500mm/s speed node and 600mm/s speed node.

Further, the set scanning pitch nodes are 0.07mm pitch nodes, 0.10mm pitch nodes, 0.13mm pitch nodes, 0.16mm pitch nodes, 0.19mm pitch nodes, 0.22mm pitch nodes and 0.25mm pitch nodes.

Further, the set scanning slice thickness node is a slice thickness node of 0.03-0.07 mm.

Further, said step C, which includes:

C1. Determine the direction of printing;

C2. Set up a support structure at the bottom of the 3D model along the printing direction, and design the height, distribution and density of the support structure.

Further, the step D is specifically:

Taking the obtained optimal processing parameters as 3D printing parameters, decompose the layered preprocessed 3D model into layers with equal layer thickness along the printing direction according to the set layer thickness, and then save the decomposed layer data to the SLM format in the print file.

Further, said step E, which includes:

E1. Wait for the 3D printing equipment to warm up to the conditions required for work;

E2. Import the print file in SLM format into the 3D printing device;

E3, 3D printing equipment uses pure titanium material powder to perform 3D printing in the way of additive printing according to the optimal processing parameters obtained.

The beneficial effects of the invention are: based on the selective laser melting technology, metal parts of various structures can be accurately manufactured according to actual requirements; the optimal processing parameters of pure titanium powder molding can be obtained by using the optimization comparison method, and the mechanical properties can be obtained according to the actual requirements. Different optimal processing parameters are set according to the situation, with high flexibility and good dynamic performance.

Description of drawings

The present invention will be further described below in conjunction with drawings and embodiments.

Fig. 1 is a flow chart of steps of a pure titanium powder forming method based on selective laser melting technology of the present invention;

Fig. 2 is the flowchart of step A of the present invention;

Fig. 3 is the flowchart of step C of the present invention;

Fig. 4 is a flowchart of step E of the present invention.

Detailed ways

Referring to Figure 1, a pure titanium powder molding method based on selective laser melting technology, including:

A. Obtain the optimal processing parameters for pure titanium powder molding by using the optimization comparison method;

B. Construct a three-dimensional model of the required part structure;

C. Perform layered preprocessing on the constructed 3D model;

D. Using the obtained optimal processing parameters as 3D printing parameters, perform layered processing on the 3D model after layered preprocessing, so as to generate the printing files required for 3D printing;

E. Import the generated printing file into the 3D printing equipment, and use pure titanium powder as the molding material for 3D printing.

Among them, the optimization comparison method refers to the optimization and comparison of processing and shaping factors such as power, scanning speed, scanning distance and layer thickness. Taking power as an example, when performing optimization comparison, different powers will be set first, and then the corresponding parts will be processed one by one according to the set power, and then the performance of the processed parts will be compared one by one, and finally according to the comparison The result is to obtain the optimal processing power.

The pure titanium powder of the present invention adopts ASTM standard grade two pure titanium powder, and its powder is spherical particle.

The 3D printing equipment adopts the YLR-100-WC optical fiber selective laser melting equipment of the model SLM-125HL produced by the German SLM Solutions Gmbh company, which supports the SLM format file.

The layered processing is performed on the 3D model after layered preprocessing, and the software used is the SLM AutoFab64 1.8 software that comes with the 3D printing equipment.

As a further preferred embodiment, the optimal processing parameters for titanium powder forming include optimal processing power, optimal scanning speed, optimal scanning distance and optimal layer thickness.

With reference to Fig. 2, further preferred embodiment, described step A, it comprises:

A1, build a cube model with a side length of 10 mm;

A2. Process one by one according to the set processing power node, scanning speed node, scanning distance node, scanning layer thickness node and the constructed cube model, so as to obtain the corresponding part model of each node;

A3. Use the coordinate measuring instrument to collect the surface scanning track images of the corresponding part models of each node, and then preliminarily determine the node range corresponding to the optimal processing parameters for pure titanium powder molding according to the collected images;

A4. Calculate the density and density of the corresponding part model of each node within the initially determined node range according to the Archimedes principle, and then determine the optimal processing parameters for pure titanium powder molding according to the calculated density and density.

Among them, the purpose of constructing a cube model with a side length of 10 mm is to make each object for optimization comparison have better comparability.

The surface scanning track refers to the melting channel of the molten pool formed by the laser scanning in rows and columns.

Density refers to the macroscopic density of the actual part.

The set processing power node, scanning speed node, scanning distance node and scanning layer thickness node are all two or more nodes.

According to prior knowledge, the density corresponding to the optimal processing parameters of pure titanium powder molding is generally above 95%.

As a further preferred embodiment, the set processing power node is 50W.

Power node, 60W power node, 70W power node, 80W power node, 90W power node and 100W power node.

Further as a preferred embodiment, the set scanning speed nodes are 100mm/s speed nodes, 200mm/s speed nodes, 300mm/s speed nodes, 400mm/s speed nodes, 500mm/s speed nodes and 600mm/s speed nodes node.

Further as a preferred embodiment, the set scanning spacing nodes are 0.07mm spacing nodes, 0.10mm spacing nodes, 0.13mm spacing nodes, 0.16mm spacing nodes, 0.19mm spacing nodes, 0.22mm spacing nodes and 0.25mm spacing nodes .

As a further preferred embodiment, the set scanning slice thickness node is a slice thickness node of 0.03-0.07 mm.

Referring to Fig. 3, further as a preferred embodiment, the step C includes:

C1. Determine the direction of printing;

C2. Set up a support structure at the bottom of the 3D model along the printing direction, and design the height, distribution and density of the support structure.

Among them, the support structure is used for the connection between the parts and the substrate of the 3D printing equipment and the heat dissipation during the processing, and to facilitate the separation of the parts and the substrate.

Further as a preferred embodiment, the step D is specifically:

Taking the obtained optimal processing parameters as 3D printing parameters, decompose the layered preprocessed 3D model into layers with equal layer thickness along the printing direction according to the set layer thickness, and then save the decomposed layer data to the SLM format in the print file.

Referring to Fig. 4, further as a preferred embodiment, the step E includes:

E1. Wait for the 3D printing equipment to warm up to the conditions required for work;

E2. Import the print file in SLM format into the 3D printing device;

E3, 3D printing equipment uses pure titanium material powder to perform 3D printing in the way of additive printing according to the optimal processing parameters obtained.

Among them, the conditions required for work refer to the temperature of the abutment of the 3D printing equipment at 0-200°C, and the oxygen content in the processing cabin is less than 0.2%. Before the 3D printing equipment is preheated, 99.999% pure argon must be introduced as a protective gas.

The present invention will be described in further detail below in conjunction with specific embodiments.

Embodiment one

This embodiment introduces the process of the present invention for preparing a pure titanium porous structure part.

The present invention adopts the 3D printing equipment of the model SLM-125HL produced by the German SLM Solutions Gmbh company, and the supporting software used is the SLM AutoFab MCS1.1 or SLM AutoFab64 1.8 software that comes with the 3D printing equipment.

The present invention is used for the process of preparing pure titanium porous structure parts, comprises:

S1. Establish a three-dimensional model of the porous structure to be prepared in the computer.

According to the actual structure of the parts to be prepared, use solidworks, UG, ProE and other engineering drawing software to design and build the 3D model of the actual porous structure, and save it in STL format. Among them, the parameters of the three-dimensional model are subject to the actual parameters of the porous structure, including the shape and size of the external whole, the shape of the internal structure, the side length of the polygon, and the wall thickness.

S2. Perform hierarchical preprocessing on the established three-dimensional model.

The layered preprocessing includes: determining the printing direction, then setting the support structure at the bottom of the 3D model along the printing direction, and designing the height, distribution and density of the support structure according to the actual situation.

S3. Setting 3D printing parameters, performing layered processing on the 3D model, and then saving and exporting a file in SLM format.

Among them, the 3D printing parameters include the placement position and placement method of the parts, as well as the laser scanning method, scanning speed, power, etc.

The 3D model is layered, that is, the 3D model is decomposed into multiple 3D structures with equal thickness along the printing direction: using SLM AutoFab64 1.8 software, the 3D model is divided into several layers with equal thickness along the printing direction, generally The layer thickness is 30-70 μm, which needs to be set according to the particle size of the pure titanium material powder used in the 3D printing equipment.

Finally, save and export in SLM format, which is a file format recognizable by 3D printing equipment.

S4. Import the exported SLM format file into a 3D printing device for 3D printing.

In this embodiment, a 3D printing equipment model SLM-125HL produced by SLM Solutions Gmbh in Germany is used for part processing.

Embodiment two

This embodiment introduces the specific process of obtaining the optimal processing parameters for pure titanium powder molding by using the optimization comparison method.

The invention firstly builds a cube model structure with a unified structure, and then compares and calculates the remarkable technical effects produced by different processing parameters.

When performing comparative observation and calculation, the present invention uses the coordinate measuring instrument Quick View 200 to observe the surface scanning track of the model, and by processing the constructed cubic model, the parts after removing the support structure and grinding the bottom surface are placed on the platform of the coordinate measuring instrument , and select a magnification of 1.5 to 2 times to clearly and comprehensively observe the state of the surface melt channel.

The present invention compares the significant technical effects produced according to different processing parameters including:

a. Power

In the default state of other processing parameters, the present invention selects powers of 50W, 60W, 70W, 80W, 90W, and 100W as power nodes, and performs processing and manufacturing respectively, and takes parts for testing after final molding, thereby obtaining its performance comparison table, As shown in Table 1 below. At the same time, the surface of the model observed by the coordinate measuring instrument Quick View 200 was scanned. It can be seen from Table 1 and the observed results that when the scanning power is 50W and 60W, the laser scanning path does not form a track (the density is less than 95%), and the surface spheroidization phenomenon is very serious. At this time, the laser energy input is not enough, resulting in powder scanning range The powder inside cannot be completely melted, so the molding of this model requires higher laser power. When the scanning power is 70W, there is a rudiment of the orbit (the density is equal to 95%), and when the scanning power is 80W, 90W, and 100W, the complete orbit has been formed (the density is greater than 95%), so the optimal scanning power should be 70W-100W.

Table 1 Performance comparison of molded parts under different power

b. power

In the default state of other parameters, the present invention respectively selects scanning speeds of 100mm/s, 200mm/s, 300mm/s, 400mm/s, 500mm/s and 600mm/s as scanning speed nodes for processing and manufacturing respectively, and in the final molding After the pick-up test, the performance comparison table is obtained, as shown in Table 2 below. At the same time, the surface of the model observed by the coordinate measuring instrument Quick View 200 was scanned. It can be seen from Table 2 and the observed results that when the scanning speed is 400mm/s, a large number of defects (the density of which is less than 95%) will appear on the surface of the part, and such defects will seriously affect the quality of the part. Therefore, the optimal scanning speed should be Not more than 400mm/s.

Table 2 Performance comparison of formed parts at different scanning speeds

c. Scanning distance

In the default state of other parameters, the present invention respectively selects the scanning distances of 0.07mm, 0.1mm, 0.13mm, 0.16mm, 0.19mm, 0.22mm and 0.22mm as the scanning distance nodes for optimization and comparison, respectively performs processing and manufacturing, and After the final molding, the parts were taken and tested to obtain the performance comparison table, as shown in Table 3 below. At the same time, the surface of the model observed by the coordinate measuring instrument Quick View 200 was scanned. From Table 3 and the observed results, it can be seen that when the scanning distance is 70 μm, 100 μm, 130 μm and 160 μm, the surface of the processed parts is smoother, the grooves are shallower, the surface is clearer, and the overlapping of different laser melting zones is better (density greater than 95%); when the scanning distance is greater than 160 μm, the surface flatness of the processed parts gradually decreases, the groove marks gradually deepen, the spheroidization phenomenon gradually becomes serious, and unmelted phenomena appear in the laser melting zone (density less than 95%). Therefore, the optimal laser scanning distance suitable for processing pure titanium should not exceed 160 μm.

Table 3 Performance comparison of formed parts under different scanning distances

d. Scan layer thickness

Actual research shows that increasing the scanning layer thickness can improve the processing efficiency, but it will affect the processing quality. Therefore, it is necessary to make corresponding adjustments to other parameters (such as power, scanning speed, scanning distance, etc.) at the same time to obtain better surface quality. and good performance parts. In this embodiment, the scanning speed is selected as a parameter to be adjusted accordingly, and the scanning layer thickness is optimized and compared.

In the default state of other parameters, the present invention respectively selects the scanning layer thicknesses of 0.03mm and 0.07 mm as the scanning spacing nodes, and also selects scanning speeds of 175mm/s, 275mm/s, 375mm/s and 400mm/s for processing Manufactured and tested for comparison after final molding. At the same time, the surface of the model observed by the coordinate measuring instrument Quick View 200 was scanned. From the observed scanning plane: when the scanning layer thickness is 0.03mm, the orbital molten pool on the surface of the machined parts at the scanning speeds of 175mm/s, 275mm/s, and 375mm/s is relatively flat, with fewer defects and the processing The effect is ideal; when the scanning speed is adjusted to 400mm/s, obvious spherical defects appear on the surface of the processed parts, indicating that the energy density at this time (energy density = power / (scanning layer thickness × scanning speed × scanning distance) ) is low, and the processing effect is poor, so it can be inferred that for pure titanium powder with a scanning layer thickness of 0.03mm, the processing scanning speed should not exceed 400mm/s, and it can also be inferred that the scanning layer thickness is 0.07mm The processing scanning speed of pure titanium powder should not exceed 375mm/s.

To sum up, for pure titanium powder, the parameters suitable for its processing (that is, the optimal processing parameters) are: the scanning layer thickness is 0.03-0.07mm, the scanning speed does not exceed 400mm/s, and the scanning distance is not greater than 0.16mm/ s, the power can be selected from 70W to 100W. In actual processing, it is also necessary to select specific processing parameters within the optimal processing parameters according to the use environment required by the parts.

Compared with the prior art, the present invention is based on the selective laser melting technology, and can accurately manufacture metal parts of various structures according to actual requirements; the optimal processing parameters of pure titanium powder molding can be obtained by using the optimization comparison method, and can be processed according to actual needs. Different optimal processing parameters are set according to the mechanical properties, with high flexibility and good dynamic performance.

The above is a specific description of the preferred implementation of the present invention, but the invention is not limited to the described embodiments, and those skilled in the art can also make various equivalent deformations or replacements without violating the spirit of the present invention. , these equivalent modifications or replacements are all within the scope defined by the claims of the present application.

Claims (10)

1. A pure titanium powder molding method based on selective laser melting technology, characterized in that: comprising: A. Obtain the optimal processing parameters for pure titanium powder molding by using the optimization comparison method; B. Construct a three-dimensional model of the required part structure; C. Perform layered preprocessing on the constructed 3D model; D. Using the obtained optimal processing parameters as 3D printing parameters, perform layered processing on the 3D model after layered preprocessing, so as to generate the printing files required for 3D printing; E. Import the generated printing file into the 3D printing equipment, and use pure titanium powder as the molding material for 3D printing. 2. A pure titanium powder molding method based on selective laser melting technology according to claim 1, characterized in that: the optimal processing parameters of the titanium powder molding include optimal processing power, optimal scanning speed, optimal Scan spacing and optimal slice thickness. 3. A method for forming pure titanium powder based on selective laser melting technology according to claim 2, characterized in that: said step A comprises: A1, build a cube model with a side length of 10 mm; A2. Process one by one according to the set processing power node, scanning speed node, scanning distance node, scanning layer thickness node and the constructed cube model, so as to obtain the corresponding part model of each node; A3. Use the coordinate measuring instrument to collect the surface scanning track images of the corresponding part models of each node, and then preliminarily determine the node range corresponding to the optimal processing parameters for pure titanium powder molding according to the collected images; A4. Calculate the density and density of the corresponding part model of each node within the initially determined node range according to the Archimedes principle, and then determine the optimal processing parameters for pure titanium powder molding according to the calculated density and density. 4. A pure titanium powder molding method based on selective laser melting technology according to claim 3, characterized in that: the set processing power node is 50W power node, 60W power node, 70W power node, 80W power node node, 90W power node and 100W power node. 5. A pure titanium powder molding method based on selective laser melting technology according to claim 4, characterized in that: the set scanning speed node is 100mm/s speed node, 200mm/s speed node, 300mm/s s speed node, 400mm/s speed node, 500mm/s speed node and 600mm/s speed node. 6. A pure titanium powder molding method based on selective laser melting technology according to claim 5, characterized in that: the set scanning pitch nodes are 0.07mm pitch nodes, 0.10mm pitch nodes, and 0.13mm pitch nodes , 0.16mm pitch nodes, 0.19mm pitch nodes, 0.22mm pitch nodes and 0.25mm pitch nodes. 7. A pure titanium powder molding method based on selective laser melting technology according to claim 6, characterized in that: the set scanning layer thickness node is a layer thickness node of 0.03-0.07 mm. 8. A pure titanium powder molding method based on selective laser melting technology according to claim 7, characterized in that: said step C comprises: C1. Determine the direction of printing; C2. Set up a support structure at the bottom of the 3D model along the printing direction, and design the height, distribution and density of the support structure. 9. A pure titanium powder molding method based on selective laser melting technology according to claim 8, characterized in that: said step D, specifically: Taking the obtained optimal processing parameters as 3D printing parameters, decompose the layered preprocessed 3D model into layers with equal layer thickness along the printing direction according to the set layer thickness, and then save the decomposed layer data to the SLM format in the print file. 10. A method for forming pure titanium powder based on selective laser melting technology according to claim 9, characterized in that: said step E comprises: E1. Wait for the 3D printing equipment to warm up to the conditions required for work; E2. Import the print file in SLM format into the 3D printing device; E3, 3D printing equipment uses pure titanium material powder to perform 3D printing in the way of additive printing according to the optimal processing parameters obtained.