CN110539485A - A 3D printer with cooling powder spreading device and printing method thereof - Google Patents

Abstract

The invention discloses a 3D printer with a cooling powder spreading device, which comprises a working cylinder body, wherein a powder recycling barrel is arranged on one side of the working cylinder body, a power air source is arranged on one side, away from the working cylinder body, of the powder recycling barrel, a heat insulation cavity is arranged at the top of the working cylinder body, a vibrating mirror is arranged at the top of the heat insulation cavity, a laser is arranged on one side of the vibrating mirror, a storage hopper is arranged on one side of the heat insulation cavity, two groups of rodless cylinders are symmetrically arranged at the front and back of the inner bottom of the heat insulation cavity in a penetrating mode, a powder spreading groove is arranged between the rodless cylinders, a powder bed is arranged at the bottom of the powder spreading groove, a. Has the advantages that: the powder can be spread bidirectionally by one-time powder falling, the powder spreading time is saved, the efficiency of laser printing is improved, and in addition, the rodless cylinder is adopted, so that the powder spreading structure of the whole machine is relatively simple, the precision is high, the work is reliable, and the cost is low.

Description

A 3D printer with cooling powder spreading device and printing method thereof

technical field

The invention relates to the technical field of 3D printing, in particular to a 3D printer with a cooling powder spreading device and a printing method thereof.

Background technique

3D printing (additive manufacturing) is a kind of rapid prototyping technology, which is based on mathematical model files, uses powdered metal or plastic and other bondable materials, and uses lasers and other heat sources to manufacture products. 3D printing process methods can be divided into FDM (fused deposition), SLS (selective laser sintering), SLM (selective laser melting molding) and other types.

Among them, SLS and SLM use laser to melt powder in a specific area for powder materials to directly manufacture products. The process is similar: CAD software is used to model a specific object, and then the model is sliced through slicing software, and the model section data obtained by slicing is transmitted to the control system, which controls a certain power laser to process and fuse a specific layer of metal powder or non-metal powder. After the initial layer is processed and fused in this way, the working platform is lowered by a layer thickness, and the powder spreading device spreads a certain layer of unprocessed powder, and continues to process and fuse the next layer of powder. Repeat this step until all the specific areas are fully fused. Get a three-dimensional product.

It can be seen from the above that the powder spreading device is a key part of the whole system, and its reliability is related to the continuity of the entire printing process. The stability and high precision of powder spreading determine the final quality of the printed product. The printing medium is fine powder, which is easy to dust, and the printing process of most materials needs to be heated to a certain temperature, which leads to the poor working conditions of the powder spreading device.

The traditional powder spreading device is generally realized by a combination of a motor and a synchronous belt, or a combination of a motor and a screw. General motors, synchronous belts and lead screws are not suitable for high temperature and high dust conditions, and the special components for high temperature resistance are complex in process, high in cost and complicated in maintenance. The lead screw and other components are all laid out outside the printing insulation cavity, which requires more additional components, complex structure, high cost, and poor accuracy, which affects the printing quality.

For the problems in the related technologies, no effective solutions have been proposed so far.

SUMMARY OF THE INVENTION

In view of the problems in the related art, the present invention proposes a 3D printer with a cooling powder spreading device and a printing method thereof, so as to overcome the above-mentioned technical problems existing in the related art.

For this reason, the concrete technical scheme that the present invention adopts is as follows:

According to an aspect of the present invention, a 3D printer with a cooling powder spreading device is provided, including a working cylinder body, a powder recovery bucket is provided on one side of the working cylinder body, and the recovery powder bucket is far from the working cylinder body A power gas source is provided on one side of the power gas source, and a pneumatic control system is arranged on the power gas source. The top of the working cylinder is provided with a thermal insulation cavity, and the top of the thermal insulation cavity is provided with a vibration One side of the galvanometer is provided with a laser, one side of the heat preservation cavity is provided with a storage hopper, and the bottom of the storage hopper is provided with an electronically controlled discharge valve, and the inner top of the heat preservation cavity is provided with There is a heating system, and two groups of rodless cylinders are arranged symmetrically at the inner bottom of the heat preservation cavity, and one end of the rodless cylinders is respectively connected to the pneumatic control system and the power air source through a conduit loop, A powder spreading groove is arranged between the rodless cylinders, a material guiding pipe is arranged above the powder spreading groove, and the top end of the material guiding pipe penetrates the insulation cavity and is fixed with the bottom end of the storage hopper connected, the bottom of the powder spreading tank is provided with a powder bed, the bottom of the powder bed is provided with a piston, and the piston is located at the inner top of the working cylinder, and the bottom of the piston is provided with a vertical motion device, and The bottom end of the vertical movement device penetrates through the working cylinder body and extends to the bottom of the working cylinder body.

Further, in order not only to provide power, but also to cool the rodless cylinder and to ensure that the temperature of the part exposed to the heat preservation cavity is within the rated working range, the power gas source uses liquefied nitrogen to provide power.

Further, in order to ensure the stability of the temperature field, the heating system adopts four or eight groups of infrared lamps for heating, and a temperature control system is arranged in the heating system.

Further, in order to facilitate powder feeding, so that the powder spreading groove can spread the powder along the powder bed at the upper end of the working cylinder body along with the movement of the cylinder piston, the lower end of the powder spreading groove is set to a V-shaped structure, and the The bottom of the powder spreading tank is provided with an open scraper, and both ends of the powder spreading tank are fixedly connected with the cylinder piston in the rodless cylinder through screws.

Further, in order to prevent powder from leaking from the gap between the piston and the inner wall of the working cylinder, a sealing felt is arranged between the circumference of the piston and the working cylinder, and one side of the sealing felt is fixedly connected to the piston. .

According to another aspect of the present invention, a printing method of a 3D printer with a cooling powder spreading device is provided, comprising the following steps:

Step S1, use the 3D modeling software in the computer to design the three-dimensional solid model of the product according to the structural characteristic of the product, utilize the slicing program to carry out slice processing by the three-dimensional model, and store the section information in the computer;

Step S2, the vertical motion device of computer control moves the piston to the inner top of the working cylinder, so that the powder spreading mechanism is positioned below the material guide pipe;

Step S3, the computer controls the electric control discharge valve on the storage hopper to open, and the powder falls into the powder spreading groove along the material guide pipe;

Step S4, when the powder in the powder spreading tank is accumulated to the preset parameter, the computer controls the electric control discharge valve to close;

Step S5, the described rodless cylinder of computer control drives the described powder trough to move horizontally to the left, and begins to lay a layer of thick powder horizontally;

Step S6, the computer controls the galvanometer to control the laser to irradiate the powder bed on which the powder is laid according to the slice cross-section data obtained by pre-selection, so that the current layer thickness powder is selectively melted and solidified;

Step S7, the computer controls the vertical motion device to drop a layer thickness distance, and drives the powder bed to drop a layer thickness distance;

Step S8, computer controls the described rodless cylinder to drive the described powder spreading tank to move in the opposite direction to the right, and then lay a layer of thick powder on the described powder bed;

In step S9, the computer controls the galvanometer again to control the laser to irradiate the powder bed on which the powder is currently laid according to the slice cross-section data obtained by pre-selection, so that the current layer thickness powder is selectively melted and solidified;

Step S10, the computer controls the described rodless cylinder to drive the horizontal movement of the powder spreading tank to the bottom of the material guide pipe to prepare for receiving material;

Step S11, repeating steps S3-S10, and printing a three-dimensional product layer by layer according to the cross-sectional information obtained by pre-selection.

Further, the slicing procedure includes the following steps:

The layering direction and layering thickness are adjusted by layering software, and the target 3D model is layered and discretized into a set of ordered two-dimensional contour sets, and the two-dimensional contour of each layer is a slice;

According to the actual demand and the acquired two-dimensional profile information of the slice, the technical parameters are set to obtain the data code that can be recognized and scanned by the 3D printer, and the 3D printing control instruction is generated according to the scanned data code.

Further, before the slice processing, the following steps are also included:

Analyze the structural characteristics of the 3D model of the product, obtain the analysis results, and find out the position where supports need to be added to the product in 3D printing according to the analysis results;

Add supports in the 3D model drawing of the product according to the position where the supports are added, and get the 3D model drawing with supports;

Determine the positional relationship between the added support and the product according to the three-dimensional model diagram with the support, and obtain a three-dimensional model diagram of the product including the positional relationship of the support.

Further, the described powder spreading groove in step S5 stops moving to the leftmost end, and at this moment, there is at least one layer of thick powder in the described powder spreading groove.

Further, in step S8, after the powder spreading tank is laid with a thickness of powder, the computer can continue to control the rodless cylinder to drive the powder spreading tank to move to the right, so that the excess powder falls into the recovery powder bucket. Inside.

Compared with the prior art, the beneficial effects of the present invention are:

1, the present invention can realize two-way powder spreading by one-time powder falling, thereby saving the powder spreading time and improving the efficiency of laser printing;

2. The cylinder itself used in the present invention can be an ordinary rodless cylinder, which has a simple and reliable structure, and the cylinder can be directly placed in the heat preservation chamber, close to the powder spreading platform, without other transmission components, and the powder spreading structure of the whole machine is relatively simple, Thereby, the precision is high, the work is reliable, and the cost is low;

3. In the present invention, since there is generally a little temperature requirement in the working insulation cavity, the working gas of the cylinder adopts a low temperature gas, generally nitrogen, which has a cooling effect on the cylinder and prevents the cylinder part from being exposed to the insulation cavity, because the thermal expansion and contraction are too severe If it fails, ensure the printing goes smoothly;

4. The cylinder itself used in the present invention has a guiding device, which omits the guide rail required in the traditional 3D printer, and has a simple structure, reliable operation and low cost;

5. The present invention adopts the cylinder to drive the execution piston to be located inside the cylinder duct, and does not contact with high dust conditions, so it has reliable operation, less maintenance and cost saving. In addition, the present invention adopts the cylinder to control the ordinary left and right two-position solenoid valve, which is simple in control and works well. reliable;

6. The present invention is a single-cylinder printing structure. Compared with the traditional three-cylinder structure of powder spreading cylinder, working cylinder and recovery cylinder, the volume of the thermal insulation cavity is significantly reduced, which is conducive to the stable control of the temperature field, and not only effectively guarantees The printing quality of the printer is improved, and the manufacturing cost of the cylinder block is effectively reduced.

Description of drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings required in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some of the present invention. In the embodiments, for those of ordinary skill in the art, other drawings can also be obtained according to these drawings without any creative effort.

1 is a schematic structural diagram of a 3D printer with a cooling powder spreading device according to an embodiment of the present invention;

2 is a schematic diagram of the internal structure of a 3D printer with a cooling powder spreading device according to an embodiment of the present invention;

Fig. 3 is according to the enlarged view of A place in Fig. 2;

4 is a schematic flowchart of a printing method of a 3D printer with a cooling powder spreading device according to an embodiment of the present invention.

In the picture:

1. Working cylinder; 2. Recycling powder bucket; 3. Power air source; 4. Pneumatic control system; 5. Insulation cavity; 6. Galvanometer; 7. Laser; 8. Storage hopper; valve; 10, heating system; 11, rodless cylinder; 12, conduit circuit; 13, powder spreading tank; 14, material guide pipe; 15, powder bed; 16, piston; 17, vertical motion device; 18, cylinder piston; 19. Sealing felt.

Detailed ways

In order to further illustrate the various embodiments, the present invention provides accompanying drawings, which are part of the disclosure of the present invention, and are mainly used to illustrate the embodiments, and can be used in conjunction with the relevant descriptions in the specification to explain the operation principles of the embodiments. For these, those of ordinary skill in the art will understand other possible implementations and the advantages of the present invention. Components in the figures are not drawn to scale, and similar component symbols are generally used to represent similar components.

According to the embodiments of the present invention, a 3D printer with a cooling powder spreading device and a printing method thereof are provided.

The present invention will now be further described with reference to the accompanying drawings and specific embodiments. As shown in Figures 1-3, according to an aspect of the present invention, a 3D printer with a cooling powder spreading device is provided, comprising a working cylinder 1, and the working One side of the cylinder block 1 is provided with a recovery powder bucket 2, and the side of the recovery powder bucket 2 away from the working cylinder block 1 is provided with a power gas source 3, and the power gas source 3 is provided with a matching power source 3. There is a pneumatic control system 4, the top of the working cylinder 1 is provided with a heat preservation cavity 5, the heat preservation cavity 5 is used to ensure the temperature stability of a specific temperature field, so that the printing work can be carried out normally, the top of the heat preservation cavity 5 A vibrating mirror 6 is provided, a laser 7 is provided on one side of the vibrating mirror 6, a storage hopper 8 is provided on one side of the thermal insulation cavity 5, and an electronically controlled discharge valve 9 is provided at the bottom of the storage hopper 8 , The heating system 10 is arranged on the inner top of the thermal insulation cavity 5, and two sets of rodless cylinders 11 are arranged symmetrically through the inner bottom of the thermal insulation cavity 5, and one end of the rodless cylinder 11 passes through the conduit circuit 12 are respectively connected to the pneumatic control system 4 and the power air source 3, a powder spreading groove 13 is arranged between the rodless cylinders 11, and a material guide pipe 14 is arranged above the powder spreading groove 13, and all the The top of the material guide pipe 14 penetrates through the heat preservation cavity 5 and is fixedly connected with the bottom end of the storage hopper 8. The bottom of the powder spreading tank 13 is provided with a powder bed 15, and the bottom of the powder bed 15 is provided with a Piston 16, and the piston 16 is located at the inner top of the working cylinder 1, the bottom of the piston 16 is provided with a vertical movement device 17, and the bottom end of the vertical movement device 17 penetrates the working cylinder 1 and Extend to the bottom of the working cylinder block 1 . In a specific application, the electronically controlled discharge valve 9 is opened when the material needs to be discharged, and the material falls into the powder spreading tank 13 along the material guide pipe 14 at the end of the storage hopper 8 under the action of gravity. It is closed after time, and the amount of powder falling into the powder spreading groove 13 can be roughly controlled according to the length of time; the vertical motion device 17 usually has a lead screw, a bearing, a motor, etc. to convert the rotary motion of the lead screw into the vertical motion of the piston .

In one embodiment, the power gas source 3 uses liquefied nitrogen to provide power. Through the use of liquefied nitrogen, it can not only provide power, but also cool the rodless cylinder 11, so that it can ensure that the temperature of the part exposed in the heat preservation cavity 5 is within the rated working range.

In one embodiment, the heating system 10 uses four or eight sets of infrared lamps for heating, and the heating system 10 is provided with a temperature control system. By setting in this way, it can have the effect of ensuring the stability of the temperature field.

In one embodiment, the lower end of the powder spreading tank 13 is set to a V-shaped structure, the bottom of the powder spreading tank 13 is provided with an open scraper, and both ends of the powder spreading tank 13 are connected to the The cylinder piston 18 in the rod cylinder 11 is fixedly connected. This arrangement not only facilitates the realization of powder unloading, but also enables the powder spreading groove 13 to spread the powder along the powder bed 15 at the upper end of the working cylinder block 1 along with the movement of the cylinder piston 18.

In one embodiment, a sealing felt 19 is provided between the circumference of the piston 16 and the working cylinder 1 , and one side of the sealing felt 19 is fixedly connected to the piston 16 . With this arrangement, the piston 16 can prevent the powder from leaking from the gap between the piston 16 and the inner wall of the working cylinder 1 when the inner wall of the working cylinder 1 moves vertically up and down.

The present invention will now be further described in conjunction with the accompanying drawings and specific embodiments, as shown in Figure 4, according to another aspect of the present invention, a printing method of a 3D printer with a cooling powder spreading device is provided, comprising the following steps:

Step S1, use the 3D modeling software in the computer to design the three-dimensional solid model of the product according to the structural characteristic of the product, utilize the slicing program to carry out slice processing by the three-dimensional model, and store the section information in the computer;

Step S2, computer controls described vertical motion device 17 to move described piston 16 to the inner top of described working cylinder 1, so that powder spreading mechanism is positioned below described material guide pipe 14;

Step S3, the computer controls the described electric control discharge valve 9 on the described storage hopper 8 to open, and the powder falls into the described powder spreading groove 13 along the described material guide pipe 14;

Step S4, when the powder in the powder spreading tank 13 is accumulated to a preset parameter, the computer controls the electronically controlled discharge valve 9 to close;

Step S5, the described rodless cylinder 11 of computer control drives the described powder trough 13 to move horizontally to the left, and begins to lay a layer of thick powder horizontally;

Step S6, the computer controls the galvanometer 6 to control the laser 7 to irradiate the powder bed 15 on which the powder is laid according to the slice section data obtained by pre-selection, so that the current layer thickness powder is selectively melted and solidified;

Step S7, the computer controls the vertical motion device 17 to drop a layer thickness distance, and drives the powder bed 15 to drop a layer thickness distance;

Step S8, computer controls the described rodless cylinder 11 to drive the described powder-spreading groove 13 to move in the opposite direction to the right, laying a layer-thick powder on the powder bed 15;

Step S9, the computer controls the described galvanometer 6 again to control the laser 7 to irradiate the described powder bed 15 of the currently laid powder according to the slice section data obtained by pre-selection, so that the current layer thickness powder is selectively melted and solidified;

Step S10, computer controls described rodless cylinder 11 to drive described powder spreading groove 13 to move horizontally to the bottom of described material guide pipe 14 to prepare for receiving material;

Step S11, repeating steps S3-S10, and printing a three-dimensional product layer by layer according to the cross-sectional information obtained by pre-selection.

In one embodiment, the slicing procedure includes the following steps:

The layering direction and layering thickness are adjusted by layering software, and the target 3D model is layered and discretized into a set of ordered two-dimensional contour sets, and the two-dimensional contour of each layer is a slice;

According to the actual demand and the acquired two-dimensional profile information of the slice, the technical parameters are set to obtain the data code that can be recognized and scanned by the 3D printer, and the 3D printing control instruction is generated according to the scanned data code.

In one embodiment, the slicing process further includes the following steps:

Analyze the structural characteristics of the 3D model of the product, obtain the analysis results, and find out the position where supports need to be added to the product in 3D printing according to the analysis results;

Add supports in the 3D model drawing of the product according to the position where the supports are added, and get the 3D model drawing with supports;

Determine the positional relationship between the added support and the product according to the three-dimensional model diagram with the support, and obtain a three-dimensional model diagram of the product including the positional relationship of the support.

In one embodiment, the powder spreading tank 13 in step S5 moves to the leftmost stop, and at this moment, there is at least one layer of thick powder in the powder spreading tank 13.

In one embodiment, after the powder spreading tank 13 has laid a thickness of powder in step S8, the computer can continue to control the rodless air cylinder 11 to drive the powder spreading tank 13 to move to the right, so that the excess powder falls. into the recycling powder bucket 2.

To sum up, with the help of the above-mentioned technical solutions of the present invention, through the use of the present invention, the powder can be spread in two directions at one time, thereby saving the powder spreading time and improving the efficiency of laser printing; the cylinder used in the present invention It can use an ordinary rodless cylinder, with a simple and reliable structure, and the cylinder can be directly placed in the heat preservation chamber, close to the powder spreading platform, without other transmission components. The powder spreading structure of the whole machine is relatively simple, so it has high precision and reliable operation. The cost is low; in the present invention, because there is generally a little temperature requirement in the working heat preservation cavity, the working gas of the cylinder adopts a low temperature gas, generally nitrogen, which has a cooling effect on the cylinder and prevents the cylinder part from being exposed to the heat preservation cavity, because the thermal expansion and contraction are too high. In addition, the cylinder used in the present invention has a guiding device, which omits the guide rails required in traditional 3D printers. The structure is simple, the operation is reliable, and the cost is low; the present invention uses the cylinder to drive the execution piston located in the cylinder. The inside of the duct is not in contact with high dust conditions, so it is reliable, less maintenance and cost saving; the present invention adopts the cylinder control as an ordinary left and right dual-position solenoid valve, which is simple in control and reliable in operation; the present invention is a single-cylinder printing structure, compared with Compared with the traditional three-cylinder structure of powder spreading cylinder, working cylinder and recovery cylinder, the volume of the thermal insulation cavity is significantly reduced, which is conducive to the stable control of the temperature field, which not only effectively ensures the printing quality of the printer, but also effectively reduces the cylinder size. body manufacturing cost.

In the present invention, unless otherwise expressly specified and limited, terms such as "installation", "arrangement", "connection", "fixation" and "swivel connection" should be understood in a broad sense, for example, it may be a fixed connection, or It can be a detachable connection or an integrated body; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the internal connection of two elements or the interaction between the two elements. Unless otherwise clearly defined, those of ordinary skill in the art can understand the specific meanings of the above terms in the present invention according to specific situations.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the scope of the present invention. within the scope of protection.

Claims (10)

1. the 3D printer with the cooling powder spreading device is characterized by comprising a working cylinder body (1), wherein a powder recycling barrel (2) is arranged on one side of the working cylinder body (1), a power air source (3) is arranged on one side, far away from the working cylinder body (1), of the powder recycling barrel (2), a pneumatic control system (4) matched with the power air source (3) is arranged on the power air source (3), a heat insulation cavity (5) is arranged at the top of the working cylinder body (1), a vibrating mirror (6) is arranged at the top of the heat insulation cavity (5), a laser (7) is arranged on one side of the vibrating mirror (6), a storage hopper (8) is arranged on one side of the heat insulation cavity (5), an electric control discharge valve (9) is arranged at the bottom of the storage hopper (8), a heating system (10) is arranged at the inner top of the heat insulation cavity (5), and two groups of rodless cylinders (11) are symmetrically arranged in a penetrating mode around the inner bottom of, and one end of the rodless cylinder (11) is respectively connected with the pneumatic control system (4) and the power air source (3) through a conduit loop (12), a powder spreading groove (13) is arranged between the rodless cylinders (11), a material guide pipe (14) is arranged above the powder spreading groove (13), the top end of the material guide pipe (14) penetrates through the heat preservation cavity (5) and is fixedly connected with the bottom end of the storage hopper (8), a powder bed (15) is arranged at the bottom of the powder paving groove (13), a piston (16) is arranged at the bottom of the powder bed (15), the piston (16) is positioned at the inner top of the working cylinder body (1), the bottom of the piston (16) is provided with a vertical movement device (17), and the bottom end of the vertical movement device (17) penetrates through the working cylinder body (1) and extends to the bottom of the working cylinder body (1).

2. 3D printer with cooling and powder spreading device according to claim 1, characterized in that the power air source (3) is powered by liquefied nitrogen.

3. the 3D printer with the cooling and powder spreading device according to claim 2, wherein the heating system (10) adopts four or eight groups of infrared lamp tubes for heating, and a temperature control system is arranged in the heating system (10).

4. the 3D printer with the cooling powder spreading device according to claim 3, wherein the lower end of the powder spreading groove (13) is arranged to be a V-shaped structure, an opening scraper is arranged at the bottom of the powder spreading groove (13), and both ends of the powder spreading groove (13) are fixedly connected with a cylinder piston (18) in the rodless cylinder (11) through screws.

5. The 3D printer with the cooling and powder spreading device is characterized in that a sealing felt (19) is arranged between the periphery of the piston (16) and the working cylinder body (1), and one side of the sealing felt (19) is fixedly connected with the piston (16).

6. a printing method of a 3D printer with a cooling powder spreading device is characterized by being used for the 3D printer with the cooling powder spreading device according to claim 5, and comprising the following steps:

S1, designing a three-dimensional solid model of the product by using 3D modeling software in a computer according to the structural characteristics of the product, slicing the three-dimensional model by using a slicing program, and storing section information in the computer;

step S2, controlling the vertical movement device (17) to move the piston (16) to the inner top of the working cylinder body (1) by the computer, so that the powder laying mechanism is positioned below the material guide pipe (14);

s3, controlling the opening of the electric control discharge valve (9) on the storage hopper (8) by a computer, and enabling powder to fall into the powder spreading groove (13) along the material guide pipe (14);

step S4, after the powder in the powder paving groove (13) is accumulated to preset parameters, the computer controls the electric control discharge valve (9) to close;

Step S5, controlling the rodless cylinder (11) by the computer to drive the powder paving groove (13) to horizontally move leftwards, and starting to horizontally pave powder with a layer thickness;

step S6, controlling the galvanometer (6) by the computer to control the laser (7) to irradiate the powder bed (15) paved with the powder according to the pre-selected section data to selectively melt and solidify the powder with the current layer thickness;

Step S7, the computer controls the vertical movement device (17) to descend by a layer thickness distance to drive the powder bed (15) to descend by a layer thickness distance;

step S8, controlling the rodless cylinder (11) to drive the powder paving groove (13) to move towards the right in a reverse direction by the computer, and paving a layer of thick powder on the powder bed (15);

step S9, the computer controls the galvanometer (6) again to control the laser (7) to irradiate the powder bed (15) of the powder paved at present according to the pre-selected section data, so that the powder with the current layer thickness is selectively melted and solidified;

Step S10, controlling the rodless cylinder (11) by a computer to drive the powder paving groove (13) to horizontally move to the position below the material guide pipe (14) to prepare for receiving materials;

and S11, repeating the steps S3-S10, and printing the three-dimensional product layer by layer according to the pre-selected section information.

7. The printing method of the 3D printer with the cooling powder spreading device according to claim 6, wherein the slicing program comprises the following steps:

adjusting the layering direction and the layering thickness through layering software, and layering and dispersing the target three-dimensional model into a group of ordered two-dimensional contour sets, wherein the two-dimensional contour of each layer is a slice;

according to actual requirements and the acquired two-dimensional profile information of the slices, technical parameters are set to obtain data codes which can be identified and scanned by a 3D printer, and a 3D printing control instruction is generated according to the scanned data codes.

8. the printing method of the 3D printer with the cooling powder spreading device according to claim 7, wherein the slicing processing further comprises the following steps:

analyzing the structural characteristics of the three-dimensional model diagram of the product to obtain an analysis result, and finding out the position needing to be additionally supported in the product in the 3D printing according to the analysis result;

Adding support in the three-dimensional model diagram of the product according to the position of the added support, and obtaining the three-dimensional model diagram with the support;

and determining the position relation between the added support and the product according to the three-dimensional model diagram with the support, and obtaining a three-dimensional model diagram of the product containing the support position relation.

9. the printing method of the 3D printer with the cooling powder spreading device is characterized in that the powder spreading groove (13) in the step S5 moves to the leftmost end to stop, and at the moment, at least one layer of thick powder still exists in the powder spreading groove (13).

10. the printing method of the 3D printer with the cooling powder spreading device is characterized in that after the powder spreading groove (13) is spread with a certain thickness of powder in the step S8, the computer can continuously control the rodless cylinder (11) to drive the powder spreading groove (13) to move to the right, so that the redundant powder falls into the recycling powder barrel (2).