CN114734054A

CN114734054A - Embedded substrate and 3D printing method based on substrate

Info

Publication number: CN114734054A
Application number: CN202210333717.2A
Authority: CN
Inventors: 陈恺; 童林聪
Original assignee: Corevoxel Hangzhou Technology Development Co ltd
Current assignee: Corevoxel Hangzhou Technology Development Co ltd
Priority date: 2022-03-30
Filing date: 2022-03-30
Publication date: 2022-07-12
Anticipated expiration: 2042-03-30
Also published as: CN114734054B

Abstract

The invention provides an embedded substrate and a 3D printing method based on the substrate, wherein the embedded substrate comprises the following components: liquid paraffin, nanoscale fumed silica and an emulsifier; wherein the using amount of the nanoscale fumed silica is 13-17% of the mass of the liquid paraffin; the dosage of the emulsifier is 0.05-0.2% of the mass of the liquid paraffin. The 3D printing method provided by the invention does not need an additional printing support member, still has better surface quality and structure precision, simplifies the process, reduces the cost, is easy to implement and has wide application prospect.

Description

Embedded substrate and 3D printing method based on substrate

Technical Field

The invention relates to the technical field of 3D printing, in particular to an embedded substrate and a 3D printing method based on the substrate.

Background

3D prints as a quick customization forming technology, develops rapidly this year, compares in traditional processing mode, and 3D printing technology can high-efficiently make complicated spatial structure, dysmorphism structure even. Common 3D printing methods can be classified into Fused Deposition Modeling (FDM), powder Selective Laser Sintering (SLS), and photosensitive resin selective curing (SLA) according to their processing principles. The three-dimensional structure and the complex inner cavity structure are formed by adopting the layer-by-layer superposition mode in the 3D printing methods. However, in the layer-by-layer stacking mode from bottom to top, when the cantilever structure is printed, the structure is prone to collapse due to suspension of the lower structure, and in the prior art, a support is generally added in an area with a suspension angle smaller than 42 degrees to prevent collapse during three-dimensional model design and path planning. The method of adding the support member has the following disadvantages:

the supporting piece is directly connected with the product, machining means such as cutting are needed during removal, the surface quality of the product can be damaged, the supporting piece is difficult to completely remove, and the precision of the product is affected.

When the supporting piece is used for supporting a complex structure and an inner cavity, the space structure is limited, so that the post-treatment is difficult to carry out, and even the post-treatment cannot be carried out.

The supporting piece is often made of the same material as the product, a large number of supporting pieces are often used to guarantee successful printing when certain structures are realized, and the supporting pieces are removed after being used, so that a large amount of materials are wasted.

Disclosure of Invention

Therefore, the invention provides an embedded substrate and a 3D printing method based on the substrate.

Specifically, the invention firstly provides an embedded matrix, which comprises the following components: liquid paraffin, nanoscale fumed silica and an emulsifier; wherein the using amount of the nanoscale fumed silica is 13-17% of the mass of the liquid paraffin; the dosage of the emulsifier is 0.05-0.2% of the mass of the liquid paraffin.

The invention discovers that the liquid paraffin is used as the main component of the embedded matrix, and the nano-scale fumed silica and the emulsifier with the dosage are added, so that the hydrophobicity, the flowability and the shape retention of the liquid paraffin can be greatly improved, and the 3D printing method based on the matrix material is ensured to have better surface quality and structure precision without additional printing support. If the dosage of the nano fumed silica exceeds 17 percent, the viscosity of the matrix is too high, the flowability is poor, and in the process of printing by inserting the printing head into the matrix, if the diameter of the outer wall of the printing head is too large or the moving speed of the printing head is high, the matrix is difficult to rapidly replenish to a position moved before the printing head, so that a cavity or more serious deformation of the matrix which cannot be recovered is caused; if the amount is less than 13%, the substrate has very low viscosity and very poor supporting effect, and the printed hydrophilic metal paste is settled by gravity.

Preferably, the emulsifier is selected from span 80 and/or span 85;

and/or the particle size of the nanoscale fumed silica is less than 500 nm; it was found in the present invention that if the particle size of the nano-sized fumed silica is larger than 500nm, the resulting embedded matrix is difficult to achieve a suitable range in viscosity and support.

And/or, the nanoscale fumed silica is hydrophobic fumed silica.

The invention provides a method for preparing the embedded matrix, which comprises the following steps: and uniformly mixing the liquid paraffin, the nanoscale fumed silica and the emulsifier to obtain the nano-composite material.

The invention also provides a 3D printing method based on the embedded matrix, wherein the extrusion type 3D printing needle head is arranged in the embedded matrix, and the 3D printing is carried out by taking metal slurry or ceramic slurry as a printing material.

The invention further discovers that the extrusion type 3D printing needle head is arranged in the embedded matrix, the metal slurry or the ceramic slurry is extruded in the matrix through the needle head, and the needle head moves according to a designed path, so that a complex three-dimensional structure can be formed. Due to the hydrophobic nature of the embedded matrix and insolubility with the slurry, the extruded slurry does not dissolve in the matrix, but remains in place; the fluidity and the shape-retaining property of the embedded matrix enable the path which is passed by the needle tube to be rapidly filled by the embedded matrix, so that the matrix keeps a void-free state, and the matrix supports the printed structure from collapsing and deforming from all directions. Furthermore, in the 3D printing process, no extra printing support is needed, extruded slurry can still keep the shape of the path planned, and the structure precision is high.

Preferably, the embedded matrix is subjected to defoaming and impurity removal treatment, and then the extrusion type 3D printing needle is placed in the embedded matrix, wherein the defoaming and impurity removal method specifically comprises the following steps: and uniformly mixing, vacuum centrifuging and presintering the embedded matrix, and then cooling to room temperature. By carrying out the treatment on the embedded matrix, the dispersed bubbles and low-boiling-point impurities in the embedded matrix can be effectively removed, and the appearance of a final product cannot be influenced by the bubbles and the low-boiling-point impurities in the matrix in the subsequent embedded printing and pre-curing processes; if the deaeration is not performed, large bubbles in the matrix may cause the extruded paste to lack the underlying supporting matrix during the printing process and deform, and small bubbles or low-boiling impurities dispersed in the matrix may expand due to heating during the pre-sintering process and form a plurality of larger bubbles, which may press the printed structure and cause deformation or even breakage.

Wherein the uniform mixing is carried out under the stirring condition of the rotating speed of 1500-;

and/or the vacuum centrifugation is carried out under the conditions that the vacuum degree is less than 0.3Kpa, the temperature is 20-30 ℃, and the rotation speed is 1500-3000 rpm;

and/or the temperature of the pre-sintering is 140-160 ℃, and the heat preservation time is 8-20 min; preferably, the temperature rise rate of the pre-sintering is 1.5-3 ℃/min.

Preferably, the 3D printing method of the present invention further includes: after 3D printing is finished, pre-curing and soaking the printed structure and the embedded substrate together to obtain a formed structure, and then sintering and curing the formed structure.

Further preferably, the temperature of the pre-curing is 140-160 ℃, and the heat preservation time is 25-40 min; most preferably, the temperature rise rate of the pre-curing is 1-2.5 ℃/min. Under the pre-curing condition, the strength of the printed structure is enhanced, and the physical and chemical properties of the embedded matrix are not changed, so that the precision of the printed structure is ensured.

Preferably, the solvent for soaking is selected from one or more of n-hexane, carbon tetrachloride, chloroform, diethyl ether, benzene and carbon disulfide.

Preferably, the sintering and curing temperature is higher than 300 ℃ and the time is more than 30 min.

Preferably, the metal Paste includes, but is not limited to, all water-soluble nano-metal pastes available for high precision extrusion 3D printing, such as E3D-A-01Silver Paste from West lake future Intelligence manufacturing Inc.

In a more preferred embodiment, the water-soluble nano-metal slurry is disclosed in chinese published patent application CN113593750A, published in 2021 at 11/02 of 2021, by jangasseri et al, "water-soluble nano-metal slurry and its preparation method and application", applicant: science and technology development limited of West lake future Intelligent manufacturing (Hangzhou). For the sake of brevity, only the disclosure of the above application should be considered as a part of the disclosure of the present application.

Preferably, the ceramic slurry comprises the following components in parts by weight: 4-6 g of nanoscale alumina, 2.5-3.5 g of polyethylene glycol diacrylate, 1-2 g of dihexylene glycol and 0.04-0.08 g of dichlorodiisonitrile.

Based on the scheme, the invention has the following beneficial effects:

the invention can realize the unsupported printing of a three-dimensional complex structure and the unsupported cantilever structure, and the suspension angle can be between-90 and 90 degrees.

The invention can realize the machining process of directly forming a complex structure on the surfaces of other parts and subsequently removing the support without an additional support.

The invention can realize 100% utilization of printing slurry.

Drawings

FIG. 1 is a flow chart of a 3D printing method provided by the present invention;

FIG. 2 is a schematic diagram of embedded printing provided in embodiment 4 of the present invention;

FIG. 3 is a schematic diagram of a blade-coating-type embedded printing method provided in embodiment 5 of the present invention;

fig. 4 is a schematic cross-sectional view of a blade-coated embedded printing provided in embodiment 5 of the present invention.

Detailed Description

The following examples are intended to illustrate the invention, but are not intended to limit the scope of the invention. Unless otherwise specified, the technical means used in the examples are conventional means well known to those skilled in the art, and the raw materials used are commercially available products.

In the following examples:

liquid paraffin: Sigma-Aldrich Paraffin wax heavy oil

Nano-scale fumed silica: firstly-Feng nano-silica KH550 treatment

Span 80: adamas-beta Span 80

3D printer: west lake future intelligent manufacturing precision series high-precision 3D printer

Metal slurry: west lake Mianzhi E3D-A-01Silver Paste

Example 1

The present embodiment provides an embedded substrate comprising: 30g of liquid paraffin, 4g of nano fumed silica and 0.03g of span 80.

Example 2

The present embodiment provides an embedded substrate comprising: 30g of paraffin, 4g of nano fumed silica and 0.015g of span 80.

Example 3

The present embodiment provides an embedded substrate comprising: 30g of paraffin, 5g of nano fumed silica and 0.06g of span 80.

Example 4

The embodiment provides a 3D printing method, which includes the following steps:

processing the embedded substrate:

1) paraffin wax, nano-sized fumed silica and span 80 were weighed according to the formulation of example 1, and then placed in a blender and mixed well at 2000 rpm.

2) The mixed substrate is put into a quartz container and placed in a vacuum centrifuge, and vacuum centrifugation is carried out at the vacuum degree of less than 0.3Kpa, the temperature of 25 ℃ and the rotating speed of 2000 rpm.

3) And (3) placing the substrate after vacuum centrifugation in a muffle furnace, heating to 150 ℃ at a heating rate of 2 ℃/min, preserving heat at the temperature for 10min, and cooling to room temperature along with the furnace.

Loading and preparing:

4) and pouring the metal slurry into the needle cylinder and connecting the needle cylinder with a pneumatic dispenser.

5) Fixing the quartz container containing the embedded substrate in the step 3) on a 3D printer base station, and inserting a needle head into the embedded substrate.

Printing and post-processing:

6) the metal slurry is extruded into the embedded matrix through the needle head, the base station moves at the same time, the slurry forms filiform metal wires in the embedded matrix, and the three-dimensional structure can be formed in a filling and layer-by-layer overlapping mode. The printing conditions were as follows: a printing head with the inner diameter of 50 mu m is selected, a pneumatic dispenser gives pressure of 30-50psi, the moving speed of a moving platform is 0.5-1mm/s, and the moving direction is unlimited in the range of quartz vessels. The printing path is from bottom to top as much as possible, the outer wall of the printing head is prevented from touching the formed metal wire, and deformation or fracture is avoided.

7) After printing, the quartz vessel containing the embedded substrate and the printed structure is taken out from the base station, placed in a muffle furnace, heated to 150 ℃ at a heating speed of 2 ℃/min, and kept at the temperature for 30 minutes for pre-curing.

8) And (3) immersing the quartz vessel into a n-hexane solution to ensure that the n-hexane completely submerges the embedded matrix, and carrying out ultrasonic cleaning until the embedded matrix is completely dissolved in the n-hexane.

9) And taking out the printed structure, placing the printed structure in a muffle furnace, sintering for 0.5h at 400 ℃ until the printed structure is completely cured, and finishing printing.

Example 5

processing the embedded substrate:

1) paraffin, nano-sized fumed silica and span 80 were weighed according to the formulation of example 2, and then placed in a blender and mixed thoroughly at 1500 rpm.

3) The substrate after vacuum centrifugation is scraped and coated on the surfaces of parts, such as silicon wafers, chip packages and electronic device surfaces.

4) And (3) placing the part coated with the embedded matrix in a muffle furnace, heating to 150 ℃ at a heating rate of 2 ℃/min, preserving the heat at the temperature for 10min, and cooling to room temperature along with the furnace.

Loading and preparing:

5) and pouring the metal slurry into the needle cylinder and connecting the needle cylinder with a pneumatic dispenser.

6) Fixing the part coated with the embedded matrix in a scraping manner and obtained in the step 4) on a 3D printer base, and inserting a needle into the embedded matrix.

Printing and post-processing:

7) the metal paste is extruded in embedded matrix through the syringe needle, and the base station removes simultaneously, and thick liquids form filiform wire in embedded matrix, and the first layer of printing and part surface contact make the structure of printing adhere to the part surface, and the rethread is filled and layer upon layer superpose mode from bottom to top can take shape spatial structure, because the supporting effect of embedded matrix, no matter whether the lower floor has the support, no matter print any kind of structure, the deformation of collapsing can not appear. The printing conditions were as follows: a printing head with the inner diameter of 30 mu m is selected, the pneumatic dispenser gives pressure of 25-50psi, the moving speed of the moving platform is 1-1.5mm/s, and the first layer connected with the substrate is recommended to use larger extrusion pressure and slower speed, such as 50psi and 1.5mm/s, so that the contact area with the substrate is increased, the overall stability is improved, and the extrusion pressure and the printing speed for upper layer printing can be adjusted according to the required line type.

8) After printing is finished, the parts are taken out from the base station, placed in a muffle furnace together, heated to 150 ℃ at the heating rate of 2 ℃/min, and preserved for 30 minutes at 150 ℃ for precuring.

9) And (3) immersing the part in a normal hexane solution to ensure that the normal hexane completely submerges the embedded matrix, and carrying out ultrasonic cleaning until the embedded matrix is completely dissolved in the normal hexane.

10) And taking out the part, placing the part in a muffle furnace, sintering the part for 0.5h at 350 ℃ until the part is completely cured, and finishing printing.

Example 6

The present embodiment provides a 3D printing method using ceramic paste as a printing paste.

The ceramic slurry includes: 5g of nanoscale aluminum oxide powder, 3g of polyethylene glycol diacrylate (PEGDA), 1.5g of dihexylene glycol (DEG), and 0.06g of dichlorodiisonitrile (AlBN).

The 3D printing method provided in this example is substantially the same as the printing method provided in example 4 or example 5, except that the curing temperature of the paste after printing is 110 ℃, and the temperature is maintained for 2 hours.

Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.

Claims

1. An embedded matrix comprising the following components: liquid paraffin, nanoscale fumed silica and an emulsifier; wherein the content of the first and second substances,

the using amount of the nano-scale fumed silica is 13-17% of the mass of the liquid paraffin;

the dosage of the emulsifier is 0.05-0.2% of the mass of the liquid paraffin.

2. The embedded matrix according to claim 1, characterized in that the emulsifier is selected from span 80 and/or span 85;

and/or the particle size of the nanoscale fumed silica is less than 500 nm;

and/or, the nanoscale fumed silica is hydrophobic fumed silica.

3. 3D printing method based on the embedded substrate as claimed in claim 1 or 2, characterized in that an extrusion type 3D printing needle is placed in the embedded substrate, and 3D printing is performed by using metal paste or ceramic paste as printing material.

4. The 3D printing method according to claim 3, wherein the embedded substrate is subjected to defoaming and impurity removal treatment, and then the extrusion type 3D printing needle head is placed in the embedded substrate, and the defoaming and impurity removal method specifically comprises the following steps:

and uniformly mixing, vacuum centrifuging and presintering the embedded matrix, and then cooling to room temperature.

5. The 3D printing method according to claim 4, wherein the uniform mixing is performed under stirring conditions at a rotation speed of 1500-3000 rpm;

and/or, the vacuum centrifugation is carried out under the conditions that the vacuum degree is less than 0.3Kpa, the temperature is 20-30 ℃, and the rotating speed is 1500-3000 rpm;

6. The 3D printing method according to any of claims 3-5, wherein the 3D printing method further comprises:

after 3D printing is finished, pre-curing and soaking the printed structure and the embedded substrate together to obtain a formed structure, and then sintering and curing the formed structure.

7. The 3D printing method according to claim 6, wherein the pre-curing temperature is 140-160 ℃ and the holding time is 25-40 min; preferably, the temperature rise rate of the pre-curing is 1-2.5 ℃/min.

8. The 3D printing method according to claim 6 or 7, wherein the solvent for soaking is selected from one or more of n-hexane, carbon tetrachloride, chloroform, diethyl ether, benzene, and carbon disulfide.

9. The 3D printing method according to any of claims 6-8, wherein the sintering curing temperature is above 300 ℃ for more than 30 min.

10. The 3D printing method according to any of claims 3-9, wherein the metal paste is a water-soluble nano-metal paste;

and/or the ceramic slurry comprises the following components in parts by weight: 4-6 g of nanoscale alumina, 2.5-3.5 g of polyethylene glycol diacrylate, 1-2 g of dihexyl diol and 0.04-0.08 g of dichloroisobutyronitrile.