阅读说明：本技术 一种基于3d打印的铁氧体器件制作工艺 (Ferrite device manufacturing process based on 3D printing ) 是由 段戈扬 张硕 鲁小刚 徐向阳 刘江博闻 陈彬 李�杰 于 2021-09-22 设计创作，主要内容包括：本发明公开了一种基于3D打印的铁氧体器件制作工艺,属于3D打印技术领域,解决了现有技术中制造铁氧体器件精度低的问题,本发明包括如下步骤：S1、制备改性铁氧体粉体；S2、制备铁氧体打印浆料；S3、打印铁氧体器件坯料；S4、坯料脱脂烧结；S6、尺寸检测：对样品进行尺寸检测,检测件要求公差≤±0.2mm；S7、性能测试：对样品进行性能测试,要求满足铁氧体器件的性能标准。本发明用于使用铁氧体材料结合3D打印技术制造铁氧体器件,产品成型好、精度高。(The invention discloses a ferrite device manufacturing process based on 3D printing, belongs to the technical field of 3D printing, and solves the problem of low precision of ferrite device manufacturing in the prior art, and the ferrite device manufacturing process comprises the following steps: s1, preparing modified ferrite powder; s2, preparing ferrite printing slurry; s3, printing a ferrite device blank; s4, degreasing and sintering the blank; s6, size detection: detecting the size of the sample, wherein the tolerance of a detection piece is required to be less than or equal to +/-0.2 mm; s7, performance test: and (4) carrying out performance test on the sample, wherein the performance standard of the ferrite device is required to be met. The invention is used for manufacturing ferrite devices by combining ferrite materials with a 3D printing technology, and has good product forming and high precision.)

1. A ferrite device manufacturing process based on 3D printing is characterized by comprising the following steps:

s1, preparing modified ferrite powder: coating the surface of ferrite with organic silicon resin to prepare modified ferrite powder with 22-28% of resin content;

s2, preparing ferrite printing slurry: taking an active diluent and a prepolymer, magnetically stirring for 0.5-1H in a yellow light environment and a water bath environment at the temperature of 30-50 ℃, adding a photoinitiator, shading and stirring for 1.5-2H until the solution is clear, and obtaining a photopolymer element premix; adding the film-coated modified ferrite, a plasticizer, a defoaming agent and a dispersing agent into the photosensitive polymer component premixed liquid, and placing the mixture in a vacuum stirring defoaming machine for mixing for 10-15min, wherein the plasticizer is a bentonite rheological agent; carrying out vacuum filtration on the slurry to obtain ferrite slurry with uniform quality; the plasticizer is a bentonite rheological agent;

s3, printing a ferrite device blank;

s4, degreasing and sintering the blank;

s6, size detection: detecting the size of the sample, wherein the tolerance of a detection piece is required to be less than or equal to +/-0.2 mm;

s7, performance test: and (4) carrying out performance test on the sample, wherein the performance standard of the ferrite device is required to be met.

2. The process of claim 1, wherein the reactive diluent in the step S2 comprises 1, 6-hexanediol diacrylate, 2-propoxylated neopentyl glycol diacrylate and acryloyl morpholine material, the prepolymer is ditrimethylolpropane acrylate material, and the plasticizer is di (2-ethylhexyl) phthalate.

3. The ferrite device manufacturing process based on 3D printing as claimed in claim 1, wherein the method of printing the ferrite device blank in step S3 is as follows:

setting laser power at 700mw, printing layer thickness at 25-50 μm, profile scanning interval at 0.08-0.1mm, profile scanning track at constant mode, filling scanning track at cross mode, filling scanning interval at 0.02-0.04mm, scanning times at 2-4 times, scanning speed at 2900-3300mm/S, and returning to step S1 to adjust material ratio if physical properties of the printed blank are not satisfactory.

4. The manufacturing process of ferrite device based on 3D printing as claimed in claim 1, wherein the blank degreasing sintering method in step S4 is as follows:

placing the degreased sample in a crucible, placing the degreased sample in an atmosphere furnace, vacuumizing the furnace by using a vacuum pump, filling nitrogen into the furnace to enable the interior to reach normal pressure, starting the atmosphere furnace to heat and cool, reducing the flow of the nitrogen in sequence after the temperature is increased to 800 ℃, reducing the flow of the nitrogen in 2 times every 15 minutes within 30 minutes, reducing the flow to 0ml/min, taking out the sample after the temperature is reduced to room temperature, and returning to the step S3 to adjust the printing parameters if the size of the sample does not reach the standard and is not formed.

5. The manufacturing process of ferrite device based on 3D printing as claimed in claim 1, wherein the temperature and time for degreasing and sintering the blank in step S4 are controlled as follows:

the temperature is 20-250 ℃, the heating rate is 0.3 ℃/min, and the time is 767 min;

the temperature is 250 ℃ and 400 ℃, the heating rate is 0.15 ℃/min, and the time duration is 1000 min;

the temperature is 400 ℃, and the heat preservation time is 60 min;

the temperature is 400-;

the temperature is 550-;

the temperature is 900 ℃, and the heat preservation time is 60 min;

the temperature is 900-20 ℃, and the temperature is reduced along with the furnace for 480 min.

Technical Field

The invention belongs to the technical field of 3D printing, and particularly relates to a ferrite device manufacturing process based on 3D printing.

Background

Ferrite is a composite oxide of an iron group element and one or more other suitable metal elements, and is classified into soft ferrite and hard ferrite according to its magnetic properties. The soft magnetic ferrite is a ferrite which is easy to magnetize and demagnetize under a weaker magnetic field. A typical representative of the soft magnetic ferrite is manganese zinc ferrite. The soft magnetic ferrite is a ferrite material with wide application, multiple varieties, large quantity and high output value at present. It is mainly used as various inductance elements, such as filter magnetic core, transformer magnetic core, wireless electromagnetic core, magnetic tape recording and video recording head, etc., and is also a key material of magnetic recording element. The hard magnetic ferrite is a ferrite which is not easily demagnetized after magnetization, and therefore, the hard magnetic ferrite is also called a permanent magnetic ferrite. Typical representatives of hard magnetic ferrites are strontium ferrite and barium ferrite, which are mainly used for magnetic cores of sound recorders, speakers and various instruments in telecommunication devices, and the like. The preparation process of ferrite (soft ferrite and hard ferrite) comprises three links of powder making, pressing and sintering, wherein the powder making and the sintering are the two most critical links and directly influence the quality and the performance of the material.

The ferrite magnetic part is generally prepared by the traditional powder metallurgy forming methods such as die press forming, injection forming, extrusion forming and the like. For these traditional forming, expensive dies are needed, complicated die design is difficult, for small-sized magnetic products with complicated shapes, problems of blank cracks, large dimension errors and the like often occur in the traditional process, and for sintered products, machining is very difficult.

The 3D printing technology, also called additive manufacturing technology, is a leading-edge technology which needs a plurality of technologies such as material science technology, electromechanical control technology, information technology and the like to be closely matched, relates to a plurality of subjects such as CAD modeling, machinery, laser, materials and the like, and is printed by means of three-dimensional model data in a layer-by-layer stacking mode from bottom to top.

Because the metal oxide property of ferrite is limited by the condition of 3D printing, the printing of ferrite devices by using conventional ferrite materials is difficult to form during printing and sintering, and the size does not meet the precision requirement, so the process becomes a technical problem.

Disclosure of Invention

The invention aims to:

in order to solve the problem of low precision of ferrite device manufacturing in the prior art, a ferrite device manufacturing process based on 3D printing is provided.

The technical scheme adopted by the invention is as follows:

a ferrite device manufacturing process based on 3D printing comprises the following steps:

s1, preparing modified ferrite powder: coating the surface of ferrite with organic silicon resin to prepare modified ferrite powder with 22-28% of resin content;

s2, preparing ferrite printing slurry: taking an active diluent and a prepolymer, magnetically stirring for 0.5-1H in a yellow light environment and a water bath environment at the temperature of 30-50 ℃, adding a photoinitiator, shading and stirring for 1.5-2H until the solution is clear, and obtaining a photopolymer element premix; adding the film-coated modified ferrite, a plasticizer, a defoaming agent and a dispersing agent into the photosensitive polymer component premixed liquid, and placing the mixture in a vacuum stirring defoaming machine for mixing for 10-15min, wherein the plasticizer is a bentonite rheological agent; carrying out vacuum filtration on the slurry to obtain ferrite slurry with uniform quality; the plasticizer is a bentonite rheological agent;

s3, printing a ferrite device blank;

s4, degreasing and sintering the blank;

s6, size detection: detecting the size of the sample, wherein the tolerance of a detection piece is required to be less than or equal to +/-0.2 mm;

s7, performance test: and (4) carrying out performance test on the sample, wherein the performance standard of the ferrite device is required to be met.

Further, the reactive diluent in the step S2 includes 1, 6-hexanediol diacrylate, 2-propoxylated neopentyl glycol diacrylate and acryloyl morpholine material, the prepolymer is ditrimethylolpropane acrylate material, and the plasticizer is di (2-ethylhexyl) phthalate.

Further, the method for printing the ferrite device blank in step S3 is as follows:

setting laser power at 700mw, printing layer thickness at 25-50 μm, profile scanning interval at 0.08-0.1mm, profile scanning track at constant mode, filling scanning track at cross mode, filling scanning interval at 0.02-0.04mm, scanning times at 2-4 times, scanning speed at 2900-3300mm/S, and returning to step S1 to adjust material ratio if physical properties of the printed blank are not satisfactory.

Further, the blank degreasing and sintering method in the step S4 is as follows:

placing the degreased sample in a crucible, placing the degreased sample in an atmosphere furnace, vacuumizing the furnace by using a vacuum pump, filling nitrogen into the furnace to enable the interior to reach normal pressure, starting the atmosphere furnace to heat and cool, reducing the flow of the nitrogen in sequence after the temperature is increased to 800 ℃, reducing the flow of the nitrogen in 2 times every 15 minutes within 30 minutes, reducing the flow to 0ml/min, taking out the sample after the temperature is reduced to room temperature, and returning to the step S3 to adjust the printing parameters if the size of the sample does not reach the standard and is not formed.

Further, the temperature and time for degreasing and sintering the blank in the step S4 are controlled as follows:

the temperature is 20-250 ℃, the heating rate is 0.3 ℃/min, and the time is 767 min;

the temperature is 250 ℃ and 400 ℃, the heating rate is 0.15 ℃/min, and the time duration is 1000 min;

the temperature is 400 ℃, and the heat preservation time is 60 min;

the temperature is 400-;

the temperature is 550-;

the temperature is 900 ℃, and the heat preservation time is 60 min;

the temperature is 900-20 ℃, and the temperature is reduced along with the furnace for 480 min.

In summary, due to the adoption of the technical scheme, the invention has the beneficial effects that:

1. according to the invention, by controlling the content of resin in the slurry and carrying out surface modification on the ferrite powder material, the mixed printing slurry can meet the bonding and fluidity in the curing process, and can ensure the content of ferrite powder in the slurry, and meanwhile, through the organic silicon surface coating, the wave absorption of ferrite is reduced, the printing quality reduction caused by the heating of a sample absorbing laser energy in the printing process is avoided, the forming condition and the size precision of a printed ferrite device are obviously improved, and various technical problems in ferrite printing are overcome.

2. According to the invention, the temperature rise rate and time are accurately controlled in the degreasing and sintering process, the solid organic matters in the green body are removed on the premise of not damaging the green body, the decomposition, gasification and diffusion rates of the organic matters are consistent, the defects of holes, cracks and the like of decomposed gas in the green body are avoided, the sintered product can meet the precision requirement of size forming, and the condition of bonding failure is avoided.

Drawings

FIG. 1 is a flow chart of the process of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

As shown in fig. 1, the present invention can be implemented as follows:

the ferrite powder used for preparing the 3D ceramic slurry has high absorption intensity at 355nm through ultraviolet absorption detection, the preparation of the 3D printing ceramic slurry by simply using the resin and the ferrite is not feasible, and the ferrite needs to be subjected to surface modification to reduce the ultraviolet absorption of the ferrite at 355 nm.

The ferrite powder material used in the present invention may have an average particle diameter of 3.59 μm. The powder has wide particle size distribution, and can effectively increase the sintering density of the ceramic. The results of the physical and chemical analysis are as follows:

volume average particle diameter: 3.59 μm

Particle size distribution: (volume)

Samples below 1.98 μm account for 10% of the total volume;

the sample with the diameter less than 3.43 μm accounts for 50% of the total volume;

the samples below 5.42 μm account for 90% of the total volume.

According to the invention, the ferrite is subjected to surface coating treatment by the organic silicon resin, the flowability of the treated ferrite powder is effectively improved, the color of the material is lightened, and the raw materials for preparing the printed ferrite slurry are as follows:

prepolymer: Di-TMPTA (ditrimethylolpropane acrylate);

prepolymer diluent: HDDA (1, 6-hexanediol diacrylate), NPG2PODA (2-propoxylated neopentyl glycol diacrylate), ACMO (acryloylmorpholine);

photoinitiator (2): PI651(1, 1-dimethoxy-1-1 phenylacetophenone);

dispersing agent: wetting dispersant with model number BYK 111;

ceramic powder: coating ferrite powder on the surface;

plasticizer:

"Haimines rheology aid Bentoni SD-2" (Haimines rheology aid SD-2): the hamming rheology auxiliary agent SD-2 is a bentonite rheology agent of an agricultural production system and is designed for a medium-to-high-performance solvent coating system.

The process for preparing the printing paste comprises the following steps:

(1) preparation of photosensitive polymer component

Mixing active diluent (HDDA 100g, NPG2PODA 150g, ACMO 100g) with prepolymer Di-TMPTA 87.5g, magnetically stirring at 40-50 deg.C water bath environment for 0.5-1H, adding photoinitiator PI 65122 g, and stirring in shade for 1.5-2H until the solution is clear.

(2) Respectively taking 9g of plasticizer phthalic acid di (2-ethylhexyl) ester, 2.3g of organic silicon defoamer and BYK1112.5g of dispersant; 1400g of film-coated modified ferrite, a plasticizer, a defoaming agent and a dispersing agent are added into the photosensitive polymer component premix liquid to be stirred and ball-milled for 4-6 hours; and filtering and separating the paste after ball milling, and defoaming the paste in a negative pressure environment to obtain ferrite slurry (the ferrite content is 75 wt%).

The viscosity of the slurry was measured by a rotational viscometer method, and the viscosity of the slurry having a solid content of 75% was measured to be 2.5 ten thousand mpa.s.

Preferably, the printer which can be used in the invention is 3d CARAM C900, the laser setting power is 700mw (laser setting value is 78%), the printing layer thickness is 25 μm-50 μm, the contour scanning track is contourr, the filling scanning track is cross, the contour scanning interval is 0.08-0.1mm, the filling scanning interval is 0.02-0.04mm, the scanning times are 2-4 times, and the scanning speed is 2900-.

Before degreasing and sintering, Differential Scanning Calorimetry (DSC) and thermogravimetric analysis (TGA) are carried out on the green body to determine the decomposition temperature interval of each component, and the test sampling is 49.9mg, the temperature interval is between 100 ℃ and 300 ℃, the weight loss is 2.5mg, and the loss of physical adsorption water is mainly seen from the test curve. Weight loss of 27.5mg between 300 ℃ and 530 ℃ is mainly the pyrolysis loss of the organic components. The weight loss tends to be stable between 530 ℃ and 700 ℃. From the DTA curve, three peaks appear in total, namely endothermic peaks of thermal cracking at 420 ℃, 440 ℃ and 500 ℃, and exothermic peaks of iron powder oxidation at 500 ℃.

The degreasing sintering process was designed according to the above analysis as follows:

the temperature is 20-250 ℃, the heating rate is 0.3 ℃/min, and the time is 767 min;

the temperature is 250 ℃ and 400 ℃, the heating rate is 0.15 ℃/min, and the time duration is 1000 min;

the temperature is 400 ℃, and the heat preservation time is 60 min;

the temperature is 400-;

the temperature is 550-;

the temperature is 900 ℃, and the heat preservation time is 60 min;

the temperature is 900-20 ℃, and the temperature is reduced along with the furnace for 480 min.

The degreasing sintering process is specifically operated as follows:

0. inputting a temperature rising/reducing program;

1. placing the degreased sample in a crucible, placing the crucible in an atmosphere furnace, and closing a furnace door;

2. fixing the nitrogen gas bottle on the gas bottle frame;

3. opening a nitrogen cylinder switch to enable the display number at the outlet of the pressure reducing valve to be 0.3MPa-0.5 MPa;

4. opening a vacuum pump, vacuumizing the furnace, and closing the vacuum pump when the gauge pressure is reduced to-0.06 MPa;

5. opening a nitrogen inlet valve switch;

6. adjusting the flow of the flowmeter, starting inflation until the vacuum meter shows normal pressure, and adjusting the nitrogen gas inlet flow (about 1 l/min);

7. opening an exhaust valve;

8. starting a temperature rise/reduction program;

9. after the temperature rises to 800 ℃, the flow is gradually reduced, and the flow is reduced to 0ml/min within 30 minutes at intervals of 15 minutes for 2 times;

10. and closing the gas cylinder switch, and taking out the sample after the temperature is reduced to the room temperature.

After the sample is taken out, the size detection and the performance detection are carried out on the sample, and the requirement of the ferrite device can be met through the test determination.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.