Cast porcelain die-casting method

Abstract

The invention discloses a ceramic casting and pressure casting method, which relates to the technical field of ceramic casting and pressure casting, and comprises the following pressure casting steps: S1, pretreatment of a casting ring, S2, roasting of the casting ring, S3, placement of a ceramic block and installation of a push rod, S4, sintering of a hearth, and S5, removal of an embedding material and completion of a casting. The method has the effect of effectively removing carbides so as to avoid casting black spots and air holes.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of ceramic casting, in particular to a ceramic casting method. BACKGROUND

[0002] Ceramic casting is a precision forming technology that melts porcelain blocks at high temperature and injects them into a casting cavity under pressure, mainly used for the manufacture of dental restorations such as full-ceramic crowns, inlays, and porcelain veneers. During the ceramic casting process, various problems may occur with the castings, such as incomplete casting, rough surface, casting defects, etc., which can be solved by official methods, but some problems cannot be solved, such as impurities in the castings due to incomplete wax vaporization.

[0003] The existing ceramic casting method usually adopts a static baking process; static baking cannot remove carbides, resulting in black spots and pores in the castings. SUMMARY

[0004] The present application provides a ceramic casting method that effectively removes carbides, thereby avoiding black spots and pores in the castings.

[0005] The present application provides a ceramic casting method, which adopts the following technical solution: A ceramic casting method, the casting step of which comprises: S1. Casting ring pretreatment After the internal embedding material and the model of the casting ring are cured, the mold release and ring removal are performed first; the top cover and the base are removed, and the operator holds the two sides of the silicone rubber ring with both hands, gently lifts it out with the index finger, and avoids using too much force to cause the casting ring to crack or the model to be damaged; then the bottom trimming is carried out, the bottom of the casting ring is polished with fine sandpaper or special trimming tools to ensure that the bottom is flat and has no protrusions, providing stability for subsequent placement and preventing deformation of the casting due to uneven stress during baking and casting; S2. Casting ring baking Preheat the Mofu furnace to 850°C, and after the temperature stabilizes, place the pretreated casting ring in the furnace; after placing, the furnace temperature drops, and the door needs to be closed until it rises to 850°C and stabilizes before starting the timer; S3. Placing of porcelain blocks and installation of push rod Select the corresponding ceramic block according to the color of the restoration, place it into the casting ring with the marked text facing up to facilitate color error prevention, and make sure it fits tightly without obvious gaps; take the alumina casting push rod and slowly insert it into the casting channel; S4. Furnace sintering Open the furnace door of the ceramic casting furnace, and place the casting ring with the porcelain blocks and push rod into the center of the furnace; after closing the door, confirm that the temperature, pressure, and vacuum degree parameters on the display screen are all green, press the start button to start the program, and the equipment will automatically complete the temperature rising, melting, pressure casting, and heat preservation cooling without manual intervention; S5. Removing the investment material and completing the casting After the die casting is completed, the casting ring is taken out when the casting porcelain furnace cools down to room temperature; the height of the casting ring is measured by an alumina push rod, and the investment material is removed in a gradient treatment manner; finally, the abrasive powder is blown away by a high-pressure air gun, and the whole process is completed.

[0006] By adopting the above technical solution, by executing the complete die casting steps including casting ring pretreatment, casting ring firing, porcelain block placement and push rod installation, furnace sintering, and investment material removal, the pretreatment stage is smoothly demolded and the bottom is trimmed to ensure stability, the firing temperature is accurately controlled, the porcelain blocks are placed according to color and the push rods are installed in a standard manner, the sintering is fully automated, and the investment material is removed in a gradient manner; the technical effects of standardizing each link and reducing human operation deviation are achieved, the casting porcelain die casting process is ensured to be coherent and controllable, problems such as casting ring cracking and casting deformation caused by improper operation are effectively avoided, the stability of the dental restoration body is improved, and a foundation is laid for subsequent reduction of casting defects.

[0007] Preferably, in S2. casting ring firing, the casting ring is placed in the muffle furnace at an angle of 45° when firing.

[0008] By adopting the above technical solution, in S2. casting ring firing, the casting ring is placed in the muffle furnace at an angle of 45°; the technical effect of significantly increasing the contact area of the casting ring with the hot air in the furnace and more uniform heat transfer is achieved, which avoids incomplete vaporization of the model material caused by uneven local heating of the casting ring, prevents the unvaporized model material from directly dropping to the bottom of the furnace body to cause pollution or cleaning problems, optimizes the firing environment, provides support for subsequent complete removal of impurities and improvement of firing quality, and helps to reduce internal defects of the casting.

[0009] Preferably, in S2. casting ring firing, the firing further includes impurity cleaning, which includes temporarily taking out the casting ring during the firing process, continuing to heat preservation after cleaning the inside of the casting ring, and being suitable for medical casting wax or light-cured 3D printing resin, dental cutting wax, etc.

[0010] By adopting the above technical solution, in S2. casting ring firing, the impurity cleaning step is added, that is, the casting ring is temporarily taken out during firing, and the inside is cleaned and then heat preserved; the technical effect of adapting to three kinds of model materials of medical casting wax and light-cured 3D printing resin dental cutting wax is achieved, which can specifically remove the incompletely vaporized substances generated during firing of different materials, avoid the formation of impurities caused by the residues of these substances, break through the limitation of traditional firing which only relies on high temperature and incomplete impurity removal, and widen the range of model materials used in ceramic die casting, while reducing casting defects caused by impurities from the source.

[0011] Preferably, the impurity cleaning adopts a special porcelain casting clamp to take out the casting ring in the roasting process, and after cleaning the internal incomplete vaporization residues with an air gun, the casting ring is taken out smoothly with a special clamp after the roasting reaches the standard.

[0012] By adopting the above technical scheme, in the impurity cleaning, the casting ring in the roasting process is taken out by a special porcelain casting clamp, and after cleaning the internal incomplete vaporization residues with an air gun, the casting ring is taken out smoothly with a special clamp after the roasting reaches the standard; the technical effects of safe taking and placing the casting ring and precise removal of internal residues are generated, the special clamp can avoid the operator being scalded and prevent the casting ring from being damaged by knocking, the air gun can clean the residues directionally and will not damage the structure of the casting ring, the continuous roasting process is ensured, the roasting effect is not affected by improper taking and placing or cleaning in time, the roasting quality stability is ensured, and the casting is prevented from being scrapped due to impurity residues or casting ring damage.

[0013] Preferably, in S3, the surface of the die-casting push rod is coated with a release agent coating, and the depth of the push rod inserted into the casting mouth channel is such that the bottom of the push rod is in contact with the surface of the porcelain block.

[0014] By adopting the above technical scheme, in S3, the surface of the die-casting push rod is coated with a release agent coating, and the depth of the push rod inserted into the casting mouth channel is such that the bottom of the push rod is in contact with the surface of the porcelain block; the technical effects of the push rod being in close contact with the porcelain block and being easy to separate without adhesion are generated, the release agent coating prevents the push rod and the porcelain block from being adhered after die casting and being difficult to disassemble, the precise insertion depth ensures that the pressure can be effectively transmitted to the porcelain block during die casting, and leakage of porcelain liquid is prevented due to not being in close contact; and the effects of ensuring smooth die casting, reducing rework due to push rod problems, improving die casting efficiency and casting forming quality are achieved.

[0015] Preferably, the thickness of the release agent coating satisfies covering the surface of the die-casting push rod and not affecting the sealing fit of the die-casting push rod and the casting mouth.

[0016] By adopting the above technical scheme, in S3, the thickness of the release agent coating is strictly controlled to ensure that it covers the surface of the die-casting push rod and does not affect the sealing fit of the push rod and the casting mouth; the technical effects that the release agent can fully play a separation role to prevent the push rod and the porcelain block or the casting mouth from being adhered, and that the push rod and the casting mouth will not have a gap due to the release agent coating being too thick, thus preventing leakage of porcelain liquid from the gap during die casting and ensuring smooth demolding subsequently, are generated; and the effects of considering demolding convenience and die casting sealing, providing protection for complete casting formation, and reducing casting defects caused by sealing problems or demolding difficulties are achieved.

[0017] Preferably, in S4, the furnace sintering, a sintering disc matching the size of the casting ring is arranged in the furnace, and the sintering disc has a groove structure for fixing the casting ring.

[0018] By adopting the technical scheme, in the S4 furnace sintering, the sintering disc with the fixed casting ring groove structure matching the size of the casting ring is arranged in the furnace, which can be accurately positioned and stably placed after the casting ring is put into the furnace, and displacement or shaking is not easy to occur in the processes of heating, melting and pressure casting, so as to avoid uneven filling of the porcelain liquid due to the displacement of the casting ring, and to avoid affecting the size precision or appearance form of the casting. The technical scheme can ensure that the size of the dental restoration casting meets the design requirements, reduce the casting deformation and size deviation caused by the unstable casting ring, and improve the qualified rate of the casting.

[0019] Preferably, in the S5 embedding material removal and casting completion, the gradient processing includes preliminary removal along the mark line 5-8 mm away from the casting edge on the outer side of the casting ring, and then fine cleaning of the residual on the surface of the casting.

[0020] By adopting the technical scheme, in the S5 embedding material removal and casting completion, the gradient processing is adopted, the embedding material is preliminarily removed along the mark line 5-8 mm away from the casting edge on the outer side of the casting ring, and then the residual on the surface of the casting is fine cleaned, which produces the technical effect that the embedding material removal is more targeted, most of the embedding material is rapidly stripped in the preliminary removal, time-consuming of the subsequent fine cleaning is avoided, the residual on the surface of the casting is deeply cleaned in the fine cleaning, and the quality of the casting is prevented from being affected by the attachment of the embedding material. The technical scheme can protect the casting body from being damaged while efficiently removing the embedding material, and improve the surface cleanliness and appearance quality of the casting.

[0021] Preferably, in the S5 embedding material removal and casting completion, the preliminary removal adopts 120-mesh alumina abrasive blasting treatment, and the fine cleaning adopts a blasting pressure which is half of the preliminary removal pressure.

[0022] By adopting the technical scheme, in the S5 embedding material removal and casting completion, the preliminary removal adopts 120-mesh alumina abrasive blasting treatment, and the fine cleaning adopts a blasting pressure which is half of the preliminary removal pressure, which produces the technical effect that a large amount of embedding material is rapidly stripped in the preliminary removal stage by using a higher pressure to improve the cleaning efficiency, and the casting surface is gently treated in the fine cleaning stage by using a lower pressure to avoid damaging the casting surface. The 120-mesh alumina abrasive can ensure the cleaning effect and will not cause excessive wear of the casting. The technical scheme can take into account the embedding material removal efficiency and the casting surface smoothness, and ensure that the appearance of the finally formed dental restoration casting is intact and meets the use requirements.

[0023] In summary, the present application has the following beneficial effects: 1. By adopting a revolutionary low-cost 3D printing resin to replace traditional dental special low-ash casting wax, and combining with the modified "blowing ring" process of ceramic pressure casting, the technical effect of complete vaporization of 3D printing resin in the baked casting ring without carbon residue is achieved, and the role of advanced replacement of traditional special wax, significant reduction of material and labor cost, and promotion of production process upgrading to standardization and automation is played.

[0024] 2. In order to solve the problem of wax mold carbide residue blocking the exhaust passage during baking, further optimization is made, and the present application also provides a baking intermediate period air gun blowing process: the casting ring is taken out at 20 minutes of baking, and the inside of the casting ring is cleaned by a high-pressure air gun. The effect of completely removing unvaporized residues is achieved, avoiding the black spots and impurity defects of the casting caused by carbon deposition in the traditional process.

[0025] 3. In order to solve the problem of single sand blasting pressure damaging the surface of the casting, further optimization is made, and the present application also provides a two-stage sand blasting marking line technology: first, mark the line at a distance of 5-8mm from the edge of the casting, and then perform fine cleaning with half pressure. The effect of protecting the surface finish of the casting is achieved, while ensuring the removal efficiency of the embedding material.

[0026] 4. In order to solve the problem of adhesion between the pressure casting push rod and the porcelain block, further optimization is made, and the present application also provides an alumina push rod separating agent coating: the coating thickness is 0.1-0.2mm, which ensures the sealing property and facilitates demolding. The effect of zero leakage during pressure casting is achieved, while reducing the loss of the push rod.

[0027] 5. Subsequently, the heat field uniformity is optimized by 45° inclined baking placement, and the casting ring stability is improved by sintering disc groove positioning, finally forming a high-precision, low-defect pressure casting system. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 is the flow chart of the ceramic pressure casting method in this embodiment. DETAILED DESCRIPTION

[0029] It is necessary to point out here that the following specific embodiments are only used to further illustrate the application, and cannot be understood as limiting the scope of protection of the application. Those skilled in the art can make some non-essential improvements and adjustments to the application according to the above application content. EMBODIMENT

[0030] The present application discloses a ceramic pressure casting method, as shown in Figure 1 The pressure casting steps include: casting ring pretreatment, casting ring baking, porcelain block placement, furnace sintering, and embedding material removal.

[0031] Specifically: S1. Pre-treatment of the casting ring The pre-treatment of the casting ring provides a foundation guarantee for the subsequent baking and die casting, and the core lies in ensuring the structural integrity and flat bottom of the casting ring. The specific operation includes: 1.1 Demoulding and demoulding: after the internal embedding material and the model of the casting ring are solidified, the top cover and the base of the casting ring are removed, the operator holds the two sides of the silicone rubber ring with both hands, and gently lifts the casting ring out with the thumb, avoiding excessive force which may cause the casting ring to crack or the model to be damaged.

[0032] 1.2 Bottom trimming: fine sandpaper or special trimming tools are used to polish the bottom of the casting ring after it is lifted out, to ensure that the bottom is flat and has no protrusions, to ensure the stability of the subsequent casting ring placement, and to avoid deformation of the casting during baking and die casting due to uneven stress.

[0033] S2. Baking of the casting ring The baking of the casting ring is a key link to remove the model wax material and improve the strength of the casting ring. The present application solves the problem of vaporization residue by precisely controlling the temperature, time and impurity cleaning process. The specific steps are as follows: 2.1 Preheating of the furnace body and placing of the casting ring: preheat the Mofu furnace to 850℃, and after the temperature is stable, place the pre-treated casting ring at an angle of 45° in the furnace. The 45° side placement method can increase the contact area between the casting ring and the hot air, ensuring uniform heating; at the same time, it can avoid the direct dropping of the residual model material in the casting ring to the bottom of the furnace, which is convenient for subsequent cleaning.

[0034] 2.2 Temperature rise and time start judgment: when the Mofu furnace door is opened to place the casting ring, the temperature in the furnace will drop instantaneously. At this time, the door should be closed, and after the furnace display screen shows that the temperature has risen to 850℃ and stabilized, the baking time can be started. This operation can avoid incomplete vaporization of the model material due to insufficient temperature, and reduce impurities from the source.

[0035] 2.3 Baking time control: the baking time is determined according to the weight of the casting ring, and the baking time of 100g specification casting ring is not less than 45 minutes, and the baking time of 300g specification casting ring is not less than 60 minutes. Differentiation of time parameters for casting rings of different weights can ensure that large-sized casting rings are fully heated and small-sized casting rings are not over-baked, achieving a balance between energy and efficiency.

[0036] 2.4 Intermediate impurity cleaning: for 100g casting ring, at 20 minutes of baking, use the special ceramic casting tongs to take it out immediately, and use the high-pressure air gun to blow the inside of the casting ring, clean the incomplete vaporization of the model material residue; after cleaning, quickly put the casting ring back into the furnace and continue to keep warm for 20-25 minutes. For 300g casting ring, the same impurity cleaning operation is performed at 40 minutes of baking, and after cleaning, it continues to keep warm for 40-45 minutes. This intermediate cleaning step can effectively remove unvaporized impurities and solve the problem of internal defects of castings caused by incomplete vaporization in traditional processes. The model material in the present application can use medical casting wax or photocurable 3D printing resin dental cutting wax, etc., and the three materials can be fully removed through the above baking and cleaning process.

[0037] It is worth noting that first, at the initial stage of baking, the wax mold melts and vaporizes rapidly, producing a large amount of gas and residue. These substances will encounter a complex and tortuous "exhaust passage" composed of micropores of the investment material during their escape from the bottom to the top of the casting ring. When the gas flow is large or the residue (such as incompletely burned carbide) is viscous, it is easy to form a physical blockage at the narrow or turning part of the passage.

[0038] The directional and high-pressure gas flow generated by the air gun acts as a "physical needle". It can directly break through the soft blockage that is being formed or has been formed. Moreover, the gas flow itself can "wrap" the vaporized residue out of the casting ring, playing a role in cleaning the passage.

[0039] Secondly, the wax material is heated in an inert atmosphere or oxygen-deficient environment. If the temperature rise curve is not perfect or the quality of the wax material itself is a problem, it will undergo a "cracking" process and produce carbide. If these carbides cannot be removed in time, they will deposit on the inner wall of the mold cavity. Subsequently, when the casting porcelain liquid is poured, these carbides will become impurities, causing black spots, pores or a decrease in surface finish of the castings.

[0040] When the carbide is just generated but not firmly attached and carbonized, the air gun is used for purging. The carbide particles in a suspended or loose state are directly blown away from the surface of the mold cavity. The introduced gas flow brings a small amount of oxygen (although the overall environment in the furnace is oxygen-deficient), which helps to promote the further oxidation and combustion of the residue, allowing it to be converted into a gas (such as CO2) that is easier to remove, thereby reducing the generation of solid carbon.

[0041] The "circle blowing" action is essentially a dynamic optimization of the static baking process. It actively intervenes and improves the physical environment (passage patency) and chemical environment (residue removal) inside the casting ring through external mechanical force (gas flow).

[0042] Finally, even if the muffle is calibrated, there can still be a slight temperature gradient in the furnace. The temperature rise rate of the center and the edge, the upper and the lower of the casting ring has a slight difference. This will cause the wax to vaporize asynchronously at different positions, and the gas pressure generated in the local area may exceed the instantaneous gas permeability of the local investment, causing gas retention.

[0043] The gas flow blown from the sprue forms a short-term, forced convection inside the casting ring. Breaks the static or stratified gas distribution formed due to uneven heat field. The gas in the high-pressure area is quickly driven to the low-pressure area, promoting overall pressure balance and avoiding the formation of local "air pockets". Moreover, the gas flow itself also carries heat, which helps to make up for the lack of heat in the local low-temperature area and promotes the complete vaporization of the remaining wax.

[0044] 2.5 Burnout and removal: After the specified burnout time is reached, use special ceramic casting tongs to clamp the edge of the casting ring, remove it smoothly from the furnace, and place it on the high-temperature-resistant placement plate next to the ceramic furnace. Ensure that the casting ring's sprue is facing upwards to prevent external impurities from falling into the casting port, and prepare for the placement of subsequent ceramic blocks.

[0045] S3. Ceramic block placement and push rod installation This step needs to ensure accurate positioning of the ceramic block and good sealing of the push rod to avoid leakage of ceramic liquid or color deviation during pressure casting. The specific operation is as follows: 3.1 Ceramic block selection and placement: Select the corresponding size of the ceramic block according to the color requirement of the restoration, place the ceramic block with the identification text facing upwards into the casting port of the casting ring. Placing the text upwards can help the operator quickly confirm the color of the ceramic block and avoid rework caused by incorrect use; at the same time, ensure that the ceramic block is tightly attached to the casting port without obvious gaps.

[0046] 3.2 Push rod treatment and insertion: Take the alumina pressure casting push rod, evenly apply a layer of special release agent on its surface, control the thickness of the coating to be 0.1-0.2mm, and ensure that the push rod surface is fully covered without omission. After the release agent is slightly dried, slowly insert the push rod into the casting port channel of the casting ring, and the insertion depth should be based on the push rod bottom and the ceramic block surface being in close contact to avoid damage to the ceramic block caused by excessive depth, and to avoid affecting the pressure transmission caused by insufficient depth.

[0047] S4. Furnace sintering Furnace sintering is the core step of ceramic block melting and pressure casting. The present invention ensures the stability of the pressure casting process by standardizing the operation process. The specific steps are as follows: 4.1 Casting ring positioning in the furnace: Open the ceramic furnace door, place the casting ring with the installed ceramic block and push rod in the corresponding groove of the sintering plate in the center of the furnace, and ensure that the casting ring is placed stably without shaking. The sintering plate groove matches the size of the casting ring, which can avoid size deviation of the casting caused by displacement of the casting ring during pressure casting.

[0048] 4.2 Parameter confirmation and die casting start: After closing the furnace door, observe the temperature, pressure, vacuum degree and other parameters on the display screen of the ceramic furnace. When all parameters are displayed in green, indicating that the preset standard is reached, press the "START" button to start the die casting process. The ceramic furnace will automatically complete the processes of heating and melting, pressure casting, holding and cooling, etc. The whole process does not need manual intervention, ensuring the stability of the parameters.

[0049] S5. Investment removal and casting completion Investment removal needs to be treated by gradient method to avoid damaging the surface of the casting. The specific steps are as follows: 5.1 Cooling and marking: After the die casting process is completed, the temperature of the ceramic furnace is reduced to room temperature, and the casting ring is taken out. The height of the casting ring is measured with an alumina ceramic push rod, and a ring-shaped mark is made on the outside of the casting ring at a distance of 5-8 mm from the edge of the casting. The mark line serves as the reference line for investment removal.

[0050] 5.2 Preliminary removal: Along the mark line, use 120-mesh alumina abrasive to sandblast at a pressure of 4 bar, or use a diamond cutting blade to cut along the mark line to remove most of the investment on the outside and bottom of the casting ring. When sandblasting, the spray gun should be kept at a 45° angle to the surface of the casting ring, and moved at a uniform speed to avoid excessive local pressure that may damage the casting ring. When cutting, the cutting depth needs to be controlled to ensure that the internal casting is not damaged. After the preliminary treatment is completed, the alumina die casting push rod is removed.

[0051] 5.3 Fine cleaning: Use 120-mesh alumina abrasive to adjust the sandblasting pressure to 2 bar for fine sandblasting treatment of the residual investment on the surface of the casting. The reduced pressure in this step can avoid scratches on the surface of the casting, while ensuring that the investment is thoroughly cleaned and the original color of the casting is revealed. After fine cleaning, use a high-pressure air gun to blow the surface of the casting to remove residual abrasive powder, completing the entire ceramic die casting process.

[0052] Working principle: First, during the casting ring pretreatment stage, the operator uses a silicone rubber ring to assist in demolding to avoid cracking of the casting ring. Then, fine sandpaper is used to polish the bottom to eliminate protrusions. This step provides a physical basis for the subsequent process: a flat bottom ensures uniform heat transfer during firing, and prevents deformation of the casting due to stress concentration during die casting.

[0053] Then, enter the casting ring firing stage. After preheating the Mofu furnace to 850°C, the casting ring is placed at a 45° angle. The inclined placement increases the contact area of hot air, accelerating the vaporization of the wax mold. Then, during the middle of the firing, a special clamp is used to remove the casting ring and blow the inside with an air gun to directly remove the unvaporized carbide. This dynamic intervention breaks the limitations of traditional static firing: the airflow not only clears the exhaust passage, but also promotes the oxidation of residual materials through a small amount of oxygen, effectively eliminating casting black spots and impurities from the root cause.

[0054] Subsequently, in the porcelain block placement stage, the color identification surface of the porcelain block is placed facing up, the push rod is coated with a separating agent and then inserted. The separating agent coating forms an isolation film at high temperature, which ensures the sealing of the push rod and the casting opening during die casting, prevents leakage of the porcelain liquid, and facilitates demolding after cooling. This design solves the problem of easy adhesion of the traditional metal push rod to the porcelain block, significantly reducing the rework rate.

[0055] Next, the furnace sintering stage is started: the casting ring is placed in the sintering disc with grooves to ensure that it does not shift during die casting. The porcelain casting furnace automatically executes a three-stage program: first, the temperature is raised to 1600°C to melt the porcelain block, then the porcelain liquid is pressed into the cavity at a pressure of 0.5 MPa, and finally, it is cooled to room temperature in a gradient manner. Full automation control avoids human operation errors, and the groove positioning ensures the dimensional accuracy of the casting.

[0056] Finally, the embedded material removal stage uses a gradient treatment: first, most of the embedded material is removed along the marking line with coarse sandblasting, and then the casting surface is cleaned with fine sandblasting. The high-pressure stage quickly peels off the main body of the embedded material, and the low-pressure stage protects the casting texture, supplemented by air gun blowing, to finally obtain a smooth and flawless casting.

[0057] Overall, the present application realizes the optimization of the whole process from raw materials to finished products, and its core is to replace passive dependence on simple high-temperature roasting with active intervention through blowing, reducing the waste rate of porcelain die casting to below 5%.

[0058] The above are preferred embodiments of the present application, and are not intended to limit the protection scope of the present application, therefore: any equivalent changes made in terms of structure, shape, principle, etc. according to the present application should be covered within the protection scope of the present application.

Claims

1. A cast porcelain pressure casting method, characterized by: The die casting step comprises: S1. Casting ring pretreatment After the internal embedding material and the model of the casting ring are cured, demolding and ring removal are performed; the top cover and the base are removed, the operator holds the two sides of the silicone rubber ring with both hands, uses the thumbs to apply uniform force to gently push out the casting ring, and avoids using excessive force to cause the casting ring to crack or the model to be damaged; then, bottom trimming is carried out, fine sandpaper or a special trimming tool is used to polish the bottom of the casting ring, the bottom is ensured to be flat and free of protrusions, stability is provided for subsequent placement, and deformation of the casting caused by uneven stress during baking and die casting is prevented; S2. Casting ring baking The Mofu furnace is preheated to 850°C, after the temperature is stabilized, the pretreated casting ring is placed in the furnace; after placement, the furnace temperature drops, the furnace door needs to be closed until the temperature rises to 850°C and is stable, and then timing starts; S3. Ceramic block placement and push rod installation The corresponding ceramic block is selected according to the color of the restoration, the block is placed into the casting mouth with the marked text facing up to facilitate color error proofing, and needs to be closely attached without obvious gaps; the alumina die casting push rod is taken and slowly inserted into the casting mouth passage; S4. Furnace sintering The furnace door of the ceramic furnace is opened, the casting ring with the ceramic block and the push rod is placed in the center of the furnace; after the furnace door is closed, it is confirmed that the temperature, pressure, and vacuum degree parameters displayed on the screen are green, the start button is pressed to start the program, and the equipment will automatically complete the processes of temperature rising, melting, pressure casting, and temperature holding and cooling, without manual intervention during the whole process; S5. Embedding material removal and casting completion After the die casting is completed, the casting ring is taken out when the ceramic furnace is cooled to room temperature; the height of the casting ring is measured by using an alumina push rod, and the embedding material is removed by using a gradient treatment method; finally, the abrasive powder is blown away by using a high-pressure air gun, and the whole process is completed.

2. The cast porcelain press molding method according to claim 1, characterized by, In S2. Casting ring baking, the casting ring is placed in the Mofu furnace at an angle of 45° when baking.

3. The cast porcelain press molding method according to claim 2, characterized by, In S2. Casting ring baking, the baking further comprises impurity cleaning, and the impurity cleaning comprises temporarily taking out the casting ring during the baking process, cleaning the inside of the casting ring, and then continuing to heat preservation, which is suitable for medical casting wax, dental cutting wax, or light-cured 3D printing resin.

4. The cast porcelain press molding method according to claim 3, characterized by, The impurity cleaning takes out the casting ring during the baking process by using special ceramic pincers, cleans the inside of the casting ring by using an air gun, and then heats it; after the baking is qualified, the casting ring is taken out stably by using special pincers.

5. The cast porcelain press molding method according to claim 1, characterized by, In S3. Ceramic block placement and push rod installation, a release agent coating is coated on the surface of the die casting push rod, and the depth of the push rod inserted into the casting mouth passage is such that the bottom of the push rod is attached to the surface of the ceramic block.

6. The cast porcelain press molding method according to claim 5, characterized by, The thickness of the release agent coating satisfies the requirement of covering the surface of the die casting push rod without affecting the sealing fit of the die casting push rod and the casting mouth.

7. The cast porcelain press molding method according to claim 1, characterized by, In S4. Furnace sintering, a sintering disc matching the size of the casting ring is arranged in the furnace, and the sintering disc has a groove structure for fixing the casting ring.

8. The cast porcelain press molding method according to claim 1, characterized by, In S5. Embedding material removal and casting completion, the gradient treatment comprises preliminarily removing along the mark line 5-8 mm away from the edge of the casting ring on the outside of the casting ring, and then finely cleaning the residual material on the surface of the casting.

9. The cast porcelain press molding method according to claim 8, characterized by, In S5. Embedding material removal and casting completion, the preliminary removal adopts 120-mesh alumina abrasive blasting treatment, and the fine cleaning adopts a method of reducing the blasting pressure to half of the preliminary removal pressure.

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