CN113319251A - Rapid manufacturing method for impression cylinder casting - Google Patents

Rapid manufacturing method for impression cylinder casting Download PDF

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Publication number
CN113319251A
CN113319251A CN202110589256.0A CN202110589256A CN113319251A CN 113319251 A CN113319251 A CN 113319251A CN 202110589256 A CN202110589256 A CN 202110589256A CN 113319251 A CN113319251 A CN 113319251A
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sand
casting
mold
core
impression cylinder
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CN202110589256.0A
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Chinese (zh)
Inventor
杨爱成
颜银标
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Nanjing University of Science and Technology
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Nanjing University of Science and Technology
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22C—FOUNDRY MOULDING
    • B22C9/00—Moulds or cores; Moulding processes
    • B22C9/22—Moulds for peculiarly-shaped castings
    • B22C9/24—Moulds for peculiarly-shaped castings for hollow articles
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22C—FOUNDRY MOULDING
    • B22C21/00—Flasks; Accessories therefor
    • B22C21/02—Sectional flasks, i.e. with divided, articulated, or interchangeable side sections
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22C—FOUNDRY MOULDING
    • B22C9/00—Moulds or cores; Moulding processes
    • B22C9/02—Sand moulds or like moulds for shaped castings
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22C—FOUNDRY MOULDING
    • B22C9/00—Moulds or cores; Moulding processes
    • B22C9/08—Features with respect to supply of molten metal, e.g. ingates, circular gates, skim gates
    • B22C9/088—Feeder heads
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22C—FOUNDRY MOULDING
    • B22C9/00—Moulds or cores; Moulding processes
    • B22C9/10—Cores; Manufacture or installation of cores
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D15/00—Casting using a mould or core of which a part significant to the process is of high thermal conductivity, e.g. chill casting; Moulds or accessories specially adapted therefor
    • B22D15/02—Casting using a mould or core of which a part significant to the process is of high thermal conductivity, e.g. chill casting; Moulds or accessories specially adapted therefor of cylinders, pistons, bearing shells or like thin-walled objects

Abstract

The invention provides a rapid manufacturing method for an impression cylinder casting, which comprises the following steps: determining a part capable of being rapidly molded, and numbering the part capable of being rapidly molded in a partitioning manner; reversely solving a core entity according to a three-dimensional model drawing of the casting to obtain a cavity three-dimensional model, respectively solving the numbered three-dimensional models of the cores of the block parts, and manufacturing sand blanks of the block parts; processing sand blanks of all parts to form all sand cores by sequentially processing a main body structure of the sand core and then finely processing a local structure of the sand core; and adopting a segmentation mode to mold the casting cavity sand box, sequentially dropping all sand cores into the cavity for mold closing, and then adopting a deluge pouring system to pour molten metal until the casting is molded. The rapid manufacturing method of the invention can directly form the core without manufacturing the core box, thereby shortening the production period, reducing the production cost and rapidly finishing the manufacturing of the casting.

Description

Rapid manufacturing method for impression cylinder casting
Technical Field
The invention relates to the technical field of metal casting, in particular to a rapid manufacturing method for an impression cylinder casting.
Background
The roller type casting generally refers to a casting with a cylindrical main body structure and a cavity. The traditional manufacturing process of the roller type casting comprises the following steps: adding process allowance according to technical requirements → manufacturing an outer die and a core box → forming a casting cavity by the outer die → forming the inner structure of a roller by the core box → assembling → pouring → cleaning and polishing. The traditional manufacturing process is long in time, low in efficiency and poor in quality, main time and labor are consumed in manufacturing of the outer die and the core box, although the production of roller castings can be completed, the manufacturing period is long, the manufacturing cost is high, and products cannot be quickly pushed out to meet the research and development design of equipment.
Disclosure of Invention
The invention aims to provide a rapid manufacturing method for an impression cylinder casting, aiming at the defects of the prior art, and a core can be directly formed without manufacturing a core box, so that the production period can be shortened, the production cost can be reduced, and the casting can be rapidly manufactured.
In order to achieve the purpose, the technical scheme adopted by the invention is as follows:
a rapid manufacturing method for impression cylinder castings, comprising:
determining a part capable of being rapidly molded, and numbering the part capable of being rapidly molded in a partitioning manner;
reversely solving a core entity according to a three-dimensional model drawing of the casting to obtain a cavity three-dimensional model, respectively solving the numbered three-dimensional models of the cores of the block parts, and manufacturing sand blanks of the block parts;
processing sand blanks of all parts to form all sand cores by sequentially processing a main body structure of the sand core and then finely processing a local structure of the sand core;
and adopting a segmentation mode to mold the casting cavity sand box, sequentially dropping all sand cores into the cavity for mold closing, and then adopting a deluge pouring system to pour molten metal until the casting is molded.
Preferably, the sand core is designed to have a negative number of 1-2mm, so that smooth core falling is ensured.
Preferably, for the sand core with a regular shape, the sand core is processed by adopting a numerical control processing technology.
Preferably, for the sand core with the irregular shape, 3D printing technology is adopted for sand core processing.
Preferably, the external mold used for molding the sand box adopts a wood mold full sample and is divided into three sections, the middle section is split into molds, and a core-pulling structure is adopted, so that the condition that the molds cannot be taken is avoided.
Preferably, the specific flask molding steps are as follows: firstly, making a casting mold at the lower part of the outer mold, matching and making a bottom box of a rain pouring channel after the resin sand is hardened, making a casting mold at the middle part of the outer mold after the resin sand is hardened, matching and making a casting mold at the upper part of the outer mold after the resin sand is hardened, making an upper box casting mold, and finally taking out the outer mold in sequence; wherein the middle part of the outer mold has no draft angle, and the mold is taken by adopting a core-pulling structure.
Preferably, the deluge gating system is one of a top-pouring deluge gating system, a bottom-pouring deluge gating system, and a stepped gating system.
Preferably, three risers are provided at the open end of the casting to supplement the liquid shrinkage of the casting during solidification and cooling.
Preferably, chills are disposed on the rolling surfaces and end surfaces of the castings for controlling the solidification sequence of the castings and accelerating the local cooling rate of the castings.
The invention has the beneficial effects that:
1. compared with the traditional casting process, the rapid manufacturing method for the impression cylinder casting saves the cost of a single piece by more than 24.6 percent, shortens the whole production period by 42 percent, and realizes small-batch production within the critical yield.
2. The invention relates to a rapid manufacturing method for an impression cylinder casting, which is used for producing the impression cylinder through production processes of three-dimensional modeling, sand core data programming, sand core numerical control cutting processing, molding, smelting, pouring, post-treatment and the like, wherein the casting is subjected to casting cavity sand box molding and fine mold assembling through fine position blocking, sand core molding and section mode, and the matching of a specific pouring system is adopted, so that the casting with complete appearance forming, accurate size, smooth surface, no sand sticking and no obvious casting defect is obtained, the product requirement is met, and the casting with better quality is obtained.
Drawings
FIG. 1 is a flow chart of the rapid manufacturing method for impression cylinder castings of the present invention.
FIG. 2 is a three-dimensional model view of a casting according to an embodiment of the present invention.
Figures 3a-3c are 1#, 2#, and 3# sand patterns, respectively, for an embodiment of the present invention.
Fig. 4a-4d are illustrations of core drop, mold build, mold close, and pour for a sand core, respectively, according to an embodiment of the present invention.
FIG. 5 is a drawing of a casting according to an embodiment of the present invention.
FIG. 6 is a schematic diagram of a critical throughput analysis according to an embodiment of the present invention.
Detailed Description
In order to better understand the technical content of the present invention, specific embodiments are described below with reference to the accompanying drawings.
In this disclosure, aspects of the present invention are described with reference to the accompanying drawings, in which a number of illustrative embodiments are shown. Embodiments of the present disclosure are not necessarily intended to include all aspects of the invention. It should be appreciated that the various concepts and embodiments described above, as well as those described in greater detail below, may be implemented in any of numerous ways.
According to an exemplary embodiment of the invention, a rapid manufacturing method for an impression cylinder casting is provided, as shown in fig. 1, production of the impression cylinder is performed through production processes of three-dimensional modeling, sand core data programming, sand core numerical control cutting processing, modeling, smelting, pouring, post-treatment and the like, and a core can be directly formed without manufacturing a core box, so that the production period can be shortened, the production cost can be reduced, and the casting can be rapidly manufactured.
A rapid manufacturing method for an impression cylinder casting according to an exemplary embodiment of the present invention includes:
determining a part capable of being rapidly molded, and numbering the part capable of being rapidly molded in a partitioning manner;
reversely solving a core entity according to a three-dimensional model drawing of the casting to obtain a cavity three-dimensional model, respectively solving the numbered three-dimensional models of the cores of the block parts, and manufacturing sand blanks of the block parts;
processing sand blanks of all parts to form all sand cores by sequentially processing a main body structure of the sand core and then finely processing a local structure of the sand core;
and adopting a segmentation mode to mold the casting cavity sand box, sequentially dropping all sand cores into the cavity for mold closing, and then adopting a deluge pouring system to pour molten metal until the casting is molded.
In a preferred embodiment, the negative number of the sand core of 1-2mm is designed for the sand core, so that the core falling is ensured to be smooth.
In one preferred embodiment, for the sand core with a regular shape, the sand core is processed by adopting a numerical control processing technology.
In another preferred embodiment, for the sand core with irregular shape, 3D printing technology is adopted for sand core processing.
Preferably, the external mold used for molding the sand box adopts a wood mold full sample and is divided into three sections, the middle section is split into molds, and a core-pulling structure is adopted, so that the condition that the molds cannot be taken is avoided.
In a specific embodiment, the specific flask molding steps are as follows: firstly, making a casting mold at the lower part of the outer mold, matching and making a bottom box of a rain pouring channel after the resin sand is hardened, making a casting mold at the middle part of the outer mold after the resin sand is hardened, matching and making a casting mold at the upper part of the outer mold after the resin sand is hardened, making an upper box casting mold, and finally taking out the outer mold in sequence; wherein the middle part of the outer mold has no draft angle, and the mold is taken by adopting a core-pulling structure.
In an alternative embodiment, the deluge gating system is one of a top-pour deluge gating system, a bottom-pour deluge gating system, and a step gating system.
Preferably, three risers are provided at the open end of the casting to supplement the liquid shrinkage of the casting during solidification and cooling.
Preferably, chills are disposed on the rolling surfaces and end surfaces of the castings for controlling the solidification sequence of the castings and accelerating the local cooling rate of the castings.
For ease of understanding, the above process is further described below with reference to specific examples.
[ example 1 ]
1. And obtaining a three-dimensional model of the casting according to the drawing and the external dimension phi 809 multiplied by 842mm of the casting, as shown in figure 2.
2. The part capable of being rapidly formed is determined according to the structure of the casting, and is divided into three parts which are numbered as No. 1, No. 2 and No. 3.
3. And reversely solving a core entity through UG software Boolean operation to obtain a cavity three-dimensional model, respectively solving the original structure and the three-dimensional entity model of the 1#, 2#, and 3# partitioned cores, and perfecting the three-dimensional design of the core head according to the process.
4. According to the size of the core, proper allowance is added to manufacture cuboid sand blanks, the size and the number of the sand blanks are shown in table 1, and the technical parameters of the sand blanks are shown in table 2;
TABLE 1 original size and quantity of sand blanks
Figure BDA0003088873900000041
TABLE 2 technical parameters of the sand compacts
Figure BDA0003088873900000042
The resulting 1#, 2#, 3# sand core is shown in figure 3.
5. And performing data programming of the numerical control cutting processing of the sand core according to the designed three-dimensional solid model of the sand core. The drawn model is stored in an STL format and exported, then the model is imported into the preprocessing software of the mold-less manufacturing processing center, and finally the numerical control cutting processing code of the sand core is generated by selecting proper processing parameters and the tool path is subjected to processing simulation inspection. And sequentially processing the main structure of the sand core, then finely processing the local structure of the sand core, and generating the processing path according to the sequence. In the processing path of the sand core, a milling cutter with a large diameter is selected to rapidly process a basic shape by adopting a cavity milling processing mode, and then a milling cutter with a small diameter is adopted to process a local microstructure which cannot be processed in the early stage, so that the complete sand core is finally obtained. After the machining path is generated, simulation can be carried out on the whole sand mold machining process so as to check whether the machining path is correct or not, whether excessive cutting or no milling to the sand mold exists in the machining process or not and the like.
6. And (4) processing the sand core according to the processing path code subjected to simulation inspection. And (3) importing the processing G code into a digital die-free casting precision forming machine, optimizing a processing path by using special software, and finally driving equipment to perform numerical control cutting processing.
And (4) after the processing is finished, the size of the sand core is checked, a 1:1 sample plate is manufactured according to the size which cannot be directly measured, and the geometric shapes and sizes of all the sand cores are measured to meet the technical requirements.
7. And (3) molding the sand box according to the determined casting process scheme, wherein the outer die of the roller is divided into three sections, the middle section of the roller is split into a die, and a core pulling structure is adopted to meet the requirement of sand box molding production. Under the existing production conditions, the quality of the casting mold is directly related to the technical level of operators. According to actual production experience, firstly, making a casting mold at the lower part of the outer mold, matching and making a stepped rain pouring gate bottom box after resin sand is hardened, making a casting mold at the middle part of the outer mold after the resin sand is hardened, making a casting mold at the upper part of the outer mold in matching and making a casting mold of an upper box, and finally taking out the molds in sequence in a reverse order. Wherein the middle part of the outer mold has no draft angle, and the mold is taken by adopting a core-pulling structure.
8. And after the casting is finished, brushing and coating are carried out together with the sand core. In the brushing process, the surface of the sand core manufactured without the mold based on numerical control cutting processing is the same as the surface of the casting mold manufactured in a factory, the surface sand grains do not fall off, and the infiltration effect of the coating is good. And after brushing the coating, drying the surface, and then performing casting mold assembly work such as positioning, core falling and the like. And sequentially dropping the 1# sand core, the 2# sand core and the 3# sand core which are processed based on numerical control cutting into the cavity made of the wood mould according to the core dropping sequence required by the process. The core falling process is smooth, the core head is accurately positioned, the negative number of the sand core is properly applied, and the size is accurate.
9. Alloy smelting is carried out by utilizing a medium-frequency induction furnace, batching is carried out according to QT500 chemical components, hard alloy such as copper, nickel and the like is added for spheroidization, the ladle spheroidization temperature is 1450 ℃, the pouring temperature is 1370 ℃, and the pouring time is 90 s.
The whole process of molding, assembling and pouring the mold is shown in fig. 4.
10. After the casting is naturally cooled after pouring, vibrating and shakeout are carried out, the casting is lifted out after opening the box, and shot blasting and polishing are carried out on the casting to obtain the casting, as shown in fig. 5.
The impression cylinder casting has the advantages of complete appearance forming, accurate size, smooth surface, no bonded sand and no obvious casting defect. The surface of the steel plate is subjected to ultrasonic detection, and casting defects such as shrinkage porosity, air holes and the like are avoided. After the surface of the cast iron is roughly processed, no obvious casting defect is found, and the technical requirement and the use requirement of the cast iron are met through inspection.
[ example 2 ]
And (3) rapidly producing qualified sample pieces by adopting a dieless casting process based on numerical control machining. In combination with the actual production conditions of the impression cylinder, the die-free casting process based on the numerical control machining technology is compared with the conventional casting process in terms of the manufacturing period and the manufacturing cost in tables 3 and 4.
TABLE 3 cycle for manufacturing of single castings
Figure BDA0003088873900000051
TABLE 4 cost of manufacture of single casting
Figure BDA0003088873900000052
As can be seen from the table, when the single piece is produced, compared with the traditional casting process, the non-mold casting process based on the numerical control machining technology saves 3.5 ten thousand yuan in cost, and shortens the time of 47 days by a single person in production period. The manufacturing cost and the production period are mainly saved by adopting a casting mold manufacturing technology based on numerical control cutting processing, and the rest links are not reduced. Under the traditional casting and molding process, the mold can be reused, the cost after the second piece is produced is 0, and the manufacturing cost of the sand core of 1.2 ten thousand yuan can be generated when each piece is produced by the mold-free casting process, so that the yield with the same cost of the two production schemes is 4-5 pieces, namely the critical yield.
From this, it can be concluded that if the critical yield of a certain cast product is M, the die-less casting process is more advantageous than M, and the conventional process is more suitable for mass production, as shown in fig. 6.
Although the present invention has been described with reference to the preferred embodiments, it is not intended to be limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the invention. Therefore, the protection scope of the present invention should be determined by the appended claims.

Claims (9)

1. A rapid manufacturing method for impression cylinder castings, comprising:
determining a part capable of being rapidly molded, and numbering the part capable of being rapidly molded in a partitioning manner;
reversely solving a core entity according to a three-dimensional model drawing of the casting to obtain a cavity three-dimensional model, respectively solving the numbered three-dimensional models of the cores of the block parts, and manufacturing sand blanks of the block parts;
processing sand blanks of all parts to form all sand cores by sequentially processing a main body structure of the sand core and then finely processing a local structure of the sand core;
and adopting a segmentation mode to mold the casting cavity sand box, sequentially dropping all sand cores into the cavity for mold closing, and then adopting a deluge pouring system to pour molten metal until the casting is molded.
2. The rapid manufacturing process for impression cylinder castings according to claim 1, characterized in that the sand core designs a negative sand core of 1-2 mm.
3. The rapid manufacturing method for impression cylinder castings according to claim 1, characterized in that for the sand cores of regular shape, numerical control machining technology is used for sand core machining.
4. The rapid manufacturing method for impression cylinder castings according to claim 1, characterized in that for sand cores with irregular shapes, 3D printing technology is used for sand core processing.
5. The method for rapid manufacturing of impression cylinder castings according to claim 1, characterized in that the external mold used for molding the sand box is a wood mold full pattern and is divided into three sections, and the split mold in the middle section is a core-pulling structure.
6. The rapid manufacturing method for impression cylinder castings according to claim 5, characterized in that the specific flask molding steps are as follows: firstly, making a casting mold at the lower part of the outer mold, matching and making a bottom box of a rain pouring channel after the resin sand is hardened, making a casting mold at the middle part of the outer mold after the resin sand is hardened, matching and making a casting mold at the upper part of the outer mold after the resin sand is hardened, making an upper box casting mold, and finally taking out the outer mold in sequence; wherein the middle part of the outer mold has no draft angle, and the mold is taken by adopting a core-pulling structure.
7. The rapid manufacturing method for impression cylinder castings according to claim 1, characterized in that the deluge gating system is one of a top-pouring deluge gating system, a bottom-pouring deluge gating system, and a step gating system.
8. The rapid manufacturing method for impression cylinder castings according to claim 1, characterized in that three risers are provided at the casting open end.
9. The rapid manufacturing method for impression cylinder castings according to claim 1, characterized in that chills are arranged on the rolling surfaces and end faces of the castings.
CN202110589256.0A 2021-05-27 2021-05-28 Rapid manufacturing method for impression cylinder casting Withdrawn CN113319251A (en)

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CN202110584505 2021-05-27

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Application publication date: 20210831