Casting method of 3D (three-dimensional) fast manufacturing iron mold sand-lined process

Abstract

The casting method of the 3D fast manufacturing iron mold sand coating process comprises the steps that firstly, three-dimensional modeling software is used for drawing an iron mold sand coating appearance mold and a three-dimensional model drawing of an iron mold; step 2, casting an iron mold of the three-dimensional model drawing in the step 1, and processing and inspecting the iron mold to obtain a finished iron mold; and step 3, filling a cavity of the finished iron mold in the step 2 with 3D printing fast-manufactured resin sand, striking off the resin sand, conveying the resin sand to a 3D printing machining center after the resin sand is cured, machining and removing redundant molding sand according to the three-dimensional data of the shape mold of the iron mold coated sand, and reserving a sand-coated layer with a preset design thickness on the finished iron mold, so as to obtain the iron mold coated sand casting mold. According to the method, production trial-manufacturing can be carried out without manufacturing a whole set of tool molds, process trial-manufacturing can be carried out only by manufacturing the iron mold, and the development speed of the iron mold sand-lined process mold is effectively increased.

Description

Technical Field

[0001] The invention belongs to the field of casting technology, and in particular relates to a casting method of a 3D fast iron mold sand coating process. Background Art

[0002] The iron mold sand coating process has its own process advantages, but it also has many process limitations. How to make the best use of its strengths and avoid its weaknesses, make adaptive improvements, suppress its process limitations, and improve process adaptability is one of the eternal tasks of foundry workers.

[0003] The advantages of the iron mold sand coating process are: (1) The mold has strong rigidity. For cast iron parts, it can fully utilize the characteristics of graphite expansion, reduce or eliminate the need for risers, and use its own expansion characteristics to achieve self-shrinkage; (2) By utilizing the adjustable thickness of the sand coating layer, it is easier to achieve balanced solidification and sequential solidification of the thick and thin parts of the casting, and the overall solidification speed is faster than that of green sand. It is easy to obtain finer graphite morphology and finer matrix structure, and the mechanical properties are significantly improved;

[0004] However, the iron mold sand coating process also has many defects in the process of new product development, including: (1) The mold cost is very high. A set of molds must include a complete set of tooling molds such as the outer mold, iron mold, shooting plate, nail hole plate, etc., and none of them can be missing (such as Figure 6 (as shown). Without any tooling, the machine cannot be molded. Therefore, the tooling and mold cost of sample development is very high; (2) Because the mold of a new product must include all the above-mentioned tooling, the manufacturing cycle is as long as 40 to 50 days. For products with urgent time requirements, it is obviously impossible to meet the development cycle requirements; (3) The mold change of the iron mold sand coating process is relatively restricted. If the mold is manufactured, some problems are found during the trial production process and the mold needs to be changed. Small changes include changes to the shape mold, shooting plate, and iron mold, which are relatively cumbersome; while large changes, in the case of fundamental process changes, can only scrap the old mold and remake a series of tooling and molds including the shape mold, iron mold, shooting plate, top plate, etc., which can be said to be a heavy loss of economy and time. And if all the tooling and molds are changed again, all the tooling and molds must be reconfigured before the next trial production can be carried out, which wastes a lot of time.

[0005] In summary, for the iron mold sand coating process, in the development of new products and new processes, the development cycle is long, the cost of tooling and molds is high, and changes are difficult. The risk of mold loss during the period when the process is not finalized is relatively high. Summary of the invention

[0006] In view of the problems existing in the above-mentioned prior art, the present invention provides a casting method for a 3D fast iron mold sand coating process. The purpose of the present invention is that the present invention does not need to produce a complete set of tooling molds for iron mold sand coating. Only the iron mold needs to be made to carry out new product development and process verification, which reduces the mold investment in the new product development stage, and also reduces the risk of excessive mold cost investment, and greatly improves the development speed of the iron mold sand coating process mold.

[0007] In order to achieve the above object, the specific scheme of the present invention is as follows:

[0008] The casting method of the 3D fast iron mold sand coating process comprises the following steps:

[0009] Step 1, using 3D modeling software to draw the 3D model drawings of the iron mold sand-covered outer mold and the iron mold;

[0010] Step 2, casting an iron mold of the three-dimensional model drawing described in step 1, and making it into a finished iron mold after processing and inspection; Step 3, filling the mold cavity of the finished iron mold with 3D printed quick-made resin sand, and scraping it flat. After the resin sand is solidified, it is sent to the 3D printing processing center, and according to the three-dimensional data of the outer shape mold of the iron mold covered with sand, the excess molding sand is processed and removed, and the sand coating layer of the predetermined design thickness on the finished iron mold is retained to obtain an iron mold covered with sand casting mold.

[0011] Furthermore, the method is suitable for producing a 25-ton lightweight balanced suspension and a 13L engine crankshaft for a tractor.

[0012] Advantages of the present invention

[0013] (1) The casting method of the 3D fast iron mold sand coating process of the present invention designs the outer shape mold and the iron mold three-dimensional model drawings through the conventional steps of the three-dimensional design software, and the other tooling molds do not need to be designed. The designed iron mold is cast, and then processed and inspected to make a set of iron mold objects consistent with the iron mold of the traditional iron mold sand coating process. There is no need to manufacture the outer shape mold. The outer shape mold only provides three-dimensional data for subsequent 3D processing. Therefore, the casting method directly skips the mold development, product verification, and the manufacturing process of the shooting plate and the top plate and directly enters the production and manufacturing of the iron mold sand coating casting. There is no need to wait for the outer shape mold, the shooting plate and other molds to be manufactured. The time for manufacturing the mold, the material cost required for manufacturing the mold and the steps of the manufacturing cycle are omitted, and more than 2 / 3 of the mold cycle is saved, thereby reducing the risk of modifying the mold or scrapping the mold due to inappropriate design of the traditional iron mold sand coating mold. Therefore, the method is simple, fast and efficient in preparing the iron mold sand coating casting. This solves the technical problem that when developing a product with the traditional iron mold sand coating process, the outer shape mold must be manufactured first, and then the shooting plate, nail hole plate, iron mold and other complete tooling molds must be manufactured, and then the machine can be installed for heating and shooting the outer shape. In addition, the iron mold made using this method does not need to occupy the resources of online production equipment and has no impact on normal production scheduling.

[0014] (2) The present invention reduces the risk of repeatedly changing the mold due to inappropriate process design, or even causing the mold to be scrapped. According to this method, if the process is not suitable and needs to be adjusted, only the iron mold cavity needs to be changed, and there is no need to change the outer mold. Even if the process needs to be overturned and started over, only one set of iron molds will be lost, and the loss is greatly reduced compared to before; while in the traditional iron mold sand coating process, if the process design is unreasonable, the mold and iron mold need to be changed. Small changes are cumbersome and may not even be possible; for large changes, if the original process design needs to be overturned, all molds will become scrap iron, resulting in heavy losses.

[0015] (3) After the iron mold sand-coated casting mold prepared by the present invention passes the process verification, the experimental iron mold sand-coated casting mold can still be used as an iron mold for mass production without causing waste; the introduction of 3D rapid production technology into the iron mold sand-coated process has played a positive role in the development of the iron mold sand-coated process and product development. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 The present invention is a flow chart of the casting method of the 3D fast iron mold sand coating process.

[0017] Figure 2 for Figure 1 Three-dimensional model of the sand-coated outer shape mold of the China Iron Mold.

[0018] Figure 3 for Figure 1 Finished iron mold.

[0019] Figure 4 for Figure 1 Cross-section of the finished iron mold filled with 3D printed quick-made resin sand.

[0020] Figure 5 for Figure 1 Cross-sectional view of the iron mold sand-coated casting mold after the sand-coating process.

[0021] Figure 6 This is a schematic diagram of the structure of a complete set of mold tooling for the traditional iron mold sand coating process.

[0022] In the figure:

[0023] 1. 3D printing quick-made resin sand; 2. Sand coating layer of predetermined thickness. DETAILED DESCRIPTION

[0024] The present invention is further explained and illustrated below in conjunction with the accompanying drawings and specific embodiments. It should be noted that this specific embodiment is not intended to limit the scope of rights of the present invention.

[0025] like Figure 1 and Figure 5As shown, the casting method of the 3D fast iron mold sand coating process provided in this specific embodiment includes the following steps:

[0026] Step 1: Use 3D modeling software to draw Figure 2 The three-dimensional model drawings of the iron mold sand-covered outer mold and the iron mold are shown. In the three-dimensional model drawings, there is no need to design tooling molds such as shooting plates and nail hole plates separately;

[0027] Step 2, casting the iron mold of the three-dimensional model drawing described in step 1, and processing and inspecting it to make it into Figure 3 The finished iron mold shown in the figure has the same structure as the iron mold manufactured by the traditional iron mold sand coating process; in this embodiment, there is no need to make the iron mold sand coating outer shape mold described in step 1;

[0028] Step 3: Fill the finished iron mold cavity with 3D printed quick-made resin sand, such as Figure 4 As shown, and scraped flat, after the resin sand is solidified, it is sent to the 3D printing processing center. According to the three-dimensional data of the iron mold sand-covered shape model, the excess molding sand is processed and removed, and the sand-covered layer of the predetermined design thickness on the finished iron mold is retained to obtain the following Figure 5 The iron mold covered with sand casting shown in the figure. The prepared iron mold covered with sand casting can be further subjected to coating, mold closing and pouring according to the traditional sand covering process.

[0029] The casting method can directly carry out trial production of new products using the iron mold sand coating process, which not only saves mold cost and time, but also reduces the risk of mold modification. The obtained iron mold sand coating casting mold is exactly the same as the iron mold sand coating casting mold of the traditional iron mold sand coating process. The iron mold sand coating casting mold described in the casting method is subjected to process and product verification. While the product processing is verified and tested, after confirming that the product and process are qualified, the full set of tooling molds for online production, such as the outer shape mold and the shooting plate, are then completed at the same time.

[0030] Embodiment 1

[0031] The first embodiment of this invention adopts the above-mentioned casting method to manufacture and produce a 25-ton lightweight balanced suspension for a tractor. From the design to the iron mold sand-coated casting of the 25-ton lightweight balanced suspension, it takes only 9 days to enter the product casting verification, and the physical investment costs about 30,000 yuan. The traditional iron mold sand-coated process requires a 50-day mold cycle and a mold cost of 250,000 yuan. The traditional iron mold sand-coated process saves 41 days of time and reduces the mold cost by 220,000 yuan compared with the traditional iron mold sand-coated process, that is, the time efficiency is increased by 5.56 times and the cost is saved by 88%.

[0032] Embodiment 2

[0033] The second embodiment of the present invention adopts the above-mentioned casting method to manufacture and produce a 13L engine crankshaft. From the design to the iron mold sand-coated casting of the 13L engine crankshaft, it takes only 7 days to enter the product casting verification, and the physical investment costs about 20,000 yuan. The traditional iron mold sand-coated process requires a 40-day mold cycle and a mold cost of 180,000 yuan. By adopting the traditional iron mold sand-coated process, the second embodiment of the present invention saves 33 days compared with the traditional iron mold sand-coated process, and reduces the mold risk cost by 160,000 yuan. The time efficiency is improved by 5.71 times, and the cost is saved by 88.89%.

Claims

1. 3D fast iron mold sand coating casting method, characterized in that: The steps include: Step 1, using 3D modeling software to draw the 3D model drawings of the iron mold sand-covered outer mold and the iron mold; Step 2, casting an iron mold of the three-dimensional model drawing described in step 1, and processing and inspecting it to make a finished iron mold; Step 3, fill the 3D printed quick-made resin sand in the finished iron mold cavity in step 2, and scrape it flat. After the resin sand is solidified, send it to the 3D printing processing center, and process and remove excess molding sand according to the three-dimensional data of the iron mold sand-coated shape mold, retaining the sand coating layer of the predetermined design thickness on the finished iron mold, to obtain the iron mold sand-coated casting mold.

2. The method according to claim 1, characterized in that This method is suitable for producing 25-ton lightweight balanced suspension and 13L engine crankshaft for tractor.

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