Brief Process of Mechanical Casting 5, Brief Process of Mechanical Casting

Let's talk about ordinary casting, the two words we commonly use as models, which are most of the process of casting.

First of all, the wood molder makes the wood model according to the parts drawings, and the wood molder will know the machining allowance, draft slope and casting corner outside the drawings, and create a wood mold that meets the requirements. (This is the "model" of "exemplary".) ）”

Molding sand for sand turning, and sand molds for wood models. Depending on the complexity of the workpiece, use two or three openers, with larger holes, and make a separate mandrel. According to the casting requirements, leave the waterway spout.

Once made, prick out the appropriate breathable eye. This makes a good sand mold to dry and set aside. (The sand mold is the exemplary "fan").

Finally, there is casting, and the caster will close the sand mold according to the production positioning. The cast iron is melted with a chemical iron furnace, and the molten iron is injected through the casting port by machinery or artificially, and the molten iron is formed in the sand mold, and after cooling, the sand mold is opened, the workpiece is taken out, and the adhered molding sand is removed, and the excess gate is removed.

In this way, a casting is made.

For precision casting, it is also a truth.

Casting probably includes wax casting, sand casting, die casting, etc.

Wax film casting, also known as the lost wax method, is the most precise casting method, which can be expensive, and the general mechanical devices are sand casting.

To put it simply, casting is to first put a model in the sandbox, and then (the sandbox is generally two parts, and there are three parts, the lower sandbox and the upper sandbox have special sand), after squeezing, and then take out the model, so that there is a gap in the sandpile, put the two sandboxes together, pour liquid metal (after or before the sandbox molding, will artificially dig some sprues in the sand, which is used to pour liquid metal into it, in addition to the sprue, there are ventilation holes, used to dissipate air and heat), and so on after cooling, a casting is made.

There are many other methods of casting, such as the lost wax method mentioned above, which is quite interesting.

In addition, China has a long history of casting, such as the bronzes of the Shang Dynasty, as well as musical instruments, ritual vessels, and bells, all of which were cast, and the achievements were also very high.

Upstairs should be more comprehensive, that is, I think if you don't know the principle of casting, it seems that some of the terms are still difficult to understand, and I hope my explanation can be useful to you.

1. Sand mixing stage: prepare molding sand and core sand for modeling, generally use a sand mixer to put in the old drawing and an appropriate amount of clay to stir.

2. Mold making stage: make molds and core boxes according to the parts drawings, generally a single piece can be made of wooden molds, mass production can be made of plastic molds or metal molds, and large quantities of castings can be made of pattern plates. Now the mold is basically used with an engraving machine, so the production cycle is greatly shortened, and the mold making generally takes 2 to 10 days.

3. Modeling stage: including modeling (using molding sand to form the cavity of the casting), core making (forming the internal shape of the casting), mold matching (putting the core into the cavity and closing the upper and lower sand boxes), modeling is the key link in casting.

4. Smelting stage: according to the required metal composition, the chemical composition is prepared, and the appropriate melting furnace is selected to melt the alloy material to form a qualified liquid metal liquid. The cupola furnace or electric furnace is generally used for smelting (due to environmental protection requirements, the cupola furnace is now basically banned, and the electric furnace is basically used).

5. Pouring stage: use the molten iron ladle to inject the molten iron in the electric furnace into the mold. To pour molten iron, you need to pay attention to the speed of pouring, so that the molten iron fills the entire cavity. In addition, pouring molten iron is more dangerous, so you need to pay attention to safety!

6. Cleaning stage: After pouring, after the molten metal solidifies, take a hammer to remove the gate and shake off the sand of the casting, and then use a sandblasting machine to blast sand, so that the surface of the casting will appear very clean, and the casting blank with low requirements can basically leave the factory after inspection.

7. Casting processing: For some castings with special requirements or some castings that cannot meet the requirements, simple processing may be required. Generally, a grinding wheel or grinder is used for processing and grinding to remove burrs and make the casting smoother.

8. Casting inspection: Casting inspection is generally in the process of cleaning or processing, and the unqualified ones have generally been found and picked out. However, there are some castings that have individual requirements and need to be inspected again.

For example, some castings require a 5 cm shaft inserted into the center hole, so you need to take a 5 cm shaft and try it out.

Techniques and methods for the production of castings by applying theoretical and systematic knowledge of casting. Including casting process, casting system, shrinkage system, air outlet, chilling system, special casting process and so on.

The casting process design content includes: the design of the casting process drawing, the design of the casting drawing, the design of the casting assembly drawing and the production of the process card.

Casting is an ancient manufacturing method that dates back 6,000 years in our country. With the development of industrial technology, the quality of casting large castings directly affects the quality of products.

Casting occupies an important position in the machinery manufacturing industry. The development of casting technology is also very rapid, especially at the end of the 19th century and the first half of the 20th century, many new casting methods appeared, such as low-pressure casting, ceramic casting, continuous casting, etc.

1.Sand casting.

2.Metal mold casting.

Pressure casting. Gravity casting.

Low-pressure casting. 3.Special casting.

4.Investment casting.

5.Ceramic mold casting.

6.Continuous casting.

7.Centrifugal casting.

8.Vacuum casting.

1.Preparation of molding sand and core sand The preparation process of molding sand directly affects the quality of molding sand, and the preparation of molding sand is generally divided into the preparation and inspection of raw materials and the preparation and quality control of molding sand.

2.Modeling The method and process of manufacturing sand mold with process equipment such as molding sand and pattern are called molding. There are many kinds of molding methods, and it depends on the shape, size, and technical requirements of the casting.

3.Smelting The process and operation of transforming the metal from a solid state to a liquid through heating, and removing impurities from the molten metal through metallurgical reactions, so that its temperature and composition meet the specified requirements, become smelting. There are many types of equipment for smelting metal, we produce cast iron platforms, and machine tool castings generally use cupola furnaces.

4.Sand drying For some large or high-quality castings, dry pouring is generally used. For example, large cast iron platforms, machine tool bed castings, machine tool workbenches, machine tool castings, etc.

5.Pouring The operation of injecting molten metal from a ladle into a mold is called pouring.

6.Cleaning The process of removing surface sticky sand, molding sand and excess metals, etc. from the casting after sand removal is called cleaning.

7.Casting heat treatment is the process of heating the casting to a certain temperature range, keeping it warm for a period of time, and then cooling to the appropriate temperature at a specified rate to obtain the expected structure and performance, which is called casting heat treatment. The purpose of heat treatment of castings is to eliminate the casting stress of the casting.

For example, cast iron platforms, machine tool castings, and machine tool tables must be processed after heat treatment.

The casting production process is a complex combination of comprehensive processes, and its main processes: 1Preparation of molding sand and core sand 2Styling 3Smelting 4Sand mold drying 5Pouring 6Cleanup 7Heat treatment of castings.

Moulding, batching, smelting, sand mixing, modeling, box closing, pouring, cleaning.

For example, the most extensive sand casting preparation includes the preparation of molding materials and the two major tasks of modeling and core making; Pouring; Cooling; to sand; Inspection; Wrap.

First prepare the abrasive, then melt the thing that needs to be cast into liquid, and then pour the liquid at the right temperature into the abrasive as required, wait until it cools to a certain temperature, open the abrasive as required, and remove the casting.

The process flow of casting production:

Foundry production is a complex multi-process process, which includes the following main processes:

1) Preparation of production process, according to the parts to be produced, production batch and delivery deadline, formulate production process plan and process documents, and draw casting process diagram;

2) Production preparation, including the preparation of materials for melting, materials and patterns for molding and core making, core boxes, sand boxes and other process equipment;

3) Modeling and core making;

4) Melting and pouring;

5) The main processes such as sand removal cleaning and casting inspection.

Forming principle. Casting production is a metal forming method in which the metal is heated and melted to make it fluid, and then poured into the casting cavity with a certain shape, filled with the cavity under the action of gravity or external force (pressure, centrifugal force, electromagnetic force, etc.), cooled and solidified into a casting (or part).

Castings are generally machined as blanks to become parts. However, there are also many castings that can meet the design accuracy and surface roughness requirements of the part without machining, and can be used directly as a part.

There are many kinds of casting, and I don't know what kind of casting process you want. Sand casting is mainly to make cores (types) and close boxes. Other special casting mold casting is also indispensable to the above steps, but the specific is not different.

The main processes are: 1. Design drawings; 2. Formulate the casting process; 3. Make wooden molds; 4. making cavities; 5. Repair the cavity and dry it; 6. a box; 7. Smelting and casting; 8. Unpack after cooling; 9. cleaning molding sand; 10. Remove the burr.

Here, there is a full zhi dao exclusive.

Prepare materials for melting, materials and patterns for molding core making, core boxes, sand boxes and other process equipment, modeling and core making, melting and pouring, sand cleaning, casting inspection and other processes.

Casting is a process in which molten metal is poured into a mold and cooled and solidified to obtain the desired shape and properties. Casting is a commonly used manufacturing method, with low manufacturing cost and large process flexibility, which can obtain complex shapes and large castings, which occupy a large proportion in machinery manufacturing, such as machine tools accounting for 60 80%, automobiles accounting for 25%, and tractors accounting for 50 60%.

Mold pattern, core making, sand matching, modeling, molten iron smelting, molten iron pouring, casting cleaning, casting testing, casting delivery.

The main processes of sand casting are:

Mold production part: make molds according to the requirements of the drawings, generally single production can be made of wood molds, mass production can be made of plastic molds, metal molds, large quantities of castings can be made of templates.

2.Sand mixing stage: according to the requirements of sand mold manufacturing and the different types of castings, prepare qualified molding sand for modeling.

3.Molding (core making) stage: including modeling (using molding sand to form the cavity of the casting), core making (forming the internal shape of the casting), and mold matching (putting the core into the cavity and closing the upper and lower sand boxes). Modeling is a key link in casting.

4.Smelting stage: according to the required metal composition with chemical composition, select the appropriate melting furnace to melt the alloy material, and form a qualified liquid metal liquid (including qualified composition and qualified temperature).

5.Pouring stage: Qualified molten metal is injected into the sand box with the mold. The danger in the pouring stage is relatively large, so special attention should be paid to it.

6.Cleaning stage: After pouring and waiting for the molten metal to solidify, remove the molding sand, knock off the gate and other accessories, and form the required casting.

The sand casting process is as follows:

Sand casting refers to the casting method of producing castings in a sand mold.

Steel, iron, and most non-ferrous alloy castings can be obtained using the sand casting method. Because the molding materials used in sand casting are cheap and easy to obtain, the casting manufacturing is simple, and it can adapt to the single production, batch production and mass production of castings, and has been the basic process in casting production for a long time.

The most widely used molding sand binder is clay, and various dry or semi-dry oils, water-soluble silicates or phosphates and various synthetic resins can also be used as molding sand binders. The outer sand mold used in sand casting can be divided into three types: clay green sand mold, clay dry sand type and chemically hardened sand type according to the binder used in the molding sand and the way it builds strength.

Compared with other casting methods, sand casting has low cost, simple production process and short production cycle. Therefore, castings such as engine blocks, cylinder heads, crankshafts, etc., of automobiles are produced by clay green sand process. When the wet type does not meet the requirements, consider using clay sand surface dry sand mold, dry sand type or other sand molds.

After pouring out, it is generally shot blasting, after shot blasting, it is to start the primary selection, heat treatment after the selection of waste products, heat treatment is shot blasting again, shot blasting is the second inspection after shot blasting, look at defects, sizes, etc., as well as flaw detection and the like, these depend on the specific parts requirements, the second inspection can be put into storage, after the storage has special requirements, according to the special requirements, such as painting, blackening, bluishing, etc., and it may be that you want to supply the finished product to take out the outsourcing processing before you can put it into storage, Then it is shipped, after the second inspection, some waste products will be found, some defects can be repaired, glue repair, or welding repair, etc., but after welding repair, heat treatment, and then shot blasting and then 、、、

Heat treatment is also a process of casting, why heat treatment, generally cast out of things have casting stress, generally we take artificial aging and natural aging to solve, for cast iron, generally do not need heat treatment, especially gray iron and the like, there is also annealing and the like, and for steel must be heat treated, because the stress is very large, no heat treatment is brittle, unusable, and some special materials, such as ZG40CR and the like, require high hardness, You can improve the hardness through the quenching and tempering treatment in the heat treatment, and some parts require metallographic components and the like can be achieved through heat treatment, some castings are made of high hardness, can not be processed, this is to reduce its hardness, but also need heat treatment to complete, in short, heat treatment can make the casting structure dense, mechanical properties are improved, and so on, so heat treatment is needed, I hope it can help you, you can go to the books, these books are much better than what I said, and they are much more detailed.