Casting:
Currently, Ningbo covers various casting processes, including the following:
clay sand: This is an ancient process, the strength of the sand mould is not strong and it is easy to adhering sand. The surface of the castings is poor, and generally produces cast iron.such as machine tool mount and equipment bases. The products are usually large, and sand casting also produces bronze castings and aluminum alloy castings. This type of product usually has low surface requirements.
Resin sand casting,this process is make some improvement on traditional casting sand materials by adding resin adhesive, which increases the strength of the sand mould greatly, reduces the deformation of the casting, and is prone to get defects such as adhering sand, sand holes, pores, and carbon slag less.
At present shell casting is the popular process for using the resin sand casting, we inject mixed sand and resin adhesive into the mold cavity to obtain the outer shell of the casting. After the sand shell hardens, the melt metal is poured into the mold cavity directly, which is more environmentally friendly and easy to remove the sand. Although the surface of the product is rough, the overall appearance is good,
Ceramsite sand casting: This is a relatively new casting method. Our factory adopts a complete set of new casting processes, combined with molding lines, with high environmental friendliness. Ceramsite sand has good fluidity and plasticity, and can cast complex shaped castings with high accuracy and easy forming. The surface of the castings is relatively beautiful, and can produce medium to large castings, ranging from 10 kg to 1000 kgs. After designing the casting process, the quality of the castings is stable. Can produce in large quantities,
Precoated sand casting, due to more and more parts have complex structure and higher Oneness request of many product designs, requires complex internal cavity structures, which increases the difficulty of demolding and casting. The design of flow channels may not solve the process difficulties caused by the structure. Therefore, Precoated sand is used as the core of the casting, and after casting is completed, the desired core structure can be obtained by directly shake out and cleaning. Generally used for complex and precise products.
Precision casting is a type of investment casting, mainly referring to the water glass casting, its process flow is
Developing tooling, wax injection to the tooling to get the wax prototype,, shell making,baking the shell,melt metal pouring,clean the sand.
Weight: 0.05-100kg Tolerance: CT7-9 Roughness of the casting surface: Ra 6.3-25
From 2000 to 2015, the local production of this process in Ningbo was very large and its application was also very wide. However, this process caused significant environmental pollution and the emission pollution. There is a lot of offscum and liquid waste. Due to the need for ammonium chloride to harden the shell during the production process, the government has requested improvements and equipped with environmental protection facilities or processes. Currently, there are many improvements, and some products are being replaced by resin sand and composite processes gradually
Investment casting: it is similar to the precision casting casting, and the process flow is similar too , but it has higher precision and is relatively environmentally friendly. Due to the inconsistent materials of wax, we also call it as medium temperature wax,
Weight: 0.02-30kg Tolerance: CT6-7 Roughness of the casting surface: Ra 6.3-25
Lost foam casting: the process is to use the mold to foam the shape of the product, and then wrap the foam with adhesive and sand for several layers. Finally, wait for the shell harden and remove the foam to get a cavity same to the product to cast the melt metal. Since the foam will remain carbon after gasification, the carbon element content of this process is not easy to control.
die-casting, also known as high-pressure casting, is divided into hot and cold chambers. Generally, the processing speed of the hot chamber is fast and it is easy to achieve automated operation. Currently, there are 80-400T hot chamber die-casting machines, but they cannot die-cast metals with high melting points. They are generally suitable for processing zinc, tin, and lead alloys, such as Zamak, and are difficult to use for processing large castings. Currently, we produce a large number of door and window accessories for zinc alloy die-casting
Cold chamber processing of aluminum alloy, with a capacity of 280-2500T, can process aluminum, magnesium, copper alloys, and zinc alloys with high aluminum content. The materials produced include A380, A356, ADC12, etc. The forming accuracy of the product is very high, and the tolerance can be controlled within+/-0.2mm generally. Except for the functional surface, there is no need for further machining generally. Moreover, due to the high pressure input, the product structure can be made very complex, and slender and flat products can also be produced, Typical examples include gearbox casing, motor casing, new energy battery box,,
Gravity casting/Permanent Casting
, also known as metal mold casting, is a casting process of pouring molten aluminum alloy into the metal mold. Due to balancing the advantages and disadvantages of sand casting and die casting, it has high dimensional accuracy and relatively few internal defects. This type of process currently has a large production capacity, and we also use this process to produce some pipeline joints.
Low pressure casting is similar to gravity casting, but it is a casting process where the below melt aluminum is sucked into the mold cavity through the low pressure at upper, which can avoid many defects such as porosity and shrinkage, improving the quality of the casting greatly,
Powder metallurgy: The local powder metallurgy industry chain in Ningbo is very developed, with the main processes being powder making, pressing, and sintering. Due to the characteristics of metals, the finer the grain size, the better the performance. Therefore, powder preparation in the early stage is very important. Currently, many materials can be produced using powder metallurgy. Usually, the products are relatively small and have complex shapes such as gears, mainly formed into finished products with high production efficiency. Currently, many automotive parts, electric tool accessories, and hardware and electrical components are produced using powder metallurgy.
Metal injection molding, currently a relatively new process, also includes metal injection molding, which forms metal powder like injection molding and then sintered and solidified like powder metallurgy. Like plastic parts, they may leave ejector hole, and the current forming accuracy is basically close to powder metallurgy. But the forming ability is stronger than powder metallurgy. Usually producing small and complex shaped products.
At present, we provide processing services for the above processes, with a product weight of 0-1000kg. The materials include carbon steel, alloy steel, gray cast iron, ductile iron, stainless steel, aluminum alloy, copper alloy, and zinc alloy,
It is widely used in construction machinery, agricultural machinery, automotive parts, medical, household hardware, municipal facilities, high-speed rail, and marine accessories,
In addition, such as centrifugal casting, we will develop it gradually,
Forging:
From ancient, forging iron and weapons, people have known that continuous forging can improve the performance of metals. We can not only quickly obtain the desired shape through mold hot forging, but also reduce machining allowance, and improve the grain structure of the metal. The advantage of forging is better than casting is that it has no defects such as porosity and shrinkage, but its forming ability does not have the advantage of casting. At present, some factories have developed multi-directional die forging to produce slightly complex and regular parts, such as valve bodies,
non-ferrous metals such as copper and aluminum alloy. Due to its low melting point and good ductility, hot stamping and other processes are also being used in large quantities. Currently, the main forging machines are friction presses, air hammers
At present, there are still some cold forging processes, such as cold heading, which are used in small and simple products such as fasteners commonly. Dies are used to directly cut and form materials with good ductility, directly obtaining the required dimensions. The accuracy is usually very high, and there is generally no need for precision machining. Only tapping the thread is required. Due to its special advantages, it is widely used in fasteners, and the cost is very low, It can be more than 60% cheaper than machining. But due to cold processing, the performance requirements for equipment and molds are very high,
In addition, there are also cold forming processes such as cold extrusion, cold drawing, and extrusion forming of materials through molds. Currently, the fixed drawing of pipes, flat steel, and aluminum profiles are widely used, mainly because they are easy to obtain established complex cross-sectional shapes and have stable dimensions.
Forging materials include copper alloy, aluminum alloy, carbon steel, alloy steel, stainless steel, etc. Forging products are widely used in the automotive parts industry due to their excellent metallurgical properties, especially for some important structural components such as drive shafts, forks, spring brackets, and steering knuckles,