For processed products, you can usually choose bars, casting blanks, forging blanks, profiles, etc. In the case of small quantities, we give priority to bar processing, because the materials are easy to buy. However, its cost is very high, the processing procedures are many, and the processing is slow. In mass production, we have to consider more cost-effective production methods to save costs and speed up production. Then it is necessary to choose different blanks for machining, but how to choose a blank?
The determination of the blank not only affects the economics of blank for machining, but also affects the economics of machining. Therefore, when determining the blank, it is necessary to consider both the thermal processing factors and the cold working requirements, so as to reduce the manufacturing cost of the parts from the process of determining the blank.
1. Types of commonly used blanks for machining
There are many types of blanks, and there are multiple manufacturing methods for the same blank. The commonly used blanks in mechanical manufacturing are as follows:
The rough parts with complex shapes should be manufactured by casting methods. At present, most castings are made of sand casting, which is divided into wooden mold manual molding and metal mold machine molding. Wooden mold manual moulding castings have low precision, large machining surface allowance, and low productivity. They are suitable for single-piece small batch production or large-scale parts casting. The metal mold machine has high molding productivity and high casting precision, but the equipment cost is high, and the weight of the casting is also limited. It is suitable for mass production of small and medium castings. Secondly, a small number of small castings with high quality requirements can be used in special casting (such as pressure casting, centrifugal manufacturing, investment casting, etc.).
For steel parts with high mechanical strength requirements, forging blanks are generally used. There are two types of forgings: free forging and die forging. Free forging forgings can be obtained by manual forging (small blanks), mechanical hammer forging (medium blanks) or press forging (large blanks). This forging has low precision, low productivity, large machining allowance, and the structure of the parts must be simple; it is suitable for single-piece and small-batch production, as well as the manufacture of large forgings.
The precision and surface quality of die forgings are better than that of free forgings, and the shape of forgings can be more complicated, which can reduce the machining allowance. The productivity of die forging is much higher than that of free forging, but it requires special equipment and forging dies, so it is suitable for medium and small forgings with larger batches.
According to the cross-sectional shape, the profile can be divided into: round steel, square steel, hexagonal steel, flat steel, angle steel, channel steel and other special cross-section profiles. There are two types of profiles: hot-rolled and cold-drawn. The hot-rolled profile has low precision, but the price is cheap, and is used for the blanks of general parts; the cold-drawn profile is small in size, high in accuracy, easy to realize automatic feeding, but the price is higher, and it is mostly used for large batch production, suitable for automatic Machine tool processing.
(4) Welding parts
Welded parts are combined parts obtained by welding methods. The advantages of welded parts are simple manufacture, short cycle time, and material saving. The disadvantages are poor vibration resistance and large deformation. They can only be machined after aging treatment.
In addition, there are other blanks such as stamping parts, cold extruded parts, powder metallurgy and so on.
2. Problems that should be paid attention to in the selection of blank types
(1) Part materials and mechanical properties
The material of the part roughly determines the type of blank. For example, casting blanks should be selected for parts made of cast iron and bronze; steel parts should be selected when the shape of steel parts is not complicated and the mechanical performance requirements are not too high; for important steel parts, to ensure their mechanical properties, forging blanks should be selected.
(2) The structural shape and dimensions of the parts
Blanks with complex shapes are generally manufactured by casting methods. Sand casting is not suitable for thin-walled parts; advanced casting methods can be considered for small and medium-sized parts; sand casting can be used for large parts. For general-purpose stepped shafts, if the diameters of the steps are not much different, round bar materials can be used; if the diameters of the steps are different, in order to reduce material consumption and machining labor, it is advisable to choose forging blanks. Large parts generally choose free forging; small and medium-sized parts can choose die forgings; some small parts can be made into integral blanks.
(3) Type of production
For mass-produced parts, a rough manufacturing method with high accuracy and productivity should be selected, such as castings using metal mold machine modeling or precision casting; forgings using die forging and precision forging; profiles using cold-rolled or cold-drawn profiles; when the output of parts is small, it should be Choose a blank manufacturing method with lower accuracy and productivity.
(4) Existing production conditions
To determine the type and manufacturing method of the blank, the specific production conditions must be considered, such as the technological level of the blank manufacturing, the condition of the equipment, and the possibility of external cooperation.
(5) Fully consider the use of new processes, new technologies and new materials
With the development of machinery manufacturing technology, the application of new processes, new technologies and new materials in blank manufacturing has also developed rapidly. Such as precision casting, precision forging, cold extrusion, powder metallurgy and engineering plastics are increasingly used in machinery. The use of these methods greatly reduces the amount of mechanical processing, and sometimes the processing requirements can even be achieved without mechanical processing, and the economic benefits are very significant. We should give full consideration when selecting the blank, and try our best to use it when possible.
3. Determination of the shape and size of the blank
The shape and size of the blank basically depend on the shape and size of the part. The main difference between a part and a blank is that a certain machining allowance is added to the surface of the part to be processed, that is, the blank machining allowance. When the blank is manufactured, errors will also occur, and the dimensional tolerance of the blank manufacturing is called the blank tolerance. The size of the blank machining allowance and tolerance directly affects the labor of mechanical processing and the consumption of raw materials, thereby affecting the manufacturing cost of the product. Therefore, one of the development trends of modern machinery manufacturing is to make the shape and size of the blanks consistent with the parts as much as possible through the refining of the blanks, and strive to achieve minimal and no cutting processing. The size of the blank machining allowance and tolerance is related to the manufacturing method of the blank, and can be determined by referring to relevant process manuals or relevant enterprise and industry standards during production.
After determining the blank machining allowance, the shape and size of the blank, in addition to attaching the blank machining allowance to the corresponding processing surface of the part, also consider the influence of various process factors such as blank manufacturing, machining and heat treatment. The following only analyzes the issues that should be considered when determining the shape and size of the blank from the perspective of mechanical processing technology.
(1) Setting of craftsman
Some parts, due to structural reasons, are not easy to be clamped and stabilized during processing. For the convenience and speed of clamping, bosses can be made on the blank, which is the so-called craftsman. The craftsman is only used when clamping the workpiece. After the parts are processed, they are generally cut off, but they can be retained if they do not affect the performance and appearance quality of the parts.
(2) Adoption of the overall blank
In machining, parts such as the three-watt bearing in the main shaft part of the grinder, the connecting rod of the engine and the opening and closing nut of the lathe are sometimes encountered. In order to ensure the processing quality of this kind of parts and the convenience of processing, they are often made into a whole blank and cut after processing to a certain stage.
(3) The use of blanks
In order to facilitate the clamping during the machining process, for some small parts with relatively regular shapes, such as T-shaped keys, flat nuts, small spacers, etc., multiple pieces should be combined into a blank, and after processing to a certain stage or most surface processing After finishing, it is processed into a single piece.
After determining the type, shape and size of the blank, a blank drawing should be drawn as the product drawing of the blank production unit. Drawing a blank drawing is based on the part drawing and adding a blank margin to the corresponding processing surface. However, the specific manufacturing conditions of the blank must be considered when drawing, such as the minimum casting and forging conditions of the hole on the casting, the hole and the gap on the forging, the flange, etc.; the draft angle of the surface of the casting and forging (draft Inclination) and rounded corners; the position of the parting surface and the parting surface, etc. And use the double-dot chain line to show the surface of the part in the rough drawing to distinguish the processed surface from the non-processed surface.
Ming Xiao Manufacturing Co., Ltd engaged in Machined Parts manufacuring more than 20years, we have old lathe turning machine, automatic turning machine, and normal & high precision CNC turning machine,CNC Machining Center, we can optimize the turning processes to make the machining cost to be lowest, accurate tolerance dimensions we use Numerical control machine, and low toleracne requested dimensions we use old lathe machine to produce, and small turned parts we use automatic lathe machine to produce.
As a professional machine parts supplier from China,we can custom producing all kinds Carbon & Stainless steel turned parts,Copper & Brass turned parts,Aluminum Turned Parts & Machined parts, such as tube coupling, hose coupling, shaft, pipe joint parts, hose connectors & transition connectors, copper machined tube, flange,bushing, knighthead, pedestal, Piston Rod, insert long pin, Dowel Pin, Drive Pin & Rod,ball head bolt, long rod machined parts, long thread tube parts, nonstandard thread bolt & nut,Extension Rod, etc. Widely use for all industries.
General CNC machining usually refers to computer digitally controlled precision machining, CNC machining lathe, CNC machining milling machine, CNC machining boring and milling machine, etc.
1. In CNC lathe processing, the determination of the processing route generally follows the following principles.
① It should be able to ensure the accuracy and surface roughness of the processed workpiece.
② Make the processing route the shortest, reduce the empty travel time and improve the processing efficiency.
③ Simplify the workload of numerical calculation as much as possible and simplify the processing procedures.
④ For some programs that are used repeatedly, subprograms should be used .
2. CNC machining has the following advantages:
① The number of tooling is greatly reduced, and complex tooling is not required for processing parts with complex shapes. If you want to change the shape and size of the part, you only need to modify the part processing program, which is suitable for the development and modification of new products.
②The processing quality is stable, the processing precision is high, and the repeat accuracy is high, which is suitable for the processing requirements of the aircraft.
③The production efficiency is higher in the case of multiple varieties and small batch production, which can reduce the time for production preparation, machine tool adjustment and process inspection, and reduce the cutting time due to the use of the optimal cutting amount.
④ It can process complex profiles that are difficult to process with conventional methods, and even process some unobservable parts.
The disadvantage of CNC machining is that the machine tool equipment is expensive and requires maintenance personnel to have a high level.
Refers to the process of changing the external dimensions or performance of the workpiece through a mechanical device. According to the difference
in processing methods, it can be divided into cutting processing and pressure processing.
1. Production process:
Refers to the entire process of making products from raw materials (or semi-finished products). For machine production, it includes the transportation and preservation of raw materials, preparation for production, manufacturing of blanks, processing and heat treatment of parts, assembly and commissioning of products, painting and packaging.
The content of the production process is very extensive. Modern enterprises use the principles and methods of system engineering to organize production and guide production, and regard the production process as a production system with input and output. In the production process, the process of changing the shape, size, position and nature of the production object to make it into a finished product or semi-finished product is called a process. It is the main part of the production process.
The process can be divided into casting, forging, stamping, welding, machining, assembly and other processes. The mechanical manufacturing process generally refers to the sum of the machining process of the parts and the assembly process of the machine, and the other processes are called auxiliary Processes, such as transportation, storage, power supply, equipment maintenance, etc.
The main feature of a process is that it does not change the processing objects, equipment and operators, and the content of the process is that the continuous steps are completed under the conditions of unchanged processing surface, unchanged processing tools, and constant cutting amount. It is called the working stroke, and it is the process step completed by the processing tool once processing on the processing surface.
3. The production types are usually divided into three categories:
1. Single piece production: produce different structures and different sizes of products individually, and rarely repeat.
2. Mass production: The same products are manufactured in batches throughout the year. The manufacturing process has a certain degree of repeatability. Mass-produced parts.
3. Mass production: the manufacturing quantity of products is very large, and most work places are often repeated processing of a certain process of a certain part.
4. Original information:
(1) Product assembly drawings, parts drawings.
(2) Quality standards for product acceptance.
(3) The annual production program of the product.
(5) The production conditions of the manufacturing plant, including the specifications, performance and existing status of machine tool equipment and process equipment, the technical level of workers, the ability of the factory to make process equipment, and the power supply and gas supply capacity of the factory.
(6) Standards required for process specification design and process equipment design, various metal parts processing, sheet metal, box, metal structure, titanium alloy, high temperature alloy, non-metallic and other mechanical processing, mold design and manufacturing, wind tunnel combustion chamber design Manufacturing, non-standard equipment design and manufacturing, mold design and manufacturing.
Precision metal parts processing:
Hardware processing is the processing of raw materials (stainless steel, copper, aluminum, iron), using lathes, milling machines, drilling machines, polishing, etc., according to customer drawings or samples into various parts, such as motor shafts, models Car parts, fishing gear accessories, product shells, mobile power shells, etc.
Various tools used in the manufacturing process. Including tools/fixtures/molds/measuring tools/checking tools/auxiliary tools/fitters’ tools/stationary appliances etc. Welding fixture, inspection fixture, assembly fixture, machine tool fixture, etc.
The scope of the Ming Xiao Mfg’s mechanical processing:
1. Precision machining.
2. Processing of precision equipment parts.
3. Processing of non-standard spare parts.
4. Processing of precision shaped parts.
5. Processing of hardware machinery parts.
6. Surface treatment of various mechanical parts.
7. Processing of clamps
Ming Xiao Mfg has been specializing in the processing of precision mechanical parts for many years to help solve customer technical problems. Can come with drawings and samples for precise mechanical processing of single parts, CNC processing, small batches of hardware parts, mechanical spare parts, etc.
Thanks to Our Denmark client for awarding these stainless steel parts to us.
These new stainless steel parts are custom produced for our Denmak client, use for Pipe Clamp, those are the fasten accessories, made from Stainless steel 304 & 316, the secrews and pins are made by cold forging firstly to get the rough parts, then machining the surface and the threads,and there is a stamping parts, for getting a good and bright surface, the outer threaded screw was chemical polished, and other parts were vibration trembing polished.
Ming Xiao is a professional Steel parts factory located in Ningbo China, specialize in custom CNC turning parts, sheet metal stamping parts for domestic & foreign customers. we do export business, more than 15 years,Our compliance is to provide customers with quality service and product quality, for customers from any trouble.
Over the years, we have been consistently satisfied and praised by our customers.
The Advantages of Turning & Milling Compound Precision CNC Machining:
(1) Shorten the manufacturing process chain of products to improve production efficiency.
The CNC du turning and milling compound center can install a variety of special tools, new tool arrangement, reduce tool change time and improve processing efficiency. Turning and milling compound processing can achieve all or most of the processing procedures in one clamping, which greatly Shorten the product manufacturing process chain.
In this way, on the one hand, the production assistance time caused by the change of the installation card is reduced, and at the same time, the manufacturing cycle and waiting time of the tooling fixture are reduced, and the production efficiency can be significantly improved.
In the machining efficiency of the CNC turning and milling compound center, the new type CNC turning and milling compound center can be loaded with more special processing tools. The tool arrangement is completely different from the previous traditional CNC processing machinery, which can reduce the tool change time and improve the processing efficiency. , Turning and milling composite processing can achieve all or most of the processing procedures in one clamping, which greatly shortens the product manufacturing process chain.
(2) Reduce the number of clampings and improve the machining accuracy.
The reduction in the number of card installations avoids the accumulation of errors caused by the conversion of the positioning reference. At the same time, most of the current turning and milling processing equipment has online detection function, which can realize the in-situ detection and precision control of key data in the manufacturing process, thereby improving the processing accuracy of the product; the high-strength integrated bed design improves the difficulty The gravity processing ability of the cutting material;
the turning-milling machine tool is equipped with an automatic feeding device, which can realize automatic feeding to continue, and basically realize the assembly line operation of a single machine tool.
During turning and milling, the tool performs intermittent cutting, which can obtain relatively short cutting of the workpiece formed of any material, which is easy to automatically remove chips. And the intermittent chip can allow the knife to have sufficient time to cool, reduce the thermal deformation of the workpiece, and also increase the service life of the tool. Compared with traditional CNC machine tools, the turning speed of turning and milling is higher, the quality of the cut products is better, and the cutting force is reduced, the precision of thin-walled rods and slender rods is improved, and the quality of the workpiece is high.
Because the cutting speed can be decomposed into the rotational speed of the workpiece and the rotational speed of the tool, according to the mechanical characteristics, the rotational speed of the tool can be increased, and the rotational speed of the workpiece can be reduced to achieve the same processing effect.
This feature is especially suitable for the processing of large forging blanks Effective, because the reduction of the forging blank speed can eliminate the periodic changes of vibration or radial cutting force caused by the eccentricity of the workpiece, thereby ensuring the smooth cutting of the workpiece and reducing the errors in the machining of the workpiece.
When the turning and milling machine tool processes the workpiece, the low speed of the workpiece can effectively reduce the centrifugal force of the workpiece, avoid deformation of the workpiece, and help improve the machining accuracy of the part. The larger longitudinal feed can also be used to achieve precise cutting in turning and milling, and the surface roughness can also be effectively guaranteed.
The turning and milling composite machine tool can use different methods such as turning, milling, drilling, and boring to process the workpiece. Able to complete multi-face machining tasks with one clamping, ensuring machining accuracy.
Ming Xiao is a professional ISO9001 certificated Hardware parts & Machine Parts manufacturer from Ningbo China,has been working in the machine parts processing industry for 20 years,We have advanced equipment and strict inspection standards,our precision CNC machining services can produce high quality, high precision and high finish mechanical parts, can meet the needs of the vast majority of high-end users.
Ningbo Dalilai Machinery Manufacturing Co., Ltd is Our main plant located in Ningbo City, China. we are the same factory, because China is a foreign exchange controling Country,and we have no export right,generally export our goods via 3rd party ( export agent company). Ming Xiao Mfg was registered in Hongkong in year 2010, for working foreign business and collect the USD dollars(control money by ourself).
Our main Business is custom metal parts and plastic parts by CNC turning, Metal Stamping, Sheet metal fabricating,Pipe/tube bending & fabriating,also
We custom stainless steel turned parts according to customer’s drawing or samples.
If you are interest in our stainless steel turning & machining services to produce your turned parts, please contact with us.
New progressive die stamping machines custom metal parts
We have introduced three new progressive die stamping machines in the end of 2017. 2 sets 45 ton, 1 set 60 ton, now can improve the production capability, can produce more bigger parts by progressive die stamping.
As a professional metal stamping parts manufacturer from China, we also provide progressive die stamping services for improve our production line, and provide our customers more cost efficient choice,if quantity is higher enough, progressive die stamping can reduce the price and speed up the production very much.
The progressive die is composed of several workplaces. The different workplaces are connected in order to complete different processing. A series of different stamping processes are completed in the stroke of the punch.
Progressive die (also called progressive die) is made up of several workstations, and each station is completed in sequence.
A series of different punching & stamping processes are completed in the stroke of the punch. After a stroke is completed, the punch feeder will move the material forward according to a fixed step, so that many processes can be completed on a pair of molds, such as punching, blanking, bending, cutting, drawing and so on.