The technology of embryo manufacturing in the mechanical industry in Vietnam

        The technology of embryo manufacturing in the mechanical industry in Vietnam 

  vietnam casting, vietnam casting, vietnam casting, 

Technology of embryo manufacturing includes casting, welding and machining pressure. It has a very important role in the basic technology which could create the original details of machines logically, an important contribution to the quality of the details.

In order to know the capacity of the mechanical manufacturing sector in Vietnam in the present time, it is nessessary to know the current status of the basic technology, including technology to create embryo. In this article we present the current status of embryo technologies in Vietnam after exploring the current state of technology via a series of typical mechanical manufacturing companies. To satisfy the requirements of a machine in the near future, the paper also introduces the trend of development of embryo technologies in the mechanical manufacturing business in Vietnam for the period 2011-2020.

I. History and development of mechanical manufacturing industry in Vietnam.

Mechanical manufacturing industry in Vietnam has been built since1956, up to now it has been 53 years, , yet it was undergone almost 20 years due to the very intense war conducted by the U.S. Nevertheless thanks to the wisdom leadership of the Party and Government, we have the fullest support of all countries in the socialist faction formerly led by the former Soviet Union to build a lot of mechanical plant quite large, scattered throughout the provinces in northern Vietnam. Many factories have been and are the pride of our country's industries, it has contributed in no small part to the construction of the facilities of socialism in the North and the solid backing for struggle to liberate the South, reunification. Typical plants are mechanical machines such as : Hanoi Mechanical Company, Song Cong Diesel Company, Cam Pha Center Mechanical Company, Vuon Cam automobile mechanic Company, Bach Dang Shipbuilding Company, Ha Long Shipbuilding Company , etc.  And hundred of large and small mechanical plants of Defense Industry and a number of other economic sectors.  After 1975 when the country's reunification, we acquired some mechanic companies that were left by the enemy in South Vietnam, including most notably motor manufacturing company and Vikino Vinappro small Diesel in Minutes Hoa and Mechanical repair companies belong to the puppet army as Z751, Bason Shipyard ... Since 1975 we have not invested much for mechanical manufacturing, Except that there are a number of industries including oil gas, rubber industry by manufacturing requirements for parts or homemade devices for themselves so they are equipped with a certain amount of machine tools. In general, the current mechanical manufacturing industry is managing a number of machine tools approximately 50,000 pieces. The great majority of the generation of machine tools since 1970 and before, meaning the control system is mainly associated with the electrical operation of the craft workers. The size of each detail processing are decided by the workers. So it is difficult to achieve stability for precision of machining. There are very few machine tool that it has been mounted positive measuring device. Recently many companies have equipped both some lathes , milling machines and automatic control system of CNC, Yet it  does not have an important role in production. This is a painting reflects the current state of the mechanical manufacturing industry in Vietnam, it is not only weak but also missing. It is very difficult to meet the development requirements in the period of industrialization and modernization of the country.

To understand the exact capacity of the mechanical manufacturing industry in our country today, we need to know the status of its basic technology, then to satisfy the requirements of the economic sectors with mechanical manufacturing sector, developing the basic technology what is reasonable. However, due to limitations of the article so we just boldly presented the current status of embryo technology in the manufacturing machine sector and the development trend in Vietnam at present.

II. Current status and trend of development of technology embryo in mechanical manufacturing.

Technology of creating embryo in mechanical manufacturing industry can be divided into the following groups:

1. Casting Technology

2. Welding Technology

3. Pressure Technology (Also known as plastic deformation machining)

II - 1. Current status and development trend of casting technology:

II-1-1. Status of casting technology in Vietnam

Casting is the most important kind of embryo technology. Before 1985 this technology in many factories still relatively backward, still using coal-fired furnace for cast iron cooking, the molds are made on fixed sand background, scraps of the casting products are often  very high (from 20% to 30%). However, after 1985, thanks to the innovation of our Party and State, the economy turns a market economy with socialist orientation, the economy is thriving, in which must mention the mechanical manufacturing industry has created. To meet the quality requirements higher and higher the casting, casting technology has strong innovation in technology and equipment. So far, most of the mechanical manufacturing plants are both large and small. They  have been equipped the electric arc furnace, intermediate frequency furnace to cook the pig iron and steel. The existing arc furnaces, cooking capacity from 0.5 tons/ batch  to 30 tons/ batch, it means that so far, the casting ability of Vietnam may cast the details  with the weight over 20 tons (if the mention to companies specializing in rolled steel casting, we have equipped many arc furnace with the capacity to cook more than 50 tons / batch). We have equipped many medium frequency furnace to cook pig iron and steel with high quality. The medium frequency furnaces have  capacity from 200kg/batch; 500kg/ batch; 750kg/ batch; 1000kg/ batch and 1500kg/ batch. There are many factories equipped with two pairs of furnaces with each pairs capacity about 1500kg/ batch. Thus, if you apply technologies to cook two parallel furnace, we can cast the iron or steel details with high quality that have weight about 2 tons. Even if the cooking ferrous metal (copper alloy, aluminum alloy) . The majority of Mechanical Companies have used frequency  electric furnaces or electric furnaces (formerly used to oil burners or coal burning furnace). Only some villages still use coal furnace to cook copper.

Along with the renewal of the equipment smelting, molding technology also important innovation, molding technology removal based on fixed sand, most companies of mechanic molding technology used fresh molds, in which each time of making the mold is done by new material preparation meticulously, allowing rapid analysis of steel samples in addition to iron furnace, many molding applications Factory sand with glassing water, a number of plants were successfully applied Furan molding technology for casting iron.

Thanks to the successful application of advanced molding technology so quality of casting is improved significantly, scrap of casting due to porosity decreased by only about 5% - 10% (for complex details). To test the components as well as to adjust the casting components in various smelting process mechanical manufacturing enterprises have equipped the emission spectrum, which allows fast analysis of steel samples in addition to iron furnace, from which time adjustments in the cooking process. It can be confirmed that we have been able to cast all kinds of good steel  as desired.

In summary, although in recent years mechanical manufacturing industry has always encountered difficulties because there is no interests of the Government, but we always try to survive and grow by changing new equipment and technology, and learn from other developed countries. The manufacturing enterprises have advanced reactors equipped for cooking steel, cast iron and alloy color, used quite common advanced technology to make the mold, as phuran mold, the mold itself hard, fresh sand mold, a number of firms with large volumes of detailed manufacturing equipment used to break the mold and the mold after the molding equipment. Many enterprises have been equipped with devices to analysts analyze and adjust the components in the casting process and has been equipped with ultrasonic detection of cracks and porous castings. The existence of the casting technology at present is the overwhelming majority of the furnaces are not equipped to test metal temperature , not equipped with automatic control of liquid metal temperature, uncontrolled reasonable temperature when pouring the metal, causing a large effect on quality of casting The casting furnace and pouring operation is manual. The problem preparing molding material although many factories were interested, but are not really uniform. The mechanization of these foundries is still very weak

II-1-2. Development trend of casting technology.

To recover the shortcomings of the casting technology in Vietnam, the development trend of casting technology will aim at the following points:
- Take control of the stage for the the furnace temperature for both black and color metal, some casting of professional firms or large Mechanical manufacturing firms should be equipped with extra large capacity of arc furnace to be cast details with weight about 30-40 tons. (GALLET furnaces of the cement plant capacity or larger ring gear for the mill, parts thermal and hydro power, etc..) equipped with medium frequency furnace and  large capacity to 5 tons / batch, it is equipped with insulated to ensure temperature stability of metal pouring.
- With fully equipped with devices quickly analyze emission spectra for the foundry enterprises, creating prerequisites for quality alloy castings.
-The large foundry or casting plants should be equipped with specialized laboratories molding material, molding makes high quality, stability and minimize casting defects caused by porosity.
- To step up mechanization of molding, pouring in metal casting and the mold discovery after casting.
- Common widely the advanced technology molding for all casting factories, carefully analyzing pros - cons of each methods of technology when using can choose the appropriate method.
- The scientific research and staff training sector needs to promote and pay more attention.

II -2. Current status and development trends of welding technology in Vietnam.

II-2-1. Status of welding technology in Vietnam.

Welding technology is also one of the important technologies to manufacture embryos: create embryos the details form the frame and box size, case slow down large hydraulic presses to thousands of tons, body slamming a box, coal engine diesel engines with capacity of up to tens of thousands of horsepowerthe whole coal shell ship etc.In addition to tasks to create casts a wide variety of products including welding also has many other special roles such as restoration of the worn, patched on a surface a layer of metal details new features in particular, giving details of which gift against high temperature resistant, etc.

After surveying the current state of technology of welding in a lot of businesses mechanic typical we can give the remark as follows: In nearly 20 years, to meet the demands of quality products the donag industrial mechanic had invested very remarkable about welding equipment and technology. We do not use the old technique of welding transformer welding machines or as large as a model child 20 years ago. Instead of the old outdated technology and equipment is the equipment for electric rectifier can with infinite voltage change. The new principles and new materials have been applied to make Inventor welding, it allows to shrink the size and weight machines down many times compared to other welders in the past, very convenient for the transport, scooped and particularly effectively when finished welding at high above. The welding semiautomatic with climate protection is CO₂ or argon, the semi-automatic welding methods under layer of cement is being used very popular in many businesses, especially in the shipyard, factory-built steel frames, beams, the factory built tank Towerassembling companies, Vietnam etc. These devices are usually imported from the famous as: Sweden (ESAB), France (Moore), USA (Lincold), etc. Most of these devices are very good and are being exploited effectively. Welding point is also used extensively in the automotive industry.

-Some sort of advanced welding technology such as Plasma welding, electron welding, ultrasonic welding slag, etc… have also been added to the Philippines. However, mining equipment and technology is also pretty modest.

-Checking the quality of welds are also businesses are also mechanic business interest. Most businesses use a variety of welding were equipped with ultrasound, x-ray equipment to check the quality of the welds.

-Scientific research and training in the field of welding technology are also interested in the Institute and universities.

In summary, the technological innovation and welding equipment are concentrated in the welding manually, semi-automatic welding under a layer of protective gas (MIG, MAG, TIG), automatic welding under a layer of slag (SAW), spot welding. The advanced welding methods such as plasma welding, Laser soldering, welding slag, welding semi-automatic powder core wire, although entered, the exploitation has not been adequate attention.

II-2-2. Development Trends of welding technology  in the near future.

In parallel with the widely using types of welding technology as at the present, in the coming we need to promote the application of automatic welding technology under layers of protection (SAW) in conjunction with the using of welding liners; need researching welding semi-automatic wire core powder has protected for climbing high quality. Need to focus on researching and putting into application technology of pipe connection automatically when the tube does not rotate. This is an important task when building and installation of the pipeline gas or liquid lead for oil and gas industry. I know, the key laboratory of surface treatment of the manufacturing Research Institute had a pipe welding equipment when the tube does not rotate. This is a very favorable condition to give this equipment for production and replication.

- Able to focus on technology applications and wire welding Plasma powder stoned to cover more surface alloy has a thin layer of special features. This is a very advanced technology should be applied to create more special features: high wear resistance, heat resistance, ... (we do not have the Plasma welding rods).

- You can speed up production welding slag technology to create embryos details plates, square shape with large thickness, etc. ... Currently in Vietnam there were many electric slag welding equipment, but do not understand the reasons what this technology has not been applied to production.

- Need to promote the research and manufacture of welding materials including wire, welded wire powder cores, welding slag in order to gradually replace imported products pastes.
Besides,  supplements scientific staff  Welding sector for key laboratory   and surface treatments to better exploit the conditions existing equipment of the laboratory, on the other hand could be here to train staff welding science of better qualified to meet the development requirements of the welding industry.

 II-3. Situation and development trend of pressure machining technology in Vietnam.

II-3-1. Status of pressure machining in Vietnam.

Pressure processing technology in mechanical manufacturing industry is a very important technology,  it allows us to create ingot details with very little residual processing, saving metal, energy and labor costs also  improve grain and metal structure thereby improving the durability of unit compare with billet casting.

Pressure processing technologies include: Wrought, volume stamping, stamping plates, flowing press, hydrostatic pressure in the cold state and hot state, flowing hydraulic presses, rolling cycle (normally between 2 rolling technology metallurgical sector).

By survey of many mechanical manufacturing business, we see our country only uses free forging technology by steam hammer machine to create the ingot of  small weight unit (under 100kg).  A few mechanical enterprises have  relatively large  number of same products  has begun using stamping technology in mould (Disoco factory has forging crankshaft billet line for Honda).  Several enterprises of military industry and producers of metal stamping technology using plates stamping and deep stamping. Some enterprise specialized in products from aluminum and copper alloys have been used flowing press in the hot state.  There is not basic to apply the technology hydrostatic pressure and hydrodynamic flow to create more billet, did not have a business that uses cycle rolling technology to create primary billet for next forging step.

The equipment for forging freedom in Vietnam is mosly using is steam hammer with beating force from 50kg-750kg . A few large companies have mechanical hammer equipment from 1 to 3 tons. Specifically, Disoco company is equipped with hammer 10 tons. Besides the hammer in the forging workshop of many enterprise is equipped with the friction presses and stamping machines crankshaft stamping force of 100 tons - 600 tons. Particularly a company equipped with mechanical crank presses with stamping capacity to 1600 tons. With the forging stamping device was very small, in addition in the forging shop was not equipped with the arm and lifting equipment appropriate transport, so they can’t forge the unit with weight up to 200kg (although the hammer 10 tons can forge  bigger unit the lacking of  arm machine lead to not be able to manipulate it).

In some enterprises have entered the horizontal hydraulic press machine with pressure up to 1650 tons (for press aluminum frame, aluminum alloy tubes) The number of horizontal press machine with such huge force is only about 10 equipment in the country. Besides the horizontal hydraulic presses, in some enterprises have entered the vertical hydraulic presses with the force of 20 tons, 40 tons, 100 tons -1000 tons. The vertical press machine  are  used in variety way: to straighten, to shape deformation in cold state, for pressing powder materials to create detailed pictures in the field of powder metallurgy, etc. ...

Our staff of science and pressure machining industry are engineers are engineers trained at home and abroad. Large number of them have knowledge and experience but we are quite many years, the number of young engineers specialized in pressure machining industry

In summary, outsourcing  pressure technology in the mechanical business of our country is so weak in terms of technology, equipment and staff. Businesses only equipped with a small steam hammer, most often below 450 kg, very few enterprises have 750 kg hammer. Number of enterprises equipped with a large hammer from 1 ton - 10 tons only about 10 enterprises (typically Disoco Company, mine mechanical plant TKV, Hanoi railway company, Z111 Army etc ...) enterprises equipped with a large hammer does not have the  transportation equipments, mechanical arm so can not forge large accessories.

Few businesses apply technology forging, stamping volume. Some businesses were equipped with a hydraulic pressure of 1,000 tons -1650 tons of great song used only for very narrow purposes, not to fully exploit the capacity of the device (multiple panels only work 30% capacity and time) The advanced technology in processing pressure were not applied. Every year dozens of technology and outsourcing pressure devices are not to be renewed and strengthened.

II -3-2.  Development trends of pressure machining technology in the near future.

- There is difference between the casting technology and welding technology, technological innovation in machining requires respectively equipment investment. The equipment in the  pressure machining is often very expensive, so when technological innovation of pressure machining need  to invest very largely.

- In fact that, free forging technology for low productivity, product quality on the geometry is not high, but it matches the production of single units or small, consistent with the characteristics of the mechanical manufacturing business in our country. On the other hand, investment is not large. So it should be fully equipped and uniform forging technology can be free to be forging greater details.

- It is necessary to invest some large workshops with steam forging hammers machine to 30 tons, 20 tons, 10 tons, 3 tons, 1.5 tons, 1 ton, 750kg, 450kg with appropriate amounts to ensure large forgings for details the country. Should invest  some large hydraulic forging  pressing machines to 5000 tons and synchronously equipped with firing chamber very necessarily to weight of embryo to 10 tons. The furnace can be used in liquid or solid fuel. Putting embryos into the furnace and take the embryos to mechanization. In the workshop the pair forging billet and forging control must be equipped with revolving cranes and cutter jib.

- The forging workshops of large mechanical enterprises such as Disoco, Cam Pha manufacturing Center, HAMECO Hanoi mechanical Company need to invest in renovating furnaces, lifting equipment, cutter jib to develop is the ability to forging. Paying special attention  the stage of mechanization in  free forging.

- Promoting the application of technology  volume stamping in the closed mold  to make the details with large volumes as embryos of automotive gears, embryos of exhaust valve motorcycles and cars, embryos cross shafts etc. ...The volume stamping technology  in the closed mold is technologies for very high productivity, consistent with the types of large production. It must be  big investment but due to large number of products and the ability to quickly recover capital (experience DISOCO)

- At present, there are many joint ventures for manufacturing automobiles and motorcycles in Vietnam, if we have a good relationship with joint venture partners and ask them to allow us to make a few of above details, we will design ourselves and ask them consultant to import the appropriate equipment. The output of details to meet their extensive market and not limited to the Vietnam market. (At first they can supervise the production process).

- Initial application  technology of hydraulic flowing pressing in the hot state and warm to make gear of cars, motorcycles with m ≤ 4 and diameter De ≤ 100mm (embryos that have gears with surface finishes Δ 5, then just fine milling or grinding. following the widespread application of this technology for the appropriate product.

Greater output,  higher efficiency ($ 100,000 or more products) can form a synchronous line of embryos preparation, furnaces, stamping machines about 400 - 600 tons (the crankshaft). The preparation of force transmission environment ( press the graphite wheels ) etc. ...

- Application of hydrostatic pressure technology in heating and cooling status bar to create of metal pipes a layer and two layers for many different targets of the economy based on expanding the use of horizontal press machine 1000 -1600 tons available in Vietnam (today only used up 30%)

- Using technology to create embryos rolled flatting mill high-quality big ring gear.

- To accomplish the these above objectives need to promote training stage science and technology staff for the pressure machining industry.

The above points, we have presented the current situation and development trend of embryo technology of mechanical manufacturing in Vietnam, we hope that manufacturing enterprises will interest and receive consensus by mechanical enterprises in our development.