Suggestions on the further development of lost foam casting technology

How to solve the challenges  opportunities faced by our country after entering the WTO? How to correctly assess the current state of my country's lost foam casting technology  its influence  role in the further development of casting technology? Application in my country's lost foam casting industry How to adapt to the general trend of the development of foundry technology in the 21st century,  develop rapidly  healthily, especially the major problems that R&D personnel engaged in professional lost foam casting production  manufacturing are eager to respond.

1 New progress in overseas lost foam casting technology in recent years

1.1 In 2001, the Saginaw Metal Casting Operation (SMCO) lost foam production line subordinate to General Motors Corporation of the United States was officially put into production, marking that the technology level of lost foam in the United States is becoming mature.

SMCO is currently the world’s most advanced  large-scale lost foam production  manufacturing plant. It has 5 molding lines,  Nissan 356 aluminum alloy 270 horsepower in-line sports sports car has 1500 6-cylinder cylinder blocks  cylinder heads. By 2002 In October, it can produce 2100 pieces each day, the internal waste rate is <10%,  the total waste rate after the pressure test is <12%.

The Vortec42006 cylinder block  cylinder head manufactured by SMCO are complex  representative EPC products at this stage, which fully reflects the superiority of EPC. This type of cylinder block  cylinder head are designed by the design department of the company, which fully considers the characteristics of the EPC method. The cylinder body mass is 40kg,  the formed cylinder head is 22kg. The product design integrates crankcase, ventilation system, oil/ The air separator, complex water jacket system  complex curved oil return pipeline are all cast, which greatly reduces drilling  bolt assembly, reduces noise, vibration  pollution, improves fuel efficiency,  reduces costs.

The SMCO process is perfect,  sintering production is fully realized. 5 pre-foaming machines  29 forming machines produce high-quality polystyrene cylinder blocks  cylinder head foaming molds every day. The cylinder body is divided into 4 pieces  bonded into 1 unit, placed horizontally during pouring, 1 box, 1 piece, cylinder head divided into 5 pieces, glued into a whole, placed vertically during pouring, 1 box 2 pieces, using high-performance mica-based paint, automatic coating by robot, After drying, the manipulator puts it into the sand box, rains  adds sand,  it is clamped  compacted in 3 stages. It is poured with a sprue cup. After the casting is cleaned  rough processed, 100% is subjected to a leakage test, undergoes T6 heat treatment,  then sent to processing The factory performs finishing.

Because of the company's huge contribution to the level of lost foam casting technology, it has repeatedly received awards  various departments in the United States. Vortec 4200 cylinder block was rated as the superior casting in 2001.

1.2 The production of lost foam castings in North America has risen linearly,  the scope of application has increased steadily. In the production of lost foam casting, the pinhole  loose defects of aluminum alloy castings have been solved,  it has matured very early. In the production  manufacturing of steel castings, it is more  more common to use the ceramic shell method of disappearing  then casting, which solves the old difficult problems such as carbon increase  slag inclusion. It is widely used for lost foam casting in railway, shipbuilding, heavy design  other industries. The application paved the way. The difficulty of castings increases, the precision is enhanced,  the superiority of the lost foam casting process is more prominent.

1.3 In the field of processing technology  mold design  manufacturing, an advanced  practical CAD/CAM/CAE system has been created, which can accurately produce  manufacture molds similar to 6-cylinder blocks  complex cylinder heads,  Flow3D simulates casting parts. The flow field  temperature field simulation software of the whole process of filling  solidification are gradually put into practical use to predict  analyze the formation of defects in the pyrolysis products of castings,  specifically guide the process technology  appropriately  the casting system.

2 Recognition  reassessment of the current status of the technical development of lost foam in my country

In our country, lost foam casting has made great progress since the upsurge appeared ten years ago. However, it is still relatively young in general. As a new technology application, it is still in the early stages of technological innovation. At this stage, the total output value of lost foam castings across the country is about 20,000 tons. The castings are  relatively simple grinding balls  grate bars. To moderately difficult intake  exhaust pipes, box parts, steel castings, ductile iron parts are plagued by carbon defects, slag holes,  pore defects,  the failure rate remains high,  the production of aluminum alloy castings is still relatively small. . Half of the imported equipment  our own imitated, relatively large-scale production lines have  yet achieved their due benefits. The management  system reasons certainly exist, but the technical immaturity, some core technologies have  been overcome, become the key reason why the high-value project investment can  get timely benefits. Some production lines with small scale of operation  relatively simple machinery  equipment mostly produce certain accessories. Due to the unstable product objects of the company, it is difficult to meet the increasing requirements of the sales market for the quality  difficulty of castings, which is in ups  downs. The situation of volatility, economic gains may go up  down.

2.1  the perspective of the development trend of foundry technology in the 21st century, the lost foam casting technology has reached the development direction,  a new climax is bound to appear. The production  manufacturing of castings must vigorously promote  give small processing allowances  accurately shaped corporate products; achieve ecological  environmental protection, achieve clean production,  at the same time apply to more humane sales market needs,  the structural design of corporate products must be greater The degree of freedom of lost foam casting can meet the requirements of the sales market  consumers in many aspects mentioned above. It has great development potential. It only needs to play its characteristics  advantages to the right,  the development prospects are very broad.

3 Several suggestions for the further development of domestic lost foam technology

3.1 The product must be on the road,  the project's pre-processing technology demonstration is indispensable.

Lost foam casting is excellent, but it is  omnipotent. It has a certain range of applications. Whether the selected casting is suitable for the selection of lost foam casting methods requires various processing techniques  careful comparison of multiple schemes. The production line is built,  then experimented,  slowly explored. This is usually very easy to cause the consequences of a large amount of investment that cannot be returned in time,  even the experimental results prove that some castings are  suitable for the use of lost foam casting at all,  the consumption is more serious. .

3.2 Overcome every technical difficulty with heart,  steadily push the lost foam technology to a new height. In the past ten years, we have done a lot of basic research work  accumulated a little actual production  manufacturing experience. The overall goal in the future is

It can produce more complex  accurate medium  high difficulty castings, such as complex box parts, cylinder heads  cylinder blocks, so that the superiority  economic benefits of lost foam casting can be fully reflected. For this reason, around the technical keys that must be overcome in the production  manufacturing of high-difficulty castings, such as the pattern  castings' dimensional specification accuracy change law, better performance coatings, optimized vibration compaction processing technology,  defect countermeasures, etc. It is necessary to solve them one by one.

3.3 Focusing on the weak links of the "white zone", increase research  development efforts. The "white zone" is a multidisciplinary field involving CAD/CAM of molds, polymer foaming materials  foaming processes  related pre- In many aspects, such as development, molding,  gluing equipment, it is necessary to strengthen the collaboration  interaction of chemical, chemical engineers, foundry workers, mold  mechanical designers,  CNC machining engineers to develop small  uniform particle sizes, large foaming ratios,  stable dimensions. , Non-deformable lost foam bead material, formulate foaming process rules; create advanced  practical mold CAD/CAM/CAE system,  master the size of the foaming mold-foam plastic-pattern-between castings The rule of specification change accumulates data for the design of complex molds; develop high-precision, high-efficiency mold-making machines  bonding machines,  realize serialization of mold-making machines  bonding machines.

3.4 Realizing the "lightweight"  "accurate" of castings, aluminum alloy lost foam casting is promising

Foreign lost foam casting first made a breakthrough  aluminum alloy castings. Now it has been able to mass-produce complex six-cylinder cylinder blocks  cylinder head castings. However, the domestic aluminum alloy lost foam casting is just relatively weak  "lightweight" with castings. In the future, we should develop special coatings for aluminum alloys to solve pinholes  loose defects of aluminum alloy castings,  establish more aluminum alloy lost foam casting production lines. It can be expected that aluminum alloy lost foam casting will be in the next ten years. Will develop rapidly.

3.5 Take the initiative to attack  realize the green manufacturing of lost foam casting. Lost foam casting itself is a new technology  new process with less environmental pollution. It only needs to further solve the two links of exhaust gas cleaning  dry sand system dust removal  renewable recycling to ensure complete green manufacturing. This will be Other casting accurate forming process methods can  match the unique advantages.

3.6 Joint operations, make full use of the overall advantages of the close integration of production, learning,  research. The sea can be turbulent. The Lost Foam Foundry of Heli Forklift Group closely combines the use of overseas advanced equipment with my country's self-made. While making full use of its own development potential, it has introduced design institutes, colleges, universities,  scientific research enterprises. The lost foam production line produced high-quality export castings in a relatively short period of time,  achieved good economic  social benefits, which is a model in the forging industry. Countless examples have proved that joint operations  making full use of the overall advantages of the close integration of industry, learning,  research are an effective way to develop lost foam technology more quickly, efficiently  economically.