A technique associated with increasing the life span of the extruder by connecting tiles associated with wear-resistant materials across the crest from the Twin Screw Extruder, as well as optionally milling the actual solidified materials to get rid of any kind of razor-sharp sides. Within an additional settings from the existing linen manufacturing extruder, dishes associated with wear-resistant materials tend to be guaranteed towards the top sides from the extruder mess posts to help extend the life span from the extruder mess.

Extrusion is really a well-known procedure that’s utilized in numerous sectors. A number of items through meals in order to optical materials, materials as well as alloys tend to be made by extrusion. Within the extrusion procedure, the actual supplies to become extruded tend to be given to the extruder, a kind of huge machine. The actual supplies tend to be combined, warmed in the event that suitable, as well as given right into a gun barrel which has an interior revolving mess. The actual mess techniques the actual fluid or even viscous materials becoming extruded (the actual inch extrudate”), away the finish from the extruder.

It’s been discovered how the outdoors sides from the mess posts within the extruder, that blend the actual extrudate as well as drive this away the finish from the extrusion gun barrel, tend to be susceptible to put on compared to other areas from the mess posts. Once the outdoors sides from the mess posts put on adequately, extrudate moves between your mess posts and also the gun barrel, that disrupts the standard extruder machine. For this finish, actions happen to be come to lengthen the actual sturdiness upon individuals areas of the actual anchoring screws which observe extra put on. This kind of actions possess incorporated using the layer of numerous fluid ingredients which solidify about the mess or even using one more coating associated with strong wear-resistant materials towards the servings from the extruder mess susceptible to put on. Nevertheless, it’s been discovered which supplies which task from the top of mess tend to be susceptible to shear throughout make use of, and also the supplies may encounter exhaustion splits. Consequently, bits of the actual materials may split away as well as become integrated within the extrudate becoming combined. Frequently this particular requires the actual fingertips associated with amounts associated with extrusion machine that are polluted along with bits of wear-resistant materials or even layer.

1. Solid relay of heating control damaged. Generally speaking, there are three reasons that can result in damage of solid relay:

• Overvoltage disruption
• Overcurrent burn out
• Overheat burn out (so it requires good radiating)

1. After disruption, its input/output terminal stays in normal open, control end doesn’t work. As a result, the heaters will keep working, thus the real temperature will be higher than setting value.

• After burn out, its input/output terminal stays in normal close, control end doesn’t work. As a result, the heaters will not work, thus the real temperature will be lower than setting value all the time. Perhaps the transfer heat from adjacent barrel can cause its temperature ascending, but it is slow obviously.

1. Malfunction of temperature modular or instruments. Temperature modular or instruments play a leading role in temperature control processing. PID setting has a direct acting on temperature control effect. You can change PID setting value appropriately when the fluctuation of temperature is over than normal range. Generally, the output voltage of temperature modular is 0-24V (DC), and the working voltage is 10-24V (DC). If the temperature is in abnormal condition, you can check whether the temperature modular or instruments damaged by testing its output voltage.
2. Malfunction of cooling. If cooling system has problems, so does the temperature control system? The major problems of cooling system are solenoid or its fuse.

Malfunctions of main extruder motor and feeding control system.

1. Generally, the problem of AC motor and feeding control system can be read from frequency inverter screen. The common alarms are overload, overheat, lack of phase and lack of load. You can solve the problem according to error message.
2. Another condition is that the frequency inverter is in run but the motor doesn’t work. In this case you should check whether the motor damaged. If the motor is in normal, you should check the mechanical parts, for example whether feeder screw jammed or bearing destroyed.

Malfunction of auxiliaries

Most problems of auxiliaries related to motor. Lack of phase and short circuit probably give rise to motor burn out, so having three phases electric resistance checked is quite necessary. In addition, too much dust and terminals loose connection is common problems that can cause abnormal control.

Cases

Equipment type: TDS75/TDD180 twin screw extruder plus single screw extruder tandem line

Processing material: RPVC

Malfunction: pressure of TDD180 single screw extruder was too high, exit of material was difficult, even was not able to. Sometimes only 1/6 holes were working. It needed a great long time to be in normal.

Solution: first of all was to check cooling of screw. Finding no valve installed at inlet, cooling water was in normal open. As a result, the temperature of screw was too low. The screw had been stuck by cooled material. After installed a valve to control the water flow, the problem of material exit had been solved. Still a few holes could not work very well. Every time when customer started the line, he started vacuum pump once the material went into single screw extruder. We suggested him starting vacuum pump when the material come out from the die of single screw extruder. With this suggestion, this problem had been solved completely.

Conclusion: starting vacuum pump too early can generate negative pressure, the negative pressure zone will baffle material exit.

Equipment type: TDS75 twin screw extruder

Processing material: PVB film

Malfunction: pressure before melt pump not stable that cause the thickness of PVB film fluctuated

Solution: at beginning we thought the circle loop of pressure control had problem. After optimization, it didn’t work well yet. Then we tested feeding system, the scaling system was in good condition. Eventually, we found that the plasticization had a great affect of pressure before melt pump. Thus we changed the configuration of screw elements, and then the problem had been solved.

Conclusion: each material has its own individual physical property of plasticization; they need the different screw configuration as well. If the screw configuration is not in proper, the pressure inside of barrel and the quality of final products will be affected.

Equipment type: TDS65 twin screw extruder

Processing material: PP modification

Malfunction: instant temperature has a great fluctuation; overcurrent alarm occurred often

Solution: after having thermal sensors checked, we believe all thermal sensors worked well. We concluded that it must have been caused by line hit. The general control cabinet equipped with a digital alarm system. We found that the real current was different from the value displayed when machine running. It was almost two or three times difference. So we could make the conclusion that line hit gave rise to the error display. We improved the ground connection, it was clear.

Conclusion: good ground connection plays a crucial role in safety and production stability. So make sure the ground connection tight before starting up your machines.

After Chinaplas 2010, there are many XPS manufacturers are interested in CO2 foam XPS production line. Some of them are looking for solutions to upgrade their existed Freon foam XPS production line.

As the market is still in chaos, I, as an insider of extrusion business, feel obliged to say something about the real CO2 foam XPS production line.

Do you really need CO2 foam?

Given this question, many people would think my mind goes wrong. CO2 is cheaper, safer and what is more, CO2 is eco-friendly. Why not CO2? Yes, I agree. But every factory has to face market, has to balance investment and return, and has to evaluate risk and opportunity. The following terms are some of my points of view about CO2 foam that every XPS manufacturer might encounter more or less, now or future.

New investment involved

Equipments:

Comparing with Freon foam, CO2 foam needs more investment for new equipments. Such as CO2 tank, complete CO2 injection system. In China, the cost of above equipments is around 50, 000USD. Besides these, CO2 foam also requires high level of extrusion system, as CO2 becomes supercritical condition only when pressure is higher than 7.3Mpa and temperature is above 31.1 celsius degrees. While it is in real production, the pressure could be up to 30Mpa. So it is a challenge for your extrusion system to work under this critical condition without leakage for long time. You might have to change your extrusion system. Certainly, it will charge you more.

Raw materials:

CO2 foam requires better quality of PS resin. Traditional Freon XPS production uses a lot of recycled material that may collected from rubbish. Actually most manufacturers in China used 100% recycled material. But this will not work for CO2 foam. Because CO2 foam requires high Vicat softening point, higher tensile strength of raw material. Only virgin GPPS or very good quality recycled GPPS can achieve aforementioned properties. These properties can provide higher Tg (glass transition point) which will help polymer encapsulate CO2 when materials come out from die exit. This means your cost of raw material will increase. You have to recalculate your market price and your cost.

Region’s Standard bar

Most regions have their own standard of thermal conductivity for XPS board/panel. For instance, Chinese National Standard of thermal conductivity for XPS board is 0.030W/m K. Normally the thermal conductivity of CO2 foam XPS board is approximately 0.033W/m K. it is really difficult to meet Chinese National Standard. That means Chinese National Standard barred CO2 foam XPS board to entry now. Surely, our company has been cooperating with some prestigious XPS suppliers in China to develop CO2 foam XPS technology. Likewise, Standardization Administration of China is also thinking whether they are going to change the current National Standard of XPS board. So you have to make sure these things will not happen on you.

How to identify machine supplier?

No one wants to buy an old technology to compete in market place. The fact is twin screw extruder plus single screw extruder tandem extrusion system is prevailing in XPS production. You must make sure your potential machine supplier has enough experience about this equipment.

Why twin screw extruder? “In twin-screw extrusion, incorporation of the physical foaming agent (PFA) is made over a limited number of barrel sections that are usually cooled. As the blowing agent is dissolved in the polymer, the plasticization effect allows for further temperature reduction, which may also slow down the diffusion of the PFA molecules in the mixture. Efficient dissolution must then be provided rapidly, and this can only be feasible through proper mixing of the two components.” (Michel A. Huneault, Jacques Tatibouët and Richard Gendron, Industrial Material Institute, National Research Council of Canada). Only twin screw extruder can offer rapid mixing within a few barrel sections.

Many XPS machine suppliers claim they can supply machines for CO2 foam XPS production. And they also claim they can supply twin screw extruder plus single screw extruder tandem extrusion system. Is it true? I doubt it. As I mentioned above CO2 foam requires high system pressure. The solubility of CO2 in PS obeys Henry’s law. Meanwhile, the number of cell in final board has a linear correlation with pressure. In a word, CO2 foam requires higher system pressure. Generally, it is between 20Mpa to 30Mpa. Can normal twin screw twin screw extruder bear this working condition? The answer is negative. The most application of twin screw extruder is for compounding which merely requires 2-3Mpa pressure. It is far away from the requirements of foam extrusion. So it is a big challenge for your gear box of TSE. On the other hand, the sealing of secondary extruder is also a big issue. When pressure is above 20Mpa, the screw and barrel of cooling extruder needs special device to avoid leakage occur.

If your potential supplier can answer you above questions well. You might think he is a right partner.

These days, the United Nations Climate Change Conference Copenhagen 2009 is going on. Between China as the representative of the developing countries and the United States, Europe and Japan, developed countries as the representative of the developed countries are having the heated debate each other. Because the developed countries are in an attempt to overule Kyoto Protocol so that China, Indian and many Africa countries wanna quit of this conference. Here I would like to express is that, whether developed or developing countries, we have only one Earth. In fact, we are in the same boat, just as the same as the Titanic. Only developed countries in the first class, and the developing countries are in economy class. It is only through helping each other in order to tide over the difficulties, rather than through political tactics to achieve intentions.

I think that these arguments not only between developed and developing countries, but the rich and the poor arguments. Can you image one country which has 85% families can not afford to buy a apartment (Chinese Academy of Social Sciences, blue book) to undertake a major national environmental obligations? It is not only unfair, this is fundamentally anti-science. People who have heard of Maslow’s theory (Maslow’s hierarchy of needs), they know human needs are divided into various stages. The first is physiological needs such as food, water, air, etc., then security needs, such as personal safety, sense of space requirements, property safety, health insurance. And then the social needs, including friendship, love. Now in China, food and clothing should be said that has been resolved, that is, the lowest level of Maslow’s needs pyramid has been resolved. However, security requirements, there are some unresolved. Our health care system is not good, medical care difficult and expensive is still one of the major social conflicts. Although we have a democratic system looks beautiful, but the execution of the democratic system is not good. Various legal systems are not perfect, the effect of the implementation is even worse, such as property law. Coupled with higher and higher outrageous housing prices has kept the people away from their house dream. All these make the families do not have the sense of security. In such a social environment, you ask people to make more contribution for global environment protection, it is impossible to achieve. I think the contribution to environmental protection is in the fourth level of Maslow’s theory belongs to others respect and self-esteem areas. Therefore, only if they meet the physiological needs, security needs, and emotional needs of the foundation. It would good to consider environmental protection issues.

What I have said these issues and not just China’s problem is the vast majority of problems of developing countries, and even in developed countries have these problems too, just more or less. Copenhagen conference is undoubtedly a political show of Game Theory, but I would like to remind the developed countries is that, perhaps you have a lot of political tricks. But developing countries have the right to withdraw from the game, once the developing countries out of the game, then the result of the game is no winner. Environmental issue is the problem of all mankind. We have more than 200 countries, seven continents, four grand oceans, three colors people, two genders, but we have only one Earth.

This United Nations Climate Change Conference Copenhagen 2009 has more worldwide attentions than before. It is also a sign to speed up the research and development of new materials and energy save materials. USEON Foam Extrusion Team has been devoting to energy save materials. We have a lot of cooperation with Institute of Plastics Processing & Application of Light Industry, Beijing University of Chemical Technology, and East China University of Science and Technology. We developed CO2 foam Extruded Polystyrene production line (XPS production line), and still researching for high thickness Polypropylene and Polyethylene sheet. Our BTB Recycle Team has been engaged in PET recycle extrusion technology, it is also a good product for energy save. In my opinion, Chinese extruders will make great contribution to developing countries. Because Chinese machine has the best cost-performance. No matter single screw extruder, twin screw extruder or complete screw extruder production line. Our price is even less than 1/4 European price with the same productivity. There are 85% people are living in developing countries. That means the majority of worldwide people are living in developing countries. Of course, developing countries need eco-friendly product, but it should be affordable. So the developed countries should take out more helps to developing countries. Since we have the different living status, but we will have the same destiny when global climate become worse and worse.

After the new CCTV Tower, as well as some domestic manufacturers’ workshop of XPS board had the big fire disaster recently, the voice of flame retardant of construction materials are getting louder and louder. In order to solve the problem of flame retardant XPS board, the most direct and effective way is to put the flame retardant agent into the raw material formulation while in production.

At present, the domestic market of flame retardants used HBCD (Hexabromocyclododecane, C12H18Br6). Including a number of subsidiaries of international corporations in China is also using this kind of flame retardant. This retardant not only has the corrosion to the processing equipments, but also has the harm to the humankind.  Therefore, the use of halogen-free flame retardants becomes the best option. The cooperation between and Clarian proven that the CESA series flame retardant provided by Clariant is a good option. We also intend to help the Clariant globally promote their flame retardants. As the flame retardants are still made in Taiwan, so the price is relatively more expensive. If the domestic demand going up, the engineers from Cleariant said that Clariant would also consider setting the production of this material in the mainland. With the fire retardant requirements of construction material is getting higher and higher, the flame retardant XPS would be compulsory in the soon future.