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Medical catheter precision extrusion production technology

another masterpiece of the cooperation between Weifang Kaide Plastic Machinery Co., Ltd. and Beijing University of chemical technology - the three-layer composite medical catheter high-speed precision extrusion production line was successfully trial produced in Weifang Kaide company recently. This is another great contribution made by Weifang Kaide plastic machinery company to the industry after the long-term technical exchange and cooperation with Beijing University of chemical technology and the series of high-speed pipe production lines launched a few days ago

this production line is a three-layer co extrusion one-time molding process. The extrusion unit and precision feeding unit of the extruder are jointly designed by Weifang Kaide Plastic Machinery Co., Ltd. and Beijing Institute of plastic machinery, which can play a role in reducing earthquake damage. The precision setting cooling unit, prestress elimination device, high-speed traction unit, high-speed precision cutting unit, etc. are independently designed and manufactured by Weifang Kaide Plastic Machinery Co., Ltd. The precision feeding system adopts the most accurate vector weight measurement feeding system in the world at present, and the feeding amount is accurate to grams; The machine head is equipped with high-speed precision extrusion device, and the front and rear melt pressure display can realize precise control and extrusion, ensuring that the size of each composite layer fully meets the design requirements; The traction machine and cutting machine adopt the high-speed multi wedge flat belt traction machine and high-speed flying knife cutting machine unique to Weifang Kaide Plastic Machinery Co., Ltd. This production line adopts the most advanced closed-loop control system, metering system, sensing system, power system and other elements in the world

in order to ensure the geometric accuracy and internal performance uniformity of the conduit, the following key technologies and equipment are used in the production unit:

(1) the use of precision drive system: servo motors are used in the drive system of extruders, melt gear pumps, parallel voltage stabilizing devices and tractors to replace variable-frequency motors or DC motors, so that the drive accuracy is increased by more than 90% and the control response time is increased by more than 80%, It fully meets the requirements of precision drive and precision control

(2) pressure stabilizing system: the stability of extrusion pressure is the key to determine the geometric accuracy of the conduit. This unit has a variety of pressure stabilizing systems to choose from according to the different materials and geometric parameters of the conduit:

a. pressure stabilizing system based on melt gear pump: so far, melt gear pump is the most effective pressure stabilizing device. For products with high geometric accuracy requirements, imported melt gear pumps will be selected as pressure stabilizing devices. After using the melt gear pump, the fluctuation of the axial size of the pipe can be reduced by more than 90%. For plastics with poor thermal stability, such as PVC, polyurethane, etc., melt gear pumps cannot be selected to prevent material degradation during processing. In addition, the price of melt gear pump is high, which is also a factor to be considered when selecting the pressure stabilizing system

b. voltage stabilizing system based on parallel voltage stabilizing device: the parallel voltage stabilizing device is a patented technology of Beijing University of chemical technology, which has the characteristics of simple structure, remarkable voltage stabilizing effect and low cost. The fluctuation of the axial size of the pipe can be reduced by more than 70% by using the parallel pressure stabilizing system. Parallel voltage stabilizing device is also not applicable to heat sensitive materials. Medical catheter processing heat sensitive materials requires other forms of voltage stabilizing system. The parallel voltage stabilizing system is suitable for the production of medium precision conduits. For materials with poor thermal stability, He said, "hybrid vehicles and all electric vehicles have also brought challenges to the industry. The connected voltage stabilizing system can use a pressure stabilizing - flow stabilizing extrusion die to improve the axial dimensional stability of the conduit. Using the patented technology of Beijing University of chemical technology can well solve this kind of problem.

(3) Precision medical catheter production mold: use CAE software to scientifically design the precision medical catheter production mold, and use advanced numerical control processing technology and electrochemical processing means to accurately process the mold, so as to meet the requirements of precision forming medical catheter

(4) application of statistical process control system: statistical process control (SPC) is a method of statistical processing and analysis of process parameters according to statistical model to realize precise process control. This method is an advanced control method based on predicting the development trend of the process in advance, which can improve the control accuracy by more than 80% compared with the conventional logic program control method (PLC). With SPC control system, the fluctuation of extrusion temperature can be controlled within ± 1 ℃

application prospect of medical catheter

with the development of catheter diagnosis and treatment technology, the clinical application of medical catheter is developing day by day, and the demand is also increasing. According to incomplete statistics, at present, there are more than 120 kinds of catheters in six categories in the world, and more than 100 kinds of catheters are used for the diagnosis and treatment of cardiovascular, cerebrovascular, tumor and other diseases. Statistics show that, only "The utilization of the above thermal insulation plastic building materials in the buildings of the United States, Japan and other countries has been 10 points mature. 16000 tons of polyurethane are used in the production of medical catheters in the United States every year, and the output value of various catheters has exceeded 2billion US dollars.

the history of China's catheter industry can be traced back to the 1950s, when it was not far away from European and American countries. The production of some simple catheters such as rubber catheters, stomach tubes, nasal feeding tubes and so on, in terms of quality The varieties are relatively close. It was in the 1970s that China and the Western conduit industry began to distance themselves. At that time, interventional medicine had just entered its development stage. People of insight in the catheter industry in Europe and the United States quickly felt that interventional medicine would be a promising career, so they quickly shifted the focus of the traditional catheter industry to interventional catheters. They firmly grasped the combination of medicine and industry in product development, boldly adopted polymer materials and the latest achievements of related science in technology, inherited the fine traditions of traditional catheter manufacturing and plastic manufacturing in industrialization, absorbed the successful experience of traditional medicine and medical device industry in marketing, and introduced a large number of venture capital in financing, Soon, interventional catheters became the most important part of the catheter industry, and made the catheter industry an important category of medical devices

by the 1980s, the interventional catheter industry in European and American countries had developed to a considerable scale, a number of catheter enterprises born in the 1960s had developed to a considerable scale, and some enterprises such as cook and kaudes had developed into global multinational companies. However, due to the impact of the "Cultural Revolution" turmoil, China's interventional catheter industry was almost an virgin land. At that time, in addition to oneortwo colleges and universities involved in interventional catheter research on a small scale, only the former Shanghai diagnostic instrument factory produced some simple and low-quality products in interventional catheter, and there was basically no development and production of interventional catheter nationwide. At that time, interventional medicine in China had just started, and the scope of interventional medicine involved in clinic was relatively narrow, mainly including angiography in interventional radiology department and some relatively simple interventional therapy. People's traditional concept of interventional medicine was basically limited to interventional radiology, and almost all products used were imported from abroad. With the help of the strong scientific research strength of the University and the CNAs National Laboratory of the company, it was extremely inconvenient to supply, And the price is ridiculously high. After the reform and opening up, especially from the mid-1980s, interventional medicine in China began to enter a period of rapid development. The obvious sign is that not only the scope of clinical application of interventional medicine has been greatly expanded, but also remarkable achievements have been made in some advanced fields of interventional medicine, such as interventional neuroradiology (also known as intravascular neurosurgery). Chinese scholars have made first-class work recognized by their peers in the world. However, the interventional catheter industry in China was almost completely stopped from the late 1980s to the early 1990s. On the one hand, the world catheter industry is changing with each passing day, and the interventional catheter market is expanding rapidly; On the other hand, China's intervention in the catheter industry has regressed, becoming a blank paper. The "blank" of national interventional catheter industry has become the bottleneck of the further development and popularization of interventional medicine in China. The annual sales of various catheters in the world have reached billions of dollars, and the number of medical catheters used in the treatment of coronary heart disease in the United States alone has reached hundreds of thousands, worth hundreds of millions of dollars. In China, various interventional therapy and other treatment technologies using catheters have been popularized to most of the tertiary hospitals, and the demand for medical catheters is increasing, but most of them use imported catheters

seizing the opportunity to realize the localization of precision medical catheter can bring significant economic benefits to catheter manufacturers, improve the national health level, and produce huge social benefits

according to the relevant international social development evaluation system, the production and consumption level of medical plastic products to a large extent reflects a country's economic and technological development level. At present, the annual per capita consumption of medical plastic products in the United States is $300, while China is only 30 yuan. At present, three out of every 10000 people in China suffer from acute and chronic renal failure. Based on this, it is estimated that nearly 300000 people in the country need dialysis treatment, and 2million disposable dialysis catheters are needed per year, each of which is 150 yuan, with a total cost of 300 million yuan. At present, the dialyzers mainly use the products of Fresenius of Germany, Baxter of the United States, Jinbao of Sweden and talmao of Japan. Compared with foreign developed countries, the development of medical catheters in China is very backward, especially medical plastic products such as high-tech interventional catheters are almost blank. According to incomplete statistics, the annual import value of medical catheters in China now exceeds 150million US dollars. Imported catheters are mainly high-precision interventional catheters. Due to the dependence on imports, the development of interventional medicine in China has been greatly restricted, and the high price of imported products is also unbearable for most people

in order to meet the production needs of medical catheters, Beijing University of chemical technology, with the support of the Ministry of education and the Beijing Municipal Science and Technology Commission, has successfully developed precision extrusion equipment that can be used in the production of medical catheters after more than three years of in-depth research and technological innovation, which has solved the bottleneck problem in the production of precision medical catheters and laid a solid technical foundation for the localization of precision medical catheters. With the localization of medical catheters, the price of catheters will decline significantly, and the amount of catheters will increase significantly. At present, the annual demand for various types of catheters is about 50million. It is estimated that in China, it will reach more than 100million tubes within five years, with a value of billions of yuan. Seizing the opportunity to realize the localization of precision medical catheter can bring significant economic benefits to catheter manufacturers, improve the health level of the people, and produce huge social benefits

during the joint test run with many professors of Beijing University of chemical technology, two specifications of three-layer composite medical catheter were produced: 6mm and 8mm. The stable production line speed of each specification of pipe reached 25m/min. The three-layer composite material produced has uniform composite, reliable bonding and bright appearance. The equipment broke the embarrassing situation that this kind of high-performance pipe has been dependent on imports for many years, and filled the blank of complete localization in the field of equipment and pipe. (end)

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