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PPR Pipes Increased Mechanical Strength To Improve Production

2018-11-15

First, the basic principles of plastic extrusion

Plastic processing industry is a highly integrated technology industry. It involves the polymer chemistry, polymer physics, interface theory, plastic machinery, plastic processing mold, formula design principles and process control and so on. The theory of extrusion mainly studies the movement and change of plastic in the extruder. The relationship between the three physical states of the polymer,PPR Pipes the relationship between the screw structure, the plastic properties and the processing conditions of the polymer in the different temperature range under the action of a certain external force in the extruder. So as to carry out reasonable process control. In order to achieve the purpose of improving the production and quality of plastic products. Plastic polymer materials, heated at constant pressure, in different temperature range, there are glass, high elasticity, viscous flow of three physical state. General plastic molding temperature above the viscous temperature.

Second, polyolefin pipe extrusion molding process control

Estrusio prozesuaren kontrol parametroak moldura tenperatura, extrusiozko lanaren presioa, torlojuen abiadura, estrusio abiadura eta trakzio-abiadura, elikadura-abiadura, hozte eta abar barne daude.

1. Pretreatment of raw materials

Poliolefina material xurgatzailea da, normalean oso hezetasun baxua duen edukia, estrusioaren beharrak ase ditzake, baina poliolefina pigmentu xurgatzaileak ditu, hala nola karbono beltzak, hezetasun sentikorra. Gainera, materialak eta betegarriak erabiltzean, uraren edukia handitu egingo da. Hezetasuna kanalizazioaren barnealdea eta kanpoaldea zakarra dela eragiten du, baina burbuilak ere eragin ditzake urtzen. Sarri lehengaiak tratatu behar dira. Lehortzeko erabilera orokorra ere gehitu daiteke gehigarrien dagokion deshumidifikazio funtzioarekin. Defoamers bezalako. PE tenperatura lehorra da, oro har, 60-90 gradu. Tenperatura honetan, PPR hodiak errendimendua% 10etik% 25era igo daiteke.

2. temperature control

Estrusioaren moldaketaren tenperatura beharrezkoa da moldura materialen plastikoen plastikoen fluxua sustatzeko. Plastikoaren materiala eta produktuen errendimendua oso eragin handia du. Plastikozko Estrusioa Tenperatura teorikoaren leihoa biskositatearen fluxuaren tenperatura eta degradazio tenperatura artekoa da. Tenperatura tarte zabala da poliolefinak. Normalean, fusio puntutik gora, 280 gradu edo gutxiago prozesatu daitezke. Estrusio moldeen tenperatura behar bezala kontrolatzeko, lehenik eta behin prozesatu beharreko materialaren tenperatura muga eta harremanaren propietate fisikoak ulertu behar ditugu. Bere ezaugarriak eta legeak ezagutu ahal izateko, estrusio moldaketarako tenperatura altuagoa aukeratzeko. Beraz, tenperaturaren ezarpenak kontuan hartu behar ditu alderdi hauek: Lehenik eta behin, polimeroa bera, esate baterako, urtze puntua, PPR hodiak pisu molekularraren tamaina eta banaketa, urtutako indizea eta abar. Ondoren ekipamenduaren errendimendua. Ekipamendu batzuk, tenperaturaren jarioaren atalak korrontean eragin handia duena. Berriz ere, hodi egiaztapena, estrusio hodiaren azalera leuna da. Burbuila eta beste fenomeno batzuk epaitzeko.

The extrusion temperature includes the set temperature of the heater and the melt temperature. The heating temperature is the temperature provided by the external heater. The melt temperature refers to the temperature of the material between the front of the screw and the head.

The barrel temperature distribution, from the feed zone to the die, may be flat, incremental, decreasing and mixed. Mainly depends on the material point and the structure of the extruder.

Head set the temperature, in order to obtain better appearance and mechanical properties, and reduce the melt outlet expansion, the general control of the body temperature is lower, the machine head temperature is higher. The machine head temperature is high, can make the material smoothly into the mold, but the shape of the extruded material is poor, the shrinkage increases. Head temperature is low, the material plastic bad, melt viscosity, nose pressure rise. Although this will make the product too dense, after the shrinkage rate is small,PPR Pipes the product shape stability is good, but the processing is more difficult, from the mold expansion larger, the product surface rough. But also lead to increased backpressure extruder, equipment load, power consumption also increases.

The temperature of the die set, the temperature of the die and the core mold have an effect on the surface finish of the pipe. In a certain range, the die mold and the core mold temperature are high and the surface finish of the pipe is high. Generally speaking,PPR Pipes the temperature of the die outlet should not exceed 220 degrees, the melt temperature of the inlet of the head is 200 degrees, and the temperature difference between the inlet and outlet of the machine head should not exceed 20 degrees. Because the higher temperature difference between the melt and the metal will cause the shark skin phenomenon. Excessive melt temperature leads to die. But the specific decision to the actual situation.

Koladaren tenperatura torlojuaren amaieran neurtutako koladaren benetako tenperatura da eta, beraz, menpeko aldagaia da. Batez ere, torlojuen abiadura eta kanoi ezarpen tenperaturaren araberakoa da. Poluzio polietilenoko kanalizazioaren tenperaturaren goiko muga, oro har, 230 gradukoa da. Orokorrean 200 gradu inguruko kontrola hobea da. Polipropilenozko kanalizazioen estrukturaren tenperatura muga muga da, oro har, 240 gradu. Urtzen den tenperatura ez da oso altua izan behar. Oro har, kontuan hartu materialen degradazioa, PPR hodiak tenperatura altuagoa den bitartean. Pipa materiala zaila da.

3. Presioaren kontrola

The most important pressure parameter in the extrusion process is the melt pressure, that is, the head pressure, in general, increase the melt pressure, will reduce the output of the extruder, leaving the product density increased, is conducive to improving product quality. But the pressure is too large,PPR Pipes will bring security problems. Melt pressure and the size of raw materials, screw structure, screw speed, process temperature, the mesh mesh number, porous plate and other factors. The melt pressure is usually controlled between 10 and 30 MPa.

4. Vacuum setting

Vacuum stereotypes mainly control the vacuum and cooling speed of the two parameters. Usually in the appearance of the quality of the pipe to meet the premise, the vacuum should be as low as possible, so that the pipe stress is small, the product in the storage process deformation small.

5. hozten

Polyethylene pipe extrusion molding in the cooling water temperature requirements are generally low, usually below 20 degrees, in the production of PPR pipe, the first paragraph of the temperature can be slightly higher, the latter part of the lower, resulting in a temperature gradient. It is also important to adjust the cooling water flow. Flow is too large, the pipe surface rough, resulting in spot pits. Flow is too small,PPR Pipes the surface of the pipe to produce bright spots easy to pull off, such as uneven distribution, pipe wall thickness uneven, or oval.

6. Torlojuen abiadura eta estrusio abiadura

Torlojuen abiadura industriako parametro astunen estrusio-tasa, errendimendua eta produktuaren kalitatea kontrolatzeko kontrolatzen da. Torloju extrusioaren abiadura handitzen da eta errendimendua handitzen da. Zizaila-tasa handitzen da eta urtutako likatasun itxurazko likatasuna gutxitzen da. Materialen homogeneizazioa bultzatzen du. Aldi berean, plastifikaziorako ona dela eta, beraz, molekulen arteko elkarrekintza indar mekanikoa areagotzen du. Baina torlojuen abiadura handiegia da, motorraren karga handiegia da, koladaren presioa oso altuagoa da, zizaila-tasa altuegia da, moldeetatik Peng hedapenetik, gainazalean hondatzea eta ezegonkortasun maila.

7. Traction speed

Traction speed directly affects the product wall thickness, dimensional tolerance, performance and appearance, traction speed ratio to be stable, and the traction speed and pipe extrusion speed match. The ratio of the traction speed to the extrusion line velocity reflects the degree of orientation that the product may occur, which is called the draw ratio and must be equal to or greater than 1. The traction speed increases and the temperature of the cooling stereotypes is constant , Then the product in the sizing sleeve, cooling the water tank to stay in the time is relatively short, after the cooling of the finished product will also be more inside the residual heat, the heat will make the product in the process of pulling the orientation of the orientation structure has occurred ,PPR Pipes Resulting in a reduction in the degree of orientation of the article. The faster the traction speed, the thinner the wall thickness of the pipe, the greater the shrinkage of the finished product after cooling. The slower the traction speed, the thicker the pipe wall thickness, the more likely to lead to stowage between the die and the sizing sleeve. Destruction of normal extrusion production. Therefore, the extrusion process in the extrusion speed and traction speed must be well controlled.

8. On - line quality control and post - processing of pipe

Polyolefin-based crystalline polymers, the performance of the down-line tubing is different from the size and performance of the pipe product when it is delivered. The main reasons are, first, polyolefin melt cooling process to occur crystallization, crystallinity and crystal form and temperature and thermal history, the time to place. Second, just off the pipe temperature is usually higher than room temperature. Third, just off the assembly line of stress in the pipe. In order to achieve the stability of the performance and size,PPR Pipes the general polyethylene pipe should be placed off the assembly line for 24 hours, the polypropylene pipe to be placed after 48 hours, according to the corresponding standards for performance testing.