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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

The control parameters of the extrusion process include molding temperature, extruder working pressure, screw speed, extrusion speed and traction speed, feeding speed, cooling and so on.

1. Pretreatment of raw materials

Polyolefin is a non-absorbent material, usually very low moisture content, can meet the needs of extrusion, but when the polyolefin containing absorbent pigments, such as carbon black, the humidity sensitive. In addition, when the use of materials and fillers, the water content will increase. Moisture not only causes the inside and outside of the pipe to be rough, but also may cause bubbles in the melt. Often the raw materials should be pretreated. General use of drying, can also be added with a corresponding dehumidification function of the additives. Such as defoamers. PE dry temperature is generally 60-90 degrees. At this temperature,PPR Pipes the yield can be increased by 10% to 25%.

2. temperature control

Tá teocht múnlaithe easbhrúite riachtanach chun plaisteachú ábhair mhúnlaithe agus sreabhadh leá plaisteach a chur chun cinn. Tá tionchar an-tábhachtach ag ábhar an phláiste agus ar cháilíocht agus toradh táirgí. Easbhrúite Plaisteacha Tá an fhuinneog teochta teoiriciúil idir an teocht sreafa slaodachta agus an teocht díghrádaithe. Tá an raon teochta leathan le haghaidh polyolefins. De ghnáth, is féidir próiseáil a dhéanamh ar an bpointe leá, 280 céim nó níos lú. Chun an teocht múnlaithe easbhrúite a rialú i gceart, ní mór dúinn an teorainn teocht den ábhar atá á phróiseáil agus a n-airíonna fisiceacha an ghaolmhaire a thuiscint. Chun a saintréithe agus a dhlíthe a fháil amach chun raon teocht níos fearr a roghnú le haghaidh múnlú easbhrúite. Dá bhrí sin, ba cheart go gcuirfí na gnéithe seo a leanas san áireamh sa suíomh teochta: An chéad, an polaiméir féin, mar phointe leá, meáchan móilíneach agus dáileadh móilíneach PPR Pipes, innéacs leá agus mar sin de. Leanúint le feidhmiú an trealaimh. Tá roinnt trealamh, an t-alt beatha ar an teocht ar an ósta a bhfuil tionchar mór aige ar an láthair. Arís, tá an dromchla feadán easbhrúite tar éis breathnú ar an bhfeadán réidh. Cibé an mboilgeog agus feiniméin eile a mheas.

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.

Socraigh an ceann an teocht, d'fhonn cuma níos fearr agus airíonna meicniúla a fháil, agus an leathnú asraonta leá a laghdú, tá an rialú ginearálta ar theocht an chomhlachta níos ísle, tá teocht an mheaisín níos airde. Tá an teocht ceann an mheaisín ard, is féidir leis an ábhar a dhéanamh go réidh sa mhúnla, ach tá cruth an ábhair easbhrúite bochta, méaduithe an chrapadh. Is í an teocht ceann íseal, an plaisteach ábhartha dona, an tslaodacht leá, an t-ardú brú na srón. Cé go ndéanfaidh sé seo an táirge ró-dhlúth, tar éis an ráta crapadh a bheith beag, tá PPR Pipes an cruth ar an táirge a chobhsaíocht go maith, ach tá an próiseáil níos deacra, ó leathnú an mhúnla níos mó, ar dhromchla an táirge garbh. Ach mar thoradh air sin tá méadú breise ar an easbhrúite, an t-ualach trealamh, an tomhaltas cumhachta ag méadú freisin.

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.

The melt temperature is the actual temperature of the melt measured at the end of the screw and is therefore the dependent variable. Mainly depends on the screw speed and barrel setting temperature. The upper limit of the melt temperature of the extruded polyethylene pipe is generally defined as 230 degrees. Generally controlled at about 200 degrees is better. Polypropylene pipe extrusion melt temperature limit is generally 240 degrees. Melt temperature should not be too high. Generally consider the degradation of materials,PPR Pipes while the temperature is too high will make pipe material difficult.

3. Pressure control

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. Socrú folamh

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. fionnuar síos

Tá múnlú easbhrúite píopaitiléine sna riachtanais teochta uisce fuaraithe i gcoitinne íseal, de ghnáth faoi bhun 20 céim, i dtáirgeadh píopa PPR, is féidir an chéad mhír den teocht a bheith beagán níos airde, an chuid dheireanach den ísle, rud a fhágann grádán teochta. Tá sé tábhachtach freisin an sreabhadh uisce fuaraithe a choigeartú. Tá an sreabhadh ró-mhór, an dromchla píopa garbh, a eascraíonn i bóithre. Tá an sreabhadh ró-bheag, Pip Pipes ar dhromchla na píopa chun spotaí geal a bheith éasca a tharraingt amach, cosúil le dáileadh míchothrom, tiús tiús balla píobáin, nó uibheacha.

6. Screw speed and extrusion speed

Is é luas an scriú rialú a dhéanamh ar an ráta easbhrúite, toradh agus ar chaighdeán táirge na paraiméadair tionscail throm. Méadaíonn luas an easbhrúite scriú aonair agus méaduithe an toraidh. Méaduithe ar an ráta curaíochta agus ar shlaodacht dealraitheach na laghduithe leá. A chabhródh le huathghiniúint ábhar. Ag an am céanna mar gheall ar plaisteachú maith, ionas go dtáinig méadú meicniúil ar an idirghníomhaíocht idir na móilíní. Ach tá luas an scriú ró-ard, tá an t-ualach mótair ró-mhór, tá an brú leá ró-ard, tá an ráta luchta ró-ard, as an leathnú Peng múnla, an meathlú dromchla, agus an méid éagobhsaíochta.

7. Luas tarraingthe

Cuireann an luas tarraingthe isteach go díreach ar thiús an bhalla táirge, ar chaoinfhulaingt, ar fheidhmíocht agus ar chuma tríthoiseach, ar an gcóimheas luas tarraingthe a bheith cobhsaí, agus an luas tarraingthe agus an luas easbhrúite píopa. Léiríonn an cóimheas idir an luas tarraingthe go dtí an treoluas líne easbhrúite an méid treoshuímh a d'fhéadfadh an táirge a bheith ann, ar a dtugtar an cóimheas tarraingthe agus caithfidh sé a bheith comhionann le nó níos mó ná 1. Méadaíonn an luas tarraingthe agus is é teocht na steiréitíopaí fuaraithe ná seasmhach, Ansin, tá an táirge sa sleamhnán sizing, ag fuarú an umar uisce chun fanacht san am a bheith réasúnta gearr, tar éis go mbeidh an táirge críochnaithe fuaraithe freisin níos mó taobh istigh den teas iarmharach, déanfaidh an teas an táirge sa phróiseas tarraingt tá treoshuíomh an struchtúir treoshuímh tarlaithe, PPR Pipes Mar thoradh ar laghdú ar mhéid treoshuímh an ailt. Is é an luas tarraingthe níos tapúla, tiús bhalla na píopa níos déine, is é sin an crapadh an táirge críochnaithe níos mó tar éis fuarú. An luas tarraingthe níos moille, an tiús bhalla píopa níos déine, is dócha go dtarlóidh stowage idir an bás agus an sleeve sizing. Scriosadh gnáththáirgeachta easbhrúite. Dá bhrí sin, ní mór an próiseas easbhrúite sa luas easbhrúite agus luas tarraingthe a rialú go maith.

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.