Iniectio CUMATIUM processus influendo factores

In the iniectio processus fingens de materia plastica, Thermoplastics, ex volumine mutatio per crystallization, fortis internus accentus, Magna RELICTUM accentus gelida in plastic pars, Fortis MOLECULA SENTENTIATIONIBUS aliisque factores, ita comparari cum thermoset materia plastica, Et DECREMENTUM Rate est maior. Et DECREMENTUM Rate est lata et directionality est obvious. Autem, Et DECREMENTUM post CUMATIUM, furnum vel humiditas curatio fere maior est quam materia plastica thermosetting.

Cum plastic pars fingitur, contactus materialium liquidarum superficies cavitatis et stratum tegumen statim refrigeratum ad densitatem solidam humiliorem formant.. Ob pauperes scelerisque conductivity plastic, interior iacuit partis plasticae paulatim refrigerata ad altum densitatis solidum iacuit cum magnis DECREMENTUM. Ergo, muri crassitudine, patiens refrigerationem, et alta densitas iacuit magis abhorrebit crassitudo. Autem, praesentia vel absentia interserit ac extensionem ac quantitatem insertorum directe afficit directionem fluxus materialis, density distribution ac DECREMENTUM resistentia. Ergo, characteres plasticae partes habent maiorem impulsum in DECREMENTUM et directionality.

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Factors such as the form, magnitudine, and distribution of the feed inlet directly affect the direction of material flow, density distribution, pressure maintaining and shrinking effect and molding time. Direct feed ports and feed ports with large cross-sections (especially thicker cross-sections) have less shrinkage but greater directivity, and shorter feed ports with shorter width and length have less directivity. The ones that are close to the feed inlet or parallel to the direction of the material flow will shrink more.

Molding conditions: high mold temperature, slow cooling of molten material, high density and large shrinkage, especially for crystalline materials, due to high crystallinity and large volume changes, so the shrinkage is greater. The mold temperature distribution is also related to the internal and external cooling and density uniformity of the plastic part, which directly affects the size and direction of the shrinkage of each part. Autem, holding pressure and time also have a greater impact on contraction, and the contraction is smaller but the directionality is larger when the pressure is high and the time is long.

The injection pressure is high, the melt viscosity difference is small, the interlayer shear stress is small, and the elastic rebound after demolding is large, so the shrinkage can also be reduced by an appropriate amount. The material temperature is high, the shrinkage is large, but the directionality is small. Ergo, adjusting the fingunt temperatus, pressura, celeritas iniectio and cooling time during molding can also appropriately change the shrinkage of the plastic part.

Cum fingunt designing, secundum DECREMENTUM rhoncus variis materia plastica, muri crassitudine et figura plasticae partis, magnitudinem ac distributionem limbi forma, DECREMENTUM rate cujuslibet partis partis plasticae determinatur secundum experientiam, et in cavitatis magnitudine computatur. Nam summus praecisio partes plasticae et cum difficulter DECREMENTUM rate, his rationibus plerumque utendum est ad formam:

Iudicium forma decernit formam, amplitudo et corona condiciones de gandi ratio.

The plastic parts to be post-processed shall be procession to determine the size change . (ad mensuram oportet 24 horis post demoding.

Corrigere forma secundum ipsam DECREMENTUM.

④ Retry the mold and appropriately change the process conditions to slightly modify the shrinkage value to meet the requirements of the plastic part.

The fluidity of thermoplastics can generally be analyzed from a series of indexes such as molecular weight, conflandum index, Archimedes spiral flow length, apparent viscosity and flow ratio (process length/plastic part wall thickness).

Small molecular weight, wide molecular weight distribution, poor molecular structure regularity, high melt index, long spiral flow length, low apparent viscosity, high flow ratio, good fluidity, plastics with the same product name must check their instructions to determine whether their fluidity is applicable For injection molding. According to mold design requirements, the fluidity of commonly used plastics can be roughly divided into three categories:

①Good fluidity PA, PE, PS, PP, CA, poly(4) methylpentene:

②Polystyrene series resin with medium fluidity (such as ABS, AS), PMMA, POM, polyphenylene ether;

③Poor fluidity: PC, hard PVC, polyphenylene ether, polysulfone, polyarylsulfone, fluoroplastics.

The fluidity of various plastics also changes due to various molding factors. The main influencing factors are as follows:

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①Higher material temperature increases fluidity, but different plastics have their own differences, such as PS (especially those with high impact resistance and higher MFR value), PP, PA, PMMA, modified polystyrene (such as ABS, AS) The fluidity of, PC, CA and other plastics varies greatly with temperature. For PE and POM, the temperature increase or decrease has little effect on their fluidity. Ergo, the former should adjust the temperature during molding to control fluidity.

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② As the pressure of injection molding increases, the molten material is subject to greater shear and fluidity, especially PE and POM are more sensitive, so the injection pressure should be adjusted to control fluidity during molding.

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③The form, magnitudine, layout, cooling system design, flow resistance of the molten material (such as the surface finish, the thickness of the channel section, the shape of the cavity, the exhaust system) and other factors of the mold structure casting system directly affect the molten material in the cavity The actual fluidity inside, if the molten material is promoted to lower the temperature and increase the fluidity resistance, the fluidity will decrease.

Cum fingunt designing, a reasonable structure should be selected according to the fluidity of the plastic used. During molding, the material temperature, fingunt temperatus, iniectio pressura, iniectio celeritatis et aliorum factorum etiam coerceri potest ut condicionem impletionis convenienter accommodet ad necessitates coronae occurrendas.

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Crystallina thermoplastica dividi possunt in materias crystallinas et non crystallinas (Etiam quae amorpho) materia plastica secundum absentiam crystallizationem in condensatione. Crystallization sic dicta phaenomenon eo refert quod cum mutationes plasticae ex statu fusili ad condensationem civitatis, moleculae independenter et omnino in inordinato. Moleculis prohibere libere, premunt leviter fixa, et habent inclinationem ad ordinandum ordinem hypotheticum. Hoc phaenomenon.

Criteria aspectus iudicandi haec duo genera materiarum materiarum per diaphaneitatem partium plasticarum crassarum determinari possunt. Fere, crystalline materials are opaque or translucent (such as POM, etc.), and amorphous materials are transparent (such as PMMA, etc.). But there are exceptions. Exempli gratia, poly(4) methylpentene is a crystalline plastic but has high transparency, and ABS is an amorphous material but not transparent.

When designing molds and selecting injection molding machines, pay attention to the following requirements and precautions for crystalline plastics:

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① A lot of heat is required for the material temperature to rise to the molding temperature, and equipment with large plasticizing ability is needed. Ad

②It emits a large amount of heat during cooling back and needs to be cooled sufficiently.

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③The specific gravity difference between the molten state and the solid state is large, the molding shrinkage is large, et DECREMENTUM ac poros pronus fieri.

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Fast refrigerationem, humilis crystallinity, parvum DECREMENTUM et excelsum diaphanum. Crystallinum comparatur ad crassitudinem parietis partis plasticae, et parietis crassitudine tarde refrigeret, crystallinum est princeps, the shrinkage is large, et physica bona sunt. Ergo, forma temperatura materiae cristallinae coerceri oportet.

-Significant anisotropy et magnum internum accentus. Moleculae, quae non vitreae sunt, cum destruendo inclinationem habent ad crystallize pergo, in industria iniquitate, et proni sunt ad deformationem et warpage. Crystallization temperatus range angustus est, et materia liquefacta in formam injicienda est, vel obstruet cibarium portui.

Heat sensitivity refers to the tendency of certain plastics to be more sensitive to heat. When heated at high temperatures for a long time or the feed port section is too small, when the shearing effect is large, the material temperature increases and the tendency of discoloration, degradation, and decomposition occurs. Plastic is called heat-sensitive plastic.

Such as hard PVC, polyvinylidene chloride, vinyl acetate copolymer, POM, polychlorotrifluoroethylene, etc. Heat-sensitive plastics produce monomers, gases, solids and other by-products during decomposition. Praesertim, some decomposition gases have irritating, corrosive or toxic effects on the human body, armorum, and molds. Ergo, attention should be paid to mold design, injection molding machine selection and molding. Screw injection molding machine should be used. The section of the pouring system should be large. The mold and barrel should be chrome-plated. There should be no corner stagnation. The molding temperature must be strictly controlled. Stabilizer, weaken its heat-sensitive performance.

quidam materia plastica (ut PC *) even contain a small amount of water, but they will decompose under high temperature and high pressure. This property is called easy hydrolysis, which must be heated and dried in advance.

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