Injection molding process related failures

In the plastics machining, often encounter a variety of plastics processing failures which express what kind of plastic machinery industry jargon used in more precise

One owed ​​Note: In plastics processing, due to the cavity filled with discontent, leading to incomplete shape plastic parts incomplete phenomenon.

2,  flash: Plastics Processing molding process, the overflow into the gap between the mold clamping surface and keep the remaining material in the plastic parts.

3, weld lines: a linear traces of plastic surface is determined by injection or extrusion material diversion of several streams in the desert with the confluence of the melt is not fully fused at the interface, they can not fused into one, resulting in fusion imprinting, affecting the appearance quality and mechanical properties of plastic parts.

4, the wave and current marks: As the melt flows in the mold cavity inappropriate, leading to produce plastic sheet ring, spiral or waveform cloudy uneven defect.

5, the surface opacity: Refers to produce plastic surface cracks and voids formed thereby damaged. Phenomenon due to the mechanical properties of the plastic below the stress caused by prolonged or repeated application of plastic parts external or internal cracks called stress cracking; due to plastic parts to withstand constant load acting a certain time at a specific temperature and a sudden burst of full-END the phenomenon known as stress cracking; certain thermoplastic member Overexposure of cracks occurring at higher temperatures is called thermal stress cracking and rupture.

6, fracturing: the resin layer covering the surface by means of a crack can be seen clearly laminated plastic layer or layers than the outer reinforcing material has.

7, ruffling: laminated plastic surface rupture and produce a defect clearly separated.

8, wrinkles: plastic processing, plastic surface layer or layers appear appearance defects creases or wrinkles.

9, cracking and whitening: the more obvious plastic surface micro cracks produced called cracking, and cracking similar bleaching cream called micro-cracks, cracks and micro cracks albino are no cracks. When the plastic is exposed to a chemical in the environment or in stress conditions, will produce environmental stress cracking.

10, silver pattern: plastic surface direction along streams produced silver needle white frost generally fine lines.

11 stripes: plastic surface or internal defects in the presence of linear stripes.

12, markings: Due to poor mixing and pigment dispersion or other causes dark spots produced plastic surface defects mica sheet.

13, orange peel: plastic parts, such as orange peel-like surface uneven appearance defects.

14, the cell stripes: refers to the foam, its inherent structural differences great cell cell layer.

15, black spots: in plastic molding process, melt overheating under high temperature and pressure conditions of decomposition, resulting in a black plastic surface to produce carbonation points.

16, white spots or bright spots: a transparent or translucent plastic film, sheet or plastic memory without fully plasticized particles, you can see a white light transmittance grain point, the point of this grain is called "fish-eye . "If the material is opaque or colored, this point is called grain white spots or bright spots.

17, pitting: Rules plastic surface appear or irregular small crater, its depth and width are usually about the same.

18, filling the spot: plastic parts in obvious scarring due to the presence of asbestos, such as flour or fillers caused.

19, dark spots: appear in the fabric of the substrate laminate structure dark stain.

20, and the charred spots paste: plastic processing, the molding conditions at high temperature and pressure, defects due to overheating of the melt decomposition carbonization, carbonized coke blend in the melt material, and the plastic surface is formed inside the scar.

21, the bubble: in plastic processing mold filling process, if a large number of residual gas in the melt, or air in the cavity is not completely drained, making the interior molding of plastic parts after the formation of clusters of smaller pores or defects.

22, vacuum bubbles or dark bulbs: When plastic parts in plastic processing cooled and solidified, due to the different cooling rates inside and outside, and sometimes the outer surface has cooled and solidified, but the interior is still in the melt state, once the central part of the cooling contraction, the internal plastic parts will produce a vacuum holes, these holes are generally called vacuum bubbles or dark bulbs, also known as shrinkage.

23, the pinhole: plastic sheet or film in the presence of pinhole defects in the size of the through hole.

24, foam collapse: the foam during the manufacturing process due to the destruction of the cell structure caused by the increase in the local density of defects.

25, recesses and deflated: cooling the plastic parts in the plastic processing process, since the cooling surface to be cooled and solidified after curing, or wall thickness of the inner portion, so that the volume contraction, contraction velocity inconsistencies outside the plastic surface of an internal pull member stretch forming depressions, producing shallow pits or lacunae.

more information www.plastic-injectionmoulding.com  www.injectionmoldchina.com