1. Uneven color or discoloration: uneven color of plastic or pigment discoloration on the surface of plastic parts due to poor distribution of pigments or fillers. The reasons for uneven color are different with the appearance of different phenomenon, the pigment is mainly distributed unevenly near the feeding port, such as the whole part of uneven color is caused by poor thermal stability of plastic, the welding part of uneven color is related to the nature of the pigment.
2, size instability: mainly due to poor mold strength, poor precision, injection machine working instability and forming conditions instability, so that the plastic part size change is unstable.
3. Air bubble: residual gas in the plastic parts is caused by excessive inflation or poor exhaust in the molten material, and it is a small volume or a series of holes (note that it should be different from the vacuum bubble).
4, pit collapse (indentation) or vacuum bubble: due to poor pressure filling material, plastic parts cooling is not uniform, uneven wall thickness and plastic shrinkage.
5, too large flash: due to bad mold closing, clearance is too large, plastic flow is too good, too much material so that plastic parts along the edge of the extrusion of excess sheet.
6. Poor welding: due to the low temperature of the material when the melt material is shunt and confluence, and the incompatibility between the resin and the adduct, etc., poor welding occurs when the melt material is confluence, and obvious fine seam lines are generated along the surface or inside of the plastic parts.
7. Ripples on the surface of plastic parts: because the molten material along the mold surface does not flow neatly to fill the cavity, but becomes semi-solidified and fluctuates in the cavity surface to flow or the molten material has stagnation phenomenon.
8. Bad demoulding: due to the strong filling effect and bad demoulding performance of the mold, it is difficult to demoulding the plastic parts or the deformation and fracture of the plastic parts after demoulding, or the residual direction of the plastic parts does not meet the design requirements.
9. Lamellar delamination of mica: due to the mixing of different materials or low mold temperature, when the molten material flows along the surface of the mold, the shear effect is too large, which causes the material to flake into thin layers and the physical properties to decline.
10. Sprue sticking: the sprue is stuck in the sprue sleeve due to mechanical resistance in the sprue sleeve, insufficient cooling or failure of the material pulling rod.
11, poor transparency: due to the melting material and the mold surface contact is bad, plastic parts surface has small cavities cause light disorderly radiation or plastic decomposition, there are foreign body impurities, or the mold surface is not bright, so that the transparent plastic transparency is poor or uneven.
12. Silver streaks: as there is water or air in the material, and too much volatile matter, the melting material is subjected to excessive shear effect, and the melting material is not closely integrated with the mold surface, or it is rapidly cooled or mixed with different materials or decomposed, so that the surface of the plastic parts along the direction of material flow appear silver and white needle-like stripes or mica flake patterns.
13. Warping and deformation: internal stress caused by residual stress, shear stress, cooling stress and uneven shrinkage during forming; Bad demolding, insufficient cooling, insufficient strength of plastic parts, mold deformation and other reasons, so that plastic parts shape distortion, warping or uneven hole, uneven wall thickness and other phenomena.
14, crack: due to the plastic parts of the internal stress is too large, bad demolding, cooling is not uniform, plastic performance or plastic parts design is bad and other defects (such as deformation) and other reasons, so that the plastic parts surface and near the material inlet crack, or cracking or in the load and solvent action does not occur cracking phenomenon.
Article 15, black, black: due to combustible volatiles in the decomposition or plastic material, such as air decomposition under high temperature and high pressure combustion, combustion with melt injection mold cavity, in the present black spots on the surface of the plastic, black stripes, or charcoal burns phenomenon 16 along on the surface of the plastic, plastic parts: mainly caused by a lack of feed, melt flow, filling the air and the venting is not good causes too much filling cavity, plastic body distortion is incomplete or multi-cavity individual cavity filling displeasure.
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