33 reasons for the production of black spots in all products
First, the cause of the mold:
(1) in addition to the full inspection of oil before, can effectively prevent the oil and rust stains products and runner material mixed with crushed material and be used (especially in the production process appears rather than in the initial test);
(2) each gate is too small or too rough, will lead to a large number of friction heat, if the mold exhaust, it will cause the gas combustion to produce obvious black stripes (black).
Reason two, equipment:
(3) dryer motor operation in the long term, shelter evil people and countenance evil practices will be cleared regularly;
(4) the dryer filter must be cleaned regularly, replaced, or will enter the foreign body or due to poor ventilation and material discoloration, agglomeration;
(5) due to negligence or dryer workers operation equipment deficiencies caused by factors such as the barrel not (fully) seal, lead into the dust in the air; or dust flying, mill products and pollution to the surrounding material within the barrel; or too large, easy to operate, ignore the angle (the feeding tube and the interface). Factors lead to refueling process, the barrel is not completely clean.
(6) long term production operations, usually not well protected, resulting in the dust mixed with equipment;
(7) the masking of the mill is not in place, resulting in pollution and other materials;
(8) the mill as far as possible black and white isolation;
(9) the nozzle aperture is too small or the inner surface roughness will produce a lot of friction heat, if the mold exhaust, will cause the gas combustion to produce obvious black stripes (black);
(10) the barrel or rubber head wear, bending crack, polymer part of heat generated black lines (spots);
(11) a rubber ring wear, adhesive is not smooth forward extrusion phenomenon, can cause excessive gas in the material tube, when the injection is smooth, and black lines due to sharp friction;
(12) a rubber ring diameter and cylinder clearance tolerance is too small to make screw melt have a greater resistance, resulting in friction heat causes black lines (can be a few small diameter grinding ring disassembly or replacement, large tolerance screw smooth glue);
(13) the screw and the material tube eccentric to produce the very big friction heat;
(14) the screw compression ratio is too large, the feeding friction force larger part of the shallow ditch and barrel wall and raw materials the material thermal decomposition produce black lines (black spot);
(15) the temperature of heating plate is not correct, the actual temperature and temperature error is too large, the temperature is not easy to overheat and intuition, using measuring device view.
Three, materials:
(16) the raw material itself with black spots, and the proportion of the black spot exceeds the permitted range of the permitted range or the permitted standard of the finished product;
(17) in the course of transportation, handling and storage of raw materials, the raw materials are damaged or contaminated;
(18) the material mixed with the impurities in the artificial ratio or the material;
(19) the need to add some lubricant in the material, if you add, will produce serious friction heat, because of too much gas exclusion is not timely, resulting in gas burning black lines (black);
(20) the lack of heat resistance of raw materials, can not withstand the operating temperature, raw materials (additives) heat cracking;
(21) the material bag or the preservation material bag is not clean, when used again, causes the foreign matter to mix.
Four, other reasons:
I believe I believe (22) long time in the barrel production of different materials, due to temperature changes, the oxidation and degradation of various materials, and days and months multiplying on the metal surface adhesion of different related factors, resulting in the surface of the screw and tube wall and nozzle etc., gradually formed carbide layer is separated, the higher viscosity encountered when a material is gradually brought out. In addition, the screw and tube wall and other parts, if there are scars or gaps, will be more likely to make the molten material retention, and stop the boot frequently, will make the problem more serious;
I believe I believe (23) do not understand the material crushing bad products, leading to confusion;
I believe your bad product (24) confirmed by the technician is crushed or abandoned;
I believe I believe (25) changing material, for convenient operation, only the wind blew off the remaining gun material chip, this method is not completely clean the barrel; or with air gun bombardment in the field, resulting in the dust in the workshop;
I believe your (26) landing or flow directly into the feed mill;
I believe I believe (27) bad products casually with air gun blowing under a few pieces;
I believe I believe (28) red box products, go directly into the crusher;
I believe I believe (29) treatment of foreign matters, only found one reason that found all the real reason;
I believe there is a scraper blade grinder (30), no timely adjustment and control of materials;
I believe I believe (31) special materials such as PP, PMMA, ABS shutdown method not grasped;
I believe I believe (32) feeding way is wrong, such as black and white materials directly to the material, may be due to electrostatic or other causes of black dust falls into the white material;
I believe your washing machine (33) did not completely replace low temperature material originally used when the tube, the operation temperature rises, resulting in low temperature materials (fire retardant, additives etc.) can not bear this temperature, the thermal degradation, this usually occurs in the nozzle (especially in the production process rather than on the initial trial occurred).
