Hvad er sorte pletter?
Sorte pletter er mørke eller mørke striber på overfladen af produkter, og sort strømlinje vises langs strømningsretningen nær porten, hvilket er et problem med overfladekvaliteten, som vist på figuren
Sort plet og sort stribe
Defektanalyse og eliminering af sorte pletter
1) Smeltetemperaturen er for høj
Hvis materialetemperaturen er for høj, smelten vil overophedes og nedbrydes, danner carbider. For at undgå overophedning nedbrydning af smelten, the temperature at the end of the barrel must be strictly controlled for PVC and other heat sensitive thermoplastic materials. When black spots and stripes are found on the surface of the plastic parts, the temperature controller of the barrel should be checked immediately to see if it is out of control, and the temperature of the barrel and die should be reduced appropriately. Imidlertid, it should be noted that if the material temperature and die temperature are too low, bright streaks will also appear on the surface of plastic parts.
2) Too large gap of material cylinder
If the wear gap between the screw and the barrel is too large, the converging melt will stay in the barrel, resulting in local overheating decomposition of the retained melt and black spots and stripes. I denne forbindelse, you can first slightly reduce the barrel temperature, observe whether the fault can be eliminated. For det andet, check the barrel, nozzle and die to see if there is any dead angle and smooth grinding.
After taking the above measures, if the fault is not eliminated, the equipment should be repaired in time, and the gap between screw and barrel should be adjusted.
3) Overheat due to friction between melt and die wall
Hvis injektionshastigheden er for høj, the injection pressure is too high, and the relative movement speed between the melt and the cavity wall is too high during mold filling, it is easy to cause friction overheating, which will cause the melt to decompose and produce black spots and wrinkles. Derfor, the injection speed and pressure should be reduced appropriately.
4) Poor exhaust of barrel and die
If the cylinder or die is not well vented, the residual gas in the melt will burn due to adiabatic compression, which will cause the melt to overheat and decompose and produce black spots and stripes. Derfor, the injection speed can be reduced appropriately, and the exhaust port structure of the barrel can be improved when the particle size and uniformity of the raw material are suitable.
For the poor exhaust of the mold part, check whether the gate position and exhaust hole position are correct, whether the gate type is suitable, remove the rust inhibitor and other volatile substances adhered in the mold, and reduce the amount of mold release agent. On the premise of no flash, the clamping force can be reduced and the exhaust clearance can be increased. Ud over, check the barrel and thimble for oil leakage.
5) Bulk coking
When the nozzle does not match with the main channel of the mold, the accumulated material will be coking near the gate and injected into the mold cavity with the flowing material, forming black spots and stripes on the surface of the plastic parts. Derfor, the relative position of the nozzle and the main channel of the die should be adjusted in time to make it fit well.
Ud over, if the hot runner of the mold is not well designed or manufactured, the molten material will not flow smoothly in the runner, stay and coke, which will also cause black spots and stripes on the surface of the plastic parts. Derfor, the surface luminosity of hot runner should be increased and the heating temperature of hot runner should be reduced.
6) Råmaterialet opfylder ikke støbekravene
If the content of volatile matter in raw materials is too high, the drying of water sensitive resin is poor, the amount of recycled materials is too much, the fine powder is too much, the raw materials are not evenly colored, the lubricant type is not selected correctly or used too much, it will lead to black spots and stripes on the surface of plastic parts in varying degrees. I denne forbindelse, we should take corresponding measures according to different situations and eliminate them separately.
Om JasonMould Industrial Company Limited
Jasonmould er en Kina mold maker af plastforme- sprøjtestøbeform, formstøbning forme, plastblæsestøbning, rotationsstøbning, medicinsk plast sprøjtestøbning, to skud plast sprøjtestøbning, indsatsstøbning, overformning, metal sprøjtestøbning, mikro sprøjtestøbning, pulverformsprøjtning, keramisk sprøjtestøbning, flydende sprøjtestøbning, husky sprøjtestøbning, husholdningsskimmel, støbeform, formværktøj, brugerdefinerede forme, porcelæn forme, værktøj til hurtig prototyping, værktøj til prototyper i plastik, slagpresseværktøj, dør og værktøj til mobiltelefon/ mobiltelefondele, bildele, støvsugere, genopladelige værktøjer, telefoner, kopimaskiner, computere, multimediehøjttalere, og mange andre elektroniske produkter og husholdningsapparater. Og også en plastproduktproducent, skimmel producent Kina- plastikdele, vandtank i plast, plastik bolde, plastbeholdere, plastspænde, plastanker, plast bøjle, plastske, rørledning i plast, tumlet plast, bordservice i plast, plastik kopper, plastik flasker, plastbakke, kosmetisk beholder af plast, plastkasse, madbeholder i plast, plaststole, plastikkapper, lukning af plasthætte, plastrør, vandrør i plast, plastik knapper, plastrør, brugskasser i plast, plaststativer og så videre.
Kontakt:
Person: James Yuan
Selskab: JasonMould Industrial Company Limited
Tilføje: LongGang Village,LongXi Town,BoLuo County,HuiZhou City,GuangDong-provinsen, Kina
Tlf: 86-752-6682869
E-mail: [email protected]
Websted: https://www.jasonmolding.com/custom-injection-molding/
