Wat zijn zwarte stippen??
Zwarte stippen zijn donkere of donkere strepen op het oppervlak van producten, en zwarte stroomlijn verschijnt langs de stroomrichting nabij de poort, wat een probleem is met de oppervlaktekwaliteit, zoals weergegeven in de afbeelding:
Zwarte vlek en zwarte streep
Analyse van defecten en eliminatie van zwarte vlekken
1) De smelttemperatuur is te hoog
Als de materiaaltemperatuur te hoog is, de smelt zal oververhit raken en uiteenvallen, vorming van carbiden. Om de ontleding van de smelt door oververhitting te voorkomen, 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. Echter, 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. In dit verband, you can first slightly reduce the barrel temperature, observe whether the fault can be eliminated. ten tweede, 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
Als de injectiesnelheid te snel is:, 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. Daarom, 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. Daarom, 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. In aanvulling, 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. Daarom, the relative position of the nozzle and the main channel of the die should be adjusted in time to make it fit well.
In aanvulling, 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. Daarom, the surface luminosity of hot runner should be increased and the heating temperature of hot runner should be reduced.
6) De poort op de winglet kan de omgekeerde poort en de puntpoort gebruiken
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. In dit verband, we should take corresponding measures according to different situations and eliminate them separately.
Over JasonMould Industrial Company Limited
Jasonmould is een Chinese matrijzenmaker van plastic mallen- spuitgietmatrijs:, spuitgietmatrijzen, kunststof blaasvormen, rotatiegieten, medisch spuitgieten van kunststof, twee schoten spuitgieten van kunststof, invoegen lijstwerk, overmolding, metalen spuitgieten, micro-spuitgieten, poeder spuitgieten, keramisch spuitgieten, vloeibare spuitgieten, husky spuitgieten, huishoudelijke schimmel, gietvorm, matrijs gereedschap:, aangepaste mallen, Chinese mallen:, tooling voor snelle prototyping, kunststof prototyping gereedschap, ponsmachine tooling, sterven en tooling voor mobiele/mobiele telefoon onderdelen, auto-onderdelen, stofzuigers, oplaadbare gereedschappen, telefoons, kopieerapparaten, computers, multimedia speakers, en vele andere elektronische producten en huishoudelijke apparaten. En ook een fabrikant van plastic producten, schimmelfabrikant China– kunststof onderdelen, plastic watertank, plastic ballen, plastic containers, plastic gesp, plastic anker, plastic hanger, Plastic lepel, plastic pijp montage:, plastic tuimelen, plastic servies, plastic bekers, plastic flessen, plastic dienblad, plastic cosmetische container, plastic verpakking, plastic voedselcontainer, plastic stoelen, plastic doppen, plastic dop sluiting, plastic buizen, kunststof waterleidingen, plastic knoppen, plastic buizen, plastic gebruiksdozen, plastic rekken enzovoort;.
Contact:
Persoon: James Yuan
Bedrijf: JasonMould Industrial Company Limited
Toevoegen: LongGang Village,LongXi Town,BoLuo County,HuiZhou-stad,Provincie GuangDong, China
Tel: 86-752-6682869
E-mail: [email protected]
website: https://www.jasonmolding.com/custom-injection-molding/
