About injection molding chinese resin
If you ask me about injection molding chinese resin most popular plastic material we used for our customer is ABS. Plastic injection molding in china, we are few company keep good price and high quality service . we not only a professional injection molds maker, also for injection molding chinese process, today, let us discuss about ABS material.
1, Plastic handle ABS the water absorption of about 0.2% -0.8%, the general level of ABS, prior to processing using an oven bake at 80-85 ℃ for 2-4 hours or 1-2 hours of the drying hopper 80 ℃ bake. Heat Resistant ABS with PC components, the drying temperature is due to increase to 100 ℃, specific drying time can be used to determine the air extrusion.
The ratio can not exceed 30% of the use of recycled materials, electroplating grade ABS can not use recycled materials.
Injection molding chinese machine selection
The choice of Ramada’s standard injection molding chinese machine (Screw Ratio 20:1 compression ratio is greater than
2, the injection pressure is greater than 1500bar). If masterbatch or product appearance requirements expected high optional small a diameter screw. The clamping force follow the 4700-6200t/m2 to determine specific needs plastic grade products require.
3, mold and gate design The mold temperature set at 60-65 ℃. Runner diameter 6-8mm. Gate width of 3mm, the thickness and products, as the gate length is less than 1mm. Vent width of 4-6mm, thickness 0.025-0.05mm.
4, the temperature of the melt
Accurately determine the available air injection. A different level, the temperature of the melt is also different, and recommendations are set as follows: Anti-leveling: 220 ℃ -260 ℃, to 250 ℃ is better Plating grade: 250 ℃ -275 ℃, to 270 ℃ is better Heat Resistant: 240 ℃ -280 ℃, to 265 ℃ -270 ℃ better Flame Retardant: 200 ℃ -240 ℃, to 220 ℃ -230 ℃ better Transparent level: 230 ℃ -260 ℃, to 245 ℃ is better Glass fiber reinforced grade: 230 ℃ -270 ℃ High requirements for the surface of the article, the use of higher melt temperature and mold temperature.
5, injection speed Fire-rated to use slow, heat fast. Higher product surface, the use of high-speed and multi-stage injection rate of fire control.
6 back pressure
Back pressure as low as possible, under normal circumstances the usual back pressure 5 bar, coloring required a high back pressure to keep the blending evenly.
7, retention time
Under a temperature of 265 ℃, ABS melt barrel residence time can not exceed a maximum of 5-6 minutes. The flame retardant shorter For downtime, you should first set the temperature as low as 100 ° C, and then a general purpose grade ABS cleanup molten plastic tube. Clean up after the mix into cold water to prevent further decomposition. Change from plastic the hit ABS material, first with the PS, PMMA or PE cleanup melting cones. Some ABS products would not be a problem in just mold release, over a period of time before there will be discolored, which may be caused by overheating or plastic in the long residence time of molten plastic tube.
8, products after processing The general ABS products do not need to after treatment, only The plating grade products subject to bake (70-80 ℃ ,2-4 hours) to the passivation of the surface traces, and the need plating products can not use the release agent, immediately after packaging products remove .
9,Injection molding pay special attention to matters There are several grades of ABS (Flame Retardant), plasticized melt great adhesion to the surface of the screw after a long time will break down. When this happens, you need to screw homogenization segment and compressed pull out smear and PS and other clean-up on a regular basis screw.
Barrel temperature The feed zone 40 ~ 60 ℃ (50 ℃) District 1 160 ~ 180 ℃ (180 ℃) Zone 2 180 ~ 230 ℃ (210 ℃) Zone 3 210 ~ 260 ℃ (240 ℃) Zone 4 210 ~ 260 ℃ (240 ℃) Zone 5 210 ~ 260 ℃ (240 ℃) Nozzles 210 to 260 ° C (240 ° C) A temperature within the parentheses is suggested as a basic setting value, stroke utilization rate was 35% and 65%, the flow length of the mold member with the wall thickness ratio of 50:1 to 100:1 A cylinder thermostat 220 ° C Mold temperature 40 to 80 ° C The injection pressure of 100 to 150MPa (1000 1500bar) Holding pressure Dwell time is relatively short, the injection pressure of 30% to 60% Melt temperature is 220 to 250 ° C Back pressure 5 ~ 15MPa (50 ~ 150bar); back pressure is too low, melt entrapped air will cause coking (gray and black lines in progress) Injection speed Best injection classification: from slow to fast; need injection speed in order to achieve good surface gloss, minimum the fusion seam as well as fusion seam high strength; ventilation tunnels need to be opened at the juncture of the first flow channel Screw speed Maximum screw speed equivalent line speed of 0.6m / s, but the best low screw speed setting that as long as the plasticizing process can be completed before the end of the cooling time Metering stroke (0.5 ~ 4) D Residual quantity 2 ~ 8mm, depending on the measurement of stroke and screw diameter Prebaked ABS In some cases, direct feeding from the feed bag without pre-drying, and otherwise in the drying temperature of 80 ° C for 3 h; wet granules products cause cracks, scratches, or bubbles Recoveries 30% can be added back to the material, provided before material does not undergo thermal degradation Shrinkage of 0.4% to 0.7% Gate system Point the gate and hot runner; minimum wall thickness of not less than 0.7mm, poor liquidity because ABS Machine downtime period No need to use other materials cleaning Barrel Equipment Standard screw, check ring, through the nozzle