Back pressure: back pressure, holding pressure: packing, resin temperature.Shrinkage – refers to the phenomenon that the surface of the workpiece is concave at the wall thickness, usually at the reinforcement ribs, countersunk holes or internal grids. Simple solution: increase packing and back pressure, reduce barrel temperature, extend cooling time… Silver Streaks – also known as material flowers, water flowers. Refers to the silver-white stripes that appear on the surface of plastic parts. Simple solution: fully dry the raw material, reduce the temperature of the barrel and nozzle, improve the exhaust of the mold…
Lack of glue (short shot) — the phenomenon that the injection molded parts are not full of glue (incomplete structure), which generally occurs around the plastic parts, and the ribs and bucklesSimple solution: case study increase gate size, increase injection speed, increase injection pressure, increase material temperature, increase mold temperature…Flash – the excess glue produced by the periphery of the injection molded parts, the thimble position, and the buckle positionSimple solution:
increase clamping force, lower material temperature, lower filling speed, case study lower injection pressure and holding pressure Charring – local charring (blackening, yellowing) of injection molded parts due to poor mold exhaust (air trapped)Simple solution:
install exhaust vents to reduce injection speed Flow lines/flow marks – traces of melt flow on the surface of injection molded partsSimple solution: increase material temperature, decrease injection speed, increase mold temperature…
Black Spots/Stripes – Black spots or streaks, or brown streaks on the surface of the injection molded partSimple solution: clean spindle barrel, lower barrel temperature, lower screw speed and back pressure Bubbles – small bubbles formed by gas entering the injection molded partSimple solution: adequately pre-dry resin, reduce injection speed and increase injection pressure, increase back pressure…
Bonding line – the line produced by the injection molded part at the bonding part of the melt flowSimple solution: increase material temperature, improve mold exhaust, select resin with good fluidity, Case Study
The phenomenon of sunken surface appears in the thick part of wall of molded piece, usually in the stiffener, counterbore or internal grids.
Simple solution: improve packing and back pressure, reduce temperature of feed cylinder and extend the cooling time.
Also known as the material flowers and spray, referring to silver stripes on the surface of plastic parts.
Simple solution: fully dry raw materials, reduce temperature of feed cylinder and nozzle and improve the exhausting of the mold.
The phenomenon that injection molded parts are not fully filled (incomplete structure), generally emerged in surrounding part, tendon and buckle place of the plastic parts.
Simple solution: increase the gate size, injection speed, injection pressure, resin temperature and mold temperature.
Surplus superfusion in the surrounding part, stiffener place and buckle place of injection molded parts.
Simple solution: improve the mold-clamping force; reduce the resin temperature, the filling speed, injection pressure and packing.
Part scorch ( negrescence and yellowing) caused by poor exhausting of mold of injection molded parts (gas trapped).
Simple solution: install exhaust port devices and reduce the injection speed.
Flow traces of melting plastics on the surface of injection molded parts.
Simple solution: increase resin temperature, reduce the injection speed, and improve mold temperature.
Black spots or stripes, or brown stripes on the surface of injection molded parts.
Simple solution: clean up principal axis feed cylinder, reduce temperature of feed cylinder, and reduce turning speed and back pressure of the screw.
Small bubbles formed by gas entering into the injection molded parts.
Simple solution: fully pre-dry resin, reduce the injection speed and increase injection pressure and back pressure.
Lines appeared in the combining place where melting plastics of injection molded parts.
Simple solution: increase the resin temperature, improve mold exhausting and select to use resin with good mobility
Case Study – Wuxi Glory plastics Case Study of Wuxi Glory Plastic Co. Ltd, a leading manufacturer of plastic processing machinery and tools, based in China has been profiled here along with a link to some relevant information. It also gives you a brief overview of the company along with providing the contact details.
Wuxi Glory Plastics Co., Ltd. is a professional plastic factory located in Wuxi, Jiangsu of China. The company was founded in 2004, and it has now become the leading professional supplier of the injection molding parts, soft-plastic sheet for common household products which manufactured and exported to Europe, America and Southeast Asia etc. Case Study