Document Owner: Lawrence Chung
leukemiaMaintained by: HK PDM
REVISION | DESCRIPTION OF CHANGE | CHANGE NO. | DATE RELEASED |
1 | Initial Relea | 26222 | May 2006 (See Agile) |
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APPROVALS OBTAINED IN AGILE |
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Injection Molding Guideline
1. Plastic Material
a.Assume the general purpo grade plastic materials to be ud for our moldingesl下载
b.In ca of special grade materials, plea list the material grade & brand on our tool plan
c.All the plastic materials for molding must be same as the materials during development stage.
d.In ca of material shortage or cost issue, the new sourced material shall be tested and confirmed acceptable prior u.
2. Colorant
a.All the colorant must be conformed to heavy elements directives for both ASTM F963 & EN71.
b.Most of the dry pigments are hygroscopic; they must be properly aled after u.
c.For the components with high color consistence, the masterbatches or pre-color plastic materials are required.
勺子英语3. Regrind Material Ratio
a.For plastic material on structural components, no regrind is allowed
b.For general purpo material on non structural components, 20% maximum runner regrind can be blended with virgin material.
c.For tho translucent or true white color components, no regrind is allowed.
d.For short glass filled materials, 15% maximum regrind can be blended with virgin material
e.For long glass filled materials, no regrind is allowed.
f.The maximum number of regrind pass for general purpo materials shall be 3.
g.Only 1 time of regrind pass is allowed for short glass reinforced materials
h.The regrind ratio shall be shown in our updated tool plan to follow.
i.The regrind ratio and no. of regrind pass has to be validated and confirmed during development stage. If not, no regrind will be allowed.
j. Burned or discolored sprues or parts must not be ud as regrind.
k.Hot nozzle & hot runner is our preference to eliminate runner scrap.
4. Material Drying
a.Most plastic resins require thorough drying prior injection molding to assure maximum properties in the molded parts. Below table plea find the recommended drying temperature & duration for reference:
b.For tho hygroscopic materials, the dehumidifying hopper dryer with clod-loop air circulating system is required to ensure acceptable moisture content to be achieved during molding.
c.For tho non-hygroscopic materials, the regrind have to be dried as 80ºC for 2 hours to prevent surface blemishes due to volatiles, such as PE, PP, POM, HIPS.
Material | Drying Temperature | Time required (Hour) | Dehumidifying Dryer required |
ABS / C-ABS | 80ºC wipilot是什么 | 2 | No |
Nylon 6 / PPO / PC+ABS | 100ºC | 2 | No |
Nylon 66 | 千玺出席青年论坛120ºC | spicy2 | No |
PU | 110ºC | 2 – 3 | Yes |
PC | 120ºC | 2 - 3 | No |
PET | 120ºC | 2 - 3 | Yes |
Regrind blench for PE / PP / HIPS / POM | 80ºC | 2 | No |
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5. Screw Design
a.For most of un-filled plastic, standard screw with L / D ratio 22:1 is recommended
b.For glass reinforced plastic, screw with lower L / D ratio 20:1 is recommended英译汉
c.Bi-metallic screw and barrel are required for glass reinforced plastic to have higher wear assistance
6. Molding Machine & Accessories Selection
a.The distance between two columns (Horizontal) shall be 10mm minimum longer than the mold width
b.For non engineering or unfilled plastic resin, up to 90% rated barrel capacity shall be utilized.
c.For engineering and all glass filled plastic resin, up to 70% rated barrel capacity shall be utilized.
d.For clamping tonnage consideration, the multiple of projectile area and fill pressure should be up to 90% of rated clamping tonnage of machine. However, the actual requirement will be depended upon the wall thickness, parts geometry and gate design. Below table plea the fill pressure factor for common u plastic for reference.
Plastic Materials | Fill Pressure (Ton/Sq Inch) |
PE / PP / EVA | 1.8 |
HIPS / ABS / C-ABS | 2 |
TPU / PC / PC+ABS | 4 |
Glass Filled Plastic | 5 and Up |
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技巧英文e.The minimum tonnage for mold size shall be put to Machine Size column on Tool Plan
f.For high precision parts & optical lens, electric molding machine is preferred.
g.Automatic parts / sprue removal system should be installed for 220 ton or above molding machines
h.Hopper loader should be installed for 220 tons or above machines
工藤新一日语i.Proportional type hopper loader should be ud for the molding with instant runner scrap recycling.
j.Hopper magnet shall be equipped for all material hoppers.
7. Mold Clamping
uqga.For machine capacity up to130 tons, all molds can be clamped onto machine platens by either clamping slots or mounting holes.
b.For machine capacity more than130 tons, all molds can only be clamped onto machine platens by clamping slots.
