3. 4. 5.
6.
7.
厚薄件一體成型，減少模具和裝配線數目 Integration of thick and thin parts, less moulds and assembly lines needed
可用較厚的肋、角板等補強件，提高製件剛性，使得製件公稱厚度得以打薄 Use of thicker stiffeners (e.g. ribs, gussets, etc.) which increases part stiffness and makes thinner nominal thickness possible 增加設計自由度 More design flexibility
型腔部份短射 Partial Shot in Cavity
氣輔注射成型 Gas-assisted Injection Moulding
模壁 Mould Wall
塑膠凝結層 Frozen Layer of Polymer
氣體 Gas
熔膠 Polymer Melt
模壁 Mould Wall 氣體穿透熔膠的斷面圖 Cross-section of gas penetration through molten plastic
氣道設計原則 Design Principles for Gas Channel Size
• Large Channels – Short Gas Penetration – Increase Cycle Time – “Racetrack” Effect • Small Channels – Fingering Into Thin Walls – Uncontrolled Gas Penetration • Properly Sized Channels – Promote Gas Into All Desired Areas With Minimal Thin Wall Penetration – Typically 2-4 Times the Wall Thickness
短射法氣輔注射成型設計指南 Short Shot Gas-Assisted Injection Moulding Design Guide
從氣口(上游)到上述非外觀面(下游)順流而下，勻稱 的配置氣道以涵蓋整個製品面。 From (upstream) gas entrance to above-mentioned (downstream) non-appearance surface, layout gas channels to cover the whole part surface evenly.
Gas entrance
1.0000
0.7547
Байду номын сангаас
0.5095
0.2642
0.0190
Gas seeks low pressure areas
Gas penetration for TV Bezel (1/2 model)
熔膠前沿推進 - 原始設計 Melt-front Advancement, Original Design
初始氣體穿透 Initial Gas Penetration
傳統和氣輔注射成型的壓力分布
傳統注射成型 Conventional Injection Moulding
氣輔注射成型
Gas-assisted Injection Moulding
氣輔注射成型的優點 Merits of Gas-assisted Moulding
1. 2. 低射壓、低鎖模力 Low injection pressure, low clamp force 壓力分布均勻、收縮均勻、殘餘應力低、不易翹曲、尺寸穩定 Even pressure distribution, even shrinkage, lower residual stress, less warpage, more stable dimensions 消除縮痕、模面再現性高 Elimination of sink marks, better plastic mould surface replication 省塑料，可用強度和價格較低的塑料 Plastic material saving, replacement of stronger & more expensive plastic material 可用強度和價格較低的模具金屬(如鋁) Use of less strong and less expensive mould metal (e.g. aluminum)
微調澆口、氣口和氣道位置和尺寸，確保氣貫氣道 ， 但不以鄰為壑。 Fine tune the location and dimensions of gates, gas entrances and gas channels to make sure gas will penetrate to the end, but not permeate to the neighborhood, of the gas channel.
氣輔注塑成型技術 Gas-assisted Injection Moulding Technology
短射工藝 Short Shot Process
熔膠注射 Polymer Injection
氣體：大多採用氮氣 Gas : Use Nitrogen, Mostly 氣體注射 Gas Injection 主要氣體穿透 Primary Gas Penetration 氣體注射 Gas Injection 二次氣體穿透 Secondary Gas Penetration
Gas Penetration
整合薄壁及厚壁的設計
避免閉路式氣道 Avoid Closed Loop Gas Channels
Solid plastic
避免氣道相鄰太近 Avoid Spacing Gas Channels Too Close Together
• 氣道相鄰過近 氣體會滲透到 薄壁中 Gas will “finger” into thin wall areas if gas channels are too close together.
氣輔設計原則 Design Principles for Gas -asist Mould Design
• 製品公稱厚度以不小於2mm為原則。 但有薄到 0.75mm厚度的氣輔塑件被開發出來。 • 氣體進口(Gas Entrance)和澆口(Gate)距離若大於 25mm，Shut-off valve就不一定要裝。 • 溢流井的體積 = 流道去掉2~3mm塑膠皮層之斷面積 x 流道長度 2004. 4. 11. 徐昌煜摘錄自”氣體輔助射出成型手冊 “ (塑膠世界雜誌社譯自日文書刊) -
選定一非外觀面作為最後充填區 Select one non-appearance surface as the last filled area.
距離非外觀面最遠處定氣口位置。
Locate gas entrance where is the farthest from a non-appearance surface.
短射法氣輔注射成型設計指南 Short Shot Gas-Assisted Injection Moulding Design Guide
氣道儘可能循二或多面交會處或粗厚處行，主氣 道以一氣(口)呵成(一氣道)為原則 。
Gas channel shall follow a line where two or more surfaces meet or where is thick. Each main gas channel, in principle, shall be penetrated by the gas from a specific gas entrance.
8.
氣體進口位置 Gas Entrance Locations
• 經噴嘴 Through the Nozzle • 經流道 Through the Runner
• 直接進製品 Directly in the Part
典型問題 Typical Problems
• • • • • 跑道現象 Race tracking effect 氣體穿透不佳 Poor gas penetration 氣體手指現象 Gas fingering 氣體吹穿 Gas blow out 製品表觀 Part surface appearance
Courtesy Power Line mould Engineering, Ltd.
Gas entrance
“Gas fingering”
30.00
22.50
15.00
7.50
0.00
Low pressure area
Pressure prior to gas transition for TV Bezel (1/2 model)
氣道設計原則 Design Principles for Gas Channel Size
• • • • • 氣道斷面任何尺寸不可大於30mm 氣道斷面大小尺寸比應小於2 氣道寬度一般是高度的0.5到1.5倍 氣道轉角內圓角半徑以大於6mm為原則 實驗表明：經穿透後的氣道壁厚度大約是直徑的1/3
2004. 4. 11. 徐昌煜摘錄自”氣體輔助射出成型手冊 “ (塑膠世界雜誌社譯自日文書刊) -
滿射工藝 Full Shot Process
熔膠注射 Polymer Injection 氣體：大多採用氮氣 Gas : Use Nitrogen, Mostly
氣體注射 Gas Injection 型腔滿射 “Full” Shot in Cavity 氣體注射 Gas Injection 最終氣體穿透 Final Gas Penetration
跑道現象 Race Tracking Effect