注塑模具venting-文庫吧資料
2024-08-14 16:51本頁面
【正文】 l design, plus an exhaust mechanism ? will increase overall cycle time by a few seconds ? needs a gasket surrounding the plete split line ? difficult to do this with some split lines and side actions ? may need seals around ejector pins, moving cores etc ? works best with tools that have hot runner valve gates ? will not stop degraded material giving mould deposit Efficient Venting Page 7 Porous materials of mould construction? ? porous = sintered ? sintered inserts are used for venting, particularly where surface aspect is not critical ? various particle sizes are available to suit different polymers ? material used for insert must have strength, pressures involved in moulding will crush it otherwise ? insert must be sparked on both sides, machining it will close the gaps between the particles ? needs to be low cost and easily replaceable, it will get blocked Efficient Venting Page 8 Priority venting, guiding principles: ? vent land must be as short as possible ? vent land must be as wide as possible ? split line venting must cover at least the last 1/2 of fill, more is better ? relief channels must exit to atmosphere without restriction ? moving cores/ejector pins must be vented ? fixed cores/inserts should also be vented ? known gas trap areas need extra venting. Additional ejector pins solely there for venting should be considered Efficient Venting Page 9 Typical split line relief channel positions: gate Continue to atmosphere Vent land length 2mm for hardened steel 5mm everything else . for endgated oblong Efficient Venting Page 10 Typical split line relief channel positions: . for centre gated disc Continue to atmosphere, 2 or more places Vent land length 2mm for hardened steel 5mm everything else Efficient Venting Page 11 Typical spl
環(huán)評(píng)公示相關(guān)推薦
鄂ICP備17016276號(hào)-1