縮短注射周期的50種經(jīng)典方法（下）

50 ways to cut yourinjection molding cycle time.

縮短注射周期的50種方法（下）

By JosephOgando

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Time ismoney. Opportunities to save some of both are often overlooked. Try out thesetips from experts who spend their time trimming the fat off molding cycles.

時(shí)間就是金錢。其實(shí)節(jié)約時(shí)間與金錢的機(jī)會(huì)無(wú)所不在，但是常常為我們所忽略。請(qǐng)?jiān)囋囈韵掠^點(diǎn)，看看專家們?cè)谧⑸溥^(guò)程中如何節(jié)約時(shí)間的。

Whatmolder doesn't want to reduce cycle times? No, not the kind of shortcuts thatsacrifice part quality. We're talking about cycle-time improvements that feedyour bottom line, not your grinder. "Just about anyone can cut their cycletimes. The real trick is doing so without ruining the part," says DonnSeres, president of Injection Molding Industries, a vendor of mold-cooling systemsin Lake Orion, Mich.

什么樣的成型商不愿意縮短循環(huán)周期？不，并不是以犧牲產(chǎn)品質(zhì)量為代價(jià)去縮短成型周期。我們所說(shuō)的是通過(guò)改進(jìn)，使循環(huán)周期達(dá)到最小，而不是像現(xiàn)在磨洋工的方法。注射工業(yè)公司是一家位于Lake Orion，Mich的銷售模具冷卻系統(tǒng)的公司，該公司總裁Donn Seres說(shuō)：“我們縮短循環(huán)周期，真正的訣竅在于并不需要對(duì)制件有任何的傷害。”

Withthat challenge in mind, take a look at the following collection of time-andcost-saving tips. It was put together with the help of technical-serviceprofessionals and auxiliary-equipment vendors who spend much of their timecoming up with the kind of cycle-time strategies that can help your processfly.

記住這樣一點(diǎn)，然后請(qǐng)看一看下邊這樣一些專家的忠告。這是一些技術(shù)服務(wù)專家和輔助設(shè)備銷售商花費(fèi)大量時(shí)間和精力對(duì)各種不同的成型周期戰(zhàn)略進(jìn)行研究總結(jié)出來(lái)的，我們相信這將有助于您的加工業(yè)突飛猛進(jìn)。

Theirrecommendations are organized by topic areas: the mold, the press, thematerial, and the auxiliaries, among others. When looking for savings, keep inmind this rule of thumb: injection molding cycle times are 5% injection, 80%cooling, and 15% ejection.

這些忠告共分為五部分：模具、注射機(jī)、材料、輔助設(shè)備、其他。在看以下條目之前，請(qǐng)記住這樣一條準(zhǔn)則：注射成型周期是由5%注射、80％冷卻和15%射膠組成的。

TOOLING SOLUTIONS

借助工具

26.Invest in mold-filling and cooling simulations. They can predict the speeds offilling and cooling, among other elements of tool design. "Simulationhelps you evaluate the effects on cycle time of reduced wall thickness,optimized cooling-channel layout, or hot-runner conversion," says JimSpann, marketing manager of software supplier C-Mold in Louisville, Ky. In arecent case, C-Mold customer James Hardie Irrigation of Laguna Niguel, Calif.,used simulation to revise the tool design for an existing medical part. The newdesign helped it shave 15% off the original cycle time, Spann reports.

26. 投資購(gòu)買充?；蚶鋮s模擬軟件，在除可用于設(shè)計(jì)外，還可以用于預(yù)測(cè)充填或冷卻的速度。C-Mold公司市場(chǎng)部經(jīng)Jim Spann說(shuō)：“采用模擬軟件可以幫助你評(píng)估影響循環(huán)周期的諸多因素，如減少壁厚，優(yōu)化冷卻系統(tǒng)布置以及熱流道系統(tǒng)的熱傳遞?！睋?jù)Spann介紹，最近，C－Mold公司的一個(gè)客戶通過(guò)利用模擬軟件修正已開(kāi)發(fā)的一個(gè)醫(yī)用制件，新的設(shè)計(jì)可以幫助客戶節(jié)省15%的循環(huán)周期。

27. Ifyou're using hot runners, think about using dedicated gate cooling, wherecooling channels are built into the gate region. "These systems can besignificantly faster," says Dario Vettor of hot-runner supplierMold-Masters Ltd., Georgetown, Ont.

27. 如果采用熱流道系統(tǒng)，考慮采用專門的澆口冷卻系統(tǒng)，該系統(tǒng)把冷卻槽直接設(shè)在澆口區(qū)域，Mold－Master公司Dario Vettor說(shuō)：“這種系統(tǒng)的效率相當(dāng)高。”

28. Onhigh-cavitation tools, don't run gate cooling in a series-type circuit or thegates at the end of the circuit will run hotter than the gates at thebeginning. Such a temperature differential could lengthen your cycles by 1-2%.

28. 對(duì)于型腔較深的模具，不要把冷卻流道設(shè)計(jì)成環(huán)形，否則末端的水溫將遠(yuǎn)高于始端的溫度。這種溫差會(huì)使循環(huán)周期加長(zhǎng)1-2%。

29. Usehot-runner valve gates whenever possible. This gating style cuts cycle timesbecause the machine can start to plasticate once the gate is mechanically shut,explains Vettor.

29. 盡可能使用熱流道鎖止閥。采用這種系統(tǒng)可以節(jié)約循環(huán)時(shí)間。因?yàn)橐坏┳⑸錆部诒粰C(jī)械關(guān)閉，機(jī)器就可以開(kāi)始下一個(gè)周期的塑化。

30.Avoid common gating mistakes. Gates that are too small make it harder to fillthe cavities and add excess shear heat to the melt. That, in turn, retardscooling and can degrade the plastic.

30. 避免常見(jiàn)的澆口錯(cuò)誤。澆口太小會(huì)造成型腔充滿困難并對(duì)熔體過(guò)渡剪切造成溫升。從而導(dǎo)致冷卻時(shí)間延長(zhǎng)或塑料老化。

31.Avoid mold designs that leave a large "slug" of material betweensubgates and short ejector pins. "That slug may be twice the thickness ofthe part wall and it takes time to cool," says Seres of this common gatingerror. Shorter cycles will result if you bring the ejector all the way to thepart. "Create a wall section closer to the ejector pin," he advises.

31. 避免模具設(shè)計(jì)缺陷造成的物料“死角”，如分流道之間或頂桿過(guò)短造成的物料死區(qū)。這種死區(qū)的厚度可能達(dá)到制件厚度的2倍，而這樣的厚度需要更多的冷卻時(shí)間。Seres針對(duì)這種問(wèn)題，提出了這樣的建議：使一個(gè)壁面接近頂桿的位置，從而可以縮短循環(huán)周期。

32.Using multiple gates to fill a cavity can reduce the overall cyclesubstantially, says Hanna's Morine.

32. Hanna公司Morine：對(duì)一個(gè)型腔采用多澆口可以充分減少循環(huán)周期。

33. Whenusing multiple gates to fill a long part, try sequential valve gating (or"cascade" molding) for further cycle-time reductions (see PT, May'95. p. 17).

33. 當(dāng)采用多澆口充填長(zhǎng)制件時(shí)，可試用連續(xù)閥澆口（或“噴射”成型）可以進(jìn)一步縮短循環(huán)周期。

34. Addsome gas to core out thick sections. Gas-assist molding isn't just for weightreduction or stiffness enhancement - it can be used solely as a way to cutcycle time by eliminating a slow-cooling thick section of a part. One appliancemolder recently retooled an existing part for gas-assist solely to boostproductivity, according to C-Mold's Spann. The part cycled 30% faster (PT,March '95, p. 49).

34. 采用氣輔成型。采用氣輔成型不僅可以減輕制件的重量或增強(qiáng)剛度，由于減少了冷卻緩慢的厚壁區(qū)，因而可以專門用于縮短注射周期。據(jù)Spann介紹，其一個(gè)客戶C－Mold進(jìn)行提高產(chǎn)品生產(chǎn)效率可能性的試驗(yàn)，制件的循環(huán)周期可以縮短30%。

MATERIAL MATTERS

材料相關(guān)

35. Molders of nylonand polyester should not short-change themselves with improper drying. It'scommon to compensate for incomplete drying with longer cycle times, says RichLair of Hoechst Technical Polymers. But it's cheaper and better in the long runto do the drying job right in the first place.

35. 成型尼龍和聚酯時(shí)，如果干燥不佳并不能實(shí)現(xiàn)節(jié)約時(shí)間的目的。人們通常采用延長(zhǎng)循環(huán)周期以補(bǔ)償干燥不足的問(wèn)題。實(shí)際上，在第一次干燥時(shí)保證干燥效果更好也更經(jīng)濟(jì)。

36.Perform regular dryer maintenance. Refresh your desiccant beds. "Justbecause the dryer is blowing hot air doesn't mean that it's doing its job. Thedewpoint could be all wrong," says Hanna's Morine. The same goes forchanging dryer filters. "If you get fines and dust into the desiccant bedyou can destroy its performance," says Dave Cosner, v.p. of UniversalDynamics Inc. in Woodbridge, Va.

36. 按規(guī)定對(duì)干燥器進(jìn)行維護(hù)，并再生干燥層。Hanna公司Morine說(shuō)：“干燥器吹出的是熱風(fēng)，并不意味著它在正常工作。露點(diǎn)可能是完全錯(cuò)誤的。”同樣需要對(duì)干燥器的過(guò)濾器進(jìn)行定時(shí)更換或清理。Universal Dynamics公司Dave Cosner說(shuō)：“如果有粉塵進(jìn)入干燥層就會(huì)破壞干燥劑的性能?！?/span>

37.Consistent materials save cycle time, resin suppliers agree. You should haveuniform, consistent melt flow throughout the entire lot in order to eliminatetime-wasting process adjustments, says Gene Sokolowski, senior processingspecialist at Bayer Corp.'s Polymer Div., Pittsburgh.

37. 樹(shù)脂供應(yīng)商認(rèn)為，采用單一材料可以節(jié)約注射周期。拜爾聚合物分公司高級(jí)加工專家Gene Sokolowski說(shuō)，單一材料加工時(shí)可以保證在整個(gè)流程中實(shí)現(xiàn)熔體穩(wěn)定、均勻的流動(dòng)，從而減少加工工藝調(diào)整造成的時(shí)間浪費(fèi)。

38. Ifpossible, switch to a higher-flow resin. "Better flow lets you cyclefaster because you can run at a lower temperature and reach your 'eject'temperature faster," says GE's Souder.

38. 如果可能，選用流動(dòng)性好的樹(shù)脂。GE公司 Souder說(shuō)：“由于流動(dòng)性好的樹(shù)脂可以實(shí)現(xiàn)較低溫度下的較快注射，因而可以有效縮短注射周期。”

39. Anendothermic blowing agent can cut cycle times - even in unfoamed parts. Thepressurized CO2 gas dissolves in the melt and acts as a viscosity reducer,permitting longer flow lengths and lower melt temperatures, says Michael Reedy,president of Reedy International in Keyport, N.J. As the part shrinks, the gasalso absorbs heat, cooling the part from the inside. Some of Reedy's moldingcustomers use endothermic blowing agents to cut cooling times by as much as5-10% (PT, March '97, p. 13).

39. 采用氣輔注射吸熱可以縮短注射周期，甚至對(duì)非發(fā)泡制件也是如此。把壓縮CO2氣體熔入熔體，可以起到降低粘度的作用，實(shí)現(xiàn)在較低溫度下的較長(zhǎng)流路。當(dāng)制件收縮時(shí)，氣體繼續(xù)吸熱，從制件的內(nèi)部進(jìn)行冷卻。Reed公司的一些客戶使用氣輔系統(tǒng)可以使冷卻時(shí)間縮短5-10%。

ROBOTICS LEND A HAND

采用機(jī)器人技術(shù)

40.Conversion from semi-automatic to fully automatic production can pay off in bigtime savings. According to a study by Yushin America, Inc., Cranston, R.I.,robot users' cycle-time reductions range from at least 15% to more than 50%,with a 30% reduction being typical. Human workers' "coffee breaks, nosescratchings, and bathroom runs" can really add up, says Yushin presidentJohn Mallon.

40. 從半自動(dòng)過(guò)渡到全自動(dòng)生產(chǎn)可以節(jié)約許多時(shí)間。根據(jù)Yushin 美國(guó)公司的研究，使用機(jī)器人技術(shù)可以使循環(huán)周期縮短15%－50%，最典型的是縮短30%。人工操作時(shí)如“工間咖啡、前端劃傷、洗浴”等時(shí)間浪費(fèi)再也不復(fù)存在。

41.Robots shorten cooling time. Many thin-wall parts and others that damage easilywhen hot have extra cooling time built into the cycle. Mallon estimates that2-3 sec can be picked up whenever a robot can ensure safe handling of hot,fragile parts.

41. 采用機(jī)械手可以縮短冷卻時(shí)間。許多薄壁制件或易碎制件通常需要增加冷卻時(shí)間以保證制品質(zhì)量。而采用機(jī)器人在保證安全取出熱的易碎制件時(shí)可以節(jié)約2-3秒的時(shí)間。

42.Eliminate double or triple ejector strokes with a sprue picker. You could savebetween 0.5 and 1 sec.

42. 采用澆口取出裝置可以減少兩或三次的頂出操作，可以節(jié)約0.5-1s的時(shí)間。

43. Ifmanual secondary operations are holding up your press cycles, a robot can help.Mallon has seen 515% shorter cycle times result when molders stop holding backtheir presses to pace a single operator that is performing post-moldoperations.

43. 如果由于手動(dòng)二次操作影響到你的成型周期，機(jī)械手就可以幫助你。與熟練工人操作相比，一般可以節(jié)約5-15%的循環(huán)時(shí)間。

44.Robots can beat free-drop ejection. Some of the latest high-speed side-entryrobots and specialized parts-handling devices like Husky's swing chutes can nowbeat part-drop systems. It may be a small advantage - about 0.2 sec, saysMallon - but it could be meaningful when considered along with automation'sother benefits.

44. 機(jī)械手甚至可以打敗自由頂落制件裝置。最新的高速側(cè)取式機(jī)械手已經(jīng)可以擊敗自由頂落裝置。它節(jié)約的時(shí)間并不多，大約0.2s，但是在自動(dòng)化技術(shù)的實(shí)現(xiàn)上，它意味著其他方面的一些優(yōu)勢(shì)。

SPEED BY DESIGN

45.Eliminate heavy sections from parts. Instead, use ribs or core out excessmaterial, says Bayer's Sokolowski. Don't overdesign your fibs, either. Thereare well-known design tricks for keeping them lean but strong (seeillustration, p. 40).

45. 消除制件較笨重的一些區(qū)域，而代之以筋板等結(jié)構(gòu)。同時(shí)也不要做過(guò)渡的設(shè)計(jì)。有一些典型的設(shè)計(jì)方法可以有助于我們?cè)O(shè)計(jì)精巧而結(jié)實(shí)的結(jié)構(gòu)。

46. Thinout those walls. Thin-wall molding may have its own set of challenges, butreducing wall thickness can have a huge effect on cycle time. GE Plasticsresearchers report that cycle times in thin-wall molding may be only one-thirdof those for comparable conventional parts. GE estimates that a 3-mm-thick partwith a cycle of 40 sec can be trimmed to under 20 sec at a 1-mm wall thickness.

46. 采用薄壁。薄壁成型有其相應(yīng)的一些問(wèn)題，但是薄壁制品確實(shí)能夠有效縮短注射周期。GE公司的研究表明，采用薄壁制件與通常的制件相比，所需要的成型周期只有原來(lái)的三分之一。GE公司估計(jì)，如果一個(gè)壁厚3mm的制件成型周期需要40s，如果采用1mm的壁厚，則成型周期會(huì)低于20s。

47.Don't skimp on draft angles. "I'm always amazed at how many tools don'thave enough draft," says Hanna's Morine. A good rule of thumb, accordingto Rich Lair at Hoechst, is to use at least 0.5 [degrees] per side of the part,though 1.5 to 3 [degrees] is preferable. "Parallel draft" can oftenavoid any thickening of the wall sections.

47. 不要吝嗇使用角度。Rich Lair認(rèn)為，至少要在制件的每一側(cè)設(shè)計(jì)0.5°的斜度，最好是不低于1.5-3°“平行設(shè)計(jì)”通?？梢员苊馊我獗诿嫖恢玫暮穸仍黾?。

AND DON'T FORGET...
48. Even the simplest maintenance lapses can affect cycle time. Hanna'sMorine has seen numerous cases of haywire thermocouples causing excessiveheating and, ultimately, longer cycles. "The simplest maintenance issueswill affect your cycle," he warns. "Just making sure everything onthe machine and the auxiliaries works and is properly maintained will savecycle time."

48. 甚至最簡(jiǎn)單的維護(hù)延誤都會(huì)影響注射周期，Hanna公司Morine曾經(jīng)看到過(guò)大量由于熱電偶導(dǎo)致的過(guò)熱現(xiàn)象，并且最終導(dǎo)致成型周期延長(zhǎng)。他警告說(shuō)：“即使最簡(jiǎn)單的維護(hù)也可能影響您的成型周期，保證機(jī)器和附件的任何部分都工作正常就能夠縮短注射周期。”

49.Maintain tight process control. "Process instability leads to longercycles," notes Van Dorn Demag's Schaffer. It takes time to overcomefluctuations in any process variable.

49. 密切注意加工控制系統(tǒng)的維護(hù)。Van Dorn Demarg公司Schaffer提醒說(shuō)：“加工過(guò)程的不穩(wěn)定會(huì)導(dǎo)致循環(huán)周期加長(zhǎng)?！奔庸み^(guò)程的任何變化都需要時(shí)間去解決系統(tǒng)波動(dòng)。

50. Lookfor new technologies. GE's Souder sees promise in research on"conformal" cooling channels that shadow the contours of the part.Other R&D at GE and elsewhere focuses on understanding little-knowncontributors to wasted cycle-time - such as heat-transfer problems caused bythe air gap between tool and part as the plastic cools and shrinks. So justwait, the fastest cycles are yet to come.

50. 關(guān)注新技術(shù)。GE公司Souder展示了其隨制件等高線設(shè)置等角度冷卻槽的研究。GE公司的其他研發(fā)部門，還有別的公司對(duì)一些影響注塑周期的知之甚少的因素，如當(dāng)塑料冷卻收縮時(shí)型腔與制件之間的氣隙導(dǎo)致的熱傳遞問(wèn)題?？梢?jiàn)，您只需要耐心的等待，最迅捷的注射成型時(shí)代就要到來(lái)了。

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