缩短注射周期的50种经典方法（下）

50 ways to cut yourinjection molding cycle time.

缩短注射周期的50种方法（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.

时间就是金钱。其实节约时间与金钱的机会无所不在，但是常常为我们所忽略。请试试以下观点，看看专家们在注射过程中如何节约时间的。

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.

什么样的成型商不愿意缩短循环周期？不，并不是以牺牲产品质量为代价去缩短成型周期。我们所说的是通过改进，使循环周期达到最小，而不是像现在磨洋工的方法。注射工业公司是一家位于Lake Orion，Mich的销售模具冷却系统的公司，该公司总裁Donn Seres说：“我们缩短循环周期，真正的诀窍在于并不需要对制件有任何的伤害。”

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.

记住这样一点，然后请看一看下边这样一些专家的忠告。这是一些技术服务专家和辅助设备销售商花费大量时间和精力对各种不同的成型周期战略进行研究总结出来的，我们相信这将有助于您的加工业突飞猛进。

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.

这些忠告共分为五部分：模具、注射机、材料、辅助设备、其他。在看以下条目之前，请记住这样一条准则：注射成型周期是由5%注射、80％冷却和15%射胶组成的。

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. 投资购买充模或冷却模拟软件，在除可用于设计外，还可以用于预测充填或冷却的速度。C-Mold公司市场部经Jim Spann说：“采用模拟软件可以帮助你评估影响循环周期的诸多因素，如减少壁厚，优化冷却系统布置以及热流道系统的热传递。”据Spann介绍，最近，C－Mold公司的一个客户通过利用模拟软件修正已开发的一个医用制件，新的设计可以帮助客户节省15%的循环周期。

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. 如果采用热流道系统，考虑采用专门的浇口冷却系统，该系统把冷却槽直接设在浇口区域，Mold－Master公司Dario Vettor说：“这种系统的效率相当高。”

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. 对于型腔较深的模具，不要把冷却流道设计成环形，否则末端的水温将远高于始端的温度。这种温差会使循环周期加长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. 尽可能使用热流道锁止阀。采用这种系统可以节约循环时间。因为一旦注射浇口被机械关闭，机器就可以开始下一个周期的塑化。

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. 避免常见的浇口错误。浇口太小会造成型腔充满困难并对熔体过渡剪切造成温升。从而导致冷却时间延长或塑料老化。

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. 避免模具设计缺陷造成的物料“死角”，如分流道之间或顶杆过短造成的物料死区。这种死区的厚度可能达到制件厚度的2倍，而这样的厚度需要更多的冷却时间。Seres针对这种问题，提出了这样的建议：使一个壁面接近顶杆的位置，从而可以缩短循环周期。

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

32. Hanna公司Morine：对一个型腔采用多浇口可以充分减少循环周期。

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. 当采用多浇口充填长制件时，可试用连续阀浇口（或“喷射”成型）可以进一步缩短循环周期。

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. 采用气辅成型。采用气辅成型不仅可以减轻制件的重量或增强刚度，由于减少了冷却缓慢的厚壁区，因而可以专门用于缩短注射周期。据Spann介绍，其一个客户C－Mold进行提高产品生产效率可能性的试验，制件的循环周期可以缩短30%。

MATERIAL MATTERS

材料相关

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. 成型尼龙和聚酯时，如果干燥不佳并不能实现节约时间的目的。人们通常采用延长循环周期以补偿干燥不足的问题。实际上，在第一次干燥时保证干燥效果更好也更经济。

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. 按规定对干燥器进行维护，并再生干燥层。Hanna公司Morine说：“干燥器吹出的是热风，并不意味着它在正常工作。露点可能是完全错误的。”同样需要对干燥器的过滤器进行定时更换或清理。Universal Dynamics公司Dave Cosner说：“如果有粉尘进入干燥层就会破坏干燥剂的性能。”

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. 树脂供应商认为，采用单一材料可以节约注射周期。拜尔聚合物分公司高级加工专家Gene Sokolowski说，单一材料加工时可以保证在整个流程中实现熔体稳定、均匀的流动，从而减少加工工艺调整造成的时间浪费。

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，选用流动性好的树脂。GE公司 Souder说：“由于流动性好的树脂可以实现较低温度下的较快注射，因而可以有效缩短注射周期。”

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. 采用气辅注射吸热可以缩短注射周期，甚至对非发泡制件也是如此。把压缩CO2气体熔入熔体，可以起到降低粘度的作用，实现在较低温度下的较长流路。当制件收缩时，气体继续吸热，从制件的内部进行冷却。Reed公司的一些客户使用气辅系统可以使冷却时间缩短5-10%。

ROBOTICS LEND A HAND

采用机器人技术

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. 从半自动过渡到全自动生产可以节约许多时间。根据Yushin 美国公司的研究，使用机器人技术可以使循环周期缩短15%－50%，最典型的是缩短30%。人工操作时如“工间咖啡、前端划伤、洗浴”等时间浪费再也不复存在。

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. 采用机械手可以缩短冷却时间。许多薄壁制件或易碎制件通常需要增加冷却时间以保证制品质量。而采用机器人在保证安全取出热的易碎制件时可以节约2-3秒的时间。

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

42. 采用浇口取出装置可以减少两或三次的顶出操作，可以节约0.5-1s的时间。

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. 如果由于手动二次操作影响到你的成型周期，机械手就可以帮助你。与熟练工人操作相比，一般可以节约5-15%的循环时间。

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. 机械手甚至可以打败自由顶落制件装置。最新的高速侧取式机械手已经可以击败自由顶落装置。它节约的时间并不多，大约0.2s，但是在自动化技术的实现上，它意味着其他方面的一些优势。

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. 消除制件较笨重的一些区域，而代之以筋板等结构。同时也不要做过渡的设计。有一些典型的设计方法可以有助于我们设计精巧而结实的结构。

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。薄壁成型有其相应的一些问题，但是薄壁制品确实能够有效缩短注射周期。GE公司的研究表明，采用薄壁制件与通常的制件相比，所需要的成型周期只有原来的三分之一。GE公司估计，如果一个壁厚3mm的制件成型周期需要40s，如果采用1mm的壁厚，则成型周期会低于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. 不要吝啬使用角度。Rich Lair认为，至少要在制件的每一侧设计0.5°的斜度，最好是不低于1.5-3°“平行设计”通常可以避免任意壁面位置的厚度增加。

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. 甚至最简单的维护延误都会影响注射周期，Hanna公司Morine曾经看到过大量由于热电偶导致的过热现象，并且最终导致成型周期延长。他警告说：“即使最简单的维护也可能影响您的成型周期，保证机器和附件的任何部分都工作正常就能够缩短注射周期。”

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统的维护。Van Dorn Demarg公司Schaffer提醒说：“加工过程的不稳定会导致循环周期加长。”加工过程的任何变化都需要时间去解决系统波动。

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. 关注新技术。GE公司Souder展示了其随制件等高线设置等角度冷却槽的研究。GE公司的其他研发部门，还有别的公司对一些影响注塑周期的知之甚少的因素，如当塑料冷却收缩时型腔与制件之间的气隙导致的热传递问题。可见，您只需要耐心的等待，最迅捷的注射成型时代就要到来了。

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