【正文】 appearance, low cost Chair seats, housings, covers, and containers Polyphenylene Oxide PPO Tough, heat resistance, flame resistance, dimensional stability, low water absorption, electroplating capability, high cost Automotive (housings, panels), electrical ponents, housings, plumbing ponents Polyphenylene Sulphide PPS Very high strength, heat resistance, brown, very high cost Bearings, covers, fuel system ponents, guides, switches, and shields Polypropylene PP Lightweight, Automotive heat resistance, high chemical resistance, scratch resistance, natural waxy appearance, tough and stiff, low cost. (bumpers, covers, trim), bottles, caps, crates, handles, housings Polystyrene General purpose GPPS Brittle, transparent, low cost Cosmetics packaging, pens Polystyrene High impact HIPS Impact strength, rigidity, toughness, dimensional stability, naturally translucent, low cost Electronic housings, food containers, toys Polyvinyl Chloride Plasticised PVC Tough, flexible, flame resistance, transparent or opaque, low Electrical insulation, housewares, medical tubing, shoe soles, toys cost Polyvinyl Chloride Rigid UPVC Tough, flexible, flame resistance, transparent or opaque, low cost Outdoor applications (drains, fittings, gutters) Styrene Acrylonitrile SAN Stiff, brittle, chemical resistance, heat resistance, hydrolytically stable, transparent, low cost Housewares, knobs, syringes Thermoplastic Elastomer/Rubber TPE/R Tough, flexible, high cost Bushings, electrical ponents, seals, washers Possible Defects Defect Causes Flash ? Injection pressure too high ? Clamp force too low Warping ? Nonuniform cooling rate Bubbles ? Injection temperature too high ? Too much moisture in material ? Nonuniform cooling rate Unfilled sections ? Insufficient shot volume ? Flow rate of material too low Sink marks ? Injection pressure too low ? Nonuniform cooling rate Ejector marks ? Cooling time too short ? Ejection force too high Many of the above defects are caused by a nonuniform cooling rate. A variation in the cooling rate can be caused by nonuniform wall thickness or nonuniform mold temperature Cost Drivers Material cost The material cost is determined by the weight of material that is required and the unit price of that material. The weight of material is clearly a result of the part volume and material density。 however, the part39。 控制注塑機(jī)的內(nèi)容 注塑機(jī)過程控制系統(tǒng)主要由兩部分組成：一是溫度控制系統(tǒng)，為了權(quán)利桶，熔體和模具的溫度控制 。 另一種比較簡單的方法是采用閉環(huán)比例閥，通過比例閥閥芯自己的閉環(huán)控制的位置，以提高控制精度。 因?yàn)樗梢院苋菀椎乜刂祈椖堪凑詹煌墓δ芤蟮母鱾€部分，如運(yùn)動控制，數(shù)據(jù)采集，報警， PID 調(diào)節(jié)運(yùn)算，通信，控制，即編制的控制程序模塊（任務(wù)），這些模塊不僅獨(dú)立運(yùn)作，彼此之間的數(shù)據(jù)，以保持一定的相互關(guān)聯(lián)的步驟，通過這些模塊后，獨(dú)立開發(fā)和調(diào)試的步驟可以下載到該委員會與 CPU 一起，在調(diào)控和管理多并行運(yùn)行任務(wù)操作系統(tǒng)下，共同實(shí)現(xiàn)項目的控制要求。每種材料都需要一組不同的過程，包括 注塑 溫 度、 注射壓力、 模具溫度、 彈射溫度和 時 間 周期 等 注塑工藝參數(shù)。 這個周期時間可細(xì)分為注射時間，冷卻時間，復(fù)位時間。此外，需要高注射壓力，可能需要更高噸位機(jī)器某些材料。用于創(chuàng)建注塑件的選材不是純粹基于對最后一部分所需的特性。 當(dāng)然，這在控制循環(huán)的CPU 運(yùn)算能 力允許的前提下，根據(jù)用戶的實(shí)際要求，任意更改。 現(xiàn)代更先進(jìn)的注塑機(jī)配備 510多級注射速度和包裝，以及熔膠背壓控制。 政協(xié)集成了一個標(biāo)準(zhǔn)的 PLC 和工業(yè)控制計算機(jī)的功能，多任務(wù)分時操作系統(tǒng)，數(shù)據(jù)計算和處理能力比 PLC 更強(qiáng)大。s application software development also has an integrated C language program capacity, thus providing powerful data puting and processing power. On the hardware structure, PCC is characterized by very significant. In its core puting module inside, PCC for its CPU is equipped with multiple conventional PLC, mass storage unit (100K/16M), this is undoubtedly a powerful system and application software provides a hardwarebased monitoring. PCC on the hardware features, but also reflected in its various signals for industrial site designed many dedicated interface module, such as the highfrequency pulses, incremental encoder, temperature, weighing signal and ultrasonic signal interface module. They will all forms of onsite signal is very convenient to PCC joint into the core of the digital control system, the user may need to use the system39。s maximum wall thickness can also play a role. The weight of material that is required includes the material that fills the channels of the mold. The size of those channels, and hence the amount of material, is largely determined by the thickness of the part. Production cost The production cost is primarily calculated from the hourly rate and the cycle time. The hourly rate is proportional to the size of the injection molding machine being used, so it is important to understand how the part design affects machine selection. Injection molding machines are typically referred to by the tonnage of the clamping force they provide. The required clamping force is determined by the projected area of the part and the pressure with which the material is injected. Therefore, a larger part will require a larger clamping force, and hence a more expensive machine. Also, certain materials that require high injection pressures may require higher tonnage machines. The size of the part must also ply with other machine specifications, such as clamp stroke, platen size, and shot capacity. The cycle time can be broken down into the injection time, cooling time, and resetting time. By reducing any of these times, the production cost will be lowered. The injection time can be decreased by reducing the maximum wall thickness of the part and the part volume. The cooling time is also decreased