压铸模温度控制方法

Die Temperature 模具温度
-Too Low 太低 Cold shots冷纹 Short shots填充不饱满 Porosity孔穴 Excessive contraction过度收缩
-Too High 太高
Hot tearing热裂 Warping弯翘 Blisters表面气孔 Porosity孔穴 Flashing飞边 Ejection problems顶出问题
Die temperature starts at ambient 从室温开始加热 Increase to operating temperature 加热至操作温度 Four methods available四种方式 Warm-up shots打料加热 Gas heating气体加热 Oil heating油加热 Electric heating电热
Die Temperature Range模温笵围 Range模温笵围
Optimum适当
Temperature温度 Temperature温度
Upper Limit 上限 Lower Limit 下限
Ambient环境
Die模具
Metal金属
Die Pre Heating模具预热 Heating模具预热
Die Temperature Control Options for Die Casting 压铸模温度控制方法
G. L. Wilson
Die Casting Seminar, Shenzhen, 2004
Die Temperature模具温度 Temperature模具温度
Significant process variable 重要的工艺参数 Effects casting quality 影响铸件质量 Effects production rate 影响生产效率 Effects casting cost 影响铸件成本
Die Pre Heating 模具预热
Electric Heating电热 电热 Advantages好处 好处 Heats from inside the die从模内加热 Efficient heating效率高 Can pre-heat out of machine Disadvantages缺点 缺点 Needs to be added to each die 需要每套模具安装
Die Cooling 模具冷却
Spray Cooling 喷涂冷却 Water and die release agents are sprayed on to the die parting face水和脱模剂喷涂於模具分模面上 Can remove heat significant quantities of heat 可带走大量热量 Difficult to control 难於控制 Can cause porosity and increased heat checking 会引致气孔和增加热裂
Die Cooling 模具冷却
Natural Cooling 自然冷却 Occurs in all Die Casting dies 发生在所有金属模 Significant in Low Pressure and Gravity Die Casting 对低压及重力铸造模很重要 For high pressure Die Casting it accounts for between 5% and 10% of Die Cooling power 占压铸模5-10%冷却功率
Die Cooling 模具冷却
Air Cooling 空气冷却 Air is passed through cooling channels or around die surfaces 空气流过冷却管道或模具表面 Useful in Low Pressure Die Casting 特别适用於低压铸造 Can be used in long cores which are difficult to cool with water可用在难於水冷的长模芯 Low power cooling 冷却功率低
Thermocouples Embedded in the Die 热电偶藏於模内
1. 3.2.来自4.K-type Thermocouples热电偶 Thermocouples热电偶
Good temperature range合 适的温度笵围 Resistance to corrosion抗 腐蚀 Low cost成本低 Readily available容易购买 Small diameter细小口径 Can be bent into position可 弯曲藏入 Easily fitted into wiring channels易於切入管道
Die Pre Heating 模具预热
Gas Heating气体加热 Advantages好处 好处 Low energy cost低能源成本 Disadvantages缺点 缺点 Heats from the outside of die外部加热 Hard to automate难於自动化 Labour intensive人手操作 Higher chance of damaging dies容易损害 模具
Manual Temperature Control人手温度控制 Control人手温度控制
Measuring Die Temperature测量模温 Temperature测量模温
Hand Held Thermocouple 手提电热偶 Hand Held Infra-red 手提红外线测温
Not suitable for continuous production不适合连续生产 Wide fluctuations likely数据波动大
Die Pre Heating 模具预热
Electric Heating Plates and Elements 电热板及元件
Die Cooling模具冷却 Cooling模具冷却
Removal of process heat during production 带走生产过程中产生的热量 Heat removal must be balanced to heat input 带走的热量要和产生的热量平衡 5 methods of die cooling五种冷却方式 : 五种冷却方式 Natural cooling自然冷却 Air cooling空气冷却 Oil cooling油冷却 Water cooling 水冷却 Spray cooling喷涂冷却
Die Pre Heating 模具预热
Oil Heating油加热 Advantages好处 好处 Heats from inside the die从模内加热 Heats the cavity inserts directly直接加热模芯 Can pre-heat out of machine Disadvantages缺点 缺点 Capital investment设备投资 Possible oil leaks有机会漏油
Die Cooling 模具冷却
Oil Cooling 油冷却 Oil is passed through channels in the cavity inserts 油流过模具的管道 High temperature oils are now available 高温导热油 Lower heat capacity and transfer coefficient than water热容量和传热系数比水小 Channels must be larger in diameter and length 管道口径和长度要大些 Medium power cooling 冷却功率中等
Continuous Measurement of Die Temperature 模温连续性测量
Opens a window inside the die 可透视模内情况 Provides operator visibility 让操作人员了解 Identify operating range 判定操作笵围 Set control limits 设定控制上下限 Identify inadequate cooling 判定不适当冷却 Identify over-cooling 判定过度冷却
Die Cooling 模具冷却
Water Cooling 水冷却 Water is passed through channels in the cavity inserts 水流过模具的管道 Highest heat capacity and transfer coefficient 高热容量和传热系数 Channels can be smaller in diameter and length 管道口径和长度要小点 Useful in cores, moving slides and thick castings 适用於模芯/滑块/厚壁铸件 High power cooling 冷却功率高
Die Pre Heating 模具预热
Warm-up shots 打料加热 Advantages好处 好处 No equipment needed无须任何设备 Disadvantages缺点 缺点 Makes defect castings制造废品 High thermal shock to die surface模具表面 受热冲击 Re-melting required需要翻熔废品 Higher chance of shipping a defect有机会 混入正品
Thermocouple Connections 热电偶接头
Metal casing 金属外壳 Metal cover with spring hinge 弹簧铰金属盖 Excludes dust, oil, flash 防尘,油,金属飞溅 No moving wires 无可移动线 Ensures reliability 保证可靠性