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压铸生产中常遇模具存在的问题注意点Die casting production often

2016-01-15 14:04:29 点击:
1. 浇注系统、排溢系统
例(1)对于冷室卧式压铸机上模具直浇道的要求:  ① 压室内径尺寸应根据所需的比压与压室充满度来选定,同时,浇口套的内径偏差应比压室内径的偏差适当放大几丝,从而可避免因浇口套与压室内径不同轴而造成冲头卡死或磨损严重的问题,且浇口套的壁厚不能太薄。浇口套的长度一般应小于压射冲头的送出引程,以便涂料从压室中脱出。  ② 压室与浇口套的内孔,在热处理后应精磨,再沿轴线方向进行研磨,其表面粗糙≤Ra0.2μm。  ③ 分流器与形成涂料的凹腔,其凹入深度等于横浇道深度,其直径配浇口套内径,沿脱模方向有5°斜度。当采用涂导入式直浇道时,因缩短了压室有效长度的容积,可提高压室的充满度。
2. 对于模具横浇道的要求
① 冷卧式模具横浇道的入口处一般应位于压室上部内径2/3以上部位,以免压室中金属液在重力作用下过早进入横浇道,提前开始凝固。  ② 横浇道的截面积从直浇道起至内浇口应逐渐减小,为出现截面扩大,则金属液流经时会出现负压,易吸入分型面上的气体,增加金属液流动中的涡流裹气。一般出口处截面比进口处小10-30%。  ③ 横浇道应有一定的长度和深度。保持一定长度的目的是起稳流和导向的作用。若深度不够,则金属液降温快,深度过深,则因冷凝过慢,既影响生产率又增加回炉料用量。  ④ 横浇道的截面积应大于内浇口的截面积,以保证金属液入型的速度。主横浇道的截面积应大于各分支横浇道的截面积。  ⑤ 横浇道的底部两侧应做成圆角,以免出现早期裂纹,二侧面可做出5°左右的斜度。横浇道部位的表面粗糙度≤Ra0.4μm。
3. 内浇口
① 金属液入型后不应立即封闭分型面,溢流槽和排气槽不宜正面冲击型芯。金属液入型后的流向尽可能沿铸入的肋筋和散热片,由厚壁处向薄壁处填充等。  ② 选择内浇口位置时,尽可能使金属液流程最短。采用多股内浇口时,要防止入型后几股金属液汇合、相互冲击,从而产生涡流包气和氧化夹杂等缺陷。  ③ 薄壁件的内浇口厚件要适当小些,以保证必要的填充速度,内浇口的设置应便于切除,且不使铸件本体有缺损(吃肉)。 (4)溢流槽  ① 溢流槽要便于从铸件上去除,并尽量不损伤铸件本体。  ② 溢流槽上开设排气槽时,需注意溢流口的位置,避免过早阻塞排气槽,使排气槽不起作用。  ③ 不应在同一个溢流槽上开设几个溢流口或开设一个很宽很厚的溢流口,以免金属液中的冷液、渣、气、涂料等从溢流槽中返回型腔,造成铸件缺陷。
1. 浇注系统、排溢系统
例(1)对于冷室卧式压铸机上模具直浇道的要求:  ① 压室内径尺寸应根据所需的比压与压室充满度来选定,同时,浇口套的内径偏差应比压室内径的偏差适当放大几丝,从而可避免因浇口套与压室内径不同轴而造成冲头卡死或磨损严重的问题,且浇口套的壁厚不能太薄。浇口套的长度一般应小于压射冲头的送出引程,以便涂料从压室中脱出。  ② 压室与浇口套的内孔,在热处理后应精磨,再沿轴线方向进行研磨,其表面粗糙≤Ra0.2μm。  ③ 分流器与形成涂料的凹腔,其凹入深度等于横浇道深度,其直径配浇口套内径,沿脱模方向有5°斜度。当采用涂导入式直浇道时,因缩短了压室有效长度的容积,可提高压室的充满度。
2. 对于模具横浇道的要求
① 冷卧式模具横浇道的入口处一般应位于压室上部内径2/3以上部位,以免压室中金属液在重力作用下过早进入横浇道,提前开始凝固。  ② 横浇道的截面积从直浇道起至内浇口应逐渐减小,为出现截面扩大,则金属液流经时会出现负压,易吸入分型面上的气体,增加金属液流动中的涡流裹气。一般出口处截面比进口处小10-30%。  ③ 横浇道应有一定的长度和深度。保持一定长度的目的是起稳流和导向的作用。若深度不够,则金属液降温快,深度过深,则因冷凝过慢,既影响生产率又增加回炉料用量。  ④ 横浇道的截面积应大于内浇口的截面积,以保证金属液入型的速度。主横浇道的截面积应大于各分支横浇道的截面积。  ⑤ 横浇道的底部两侧应做成圆角,以免出现早期裂纹,二侧面可做出5°左右的斜度。横浇道部位的表面粗糙度≤Ra0.4μm。
3. 内浇口
① 金属液入型后不应立即封闭分型面,溢流槽和排气槽不宜正面冲击型芯。金属液入型后的流向尽可能沿铸入的肋筋和散热片,由厚壁处向薄壁处填充等。  ② 选择内浇口位置时,尽可能使金属液流程最短。采用多股内浇口时,要防止入型后几股金属液汇合、相互冲击,从而产生涡流包气和氧化夹杂等缺陷。  ③ 薄壁件的内浇口厚件要适当小些,以保证必要的填充速度,内浇口的设置应便于切除,且不使铸件本体有缺损(吃肉)。 (4)溢流槽  ① 溢流槽要便于从铸件上去除,并尽量不损伤铸件本体。  ② 溢流槽上开设排气槽时,需注意溢流口的位置,避免过早阻塞排气槽,使排气槽不起作用。  ③ 不应在同一个溢流槽上开设几个溢流口或开设一个很宽很厚的溢流口,以免金属液中的冷液、渣、气、涂料等从溢流槽中返回型腔,造成铸件缺陷。
 
1. The pouring system, overflowing system

Cases (1) for cold chamber on the horizontal die casting machine mold of SPR requirement: (1) pressure interior diameter size should be according to the required pressure and pressure chamber full of degrees to selected, at the same time, the gate of the inner diameter of deviation should be than the interior diameter deviation of proper amplification several silk, thus can avoid by interior diameter not coaxial gate set and pressure caused by the wear punch card to death or serious problem, and the gate of wall thickness can't be too thin. Sprue injection punch heads made of general should be less than the length of the set of send out process, in order to paint emerge from the pressure chamber. (2) the pressure chamber and the gate of the inner hole of, should be fine grinding after heat treatment, and then along the axis direction of grinding, the surface rough Ra0.2 mu m or less. (3) shunt concave cavity and formation of coating, the concave depth is equal to the depth of the runner, its diameter with a gate set of inner diameter, along the parting direction have 5 ° slope. When apply the import type SPR is used, because of the effective length shortens the pressure chamber volume, can improve the pressure chamber full of degrees.

2. To the requirement of mold runner

(1) cold horizontal mold runner shall generally be located in the entrance to the pressure chamber of the upper parts inside diameter of the two-thirds, in order to avoid pressure chamber in the liquid metal under the action of gravity prematurely into the runner, solidifies ahead of time. (2) the runner of the cross-sectional area from the sprue to the gate should be gradually decreases, and for a section, the liquid metal flows through negative pressure would appear, easy type suction points on the surface of the gas, increase the eddy current in liquid metal flow in gas. Generally at the exit section are smaller than inlet 10-30%. (3) runner should have a certain length and depth. Keep a steady flow is the purpose of a certain length and orientation. If depth is not enough, the liquid metal cooling fast, depth is deep, by condensation too slow, affect the productivity and increase the dosage of furnace charge back. Within the area should be greater than 4 runner gate area, to ensure that the speed of the liquid metal into the type. Cross section area of the main runner should be greater than the cross-sectional area of each branch runner. (5) on both sides should make rounded corners on the bottom of the runner, lest appear early crack, two sides can make about 5 ° slope. Runner parts of the surface roughness of the Ra0.4 mu m or less.

3. The gate

Type (1) into the liquid metal should not be closed immediately after parting surface, the overflow tank and exhaust slot unfavorable positive impact core. The flow of liquid metal into the type as possible along the rib steel and heat sink, cast into to the thin walled in by the thick wall filling, etc. (2) the gate location choice, as far as possible make the liquid metal flow the shortest. Using multiple strands of gate, to prevent the type a few strands of metal liquid confluence, after impact each other, resulting in a vortex vadose and oxide inclusion defects. (3) gate thickness of thin-wall pieces to appropriate, to ensure that the necessary fill speed, the gate should be set up to facilitate removal, and does not make the casting ontology has defects (meat). (4) the overflow tank (1) the overflow tank to facilitate removal from the casting, and try not to damage the casting body. (2) open the exhaust slot on the overflow tank, need to pay attention to the position of the overflow mouth, avoid premature blocking the vent groove, the exhaust slot doesn't work. (3) should not be opened on the same overflow trough a few overflow mouth or to open a very thick of the overflow mouth wide, so as to avoid metal liquid in the cold liquid, slag, gas, coatings, such as returned from the overflow groove cavity, casting defects.

1. The pouring system, overflowing system

Cases (1) for cold chamber on the horizontal die casting machine mold of SPR requirement: (1) pressure interior diameter size should be according to the required pressure and pressure chamber full of degrees to selected, at the same time, the gate of the inner diameter of deviation should be than the interior diameter deviation of proper amplification several silk, thus can avoid by interior diameter not coaxial gate set and pressure caused by the wear punch card to death or serious problem, and the gate of wall thickness can't be too thin. Sprue injection punch heads made of general should be less than the length of the set of send out process, in order to paint emerge from the pressure chamber. (2) the pressure chamber and the gate of the inner hole of, should be fine grinding after heat treatment, and then along the axis direction of grinding, the surface rough Ra0.2 mu m or less. (3) shunt concave cavity and formation of coating, the concave depth is equal to the depth of the runner, its diameter with a gate set of inner diameter, along the parting direction have 5 ° slope. When apply the import type SPR is used, because of the effective length shortens the pressure chamber volume, can improve the pressure chamber full of degrees.

2. To the requirement of mold runner

(1) cold horizontal mold runner shall generally be located in the entrance to the pressure chamber of the upper parts inside diameter of the two-thirds, in order to avoid pressure chamber in the liquid metal under the action of gravity prematurely into the runner, solidifies ahead of time. (2) the runner of the cross-sectional area from the sprue to the gate should be gradually decreases, and for a section, the liquid metal flows through negative pressure would appear, easy type suction points on the surface of the gas, increase the eddy current in liquid metal flow in gas. Generally at the exit section are smaller than inlet 10-30%. (3) runner should have a certain length and depth. Keep a steady flow is the purpose of a certain length and orientation. If depth is not enough, the liquid metal cooling fast, depth is deep, by condensation too slow, affect the productivity and increase the dosage of furnace charge back. Within the area should be greater than 4 runner gate area, to ensure that the speed of the liquid metal into the type. Cross section area of the main runner should be greater than the cross-sectional area of each branch runner. (5) on both sides should make rounded corners on the bottom of the runner, lest appear early crack, two sides can make about 5 ° slope. Runner parts of the surface roughness of the Ra0.4 mu m or less.

3. The gate

Type (1) into the liquid metal should not be closed immediately after parting surface, the overflow tank and exhaust slot unfavorable positive impact core. The flow of liquid metal into the type as possible along the rib steel and heat sink, cast into to the thin walled in by the thick wall filling, etc. (2) the gate location choice, as far as possible make the liquid metal flow the shortest. Using multiple strands of gate, to prevent the type a few strands of metal liquid confluence, after impact each other, resulting in a vortex vadose and oxide inclusion defects. (3) gate thickness of thin-wall pieces to appropriate, to ensure that the necessary fill speed, the gate should be set up to facilitate removal, and does not make the casting ontology has defects (meat). (4) the overflow tank (1) the overflow tank to facilitate removal from the casting, and try not to damage the casting body. (2) open the exhaust slot on the overflow tank, need to pay attention to the position of the overflow mouth, avoid premature blocking the vent groove, the exhaust slot doesn't work. (3) should not be opened on the same overflow trough a few overflow mouth or to open a very thick of the overflow mouth wide, so as to avoid metal liquid in the cold liquid, slag, gas, coatings, such as returned from the overflow groove cavity, casting defects.