product news/產品新聞
shot velocity, low cycle time, minimal contamination and zero porosity. Te gap between plunger tip and shot sleeve must be maintained at less than 0.1mm at all times, other- wise, aluminum will blowby and cause excessive wear. Unfortunately, the gap between the plunger and the
shot sleeve never remains constant during casting. Figure 1 depicts the situation when the plunger tip is not thermally stable and a 165.1-mm sleeve is not thermally regulated. Typically for such a plunger system, a water jacket is imple- mented at the die end of the shot sleeve to assist biscuit cooling, because the conventional plunger is so hot. At the beginning of the casting cycle the sleeve is very
hot where the alloy is poured, due to direct impact of molten aluminum. Te plunger tip is comparatively cool at the beginning of the cycle. As the plunger moves toward the die end, the tip becomes hotter since the plunger face is in direct contact with liquid aluminum. Te die end sleeve is normally cooled as mentioned. If the initial clearance at the pour end is small enough to prevent penetration of the alloy past the tip of the plunger, and the temperature of both plunger and short sleeve is not adequately controlled; the plunger may seize in the sleeve before reaching the end of the stroke. Figure 2 shows the uniform scorching marks due to the shot sleeve restricting the movement of the plunger at the die end. It is clearly shown the water jacket (blue circular pattern) is at 80C. —Paul Robbins, Castool Tooling Systems ■
短、污染最小并且无气孔。冲头和压射缸之间的距离 必须总是保持在0.1mm以内，否则，铝液将会窜漏， 从而导致过度磨损。
但是，在铸造过程中，柱塞和压射缸之间的距离从 来不会保持稳定状态。如图1所示位置，冲头的热稳 定性和165.1mm套筒的热稳定性不佳。一般情况下， 对于这样的柱塞系统，在射压缸的冲模末端将会安装 水套来辅助降温，因为通常柱塞是非常热的。 在铸造环节初期，合金注入套筒内，由于铝液的 直接影响，套筒变得非常热。此时，冲头的温度相对 较低。随着柱塞向冲模端移动，柱塞面与铝液直接接 触，冲头变得越来越烫。如上所述，冲模端的套筒可 以正常冷却下来。如果浇注端最初的空隙足够小以 阻止合金液渗入到柱塞头，且未能适当控制柱塞和套 筒的温度，那么，柱塞在冲程结束之前可能会被套筒 卡住。图2所示，由于压射缸阻碍了柱塞在冲模端的 移动，产生了均匀的灼热痕迹。可以清楚地看到，水 套（蓝色环形图案）的温度为80℃。—Paul Robbins, Castool Tooling Systems ■
Figure 2. Scorching marks due to plunger tip over expanding and cold sleeve at die end.
图2：冲模末端，冲头过度膨胀且套筒冷却产生的灼热痕迹。
JDN Hoists Make Light Work of Loads JDN提升机使装载工作更轻松
Workplace injuries can occur when personnel are
lifting or moving inappropriately heavy loads. Me- chanical lifting equipment can help, but can be time consuming, particularly where rope or chain wheel manual operations are associated with raising loads to
工人在车间里举起或搬运重物时操作不当，可能 受伤。借助机械化提升设备辅助工作，比较耗时， 尤其是在将货物升至超过头顶时，需要手动操作绳
September 2014
FOUNDRY-PLANET.COM | MODERN CASTING | CHINA FOUNDRY ASSOCIATION | 75
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74 |
Page 75 |
Page 76 |
Page 77 |
Page 78 |
Page 79 |
Page 80 |
Page 81 |
Page 82