温度对机床加工精度的影响

 
<span style="color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; letter-spacing: 0.544px; text-align: justify; margin: 0px; padding: 0px; max-width: 100%; font-size: 15px; box-sizing: border-box !important; overflow-wrap: break-word !important;”>热变形是影响加工精度的原因之一机床受到车间环境温度的变化、电动机发热和机械
<span style="color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; letter-spacing: 0.544px; text-align: justify; margin: 0px; padding: 0px; max-width: 100%; font-size: 15px; box-sizing: border-box !important; overflow-wrap: break-word !important;”>运动摩擦发热、切削热以及冷却介质的影响，造成机床各部的温升不均匀，导致机床形态精度及加工精度的变化。
<span style="color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; letter-spacing: 0.544px; text-align: justify; margin: 0px; padding: 0px; max-width: 100%; font-size: 15px; box-sizing: border-box !important; overflow-wrap: break-word !important;”>例如，在一台普通精度的数控铣床上加工70mm×1650mm的螺杆，上午7:30-9:00铣削的工件与下午2:00-3:30加工的工件相比，累积误差的变化可达85m。
<span style="color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; letter-spacing: 0.544px; text-align: justify; margin: 0px; padding: 0px; max-width: 100%; font-size: 15px; box-sizing: border-box !important; overflow-wrap: break-word !important;”>而在恒温条件下，则误差可减小至40m。
<p style="margin: 0px 8px 15px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; text-indent: 0px; box-sizing: border-box !important; overflow-wrap: break-word !important;”> 

<p style="margin: 0px 8px 15px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; text-indent: 0px; box-sizing: border-box !important; overflow-wrap: break-word !important;”><span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>再如，一台用于双端面磨削0.6～3.5mm厚的薄钢片工件的精密双端面磨床，在验收时加工200mm×25mm×1.08mm钢片工件能达到mm的尺寸精度，弯曲度在全长内小于5m。<span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>但连续自动磨削1h后，尺寸变化范围增大到12m，冷却液温度由开机时的17℃上升到45℃。<span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>由于磨削热的影响，导致主轴轴颈伸长，主轴前轴承间隙增大。<span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>据此，为该机床冷却液箱添加一台5.5kW制冷机，效果十分理想。<span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>实践证明，机床受热后的变形是影响加工精度的重要原因。<span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>但机床是处在温度随时随处变化的环境中；<span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>机床本身在工作时必然会消耗能量，这些能量的相当一部分会以各种方式转化为热，引起机床各构件的物理变化，这种变化又因为结构形式的不同，材质的差异等原因而千差万别。<span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>机床设计师应掌握热的形成机理和温度分布规律，采取相应的措施，使热变形对加工精度的影响减少到最小。

<p style="margin: 0px 8px 15px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; text-indent: 0px; box-sizing: border-box !important; overflow-wrap: break-word !important;”><span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>机床的温升及温度分布、自然气候影响我国幅员辽阔，大部分地区处于亚热带地区，一年四季的温度变化较大，一天内温差变化也不一样。<span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>由此，人们对室内（如车间）温度的干预的方式和程度也不同，机床周围的温度氛围千差万别。<span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>例如，长三角地区季节温度变化范围约45℃左右，昼夜温度变化约5～12℃。<span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>机加工车间一般冬天无供热，夏天无空调，但只要车间通风较好，机加工车间的温度梯度变化不大。<span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>而东北地区，季节温差可达60℃，昼夜变化约8～15℃。<span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>每年10月下旬至次年4月初为供暖期，机加工车间的设计有供暖，空气流通不足。<span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>车间内外温差可达50℃。<span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>因此车间内冬季的温度梯度十分复杂，测量时室外温度1.5℃，时间为上午8:15-8:35，车间内温度变化约3.5℃。<span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>精密机床的加工精度在这样的车间内受环境温度影响将是很大的。

<p style="margin: 0px 8px 15px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; text-indent: 0px; box-sizing: border-box !important; overflow-wrap: break-word !important;”><span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>周围环境的影响机床周围环境是指机床近距离范围内各种布局形成的热环境。

<p style="margin: 0px 8px 15px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; text-indent: 0px; box-sizing: border-box !important; overflow-wrap: break-word !important;”><span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>它们包括以下4个方面：

<p style="margin: 0px 8px 15px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; text-indent: 0px; box-sizing: border-box !important; overflow-wrap: break-word !important;”><span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>1）车间小气候：<span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>如车间内温度的分布（垂直方向、水平方向）。<span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>当昼夜交替或气候以及通风变化时车间温度均会产生缓慢变化。

<p style="margin: 0px 8px 15px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; text-indent: 0px; box-sizing: border-box !important; overflow-wrap: break-word !important;”><span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>2）车间热源：<span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>如太阳照射、供暖设备和大功率照明灯的辐射等，它们离机床较近时可直接长时间影响机床整体或部分部件的温升。<span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>相邻设备在运行时产生的热量会以幅射或空气流动的方式影响机床温升。

<p style="margin: 0px 8px 15px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; text-indent: 0px; box-sizing: border-box !important; overflow-wrap: break-word !important;”><span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>3）散热：<span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>地基有较好的散热作用，尤其是精密机床的地基切忌靠近地下供热管道，一旦破裂泄漏时，可能成为一个难以找到原因的热源；<span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>敞开的车间将是一个很好的“散热器”，有利于车间温度均衡。

<p style="margin: 0px 8px 15px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; text-indent: 0px; box-sizing: border-box !important; overflow-wrap: break-word !important;”><span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>4）恒温：<span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>车间采取恒温设施对精密机床保持精度和加工精度是很有效果的，但能耗较大。

<p style="margin: 0px 8px 15px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; text-indent: 0px; box-sizing: border-box !important; overflow-wrap: break-word !important;”><span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>3、机床内部热影响因素

<p style="margin: 0px 8px 15px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; text-indent: 0px; box-sizing: border-box !important; overflow-wrap: break-word !important;”><span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>1）机床结构性热源。<span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>电动机发热如主轴电动机、进给伺服电动机、冷却润滑泵电动机、电控箱等均可产生热量。<span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>这些情况对电动机本身来说是允许的，但对于主轴、滚珠丝杠等元器件则有重大不利影响，应采取措施予以隔离。<span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>当输入电能驱动电动机运转时，除了有少部分（约20%左右）转化为电动机热能外，大部分将由运动机构转化为动能，如主轴旋转、工作台运动等；<span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>但不可避免的仍有相当部分在运动过程中转化为摩擦发热，例如轴承、导轨、滚珠丝杠和传动箱等机构发热。

<p style="margin: 0px 8px 15px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; text-indent: 0px; box-sizing: border-box !important; overflow-wrap: break-word !important;”><span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>2）工艺过程的切削热。<span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>切削过程中刀具或工件的动能一部分消耗于切削功，相当一部分则转化切削的变形能和切屑与刀具间的摩擦热，形成刀具、主轴和工件发热，并由大量切屑热传导给机床的工作台夹具等部件。<span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>它们将直接影响刀具和工件间的相对位置。

<p style="margin: 0px 8px 15px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; text-indent: 0px; box-sizing: border-box !important; overflow-wrap: break-word !important;”><span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>3）冷却。<span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>冷却是针对机床温度升高的反向措施，如电动机冷却、主轴部件冷却以及基础结构件冷却等。<span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>高端机床往往对电控箱配制冷机，予以强迫冷却。

<p style="margin: 0px 8px 15px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; text-indent: 0px; box-sizing: border-box !important; overflow-wrap: break-word !important;”><span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>4、机床的结构形态对温升的影响在机床热变形领域讨论机床结构形态，通常指结构形式、质量分布、材料性能和热源分布等问题。<span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>结构形态影响机床的温度分布、热量的传导方向、热变形方向及匹配等。

<p style="margin: 0px 8px 15px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; text-indent: 0px; box-sizing: border-box !important; overflow-wrap: break-word !important;”><span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>1）机床的结构形态。<span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>在总体结构方面，机床有立式、卧式、龙门式和悬臂式等，对于热的响应和稳定性均有较大差异。<span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>例如齿轮变速的车床主轴箱的温升可高达35℃，使主轴端上抬，热平衡时间需2h左右。<span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>而斜床身式精密车铣加工中心，机床有一个稳定的底座。<span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>明显提高了整机刚度，主轴采用伺服电动机驱动，去除了齿轮传动部分，其温升一般小于15℃。

<p style="margin: 0px 8px 15px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; text-indent: 0px; box-sizing: border-box !important; overflow-wrap: break-word !important;”><span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>2）热源分布的影响。<span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>机床上通常认为热源是指电动机。<span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>如主轴电动机、进给电动机和液压系统等，其实是不完全的。<span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>电动机的发热只是在承担负荷时，电流消耗在电枢阻抗上的能量，另有相当一部分能量消耗于轴承、丝杠螺母和导轨等机构的摩擦功引起的发热。<span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>所以可把电动机称为一次热源，将轴承、螺母、导轨和切屑称之为二次热源。<span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>热变形则是所有这些热源综合影响的结果。<span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>一台立柱移动式立式加工中心在Y向进给运动中温升和变形情况。<span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>Y向进给时工作台未作运动，所以对X向的热变形影响很小。<span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>在立柱上，离Y轴的导轨丝杠越远的点，其温升越小。<span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>该机在Z轴移动时的情况则更进一步说明了热源分布对热变形的影响。<span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>Z轴进给离X向更远，故热变形影响更小，立柱上离Z轴电动机螺母越近，温升及变形也越大。

<p style="margin: 0px 8px 15px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; text-indent: 0px; box-sizing: border-box !important; overflow-wrap: break-word !important;”><span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>3）质量分布的影响。<span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>质量分布对机床热变形的影响有三方面。<span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>其一，指质量大小与集中程度，通常指改变热容量和热传递的速度，改变达到热平衡的时间

<p style="margin: 0px 8px 15px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; text-indent: 0px; box-sizing: border-box !important; overflow-wrap: break-word !important;”><span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>二，通过改变质量的布置形式，如各种筋板的布置，提高结构的热刚度，在同样温升的情况下，减小热变形影响或保持相对变形较小；

<p style="margin: 0px 8px 15px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; text-indent: 0px; box-sizing: border-box !important; overflow-wrap: break-word !important;”><span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>其三，则指通过改变质量布置的形式，如在结构外部布置散热筋板，以降低机床部件的温升。

<p style="margin: 0px 8px 15px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; text-indent: 0px; box-sizing: border-box !important; overflow-wrap: break-word !important;”><span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>材料性能的影响：<span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>不同的材料有不同的热性能参数（比热、导热率和线膨胀系数），在同样热量的影响下，其温升、变形均有不同。<span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>机床热性能的测试

<p style="margin: 0px 8px 15px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; text-indent: 0px; box-sizing: border-box !important; overflow-wrap: break-word !important;”><span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>1、机床热性能测试的目的控制机床热变形的关键是通过热特性测试，充分了解机床所处的环境温度的变化，机床本身热源及温度变化以及关键点的响应（变形位移）。<span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>测试数据或曲线描述一台机床热特性，以便采取对策，控制热变形，提高机床的加工精度和效率。

<p style="margin: 0px 8px 15px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; text-indent: 0px; box-sizing: border-box !important; overflow-wrap: break-word !important;”><span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>具体地说，应达到以下几个目的：

<p style="margin: 0px 8px 15px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; text-indent: 0px; box-sizing: border-box !important; overflow-wrap: break-word !important;”><span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>1）机床周围环境测试。<span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>测量车间内的温度环境，它的空间温度梯度，昼夜交替中温度分布的变化，甚至应测量季节变化对机床周围温度分布的影响。

<p style="margin: 0px 8px 15px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; text-indent: 0px; box-sizing: border-box !important; overflow-wrap: break-word !important;”><span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>2）机床本身的热特性测试。<span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>尽可能地排除环境干扰的条件下，让机床处于各种运转状态，以测量机床本身的重要点位的温度变化、位移变化，记录在足够长的时间段内的温度变化和关键点位移，也可用红外线热相仪记录各时间段热分布的情况。

<p style="margin: 0px 8px 15px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; text-indent: 0px; box-sizing: border-box !important; overflow-wrap: break-word !important;”><span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>3）加工过程测试温升热变形，以判断机床热变形对加工过程精度的影响。

<p style="margin: 0px 8px 15px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; text-indent: 0px; box-sizing: border-box !important; overflow-wrap: break-word !important;”><span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>4）上述试验可积累大量的数据、曲线，将为机床设计和使用者控制热变形提供可靠的判据，指出采取有效措施的方向。

<p style="margin: 0px 8px 15px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; text-indent: 0px; box-sizing: border-box !important; overflow-wrap: break-word !important;”><span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>2、机床热变形测试的原理热变形测试首先需要测量若干相关点的温度，包含以下几方面：

<p style="margin: 0px 8px 15px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; text-indent: 0px; box-sizing: border-box !important; overflow-wrap: break-word !important;”><span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>1）热源：<span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>包括各部分进给电动机、主轴电动机、滚珠丝杠传动副、导轨、主轴轴承。

<p style="margin: 0px 8px 15px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; text-indent: 0px; box-sizing: border-box !important; overflow-wrap: break-word !important;”><span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>2）辅助装置：<span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>包括液压系统、制冷机、冷却和润滑位移检测系统。

<p style="margin: 0px 8px 15px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; text-indent: 0px; box-sizing: border-box !important; overflow-wrap: break-word !important;”><span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>3）机械结构：<span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>包括床身、底座、滑板、立柱和铣头箱体和主轴。<span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>在主轴和回转工作台之间夹持有铟钢测棒，在X、Y、Z方向配置了5个接触式传感器，测量在各种状态下的综合变形，以模拟刀具和工件间的相对位移。

<p style="margin: 0px 8px 15px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; text-indent: 0px; box-sizing: border-box !important; overflow-wrap: break-word !important;”><span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>3、测试数据处理分析机床热变形试验要在一个较长的连续时间内进行，进行连续的数据记录，经过分析处理，所反映的热变形特性可靠性很高。<span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>如果通过多次试验进行误差剔除，则所显示的规律性是可信的。<span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>主轴系统热变形试验中共设置了5个测量点，其中点1、点2在主轴端部和靠近主轴轴承处，点4、点5分别在铣头壳体靠近Z向导轨处。<span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>测试时间共持续了14h，其中前10h主轴转速分别在0～9000r/min范围内交替变速，从第10h开始，主轴持续以9000r/min高速旋转。

<p style="margin: 0px 8px 15px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; text-indent: 0px; box-sizing: border-box !important; overflow-wrap: break-word !important;”><span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>可以得到以下结论：

<p style="margin: 0px 8px 15px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; text-indent: 0px; box-sizing: border-box !important; overflow-wrap: break-word !important;”><span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>1）该主轴的热平衡时间约1h左右，平衡后温升变化范围1.5℃；

<p style="margin: 0px 8px 15px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; text-indent: 0px; box-sizing: border-box !important; overflow-wrap: break-word !important;”><span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>2）温升主要来源于主轴轴承和主轴电动机，在正常变速范围内，轴承的热态性能良好；

<p style="margin: 0px 8px 15px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; text-indent: 0px; box-sizing: border-box !important; overflow-wrap: break-word !important;”><span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>3）热变形在X向影响很小；

<p style="margin: 0px 8px 15px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; text-indent: 0px; box-sizing: border-box !important; overflow-wrap: break-word !important;”><span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>4）Z向伸缩变形较大，约10m，是由主轴的热伸长及轴承间隙增大引起的；

<p style="margin: 0px 8px 15px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; text-indent: 0px; box-sizing: border-box !important; overflow-wrap: break-word !important;”><span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>5）当转速持续在9000r/min时，温升急剧上升，在2.5h内急升7℃左右，且有继续上升的趋势，Y向和Z向的变形达到了29m和37m，说明该主轴在转速为9000r/min时已不能稳定运行，但可以短时间内（20min）运行。<span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>机床热变形的控制由以上分析讨论，机床的温升和热变形对加工精度的影响因素多种多样，采取控制措施时，应抓住主要矛盾，重点采取一、二项措施，取得事半功倍的效果。<span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>在设计中应从4个方向入手：<span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>减少发热，降低温升，结构平衡，合理冷却。

<p style="margin: 0px 8px 15px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; text-indent: 0px; box-sizing: border-box !important; overflow-wrap: break-word !important;”><span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>1、减少发热控制热源是根本的措施。<span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>在设计中要采取措施有效降低热源的发热量。

<p style="margin: 0px 8px 15px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; text-indent: 0px; box-sizing: border-box !important; overflow-wrap: break-word !important;”><span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>1）合理选取电动机的额定功率。<span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>电动机的输出功率P等于电压V和电流I的乘积，一般情况下，电压V是恒定的，因此，负荷的增大，意味着电动机输出功率增大，即相应的电流I也增大，则电流消耗在电枢阻抗的热量增大。<span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>若我们所设计选择的电动机长时间在接近或大大超过额定功率的条件下工作，则电动机的温升明显增大。<span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>为此，对BK50型数控针槽铣床铣头进行了对比试验（电动机转速：<span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>960r/min；<span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>环境温度：<span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>12℃）。<span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>从上述试验得到以下概念：<span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>从热源性能考虑，无论主轴电动机还是进给电动机，选择额定功率时，最好选比计算功率大25%左右为宜，在实际运行中，电动机的输出功率与负荷相匹配，增大电动机额定功率对于能耗的影响很小。<span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important; font-size: 15px;”>但可有效降低电动机温升。