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I、 底片变形的原因及解决方法：

原因：

（1） 温湿度控制故障（2）曝光机温升过高

解决方案：

（1） 通常，温度控制在22±2℃，湿度为55%±5%RH。（2）应使用带冷光源或冷却装置的曝光机，并不断更换背膜。

II、 胶片变形校正的工艺方法：

(1)Under the condition of mastering the operation technology of the digital programming instrument, first install the negative film to compare with the drilling test plate, measure its length and width, lengthen or shorten the hole position according to the size of the deformation on the digital programming instrument, and use the drilling test plate after lengthening or shortening the hole position to match the deformed negative film, so as to avoid the tedious work of splicing the negative film, and ensure the integrity and accuracy of the graphics. This method is called "hole location change method".

(2)In view of the physical phenomenon that the negative film changes with the change of ambient temperature and humidity, take out the negative film in the sealed bag before copying the negative film, and hang it in the air for 4-8 hours under the working environment to deform the negative film before copying, so that the deformation of the copied negative film will be very small. This method is called "hanging in the air method".

(3)For graphics with simple lines, large line width and spacing, and irregular deformation, the deformed part of the negative film can be cut off and compared with the hole position of the drilling test plate, and then copied, which is called "splicing method".

(4)This method is called "pad overlap method", which uses holes on the test board to enlarge the pad to remove heavy and deformed circuit pieces to ensure the minimum ring width technical requirements.

(5)This method is called "mapping method", in which the figures on the deformed negative film are scaled up and remapped for plate making.

(6)The camera is used to enlarge or reduce the deformed figure, which is called "photographic method".

III、 相关方法说明：

（1） 拼接方法：

适用于线条不密集、各层薄膜变形不一致的薄膜；特别适用于电阻焊负片和多层电源层负片的变形；不适用于导体密度高、线宽和间距小于0.2mm的薄膜；

注意事项：在不损坏焊盘的情况下，应尽可能少地切割导体。拼接副本后编辑时，注意连接关系的正确性。

（2） 更改孔位置方法：

适用于每层底片的一致变形。这种方法也适用于线条密集的薄膜；不合适薄膜变形不均匀，尤其是局部变形。

注意事项：使用编程器延长或缩短孔位置后，应重置超过公差的孔位置。

（3） 空气悬挂方法：

适用；复印后未变形且防止变形的负片；它不适用于变形薄膜。

注意事项将底片挂在通风、黑暗的环境中（如果安全的话），以避免污染。确保悬挂处的温度和湿度与操作处的温度、湿度一致。

（4） 填充重叠方法：

适用：图形线条不太密集，线条宽度和间距大于0.30mm；不适用。特别是用户对印刷电路板的外观有严格的要求；

注意：重叠副本后，焊盘是椭圆形的。重叠复制后线条和磁盘边缘的光晕和变形。

（5） 摄影方法：

适用：底片在长度和宽度方向上的变形率是一致的，因此当不方便再次钻孔测试板时，只有银盐底片适用。不适用薄膜在长度和宽度方向上变形不一致。

注意事项：拍照时应准确对焦，防止线条变形。底片损失很多。通常，经过多次调试后，可以获得令人满意的电路图。