自由折弯因其模具通用性好、加工效率高,因而在小批量板料折弯成形中得到广泛应用。但对其加工精度的控制,特别对与成形角度直接相关的V形板料折弯滑块下压量的精度控制一直是业内一个难点问题。为获得更高的角度精度,常采用多次试折法,渐进达到加工要求,且对加工人员经验要求较高。对自由折弯成形中滑块下压量进行理论计算推导,提出一种通过角度经验校正数据库修正理论计算的方法。基于以上方法在不同模具上使用不同厚度的Q235和不锈钢板料进行不同折弯角度折板实验,两次试折后,实验折弯角度误差在±0.5°,满足国标GB/T 14349-2011中对钣金产品折弯角度的精度要求。该方法已应用于本实验室自主研发的折弯机数控系HNC-SPB60中。 Free bending because of its versatility of the mold, processing efficiency, which in small quantities of sheet metal bending forming is widely used. However, it is always a difficult problem in the industry to control the machining accuracy, especially the precision control of the bending amount of the V-shaped sheet bending slider which is directly related to the forming angle. To obtain a higher degree of accuracy, often using a number of trial folding method, gradually reached the processing requirements, and processing personnel experience higher requirements. Based on theoretical calculation and calculation of the amount of depression of the slider in the free-form bending process, a method of correcting the theoretical calculation based on the empirical database of angle correction is proposed. Based on the above method, different thickness Q235 and stainless steel sheets were used on different molds to make bending experiments with different bending angles. After two folding tests, the experimental bending angle error was within ± 0.5 °, meeting the requirements of GB / T 14349-2011 The precision of the bending angle of sheet metal products. The method has been applied in our laboratory independently developed CNC machine HNC-SPB60 bending machine.