嘉陵摩托车曲柄锻件(见图1)外形复杂,要求特殊。其配重部分重量为17±1g,要求直接锻出,不进行机械加工。不加工表面凹陷深度不能大于0.5mm,全部凹陷刻痕、黑点面积不能大于不加工面面积总和的5％,所以要求很高,难度很大。我们打破常规,从改进加工方法和操作上想办法,克服了缺少专用设备和设备精度差的问题,土法上马,使 Jialing motorcycle crank forgings (see Figure 1) complex shape, special requirements. The weight part of the weight of 17 ± 1g, requiring direct forging, not for machining. Not machined surface depression depth can not be greater than 0.5mm, all the concave notch, black spot area can not be greater than 5% of the total surface area, so demanding, very difficult. We break the routine and try to find ways to improve the processing methods and operations and overcome the problem of the lack of precision of special equipment and equipment.