Metal Preparation 金属前处理
Body Shop Washer 车身车间清洗设备
Effective body shop washers loosen and remove mill oils, pre-lubes, and stamping compounds from the body-in-white. Good pre-cleaning with high-pressure water and soap increases the effectiveness of the phosphating operation. Cleaning also reduces crater-causing contamination which is carried into the tank or which can blow out in the oven. The latter problem is most evident in the oil which collects in hem flanges.
有效的车身车间清洗设备应具有分散并除掉车身上矿物油,润滑剂及冲压拉延油。用高压水及皂液进行良好的预清洗能提高磷化作业效果。清洗也可减少带入电泳槽的或电泳涂膜烘干时发生缩孔的污染物。漆膜烘干时出现缩孔的问题在翻边及焊缝处最明显。
Pre-cleaning should include the removal of metal filings and weld splatter: both are potential sources for dirt in phosphate and electrocoat. Washing of the floor pan is an essential part of the pre-cleaning operation.
预清洗系统包括清除金属屑及焊渣, 它们是磷化和电泳槽内的污染物的来源。车底板亦是预清洗操作的重点部位之一。。
1.1.2. Phosphating
磷化
Phosphating technology has been developed specifically for use with cathodic electrocoating. Phosphating products have unique characteristics based upon controlled crystal structures. The success of the phosphating operation depends entirely upon thorough body cleaning, uniformity of approved phosphate coating product, and low conductivity of the residual final DI rinse.
磷化技术的开发是为阴极电泳涂装而服务的。磷化材料的特性取决于可否控制晶体的结构。成功的磷化操作完全取决于车身的清洁程度,磷化膜均匀与否以及最终残留的去离子水电导率 是否低。
Thorough pre-cleaning includes removal of all oils and stamping compounds, metal filings and other particulate debris, and elimination of all phosphate sludge. The phosphate coating should be uniform, without streaks, patterns, or hashmarks. Crystal size should be small and dense, with a coating weight appropriate to the particular phosphate method. The recirculated DI rinse should be held below 100 micromhos and followed by a pure DI water rinse of less than 25 micromhos. Phosphated bodies should be uniformly wet or dry when they enter the phosphate bath. Non-uniform wetness can result in patterns or marks in the electrocoat film. A "camel-back" in the conveyor can aid in draining pockets which might hold rinse residues.
彻底的预清洗包括除去所有的油,冲压拉延剂,金属屑,其它碎屑颗粒及除掉所有的磷化残渣。磷化膜应完全均匀,无条痕,花纹或染色斑痕。晶粒应小而致密,膜重与磷化方式相称。水洗用循环去离子水的水质要保持在10us/cm2以下,而随后的新鲜去离子水洗的水质电导应低于25us/cm2。磷化过的车身必须全湿或全干状态进入电泳槽。干湿不均匀可导致电泳膜产生花纹或斑痕。运输链设一个驼峰有助于沥净冲洗水残液。
Accumulators, transfers, and delivery conveyors between phosphate and electrocoat should be tunneled to prevent body contamination from airborne dirt and oil. This enclosure should have adequate ventilation to prevent condensation and subsequent contamination of the production unit. Exposed accumulators should not travel alongside the phosphate machine, since airborne phosphate mist can cause craters or other blemishes in the electrocoat finish. Similar problems result from DI water regeneration tanks placed too close to unprotected car bodies. Phosphate mist and DI regeneration stations comprise, however, only two of several possible sources of contamination.
磷化和电泳之间的储存链,转移链及传送链要设封闭隧道,以防止悬浮于空气中的灰尘及油对车身的污染。此封闭隧道要有充分的通风,防止凝结及对产品的再污染。外露的储存链不能沿着磷化设备运行,因为空气中的磷化液雾可引起电泳漆膜产伸缩孔或其它缺陷。去离子水再生槽的布置太靠近未加保护的车身也可引起类似的问题。磷化液雾和去离子水再生仅仅是各种可能污染源的两种。
Removal of dirt by forced-air blow-off is not recommended because of the possibility of damage to the finish by air-driven contaminants. If a dry-off oven is used, the car body temperature should be cooled to paint-bath temperature. The warmer bodies also place a heavier load on paint-cooling equipment.
不推荐用压缩空气吹除灰尘。原因是空气所带的污染物对涂层仍有损害的可能性。如使用加热烘设备时,车身温度要冷却到电泳槽液的温度。车身温度高也会增加油漆冷却设备的负荷。