Problems and solutions in coating pretreatment process

The original reason for the problem in the process is that the oil removal part is not clean 1 The concentration of the oil removal liquid is low 1 The concentration is increased 2 The oil removal time is short 2 The time is extended 3 The oil removal temperature is low 3 The temperature is increased 4 The local oil is too thick 4 The pretreatment (manual) is increased 5 The oil floating layer on the oil removal tank surface is thick 5 Skim out the oil layer 6 The spray nozzle is blocked 6 Strengthen the cleaning of the nozzle 7 The processing capacity of the workpiece is large and there is no supplement in time 7 Timely add chemicals to remove the rust part The rust removal is not complete 1 The concentration of the rust removal solution is low 1 Increase the concentration 2 The rust removal time is short 2 Extend the time 3 The oxide skin formed by high temperature is too thick and thick 3 Increase mechanical auxiliary derusting 4 The content of iron ion in derusting solution is too high, and the antirust solution fails 4 Replace the new tank solution The acid in derusting solution is too large or the workpiece has hydrogen embrittlement or over corrosion after derusting 1 The concentration is too high 1 Add water to dilute 2 The additive is insufficient 2 Add additive 3 The time is too long 3 The time reduces the crystallization roughness of phosphating film 1 High free acidity 1 Use neutralizer to reduce free acidity 2 Have residual acid 2 Strengthen neutralization and water washing 3 The surface of workpiece is corroded 3 Control concentration and time The phosphating film is too thin without obvious crystal 1 Low free acidity 1 Add phosphating solution and neutralizer to adjust 2 High total acidity 2 Dilute with water 3 There is hardening layer on the surface of workpiece 3 Strengthen acid pickling 4 The temperature is too low 4 Increase the temperature 5 The content of ferrous ion is too low 5 Increase the corrosion resistance of ferrous ion phosphating film Rust return occurs in the drying process 1 The thickness of phosphating film 1 Reduce the free acidity 2 The total acidity is low 2 Increase the phosphating solution 3 Residual liquid 3 Strengthen neutralization and water washing 4 Low phosphating temperature 4 Increase of temperature 5 Short phosphating time 5 Increase of time 6 Overlapping of workpiece during drying 6 Separate monomer placement 7 Local water accumulation of workpiece 7 Change of workpiece placement angle after phosphating 1 Low free acidity 1 Increase of free acidity 2 Unclean washing 2 Uneven phosphating film 1 Unclean oil removal 1 Enhanced oil removal 2 Hardening layer on workpiece surface 2 Enhanced pickling 3 Uneven material after heat treatment 3 Enhanced pickling 1 High ferrous ion content 1 Treatment with hydrogen peroxide 2 Pickling bath solution brought into phosphating solution 2 Enhanced neutralization and water washing Pay attention to operation process