Process and device for high-pressure coating of selected elements of parts, especially internal threads on fastening members

摘要

A process and an apparatus for high-pressure contact- coating of sections of workpieces, such as threaded openings 23 in fastening members 22, avoiding contamination of other sections of the workpieces with the coating material. A metered quantity of coating material 62 is loaded into a duct 56 and displaced with high-pressure air to a chamber 63 before an atomization nozzle 43. High-pressure air is introduced into the duct 56 and the coating material 62 is converted to mist in a chamber delimited by the workpiece 22 and tools 20, 21. Contact of the cloud with the chosen surfaces 23 follows under ventilation conditions. A restriction 45 in the ventilation line 46 brings about the necessary delay and halts the system for accomplishment of the coating. The machine construction facilitates use of the coating device with a large variety of internally threaded fastening members and accomplishes the process stage, whilst at the same time enabling rinsing of the ducts 45,56 and drying of the workpiece.