There are two types of special hangers for rack plating equipment:
One is a special hanger designed for mass production of parts;
The other is a special hanger designed according to the complex geometry of parts and special process requirements.
Aluminum and aluminum alloy hangers
When anodizing aluminum parts, aluminum and aluminum alloy hangers should be used. The hanger should be elastic to clamp the parts to avoid the formation of non-conductive oxide film due to loose contact, which will affect the continuation of anodizing.
General hanger
General hanger is suitable for a variety of parts and processes. The form and structure of general electroplating hangers should be determined according to the geometry of the plated parts, the technical requirements of the coating, the process method and the size of the equipment. For example, sheet-shaped plated parts will drift with the resistance of the plating solution between the upper and lower processes. When using hangers, the plated parts should be clamped or tied with copper wire. If the plated parts are heavy and have holes, hook-shaped hangers can be used. The use requirements are as follows:
- After using the hanger, it should be cleaned and properly stored for standby.
- Hangers used for manual operation. The loading weight is generally 1~3kg.
- The hook should have a sufficient conductive area, and its type should make it conductive. The hook of the hanger should be cleaned frequently.
- When using, be careful to load and put it gently, and try not to damage the insulation layer. Otherwise, it will cause the hanger and the workpiece to compete for electricity, resulting in partial plating or roughness of the workpiece, affecting the quality of the coating.
- After using the hanger for a period of time, it is necessary to deal with it in time and remove the coating on the hanger to ensure good conductivity. If cracks appear in the insulation layer of the hanger, it should be repaired or re-insulated in time.
Hangers for chemical treatment
When phosphating and oxidizing steel parts, you can use hangers or hangers. For general parts, try to use hangers. Under the condition of lifting equipment, the hanger can be larger. The hanger is made entirely of steel materials. Copper or brass is not required to ensure the quality of the film layer, because copper will dissolve in these solutions and contaminate the solution, affecting the quality of the film layer. The method of the hanger is the same as that of electroplating except that there is no requirement for conductive function.
The hangers and baskets used for pickling are easily damaged. Materials with good corrosion resistance or plastic products should be selected directly. Its shape is the same as that of small parts electroplating.
The oxidation of steel parts does not require electricity. Usually, a hanging basket is used. It only requires high mechanical strength, good corrosion resistance, and easy loading and unloading of workpieces. For more precise workpieces or workpieces with external threads, it is better to use hangers to avoid mutual collision.
Special hangers
(1) Bipolar method for plating inner hole fixtures.
(2) Chrome plating fixtures. The chrome plating solution has strong oxidation ability. The hanger material should be stable. Titanium or copper can be used as the hanger. The conductive part of the fixture should have a sufficient cross-sectional area and not generate heat. The fixture structure is connected by welding, and the conductive copper hook should be bent into a right angle. The fixture and the part should be in threaded contact as much as possible. The positive and negative poles of the inner hole chrome plating fixture must be electrically isolated.
Use insulating blocks (hard plastic plates or plexiglass) to replace the protective cathode. The non-working surface of the fixture should be insulated to reduce the current consumption. The gas should be exhausted as easily as possible at the location where the parts are hung. The hanger should be as light, simple, universal, and easy to load and unload as possible while ensuring applicability.
Hanger for electroplating of small parts
Small parts can be electroplated by barrel plating. If barrel plating conditions are not available, a hanging basket can be used as an electroplating tool. The frame of the hanging basket is brass or iron wire, and metal wire mesh is used at the bottom and around. The size of the mesh is based on the standard that the parts do not leak out of the hole. A slightly larger hole is conducive to obtaining a uniform thickness of the coating. In order to improve the quality of the coating and increase the deposition rate, a drilled plastic plate can be used to replace the surrounding metal mesh.