The last step after electroplating is dehydration drying. This process is not so complicated and technical in comparison with the previous processes. In the eyes of ordinary people, it is just a few waters. It is not a technology.
If you don't pay attention to it, you may have problems in this process, and you should pay attention to it and you can't ignore it. The general phenomenon is that there is a trace of water from top to bottom.
Some workpieces with complicated shapes are slowly ejected after the plating solution left in the screw holes is baked. When the performance is slight, a stain is emitted. The serious performance is that the surrounding coating is corroded (such as bronze). It is unqualified, can not meet the requirements of the guests, can only be reworked, so the treatment is not good, not only delay the delivery period, but also waste a lot of manpower and material resources. For the solution of this problem, we generally take a few methods:
1) using ultrapure water
Whether the electroplated workpiece is clean or not, the most important thing is to clean the water. If the post-treatment water quality is not clean, the water has high hardness, contains a lot of salt, microorganisms, etc., the surface condition of the workpiece after cleaning will be very bad, such as the color change of the workpiece. , a lot of smudges, etc.
The water quality problem can be solved by the general factory. It is solved by reverse osmosis + ion exchange device. After treatment, the conductivity of water is generally below 5 Ω/cm 3 , and some are even lower. The lower the conductivity, the better. An increase in conductivity after time requires regeneration of the ion exchange.
2) Adding auxiliary devices
Some complex workpieces can generally assist some blowing and suction equipment. With the compressed air purging, it is easy to blow off some of the more sturdy workpiece surface water droplets, especially the workpiece with relatively large smooth surface.
For some workpieces that are only hooked on the hanger, only the method of suction can be adopted. If a purge is also taken, the workpiece is blown off and flowered. This method is especially suitable for some workpieces with holes. For example, vacuum cleaners can be used to modify some front water nozzles.
The water in the last two tanks during the bleaching process is properly heated. Generally speaking, the temperature is controlled at about 60 degrees, but the temperature should not be too high. The too high temperature will cause the water to evaporate faster and the extraction operation is not safe.
The temperature increases the surface tension of the water, on the one hand, accelerates the water from the surface of the workpiece, and the workpiece with a certain heat has a certain help effect when it enters the tunnel furnace to dry, which can speed up the temperature increase, and the water droplet is easily separated under the hot air blowing. The surface of the workpiece.
4) taking dehydrated oil
This method has been used in the past, such as multi-stage anhydrous ethanol dehydration, dehydration anti-rust oil, etc. This method is not suitable for the cleaning of the post-plated workpiece, and will not be discussed here.
5) Adding a dehydrating agent
The above method can easily remove the water droplets on the surface of some simple electroplated workpieces, but it is also ineffective for some complicated workpieces. The above method adds a lot of manpower and material resources. If a little dehydrating agent is added to the drifting tank, then the back The cleaning effect has been greatly improved.
The dehydrating agent is a composite of various surfactants, corrosion inhibitors and the like. Its biggest feature is that it can quickly form a hydrophobic film on the surface of the workpiece, replace a large amount of water and prevent discoloration, thus greatly reducing the labor of the method of blowing and sucking.
The biggest weakness of using dehydrating agent is: if it is used improperly or uses inferior dehydrating agent, some workpieces pass through the spray frame, the bonding force between the force frame and the surface of the workpiece is low, the hardness of the force frame is greatly reduced, the protection is lost, and the friction and scratching are slightly It is also not advisable to take off the frame. This type of problem can be avoided only by using a good quality dehydrating agent.
At present, the special dehydrating agent for post-plating treatment developed by some manufacturers on the market can fully meet this requirement, with less dosage, high dehydration efficiency, no dust on the surface after dewatering, and good adhesion with the force frame. After a number of factory trials, the response is better. There are better methods or suggestions for post-treatment dehydration in metal plating. I hope everyone can discuss and share work experience.
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