Often, small parts are plated in a rotating plating barrel in bulk. The barrel is immersed into the plating tank and rotated slowly. There are several methods used to make electrical contact to the parts. The configuration of some parts is such that the plating is distributed unevenly. Also, some parts have non-conductive plastic or ceramic areas. The media is added to make better contact to the parts and to balance out the plating. Depending on the parts, different type media is used. The most common are small plastic balls that have been metalized with copper. Also, steel shot, of different shapes, is used.
The media builds up with the same plating layers that are put on the parts. The media is used over and over and goes through many plating cycles. There could be hundreds of layers of various metals on the media. When the media gets too big, it is scrapped.
If PMs are present, a large refinery would simply melt the steel media, along with added copper. The plastic balls would be burned and the residue melted. The bars are then shipped to a primary smelter for recovery.
For the little guy, acids are usually used to dissolve the layers. This is difficult because there is no definite sequence to the layers. One has to keep changing acids, depending of what the top layers are.
I have always liked the idea of using abrasion to remove plating and plating media might be the perfect application for this. The vibratory finisher, mentioned by GeeDub, might just work very well for this.
A crazy possibility that just occurred to me. In the past, I have mentioned my experiments with using shot peening for removing plating from plated parts, such as pins. The peening stretches the plating laterally and it breaks into flakes and falls off. What if you could load the plated media into a blaster inside of a hood and shoot the media against a heavy steel plate. Would the same thing happen? I have no idea how one could blast these parts.
The media builds up with the same plating layers that are put on the parts. The media is used over and over and goes through many plating cycles. There could be hundreds of layers of various metals on the media. When the media gets too big, it is scrapped.
If PMs are present, a large refinery would simply melt the steel media, along with added copper. The plastic balls would be burned and the residue melted. The bars are then shipped to a primary smelter for recovery.
For the little guy, acids are usually used to dissolve the layers. This is difficult because there is no definite sequence to the layers. One has to keep changing acids, depending of what the top layers are.
I have always liked the idea of using abrasion to remove plating and plating media might be the perfect application for this. The vibratory finisher, mentioned by GeeDub, might just work very well for this.
A crazy possibility that just occurred to me. In the past, I have mentioned my experiments with using shot peening for removing plating from plated parts, such as pins. The peening stretches the plating laterally and it breaks into flakes and falls off. What if you could load the plated media into a blaster inside of a hood and shoot the media against a heavy steel plate. Would the same thing happen? I have no idea how one could blast these parts.
