Vibratory finisher, vibe, tumbler, rumbler, shakers, polisher, or however you might call it, is loud, messy, and never works like it used to right?... well it can come down to a few tweaks keeping it from being the most reliable, repeatable, and your all-time favorite machine.
Vibratory media is a critical component of the process, and if it goes unmaintained, your time-cycles will increase, parts will become dull and dirty, and dissatisfaction with the process can shy people away from utilizing vibratory machines to their full potential.
Glazed media is a big reason for the loss of productivity in a vibe. Just like a grinding wheel, media is designed to provide some surface altering characteristics by means of abrasive. Soils and contaminants build up on the surface of the media, significantly reducing the effectiveness of the abrasive.
The media in this evaluation is Washington Mills "C" bond, which is considered a "medium cut" media. There is enough soil buildup in this media to effectively eliminate all cutting potential, resulting in exponential increases in time cycles as well as unpleasant finish quality. The graphical comparison below shows a roughness differential of over 200Ra.
This is a result of processing high volumes of aluminum parts with improper compound selection and a flowrate that is incapable of flushing the amount of soil out of the machine at a high enough rate.
You will notice glazing takes place quickly when the materials being processed are on the softer side like brass, copper, aluminum and some non-heat treated steels. When parts are processed with high piece-counts, burrs, manufacturing soils, and substrate
attrition will rapidly concentrate the effluent and the discharge become visibly dirty.
Some discoloration is to be expected, however, if your wastewater discharge is as concentrated as the above images, there is a high probability the media is glazed to some degree and should be monitored for productivity loss.
Largely, glazing is due to improper chemistry selection and/or dosing methods. Chemistry selection is based on many factors such as materials being processed, types of manufacturing soils, and resulting finish requirements. Many times we will find chemistry being used because it was what came with the machine or the ... "that's what we use for everything". ... answer.
If your process requires the drain on the machine to be closed, you will need to cycle the fluid in the machine by filling and draining frequently to avoid concentrating the soils and redepositing soils back onto the parts. Ideally, for a process that has high part loads, the drain should remain open and the fluid should be able to flow through the machine. This flushing action will allow the compound to carry out the media residue and soils creating a clean finishing environment while increasing the luster and cleanliness of the part.
Cleaning glazed media is actually fairly simple. Our chemistry line, Chemtrol, manufactures chemistry to do just that. Depending on what your media is glazed with, our Sales Engineers can recommend a product like Chemtol 409
to recondition media with proper cycle time and concentrations.
Utilizing dosing pumps or batch processing, the Chemtrol product is added to the media mass to begin emulsifying and dissolving residual manufacturing soils and metals. There is no standard cycle time for this process, however, you will start to see results in minutes. If your process is part intensive and glazing can not be avoided, it is a good idea to incorporate media maintenance into your PM's. Reach out and we will put you in touch with your Sales Engineer who can guide you on media conditioning processes as well as help you improve the root cause of the glazing.
- The Precision Finishing Team
"Committed to better results... We'll prove it."