Compound is the part most people treat as a detail. That is an expensive mistake: both surface quality and media life depend on it.
What it actually does
It sets the optimum contact between media and part. Contact that is too hard means aggressive grinding. Damped contact means fine grinding. Compound is what regulates this.
It carries impurities out. It picks up particles removed from the part and from the media and transports them out of the bowl.
It keeps the media surface clean — and with it, the grinding capacity. Media loaded with deposits stops working.
It washes and degreases the parts. This is why vibratory finishing does not necessarily require a separate washing machine.
It protects against corrosion, during and after processing.
How it is selected
Three criteria, in this order.
Part material. Steel and iron, stainless steel, copper and brass, aluminium, zinc, magnesium — each calls for a different compound.
Desired effect. Grinding and deburring, degreasing, smoothing, polishing, oxide removal.
Required properties. Corrosion protection, cleaning power, foaming level, brightening effect.
Concentration
Compound is used at concentrations from 0.2% to 1%.
Low concentration — clean parts, no corrosion protection required, ordinary surface quality, soft water.
High concentration — dirty parts, corrosion protection required, high quality demanded, hard water.
Flow rate
Solution flow is calculated per kilogram of media: 0.2 to 0.5 l/h for each kilogram.
Low flow for coarse processing on relatively clean parts. High flow for finishing, where a good surface is required and parts come in dirty.
Open or closed circuit
Open circuit — waste water goes to the drain. The values above apply directly.
Closed circuit — water is recovered, filtered and reused. Here the values are corrected: concentration is multiplied by three, flow rate by one and a half.
A closed circuit costs more to install and consumes more compound, but it removes the cost of treating waste water.
Related reading
- Vibratory Finishing Consumables
- How to choose vibratory finishing media
- What industrial parts washing is and when you need it
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