Machinery and media are nothing in the mass finishing world without the right compound.
A manufactured object can be designed to specifications, but if it doesn’t look and feel finished, it may be rejected. A metal alloy can be structurally perfect, but surface corrosion may make it less presentable. Process water may work well for initial cycles before contaminants wear down its effectiveness over time.
The right compound for a given mass finishing process can solve each of these problems and more.
The quality of consumables used in mass finishing is a key factor in surface processing. Using consumables with a consistent high quality is crucial to attain set surface specifications, process times, costs and to manage considerations to any environmental impact.
There are in excess of 1700 types of vibratory media consisting of various shapes, sizes and incorporating a percentage of abrasive. These are divided typically between ceramic and plastic families.
Ceramic Media Production
A ceramic media has a higher density than that of plastic media. Ceramic chips of various shapes and sizes are formed, fired and held at certain temperatures and durations; providing an infinite range of variation and capability.
A consistent, supreme quality media is extremely important for the user to obtain a uniquely stable and reproducible surface finishing result.
Ceramic media is manufactured to exacting standards, controlled in a fully-automated way.
Plastic Media Production
The manufacture of the plastic media is also totally automated.
The plastic media is of a lower density than that of the ceramic media, therefore it is suitable for a more gentle treatment of critical component parts and softer metals.
The process involves mixing, forming and curing of the media and the whole process is computer controlled and continuously monitored. This quality standard ensures a consistent wear and cutting performance, and repetitive results during the finishing process.
Surface Finishing Compounds
Compounds can be added to the vibratory process, optimising the surface specification for: degreasing, brightening, polishing, corrosion protection and producing surfaces free of stains.
Another important function is keeping the process clean. The compound continuously flushes tiny metal particulates from the chip media and other contaminants out of the mass finishing system, keeping the media active and the parts free from contamination.
Depending on the specific process, compounds will provide various options of acidity and alkalinity as a pH factor.
Despite compounds being used for many years in mass finishing applications research and development constantly progress new formulations for special applications.
The range of different compounds is broadly diversified:
Compound for mass finishing machines is an essential part of the process. There are a huge variety of compounds available and their function is to:-
Maintain the action of the media by loosening and separating metal fines from the surface of the chips and to keep them suspended in solution so that they can be carried out of the process tub.
Change the action of a media by chemical activity
Provide an aqueous solution contained water-softening ingredients, detergents for cleaning both media and component, to chemically brighten and to provide inhibitors to prevent rust on ferrous components and tarnish on all metals
Calcium () and Magnesium () are the two most common ions that are found in hard water, while iron (Fe2+), Manganese (Mn2) and Aluminium (Al3+) can also contribute to hardness.
Hardness is defined as the sum of the calcium (Ca2+) and magnesium (Mg2+) concentrations, both expressed as calcium carbonate in milligrams per litre (mg/l). Iron (Fe2+), manganese (Mn2+) and Aluminium (Al3+) can also contribute to water hardness.
The water hardness has a significant effect on the performance of compounds. Soft water will cause foam; hard water will increase the compound usage and can cause spots on component parts during drying.
With everything that you’ll be thinking of ahead of a shut down one thing people often overlook is cleaningtheir compound dosing pump for their mass finishing machine. Whilst usually it’s a case of putting a compound drum at the bottom of the non-return valve and the pump just works when it has the chance to stand idle for a period of time it is wise to give it a little attention. Many pumps contain diaphragms and these use a plastic tube which is opened and closed to encourage the compound to move.