Mass finishing from A-Z
The process
Mass finishing is a separating process for the surface treatment of primarily metallic workpieces. The workpieces to be processed are placed in a container together with abrasive bodies (so-called chips) and, in many cases, a chemical additive in aqueous solution (compound), usually as bulk material. An oscillating or rotating movement of the working container creates a relative movement between the workpiece and the abrasive body, which causes material removal on the workpiece, especially on its edges. The surface appearance of the workpieces, the roughness, the material removal and the deburring performance can be varied almost at will by the machines and tools used (grinding tools and compound).
The following machining objectives can be achieved by vibratory finishing:
- Deburring, edge rounding
- Shining, smoothing, polishing
- Descaling, cleaning
- Matt finishing
- Grinding
- Degreasing
The variants
The generation of the relative movement determines the type of process. A distinction is made between six variants:
Vibratory finishing (TV, RV)
Large vibrators cause the entire content to vibrate, thus enabling the processing of heavy or large workpieces that would remain at the bottom of the batch, get stuck or bump into the container during drum and centrifugal grinding. The content moves in a horizontal screw mould or roller. The design of the machines is either pot or trough shaped for batches or trough and screw shaped for continuous processes.
Centrifugal finish (TE)
Centrifugal grinding has been able to establish itself on the market mainly in two variants. With both processes, only light to medium-heavy workpieces can be machined.
Planetary centrifugal grinding is characterised by a rotor with several drums mounted on the circumference, whose direction of rotation is opposite to that of the rotor.
In disc centrifugal grinding, the batch is in a stationary, pot-shaped container whose concave plastic base rotates.
Drum finish (not at AVAtec)
In drums, a horizontal or inclined container, the drum, is rotated around its longitudinal axis. The rotational speed of the drum has a decisive influence on the metal removal rate and the surface quality achieved. As the speed increases, the contents are carried along the wall in the direction of rotation and thus lifted off. The solid components slide down the slope above a certain speed.
Drag finishing (not with AVAtec)
Drag grinding systems are ideal for high-quality and damage-sensitive workpieces that need to be ground or polished without contact. A rotating carrier carousel, equipped with up to twelve rotating spindles, immerses the workpieces attached to it in the stationary chip mass. The carousel rotation and the rotary movement of the spindles guarantee uniform workpiece machining.
Plunge-slide machining (not with AVAtec)
This process is the only one in which individual or several workpieces are held simultaneously by means of a gripper and held in the flowing chip mass. As a rule, the chip medium is located together with the compound in a pot-shaped, rotating container.
Chips (abrasivs)
To process the finish of the workpieces, the workpieces are placed in a container as bulk material together with abrasives (see "C for chips") and additives (see "A for additives").
Criteria for process selection (workpiece, result, chips)
In order to select the appropriate process for processing, the following criteria must be considered:
Which workpiece is involved? Which material? Which geometries?
What result is to be achieved? Are there any specifications for the desired surface?
Which chips, compounds and additives are suitable?
Depending on the workpiece and the result, more than one process step may be necessary to achieve the desired result.
Care and maintenance
In order to keep our machines running as long as possible, it is recommended to clean the machines regularly and to maintain them at certain intervals. We provide you with instructions here that make care and maintenance easy and uncomplicated for you to carry out yourself. You can find more information here!
AVAtip: We offer individual workshops on the subject of mass finishing. Together with our free sample processing, we will provide you with the relevant know-how and work out the right process for your workpieces. Contact us at +49 711 68700760 or info@avatec.de.
No liability is assumed for the correctness and completeness.