Process

Aims

Potential Problems

Belt grinding

Processing separations lines, removal of surface defects.

Uncovering of micro-porosities, deep casting burrs may not be removable, excessive metal removal, depositing of dust.

Drum polishing

De-burring and removal of dirt from the castings. If correctly set up, this process can be used for polishing.

Excessive removal can lead to surface damage. Castings can become distorted.
Wet processes may cause stains that are difficult to remove.

Vibration grinding

Rounding off of corners, gloss grinding, removal of oxides (adherence of solid matter and corrosion possible).

Damage through hammering, depositing of rubber.
Wet process can cause stains. Depositing of filings.
Excessive removal of metal.

Polishing

Achieving a high degree of gloss.

Buffing wheels can cause pressure points.
Residual polishing agent on the castings.
Excessive removal of metal. Contour changes.

Degreasing (solvents)

Dissolving separation and grease deposits and any processing residues.

With too low a cleansing effect not all surface impurities are removed.
A too great cleansing effect can lead to corrosion caused by acid production.

Degreasing (water and lye)

Dissolving separation and grease deposits and any processing residues.

Lye remaining on the surface can cause corrosion.

Equipment

Stand for galvanisation and for contacts.

Contact marks (stains), varying bearing strengths.

Anodic degreasing

Final degreasing process and removal of dirt.
Achieving a chemically pure surface.

Not all dirt may be removed causing subsequent adhesion problems.

Rinsing

Action to remove oxide and dirt that may be deposited during anodic de-greasing.

The water must be absolutely pure as otherwise
stains could form.

De-scaling (pickling)

Action to remove oxide and dirt that may be deposited during anodic de-greasing.

Acid left behind in concavities or at seams leads to corrosion and galvanisation bubbles.