Lubricants for a drawing process must have an adequate film strength in order to withstand
the high pressures and high temperatures associated with drawing. The lubricant’s wetting
ability should be considerable as well, to spread readily over the ever-expanding surface
area of the part. Oiliness control is of essence, since a certain amount of it is necessary,
while its excess may prove harmful.
Drawing lubricants, as any other lubricants, must be nonaggressive toward the part,
toward the tooling, the machinery, and the operator. Their application and removal must be
uncomplicated and economical.
There is a variation in a lubricant’s qualities with each material drawn. For example,
aluminum alloys are more plastic and may be drawn into greater depths without tearing or
fracturing. However, they also possess a high coefficient of friction, which, on the die side,
must be decreased with proper lubrication. Such a decrease should be controlled, as an
excessive oiliness of the lubricant will certainly produce slippage of the material, with
resulting damage to the part and perhaps even to the die.
When selecting the lubricant for a given drawing operation, all subsequent manufacturing
processes must be taken into account, such as heat treatment and surface treatment.
Some lubricants, usually those of high lubricating qualities, are highly adherent and for that
reason difficult to remove off the part.
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