Grit blasting tooling maintenance

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Abrasive grit blasting when used as a pre-cursor to subsequent processing such as coatings of the thermal spray family almost always have requirements of blasting required, blasting optional and no blast allowed areas. This is from component design criteria. Such criteria may preclude abrasive grit blasting from being existent in some areas. And how can this be accomplished? Well there are two ways in which abrasive grit blasting is prevented in certain areas: one is by masking tape and the other is by hard tooling. The former is generally used in one piece or otherwise low volume applications and the latter is used in high volume applications. In this post, we will limit ourselves to abrasive grit blasting on high volume applications.

When it comes to high volume applications, abrasive grit blasting tooling becomes very important. We are referring to the grit blast masking tooling. Such tooling is generally made out of an organic material such as ultra high molecular weight polypropylene or sometimes even polyvinyl chloride. At other times, there could be a steel masking tooling with a piece of masking tape underneath it. This latter is used when there is aggressive blasting and the tape is used as a secondary level of protection against overblasting.

In such cases, it is imperative to perform a hard tooling maintenance check on the grit blasting tooling. Because over time, the repeated abrasive blasting environment that the tooling “sees” can end up fraying the edges and the next thing you know the sharp cut offs that may be required are no longer evident. Unlike in tooling used for coatings masking operations, hard tooling used in abrasive grit blasting seldom see a build up; rather they see a wear down.

There have been cases where I have observed abrasive grit blasting tooling failing simply because of mechanical abuse. It is thus important to keep a watchful eye on such hard tooling because all of the subsequent operations will get affected if the blasting operation is not performed accurately.