Over the last sixteen years the majority of non-appearance, functional plastic parts that AGS has run across are black in color. This still leaves a significant number of these types of parts being molded in virgin, natural plastic. This begs the question, why are some non-appearance parts molded in natural instead of black?
In some cases there is a good reason for specifying the natural color such as a simple visual cue for identifying two different parts that may look identical or to provide a contrast against a dark background for poke-yoke vision systems. However, based on our experience this line of reasoning seems to be the exception rather than the rule.
The primary reason is the fact that natural, virgin materials often cost less than their black, virgin counterparts. In the virgin resin world, plastic materials come out of the polymerization reactor in their respective natural color. For example, natural acetal, ABS, polypropylene, and polyethylene look white in color while natural nylon appears light tan. In order to make virgin materials black an additional manufacturing step is required which adds cost.
In the recycled plastic world, the bulk of recovered post industrial and post consumer scrap materials have already been pre-colored. For example, it is not unusual to see orange regrind a few months before road construction season or Halloween. Black color concentrate is added to these multi-colored feedstocks in order to end up with a consistent looking material.
Surprisingly, the greatest resistance that customers have shown when converting from virgin, natural resin to an AGS Injectoblend recycled alternative is the change to black. Since the parts has always been molded in natural, there is the perception that there must have been an engineering basis for this callout. Usually when this issue is fully investigated the customer finds the decision to use natural color was in fact driven by the same motive driving the conversion to the AGS Injectoblend recycled alternative; lower cost.