Increase Profitability With More Efficient Color Changes

Plastic processing companies around the world are scrambling to gain an advantage over their competition. The economic slowdown has resulted in companies having to re-evaluate certain areas to decrease production costs in hopes of increasing profit margins. Lean manufacturing is one of the first directions many companies look to when reducing costs. The essence of lean manufacturing is “doing more with less.” For example, a color change is one common sector where this type of improvement may be needed during production. This article will highlight the benefits of using an efficient purging compound for color changes.

The two major costs associated with color changes are downtime and scrap resin. Minimizing downtime and scrap is the goal for a company that is trying to institute the lean manufacturing philosophy for color changes. Many companies will claim that the scrap produced is not a major issue because it can be sold to their scrap dealer. It is true that a company will receive payment for their scrap, but never will they be able to recover a 100% of the initial virgin resin cost. The difference between what the scrap dealer will pay and the cost of the virgin resin results in a loss. Other companies will note that the scrap produced during color changes will be used as regrind and be made into parts. Yes, in this situation there will be no material loss (scrap resin); however, there is still a cost associated with the color change. Every minute of downtime due to a color change is a minute the company is not producing good parts and earning a profit. Typically, the largest cost associated with a color change is due to the downtime that is created. However, using an effective purging compound will reduce both the downtime and the scrap rate.

Below is a graph comparing the cost of using resin to purge a machine versus the cost of using a purging compound (Ultra Purge was used for this study). The trial was performed on a 300 ton injection molding machine (with hot runners) going from red HDPE to white HDPE. Using a purging compound resulted in a 55% reduction in material costs and a 75% reduction in downtime (machine time = $300/hr). The total savings attributed to using the purging compound for this trial was $1,001. Also note that the purging compound used in this trial was 100% recyclable.

In conclusion, using an efficient purging compound will result in significant savings for each color change, and the associated savings may give companies an edge over their competition.