Evaluation Method for Purging Compounds – Resin Change and Color Change Edition –

There are two common patterns of issues during material changeovers. Please review the costs associated with each problem. Issue Patterns

1. It takes a long time for the previous material to be fully purged (the subsequent material purge takes a long time to complete).
2. It seems that the material replacement is complete, but foreign material believed to be the previous material is found mixed in during production.

In the case of [1], specifically, consider how much “cleaning agent” is being used. If possible, also check the “cost of disposing of the lost material.” For [2], a similar approach is recommended, but in addition to [1], it is suggested to estimate the “time loss (time spent on re-purging until completion).” When comparing color change and resin replacement performance, it is important to consider the balance with the unit cost of the purging compound itself. Understanding the costs involved in a single changeover is crucial if you want to compare unit costs and performance on the same footing. While customers often consider “amount of cleaning agent used × unit cost,” there have been many cases where results were reversed by also considering factors like “time required for re-purging × labor cost” and “amount of waste × disposal cost.”

We recommend “first trying it with the manufacturer’s recommended method.” Each purging agent has an optimal usage method specific to the product. If the manufacturer’s recommended method differs from your usual purging method, “changing the purging procedure” can be a burden, and it may not be easy to use it as recommended. However, it is also true that the performance of purging agents varies significantly depending on injection conditions and usage temperature. For example, our cleaning agent Ecomaru is recommended to be used with injection purging, as detailed in the “How to Use Purging Agents” guide. It is important to understand that the optimal usage method varies with each purging agent, and first measure its effectiveness accordingly.

It is recommended to try it in various situations. Since the materials and cleaning principles adopted by different companies and products vary, the effects may not be apparent under certain evaluation conditions. If you are addressing a specific problem, judging based on one condition might suffice, but as much as possible, change the resin to be cleaned and the replacement material. By conducting a comprehensive evaluation, you will be able to see the advantages and disadvantages.

Summarize the current situation and results confirmed in Step 1 as a “cost estimation” and compare the performance in numerical terms. Please use the “Cost Estimation Sheet.” Many companies that have evaluated purging agents have reported that the costs associated with purging operations were significantly higher than expected. By roughly estimating the costs, you may find opportunities for improvement, such as realizing that you have been spending a lot of time and money on purging operations. We recommend quantifying these costs as a step toward improving cost and efficiency.