Maintaining profitability in plastic processing is dependent on many variables, but a critical factor you must consider is your total purging costs.
The purging process and compounds you use have far-reaching financial impacts, well beyond cost per pound. Perhaps, like many plastics manufacturers, you don’t realize how properly purging and cleaning your machines affects your bottom line.
Many plastic processors fail to use the appropriate purging compounds, and others fail to implement proper purging procedures, or a combination of both. Either issue results in a significant cut to your profitability.
Learn how purging impacts your efficiency and profitability with three vital tips to maximize your bottom line.
Tip #1: Stop Cleaning With Natural Resin Or Regrind
Natural resin and regrind are not formulated to clean your screw and barrel. It’s a misconception that the cheapest price per pound is the best way to save. Purging your machine with the next resin or regrind is time-consuming, a waste of material, and ineffective at eliminating color and carbon contamination.
These materials are not designed to clean. In actuality, they’re creating another layer of contamination on top of what’s already present in your barrel, making it even more difficult to purge. This costs you more in the long run, especially in machine downtime.
Tip #2: Start Purging With A Compound Specific To Your Process
To completely clean your screw and barrel, you must use a high-quality, high-performance purging compound. However, determining the proper purging compound depends on your specific process.
For instance, mechanical purges are typically great for injection molding machines, whereas chemical purges might be more suitable for extrusion processes involving low flow or low pressure environments, or with complex tooling and downstream equipment such as melt pumps or dies.
You may need to use a different product grade to purge when making color changes versus purging for heavy color or carbon contamination. In addition, you will need to use different grades of purging compounds when purging for low-temperature resins as opposed to high-temperature resins.
Using the proper type and grade of purging compound on a consistent basis minimizes the frequency that you need to perform screw pulls, ensuring complete purges and eliminating contamination buildup.
Tip #3: Seal Your Screw And Barrel During Downtime
Using a heat-stable purging compound to completely seal your screw and barrel is an important preventative measure to take for a number of reasons.
Whether for extended downtime or simply over the weekend, sealing your machine prevents oxidation. It’s a step that protects against carbon contamination and cuts back on how often you would otherwise need to manually clean your screw.
Additionally, sealing protects against rejects upon startup, which can create unnecessary (and often significant) material waste. Equally important, sealing enables you to start production runs more quickly by cutting waste and defects from your startup process. It increases your uptime and enables you to churn out more high-quality products.
To make plastic processing as efficient and profitable as possible, you must take into account the true and complete costs of purging. Machine downtime, purging materials and replacement materials are just some of the inputs that go into calculating your costs. Without a complete analysis of your costs and efficiency, you allow inefficient processes to cut into your potential profit.
Learn more about improving your profitability with proper purging compounds and processes.
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