How Often Should You Purge Your Injection Molding Maintenance?

Regular maintenance is crucial in the injection molding industry, and one of the most essential tasks in any production schedule is purging. The Use of a Purging Compound for Injection Molding is not only about keeping your machines clean—it’s also about maximizing efficiency, reducing downtime, and ensuring product quality. 

But how often should you purge your injection molding machine? The answer depends on several factors, including material changes, production cycles, machine usage, and the type of resin being processed.

Purge During Material or Color Changes

One of the most common times to use a Purging Compound is during material or color transitions. Without Purging, remnants of the previous material or pigment can remain inside the screw and barrel, leading to contamination in the next run. This can cause inconsistent coloration, black specks, or even defective parts.

If you’re changing from a dark to a light color or switching between incompatible materials, always schedule a purge between transitions. This minimizes scrap and maintains product integrity.

Purge at the End of Each Production Run

Many manufacturers schedule a purge at the end of each production cycle. This practice helps clear out leftover resin before it cools & hardens inside the barrel. Cold resin buildup can lead to significant downtime during startup and may require manual cleaning.

By Purging at the end of a shift or job, you ensure the system is clean and ready for the next run—saving both time & labor.

Purge Before Machine Shutdowns

If your injection molding machine will be idle for an extended period, purging before shutdown is a smart move. Sitting resin can degrade and carbonize, making it difficult to remove once operations resume. This not only affects product quality but can also damage the equipment over time.

Using a High-quality Purging Compound for Injection Molding helps prevent thermal degradation and keeps internal surfaces in optimal condition.

Routine Preventive Maintenance Purging

Even if you’re not switching materials or shutting down the machine, regular preventive purging is recommended. Based on your production volume and the types of materials used, a purge every 100 to 300 hours of operation is a good starting point. This removes unseen residue and prevents long-term contamination or wear inside the barrel.

Watch for Warning Signs

If you’re seeing signs like dark specs, inconsistent melt flow, or part discoloration, it may be time to purge—even if it’s earlier than your routine schedule. These are indicators that residue is building up inside the machine & affecting production quality.

Keep Your Machine Production-Ready

Routine Purging keeps your injection molding equipment running efficiently and your final products consistent. Whether you’re performing regular maintenance, switching materials, or preparing for downtime, having a trusted Purging Compound on hand makes all the difference.

Explore industry-tested solutions with Unicleanplus—trusted for performance & reliability in plastic processing.