Five Signs it is Time to Replace Your Injection Molding Barrel or Feed Screw

Regular cleaning and maintenance of injection molding barrels and feed screws are essential to ensuring they remain in optimal condition. Without proper upkeep, both the quality of plastic components and the overall project’s budget can be compromised. Although barrels and feed screws are designed to withstand significant wear and tear, they experience considerable stress over time. Eventually, repairs and replacements will be necessary to maintain the quality and efficiency of your production process. But how can you determine when it is time to replace these critical components?

Knowing when to replace your injection molding barrel and feed screw is crucial for maintaining product quality and minimizing downtime. Several signs indicate that it may be time to replace a barrel or feed screw, including:

1.) Excessive Wear and Tear

• Surface Damage: Over time, barrels and feed screws can accumulate surface damage such as cracks, pitting, or erosion, particularly in high-stress areas. Worn feed screws may develop uneven wear patterns, reducing their ability to properly convey and melt material, leading to inconsistent molding results.
• Changes in Part Quality: If you start noticing defects like inconsistent dimensions, surface imperfections, or poor surface finish in your molded parts, it could indicate that the barrel or feed screw has worn down and is no longer producing consistent results.

2.) Diminished Efficiency

• Longer Cycle Times: If the barrel or feed screw requires longer cycle times to complete the molding process, it may lose its precision and effectiveness. A worn feed screw can cause improper material melting and mixing, resulting in inconsistent material flow and longer processing times.
• Frequent Downtime: If maintenance and repairs are becoming more frequent and prolonged, it may be a sign that the barrel or feed screw has reached the end of its useful life.

3.) Increased Maintenance Costs

• If the cost of maintaining and repairing the barrel or feed screw exceeds the cost of replacing it, it may be time to invest in a new one. Frequent repairs also mean more downtime, which can impact overall productivity.

4.) Obsolescence & Design Limitations

• If you are introducing new materials or changing the design of the part being molded, older barrels and feed screws may not be suitable for these new requirements. A replacement might be necessary to accommodate the new design or material properties.
• If your current barrel or feed screw design is outdated and unable to keep up with production demands, higher precision requirements, or new technologies, it may be time to upgrade to a more advanced component.

5.) Barrel & Feed Screw Age & Loss of Precision

• As barrels and feed screws age, the accuracy and consistency of the molded parts can decrease. If you are unable to meet tight tolerances due to wear, or if the feed screw no longer maintains proper material flow, replacement is necessary.
• Every barrel and feed screw has a useful lifespan based on its material, design, and the number of cycles it has undergone. After several cycles, degradation occurs, necessitating replacement to maintain optimal production.

As the feed screw spins within the barrel ID they are particularly susceptible to friction and mechanical breakdown over time. The combined effect of friction, heat and resins can cause wear on various components, leading to compromised contact points or inefficient material processing. When a barrel experiences excessive wear, it can lead to inconsistent shot control, higher melt temp, and increased resistance during the molding process. Similarly, a worn feed screw may develop dead zones or reduced compression efficiency, leading to poor melt quality and material degradation with longer cycle times due to slippage.

By regularly monitoring the condition of your barrel and feed screw, you can identify early signs of wear and address issues before they lead to significant problems. While maintenance costs are generally lower than the expense of replacing a barrel or feed screw, there are situations where replacement may be the most cost-effective and efficient solution in the long run. Ultimately, staying proactive about maintenance ensures that production continues smoothly and product quality remains high.

How can we help you?

The doors have been open at Santa Fe Machine Works, Inc. since 1923. For the past 45 years, we have been dedicated solely to manufacturing and supplying new & rebuilt injection & extrusion screws, barrels & valves to the plastics industry. We also offer custom-tailored screw, barrel, and valve combinations, allowing our customer’s production goals to be met in the best, fastest, and most cost-effective ways possible. Our employees have over 200 years of combined experience in the plastics industry and are eager to support your specific extrusion or injection needs. Have a question, need assistance, or looking for a quote? Contact us today!