Adjustment Methods for Spindle and Needle Plate Circularity and Flatness

Circular knitting machines are intricate devices designed to produce continuous tubes of fabric. Their operation relies heavily on precise mechanical components that rotate around a central axis. Over time, regular maintenance becomes crucial to ensure these machines operate at optimal performance levels. This maintenance includes comprehensive overhauls involving cleaning, part replacement, and meticulous inspection to detect deviations from specified tolerances. Adjustments are then made to restore precision and functionality.

Common Causes of Circular Knitting Machine Failures

Pulley Rotation Inaccuracy

One of the primary causes of circularity issues in circular knitting machines is inaccuracies in pulley rotation. This problem often stems from wear and tear in the locating grooves between the plate and pulley, leading to looseness. As a result, the cylinder's circularity can be compromised. To diagnose this, a dial gauge is used to measure variations in the toothed disc holder or needle cylinder when manipulated forcefully.

Uneven Contact Surfaces

Uneven contact surfaces between cogs and the piston cylinder, or between the pin plate and the base, can cause elastic deformation under tension. This deformation deviates from the required roundness of the cylinder, impacting fabric quality. Identifying and rectifying these uneven surfaces is critical during maintenance.

Adjustment Process for Circular Knitting Machines

Relax and Adjust Screws

Begin the adjustment process by loosening screws that secure critical components like the syringe and needle plate. Gradually adjust these components to achieve a near-circular shape within a tolerance range typically around 0.03 mm in diameter. Use precision gauges to monitor changes and insert spacers as necessary to achieve the desired alignment.

Fine-Tuning with Gauge

Once the components are adjusted to the correct shape, securely tighten the screws. Use a gauge to check for any remaining gaps between components, aiming for minimal post-adjustment changes (usually less than 0.01 mm). Adjust by adding or removing spacers as needed and ensure all screws are tightened evenly to maintain uniform tension across the assembly.

Ensuring No Gaps

Repeat the adjustment process for each screw, ensuring there are no gaps where the screws are tightened. It's crucial to maintain a relaxed state for the syringe and needle plate throughout this process to prevent unnecessary stress that could affect machine performance.

Checking Flatness

Inspect the flatness of the syringe and needle plate surfaces using precision instruments. If the pointer readings indicate deviations exceeding 0.05 mm, adjust the flatness by inserting shims strategically. This step ensures uniform fabric tension and quality during the knitting process.

Adjusting Circularity

Achieve optimal circularity of the syringe plate using a self-tapping tap head, adjusting it within a tolerance range of approximately 0.05 mm. Secure all screws after achieving the desired circular shape to maintain stability and precision in machine operations.

Precision Issues with Other Components

Sinker, Cam Base Plate, or Shuttle Frame

While not requiring the same level of precision as needle plates, these components are critical for accommodating product variations during production. Proper installation and tuning ensure they function smoothly and contribute to consistent fabric quality.

Adjustment Method for Life-Killing Board

Maintain balance by adjusting the tray level using screws and position blocks as necessary. Use a dial gauge to detect gaps between components and adjust with shims to ensure optimal alignment and performance.

Maintaining Double Jersey Machine Roundness and Flatness

Address deviations in machine diameter and flatness by adjusting bearings and pulleys. Fine-tune these adjustments using the machine's built-in adjustment screws to ensure uniform fabric tension and quality across the entire knitting process.

Final Checks and Adjustments

Ensure No Internal Stresses

After completing adjustments, conduct thorough checks to ensure no internal stresses are present within the machine. Internal stresses can compromise component integrity and lead to premature wear or failure during operation.

Diagonal Reference Points

For machines with eccentric motion, monitor diagonal readings to detect any elliptical motion paths. Reshape or repair components as needed to restore circular knitting machine functionality and ensure consistent fabric quality.

Addressing Wear or Deformation

If deviations from optimal performance are due to wear or deformation of critical components, prioritize repair or replacement. This proactive approach minimizes downtime and ensures continuous operation of circular knitting machines in manufacturing environments.

Conclusion

Maintaining the precision and functionality of circular knitting machines requires a systematic approach to inspection, adjustment, and fine-tuning. Focus on eliminating gaps, ensuring even contact surfaces, and restoring circular motion paths are essential steps to achieving consistent fabric quality and production efficiency. Regular maintenance not only prolongs machine lifespan but also enhances overall operational reliability in textile manufacturing processes.