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Views: 0 Author: Site Editor Publish Time: 2026-10-15 Origin: Site
Warp knitting machines used for shade net production operate continuously under high-speed and high-tension conditions. Even minor variations in yarn properties, machine synchronization, or knitting settings can quickly affect fabric formation and production stability.
This guide highlights common machine operating problems, their diagnostic symptoms, and the key areas operators should inspect first, providing a practical approach to faster and more effective troubleshooting.
Yarn breakage may result from yarn-related defects, such as knots, uneven yarn thickness, or irregular yarn quality.
Mechanical causes may include:
Friction or interference between guide needles and latch needles.
Guide needles positioned too low.
Excessive warp yarn tension.
Insufficient clearance between the knitting needles and the knock-over plate.
Incorrect guide bar shogging timing.
Insufficient guide bar return force.
Check and adjust the positions of the guide needles and knitting needles.
Reduce yarn tension to the appropriate level.
Inspect and correct the guide bar shogging timing.
Adjust the guide bar return spring and its tensioning mechanism.
Missed stitches generally occur when guide needles are incorrectly installed or when the guide bar is positioned too high.
Insufficient warp yarn tension can also cause missed stitches, particularly along the fabric edges.
Check and correct the guide needle positions.
Lower the guide bar to the appropriate working height.
Adjust and maintain consistent warp yarn tension.
Missing weft insertion occurs mainly when the inserted weft yarn length is insufficient, usually due to excessive yarn tension or incorrect guide bar positioning.
Reduce the weft insertion yarn tension to the proper level.
Inspect and adjust the guide bar position.
Ensure that sufficient yarn is supplied for proper weft insertion.
Irregular loops are mainly caused by incorrect guide bar shogging timing during the underlap movement.
If the guide bar moves too early, some yarns may accidentally enter the hooks of the latch needles, resulting in irregular loop formation.
Check and adjust the positions of the knitting needles and guide bars.
Verify and correct the guide bar shogging timing.
Ensure proper synchronization between yarn guiding and needle movements.
Stop marks, also known as horizontal stop lines, are primarily caused by sudden changes in knitting speed, especially during machine stopping and restarting.
These speed fluctuations may produce visible horizontal lines or variations in fabric density.
Maintain stable machine operating speeds whenever possible.
Avoid unnecessary machine stops during production.
Stop the machine only when necessary, such as in cases of yarn breakage or mechanical problems.
Ensure smooth acceleration and deceleration during machine startup and shutdown.
Needle breakage is generally caused by mechanical malfunctions, incorrect component positioning, or excessively high yarn tension.
Inspect the knitting mechanism for mechanical interference.
Reduce excessive yarn tension.
Check needle alignment and the condition of related knitting components.
Improve operator training and maintenance practices to prevent improper machine adjustments.
Unwanted tuck stitches are mainly caused by improper yarn tension settings.
Common contributing factors include:
Insufficient chain yarn tension.
Excessive weft insertion yarn tension.
Excessive pile yarn tension.
Incorrect sinker positioning, especially when the sinkers are set too high.
Adjust the chain yarn, weft insertion yarn, and pile yarn tensions to suitable levels.
Check the sinker positions and lower them when necessary.
Ensure that the sinkers properly hold down the inserted weft yarns to prevent them from lifting during the knitting process.
Correct sinker positioning can effectively reduce unwanted tuck formation and improve fabric quality.
When an electrical or control system malfunction occurs, the machine usually displays an alarm message or fault code on the operator interface (HMI).
The meaning of each alarm depends on the machine brand, control system, and specific alarm code.
Check the alarm message or fault code displayed on the HMI.
Refer to the machine manufacturer's alarm code list or troubleshooting manual.
Inspect the relevant electrical components, sensors, drives, or control circuits according to the alarm information.
Resolve the underlying fault before restarting the machine.
Operators should avoid adjusting multiple machine parameters simultaneously. Instead, troubleshooting should follow a systematic process, starting with the visible symptoms and tracing them back to their root causes.
First, check any machine alarms or visible fabric defects and identify the operating conditions when the problem occurred.
Next, inspect the relevant yarn paths, knitting components, mechanical systems, and machine settings.
Adjust one parameter at a time, observe the results, and then make further changes. This approach helps identify the root cause and prevents unnecessary adjustments.
Effective troubleshooting involves more than simply correcting visible fabric defects.
For shade net manufacturers, the key objective is to identify early warning signs, locate the root causes of machine problems, and prevent recurring faults through standardized inspection and preventive maintenance.
By adopting a systematic troubleshooting approach, manufacturers can improve machine operating stability, reduce unplanned downtime, increase production efficiency, and maintain consistent shade net quality.
