Firstly, we conduct inspections after each production stage. For the final finished products, we perform full inspections in accordance with customer requirements and international standards.

We will respond within 24 hours of receiving your enquiry on working days.

Please provide product task requirements list and processing drawings , and contact our sales manager.

Springback (Under/Over Angle)

• Phenomenon: After bending, the tube angle deviates from the set value (usually less than the set value).
• Main Causes:
• Material properties (different elastic moduli of metals from different batches or grades).
• Mold wear or size mismatch.
• Incorrect springback compensation value set in the program.
• Solution: Perform a trial bend, measure the actual angle, and increase or decrease the springback compensation amount in the control system. For new materials, springback parameters must be retested.

Ovalization (Tube Collapse)

• Phenomenon: The cross-section of the bent tube changes from circular to elliptical.
• Main Causes:
• Mandrel issues: Mandrel not used, incorrect mandrel type selected (e.g., insufficient number of ball mandrels), incorrect mandrel position (advance amount) adjustment, or mandrel wear.
• Excessive pressure: Excessively high pressure from the clamp die or pressure die directly flattens the tube.
• Poor mold matching: Groove dimensions of the bending die or clamp die do not match the tube outer diameter (too large or too small).
• Solution: Check and correctly install/adjust the mandrel; optimize pressures of each die; ensure mold dimensions match the tube.

Wrinkling (Inner Wall Folds)

• Phenomenon: Wavy folds occur on the inner wall of the bent tube.
• Main Causes:
• Mandrel issues: Mandrel not used or positioned too far back, failing to effectively support the tube wall.
• Mold issues: Anti-wrinkle plate (pressure block) not installed, incorrectly positioned, or worn, failing to effectively flatten the inner material.
• Excessively fast bending speed: Material flow cannot keep up.
• Solution: Ensure mandrel and anti-wrinkle plate are installed and correctly adjusted; appropriately reduce bending speed; this is a key issue to prevent for thin-walled tubes.

Wall Thinning or Cracking

• Phenomenon: Significant thinning of the outer wall at the bend, even cracks.
• Main Causes:
• Poor material ductility or defects.
• Excessively small bending radius exceeding material limits.
• Insufficient mandrel support leading to excessive stretching of the outer wall.
• Solution: Check material quality; increase bending radius (use a larger radius bending die); optimize mandrel support; consider hot bending process (for thick-walled tubes or special materials).

Oil Circuit Failure

• Phenomenon: Insufficient pressure, slow movement, crawling, abnormal noise.
• Main Causes: Contaminated hydraulic oil, low oil level, damaged oil pump, oil pipe leakage, blocked or damaged valve block, clogged filter element.
• Solution: Regularly check oil level and quality; replace hydraulic oil and filter element on schedule; check pipeline tightness; have hydraulic pump and valves inspected by professionals.

Mold-Related Failures

• Phenomenon: Tube scratching, bending slippage, loud noise.
• Main Causes: Severe wear of molds (bending die, clamp die, pressure die), loose installation, insufficient lubrication, poor manufacturing precision of molds themselves.
• Solution: Regularly check mold wear and replace as needed; ensure secure installation; apply special lubricant to tube-mold contact surfaces to reduce friction and scratching.

Transmission System Failure

• Phenomenon: Accuracy loss, backlash, abnormal noise.
• Main Causes: Wear or lack of lubrication in lead screws, guide rails, bearings, etc.; increased gear backlash; servo motor/encoder failure (for CNC tube benders).
• Solution: Regular maintenance and lubrication with specified oil; check and tighten mechanical connections; calibrate servo system.

Program Errors/Data Loss

• Phenomenon: Chaotic movements, failure to execute commands, parameters reset to default.
• Main Causes: Operator input errors; memory loss due to dead backup battery; system software failure.
• Solution: Recheck and re-enter program; replace control system backup battery; contact manufacturer for software repair or upgrade.

Servo Alarm/Over-Travel Alarm

• Phenomenon: Equipment emergency stop, servo or axis over-travel alarm displayed on control panel.
• Main Causes: Mechanical jamming; damaged or malfunctioning limit switch; servo drive/motor overload or failure; interference.
• Solution: Manually check mechanical smoothness; inspect limit switch status; restart equipment to see if it can reset; check grounding and line shielding for anti-interference.

Sensor Malfunction

• Phenomenon: Inaccurate detection of mandrel position, Y-axis distance, etc.
• Main Causes: Sensors such as proximity switches, encoders, or linear scales covered with oil, metal shavings, or damaged.
• Solution: Clean sensor sensing surfaces; check connection lines; replace sensors if necessary.

Inaccurate Tube Feeding (Y-axis) Positioning

• Phenomenon: Incorrect straight length between each bend.
• Main Causes: Insufficient clamp die clamping force causing tube pullback during bending; backlash or slippage in feeding mechanism (e.g., carriage); incorrect programmed feeding length.
• Solution: Increase clamp die clamping force; check and adjust feeding mechanism mechanical backlash; calibrate feeding zero point.

Inaccurate Spatial Angle (B-axis) Rotation

• Phenomenon: Multiple bends not in the same plane (for 3D tubes).
• Main Causes: Large backlash in rotation mechanism; incorrect programmed angle; axial rotation of tube in clamp die.
• Solution: Mechanical adjustment to eliminate backlash; check program; ensure clamp die effectively prevents tube rotation.

1. Observation and Description:Clearly record failure phenomena (when, during which action, any abnormal sounds or alarms).
2. Safety Check:First stop machine, relieve pressure, cut off power, and ensure safety before inspection.
3. From Simple to Complex:

• First check operation: Are program and parameter settings correct?
• Then check process conditions: Are mold, mandrel, and lubrication correct?
• Next check mechanical and hydraulic: Any looseness, leakage, or abnormal noise?
• Finally check electrical and control: Alarm codes, sensor signals, line connections?

4. Consult Manual: Always refer to equipment manufacturer's operation and maintenance manual.
5. Seek Support: For complex electrical or hydraulic failures, contact equipment supplier or professional maintenance personnel promptly.

Developing and strictly implementing a regular maintenance plan for tube benders (daily, weekly, monthly, annual maintenance) is the most effective and economical way to reduce the occurrence of the above issues. Maintenance content includes cleaning, lubrication, tightening, checking hydraulic oil and filter elements, calibration, etc.