Problem Analysis and Solutions for Pipe grooving machine

In modern pipeline engineering, the roll grooving machine has gradually replaced traditional welding and threaded connection methods as an efficient pipe pre-processing tool. By processing standard grooves at the end of pipes, it provides a precise foundation for the rapid installation of grooved pipe fittings, and is widely used in fire protection, HVAC, water supply, and petrochemical industries.

The working principle of the roll grooving machine utilizes an electric motor to drive the concave pressure wheel to rotate, while the hydraulic system drives the convex pressure wheel to apply pressure to the rotating pipe, thereby extruding the required groove in the pipe wall. This method not only processes quickly, completing a groove in seconds, but also achieves precision up to 0.1 mm, effectively ensuring the sealing of pipe connections and avoiding leakage risks. Compared with traditional processes, using a roll grooving machine can reduce long-term costs by about 40% and shorten installation time by 30%.

• Applicable pipes: Seamless steel pipes, galvanized pipes, plastic-lined pipes, etc.
• Working principle: The rotating concave pressing wheel (lower wheel) drives the pipe to rotate, and the convex pressing wheel (upper wheel) gradually applies pressure to the pipe under the action of the hydraulic cylinder, forming a groove.
• Common parameter reference:
  • Voltage: Usually three-phase 380V.
  • Processing range: Common models cover specifications such as DN50-DN300 (2"-12").
  • Spindle speed: Usually low-speed rotation (about 23 rpm).

1. Site and power supply:
   • Place the machine on a flat and level ground. For large-diameter machines, it is recommended to fix it with anchor bolts.
   • Check if the power supply is 380V, ensure there is no phase loss, and the motor rotation direction is correct (usually clockwise when viewed from the handle side, or observe whether the pipe rotation direction is close to the positioning plate).
2. Machine inspection:
   • Check if the reducer is short of oil and whether the hydraulic oil tank level is normal.
   • Check if the rollers (pressing wheel and knurling wheel) are installed correctly, and whether the specifications match the steel pipe to be processed.
3. Workpiece treatment:
   • Pipe cutting: The pipe end cut must be perpendicular to the pipe axis.
   • Deburring: Remove burrs, rust, and dirt from the inside and outside of the pipe end.
   • Weld seam treatment: For welded steel pipes, the internal weld seam at the pipe end must be ground flat, with a grinding length of no less than 60mm.

1. Pipe support:
   • Place a triangular support at the rear of the machine according to the pipe length.
   • Put one end of the steel pipe into the lower roller and support of the grooving machine, and the other end on the support.
   • Leveling: Adjust the support height to make the steel pipe in a horizontal state, or make the support end slightly higher (about 1 degree) to prevent the pipe from deviating outward during grooving.
   • Press the pipe end against the machine's positioning plate (baffle).
2. Depth adjustment (key step):
   • Start the machine and let the lower roller drive the steel pipe to rotate.
   • Press down the hydraulic handle to make the upper pressing wheel contact the pipe surface.
   • Set the limit:
     • Refer to the "grooving depth parameter table" on the machine nameplate.
     • Adjust the limit nut. The usual method is: first let the upper wheel contact the steel pipe, rotate the limit nut until it contacts the top surface of the cylinder, and then reverse rotate the nut by the corresponding scale according to the required depth (e.g., 2.0mm).
     • Note: The gap between the limit nut and the top surface of the cylinder is the grooving depth.
3. Grooving operation:
   • After confirming everything is ready, keep the machine running.
   • Slowly press down the hydraulic handle, and the upper pressing wheel starts to apply pressure to the steel pipe.
   • Observation: When the limit nut contacts the top surface of the cylinder (or reaches the set depth), do not stop the machine immediately.
   • Shaping: Let the steel pipe continue to rotate for 1-2 revolutions to ensure the groove is round.
4. Unloading and measurement:
   • Turn off the power and stop the machine.
   • Turn the pressure relief valve counterclockwise to raise and reset the upper pressing wheel.
   • Take out the steel pipe, and use a groove gauge (caliper) to measure the groove depth and width, confirming whether they meet the standard (e.g., GB5135.11).
     IV. Problem Analysis and Solutions

     Problem No.	Problem Description	Causes Analysis	Solutions
     1	Flaring or cracking at the pipe sealing surface after grooving	1. Excessive working clearance 2. Incorrect lower roller installation 3. Pipe material too hard	1. Adjust working clearance (e.g., add adjustment shims) 2. Replace with correct lower roller according to pipe specifications 3. Verify pipe material meets processing requirements, replace if necessary
     2	Roller cannot reach proper position, elastic feeling when pressing lever	1. Insufficient hydraulic oil 2. Air entered oil circuit 3. Check valve seal not tight	1. Check oil level and add clean 32# hydraulic oil or motorcycle oil 2. Loosen check valve and oil drain screw, cycle press to remove air 3. Clean oil circuit: disconnect power, remove oil tank, clean with gasoline
     3	Abnormal sharp noise during grooving	1. Improper pipe support position 2. Pipe end not perpendicular 3. Excessive friction	1. Adjust pipe support position left or right to optimal point 2. Recut pipe end vertically using special tool 3. Apply thin layer of lubricant on pipe end
     4	Pipe cannot advance or shakes left and right during grooving	1. Equipment or pipe not level 2. Stabilizing wheel not engaged 3. Pipe end damaged	1. Use level to calibrate, adjust support to keep pipe and equipment level 2. Slightly offset pipe by 1°-2°, then re-tighten stabilizing wheel 3. Cut off damaged pipe end or smooth it

     V. Safety and Maintenance Precautions
     1. Safety first:
        • Operators must wear protective equipment. It is strictly forbidden to operate rotating parts with gloves (to prevent entanglement), and long hair must be tied up.
        • When the machine is running, it is strictly forbidden to put hands into the roller area.
        • Before any adjustment or roller replacement, the power supply must be cut off.
     2. Daily maintenance:
        • Lubrication: Grease the pressing wheel shaft and spindle daily; regularly check reducer lubricating oil.
        • Cleaning: Clean iron filings and debris on the knurling wheel surface with a wire brush daily to prevent slipping.
        • Inspection: Regularly check if U-frame bolts are loose and if circuits are aging.