{"id":8746,"date":"2026-06-22T07:55:15","date_gmt":"2026-06-22T07:55:15","guid":{"rendered":"https:\/\/zhongtuomachine.com\/?post_type=product&p=8746"},"modified":"2026-06-22T07:55:17","modified_gmt":"2026-06-22T07:55:17","slug":"common-faults-causes-and-solutions-for-steel-purlin-forming-machines","status":"publish","type":"product","link":"https:\/\/zhongtuomachine.com\/ar\/product\/common-faults-causes-and-solutions-for-steel-purlin-forming-machines\/","title":{"rendered":"Common Faults, Causes, and Solutions for Steel Purlin Forming Machines"},"content":{"rendered":"

 <\/p>\n

This document is designed for universal cold bending machines used with C-beams, Z-beams, U-beams, and purlins. It categorizes issues into five major types\u2014defects in finished product formation, feeding system malfunctions, precision cutting errors, mechanical operation failures, and electrical control system failures\u2014and provides corresponding solutions: temporary emergency measures, standard corrective actions, and preventive maintenance plans, making it ideal for frontline workshop operations.<\/p>\n

 <\/p>\n

Forming defects in finished profiles (the most common type of failure)<\/b><\/strong><\/h2>\n

Profile distortion, lateral bending, and arching<\/b><\/strong><\/h3>\n

Malfunction:<\/b><\/strong>\u00a0The finished product exhibits full section torsion, unilateral outward bending, central arching, and cross-sectional angle deviation, making it unable to fit the installation reference.<\/p>\n

Key causes:<\/b><\/strong><\/h4>\n

\u2460 Asymmetric left-right gaps and frame misalignment of each forming roll;
\n\u2461 Excessive pressure on a single roll set leading to internal stress imbalance in the sheet;
\n\u2462 Improper distribution of bending angles across forming passes, resulting in excessive deformation at the first bend;
\n\u2463 Uneven thickness and significant hardness variation across batches of raw steel strips;
\n\u2464 Inconsistent height differences between discharge rollers causing inclined loading during material discharge.<\/p>\n

Solution \uff1a<\/b><\/strong><\/h4>\n

Emergency procedure:<\/b><\/strong>\u00a0Stop operation to calibrate the bilateral gaps of each roll set, ensuring consistent roller clearances on both sides at the same workstation; make fine adjustments to unilateral pressure relief and release internal stresses in the sheet metal.<\/p>\n

Rectify and reform:<\/b><\/strong>\u00a0Level all forming frames using a level; adjust the coaxiality of the drive shaft; reconfigure the bending path angles; reduce the deformation amplitude in the initial bending stage.<\/p>\n

Prevention:<\/b><\/strong>\u00a0Standardize the material and thickness tolerances of the feeding steel strip; adjust the height of discharge rollers, and install limiters and anti-deviation guide wheels.<\/p>\n

The cross-sectional dimensions of the profile exceed the specified limits; the edge heights are inconsistent; and the angles do not meet the required standards.<\/b><\/strong><\/h3>\n

Fault phenomenon\uff1a<\/b><\/strong>The steel profile flanges vary in height and length; the bending angles are either too large or too small; the opening dimensions exceed tolerance limits, resulting in batch-wide nonconformities.<\/p>\n

Core Causes\uff1a<\/b><\/strong><\/h4>\n

\u2460 Roll wear, surface chamfering, or deformation;
\n\u2461 Loose roll locking bolts causing operational displacement;
\n\u2462 Misalignment of feed guide plates resulting in improper steel strip feeding;
\n\u2463 Fluctuating servo feed speed leading to unstable forming forces.<\/p>\n

Solution<\/b><\/strong>\uff1a<\/h4>\n

Testing<\/b><\/strong>\uff1aMeasure the finished cross-section section by section using a caliper, compare it with the roller at the most worn position, and mark the replacement point.<\/p>\n

Rectify and reform<\/b><\/strong>\u00a0\uff1aTighten all roller lock nuts and frame mounting bolts; recalibrate the feeding guide plate to center it; grind or repair lightly worn rollers, and replace severely worn rollers with matching tooling rollers.<\/p>\n

\u0627\u0644\u0645\u0639\u0644\u0645\u0629<\/b><\/strong>\u00a0\uff1aStandardize the feeding speed across the entire line; prohibit frequent switching between high and low speeds during molding.<\/p>\n

The profile surface exhibits scratches, dents, and peeling.<\/b><\/strong><\/h3>\n

Fault phenomenon\uff1a<\/b><\/strong>Continuous scratches on both sides of the steel strip, punctate pressure pits, and galvanization layer detachment, compromising both corrosion resistance and appearance.<\/p>\n

Core Causes\uff1a<\/b><\/strong><\/h4>\n

\u2460 Iron chips, welding slag, and oxide scale adhere to the roller surface;
\n\u2461 The roller surface is corroded with burrs and sharp edges;
\n\u2462 The guide wheel lacks sufficient hardness, causing jamming and material scraping;
\n\u2463 Lubrication-free forming results in dry friction-induced damage to the plate surface.<\/p>\n

Solution<\/b><\/strong>\uff1a<\/h4>\n

Daily\uff1a<\/b><\/strong>Stop the machine to clean all roller and guide wheel surfaces of metal chips and impurities, then use an oil stone to remove surface burrs.<\/p>\n

Rectify and reform \uff1a<\/b><\/strong>Replace the damaged guiding nylon wheel to prevent severe metal friction; apply specialized forming lubricant to galvanized steel profiles during molding.<\/p>\n

Management and control\uff1a<\/b><\/strong>During raw material intake and storage, remove oxide slag from the steel strip surface; install a dust removal and slag scraping plate before feeding.<\/p>\n

The profile plate exhibits surface bulging and internal creases.<\/b><\/strong><\/h3>\n

Fault phenomenon\uff1a<\/b><\/strong>wrinkling occurs at the rounded corners of bending, with localized blistering on the plate surface; this phenomenon is highly prevalent in thin-walled steel sections.<\/p>\n

Cause&Solution\uff1a<\/b><\/strong>Excessive roller pressing force \u2192 Reduce the rolling stroke per station; Insufficient bending radius \u2192 Replace with a roller featuring larger radius; Excessive feeding tension \u2192 Release the material feeding\/discharging damping device<\/p>\n

\"C<\/a><\/p>\n

Malfunctions related to delayed material feeding<\/b><\/strong><\/h2>\n

The steel strip deviates during feeding, and material flows off to one side.<\/b><\/strong><\/h3>\n

Cause\uff1a<\/b><\/strong>The feed guide groove is eccentric; the pressure from the upper and lower rollers is uneven on both sides; the wound coil is eccentric; and the ground frame is tilted.<\/p>\n

Solution\uff1a<\/b><\/strong>Adjust the bilateral feed guide plates centrally; evenly adjust the pressure adjustment spring of the feed roller; install a centering and tightening device on the material roll; re-level the equipment base.<\/p>\n

Frequent material jams, blockages, and situations where the steel strip bends and gets stuck at certain processing stations.<\/b><\/strong><\/h3>\n

Cause\uff1a<\/b><\/strong><\/h4>\n

\u2460 The gap between the first forming roller is too small;
\n\u2461 Waste material from irregular edges or corners is trapped within the roller gap;
\n\u2462 The overlap thickness of steel strip joints exceeds the specified limit;
\n\u2463 The speed ratio between the feeding motor and the forming roller is incorrect.<\/p>\n

Solution\uff1a<\/b><\/strong>Increase the gap between the initial forming rolls; perform scheduled cleaning of waste materials at the processing station; grind and flatten steel strip joints before feeding; ensure electrical control synchronization between feeding speed and forming rotation speed; install an overload-based reverse feeding program.<\/p>\n

The feeding mechanism is slipping; the material feed is rotating without movement; the lengths of the profiles vary.<\/b><\/strong><\/h3>\n

Cause\uff1a<\/b><\/strong>The shipping roller exhibits smooth wear, insufficient pressing force, and oil contamination on its surface; the steel belt surface also becomes slippery due to oil contamination.<\/p>\n

Solution\uff1a<\/b><\/strong>Polish the surface of the feed roller and adjust the clamping pressure; wipe off oil stains from the roller surface and steel belt; replace worn rubber rollers with anti-slip patterned rollers.<\/p>\n

\"CZ<\/a><\/p>\n

Cut length fixed, punching failure<\/b><\/strong><\/h2>\n

The final product’s length does not meet the specified dimensions, and there are variations in length across batches.<\/b><\/strong><\/h3>\n

Cause\uff1a<\/b><\/strong>Encoder offset; loss of counting parameters; displacement caused by feeding slip; zero point offset of the cutting servo; incorrect modification of PLC length parameters<\/p>\n

Solution\uff1a<\/b><\/strong>Encoder offset; loss of counting parameters; displacement caused by feeding slip; zero point offset of the cutting servo; incorrect modification of PLC length parameters<\/p>\n

The hydraulic cutting tool exhibits significant burr on the cutting surface, skewed cuts, and chip breakage.<\/b><\/strong><\/h3>\n

Cause\uff1a<\/b><\/strong>Excessive clearance between the upper and lower cutting blades; dulled cutting edges; failure to adjust clearance when cutting steel of varying thicknesses; excessively high hydraulic descent speed causing impact on the cutting edge.<\/p>\n

Solution\uff1a<\/b><\/strong>Fine-tune the cutting blade fit clearance; grind and polish the cutting edge; replace the alloy cutting blade; set the cutting gap according to thickness requirements; adjust the hydraulic throttle valve to reduce the downward cutting speed.<\/p>\n

<\/b>H<\/b><\/strong>ole position deviation, hole diameter deformation, punching tear<\/b><\/strong><\/h3>\n

Cause\uff1a<\/b><\/strong>Misalignment of punching die; wear of die core; failure to center the profile after forming; excessive hydraulic punching pressure<\/p>\n

Solution\uff1a<\/b><\/strong>Ibrate the punching die for coaxiality; install a punching limit fixture; replace the worn punch and die; reduce the hydraulic pressure for punching<\/p>\n

 <\/p>\n

Mechanical transmission failure; frame operation malfunction<\/b><\/strong><\/h2>\n

Abnormal noises during device operation, at specific locations, or under load<\/b><\/strong><\/h3>\n

Fault Point Identification\uff1a<\/b><\/strong><\/h4>\n

Chain abnormal noise\uff1a<\/b><\/strong>Chain slack, oil deficiency, tooth wear \u2192 Tension the chain, apply gear oil, replace worn sprockets<\/p>\n

Abnormal noise at the roller shaft station\uff1a<\/b><\/strong>Lubrication deficiency in the bearing, damaged balls, excessive clearance in the bushing \u2192 Replace the bearing and apply high-temperature resistant grease.<\/p>\n

Load friction noise\uff1a<\/b><\/strong>Rolls are misaligned and rub against each other; the profile also rubs against the frame \u2192 The parallelism of the roller assembly needs to be recalibrated.<\/p>\n

Significant body vibration, operational shaking, and base displacement<\/b><\/strong><\/h3>\n

Cause\uff1a<\/b><\/strong>Coaxiality deviation of the drive shaft; loose coupling; aging of the base shock absorber pads; uneven force distribution across multiple roller sets; loose motor mounting bolts<\/p>\n

Solution\uff1a<\/b><\/strong>Ibrate the drive shaft concentricity and tighten the coupling; replace the shock-absorbing foot pads; evenly distribute forming pressure across all stations; tighten the bolts on the main motor base.<\/p>\n

Hydraulic system oil leakage, insufficient pressure, inadequate cutting force<\/b><\/strong><\/h3>\n

Cause\uff1a<\/b><\/strong>Aging of the oil seal ring, insufficient hydraulic oil level, clogged filter element, wear of the hydraulic pump, and failure of the relief valve pressure regulation.<\/p>\n

Solution\uff1a<\/b><\/strong>Replace all oil seal rings; add hydraulic oil of the same grade with wear-resistant properties; clean the hydraulic filter element regularly; adjust the operating pressure of the relief valve; replace the hydraulic pump directly when pressure attenuation occurs in the pump body.<\/p>\n

\"\"<\/a><\/p>\n

Malfunctions in the electronic control and frequency conversion systems<\/b><\/strong><\/h2>\n

The device experiences lag during startup and shutdown, along with an overload alarm for the frequency converter.<\/b><\/strong><\/h3>\n

Cause\uff1a<\/b><\/strong>Excessive load during forming operation; mismatched motor power; insufficient current limiting parameters in the frequency converter; aging wiring causing short circuits; motor stalling due to jammed workstations.<\/p>\n

Solution\uff1a<\/b><\/strong>Reduce the pressure on individual rolls; increase the overload protection threshold of the frequency converter; inspect the power circuit; install an overload shutdown protection program for machine idling.<\/p>\n

Touch panel parameters are malfunctioning with random data fluctuations<\/b><\/strong><\/h3>\n

Cause\uff1a<\/b><\/strong>Electromagnetic interference in the workshop, loose wiring on the panel, malfunctioning PLC program, and unstable power supply voltage.<\/p>\n

Solution\uff1a<\/b><\/strong>Install shielding grounding wires on the electrical control cabinet; secure communication wiring terminals; power down and restart the PLC for reset; install a voltage stabilizer to accommodate fluctuating workshop voltages.<\/p>\n

Emergency stop failure; limit switch malfunction<\/b><\/strong><\/h3>\n

Cause\uff1a<\/b><\/strong>The travel switch is blocked by metal shavings; the wiring is broken; and the contacts are oxidized.<\/p>\n

Solution\uff1a<\/b><\/strong>Clean the sensor contact points; replace the waterproof limit switch; regularly check the safety circuit’s operation.<\/p>\n

 <\/p>\n

Key Principles of Universal Preventive Maintenance (Reduce Failures by 80%)<\/b><\/strong><\/h2>\n

Daily pre-shift tasks:<\/b><\/strong>\u00a0Clean iron debris from the rolls, check hydraulic fluid level, and test the emergency stop limit function.<\/p>\n

Weekly: <\/b><\/strong>Apply grease to chains and bearings, and verify the dimensional accuracy of all profiles.<\/p>\n

Monthly:<\/b><\/strong>\u00a0Adjust the rack level, tighten all vehicle bolts, and calibrate the encoder’s zero point.<\/p>\n

Material control:<\/b><\/strong>\u00a0The use of steel strips with thickness deviations, excessive joint overlap, or severe corrosion is strictly prohibited during production.<\/p>","protected":false},"excerpt":{"rendered":"

  This document is designed for universal cold bending machines used with C-beams, Z-beams, U-beams, and purlins. It categorizes issues into five major types\u2014defects in finished product formation, feeding system malfunctions, precision cutting errors, mechanical operation failures, and electrical control system failures\u2014and provides corresponding solutions: temporary emergency measures, standard corrective actions, and preventive maintenance plans, […]<\/p>\n","protected":false},"featured_media":8747,"template":"","meta":{"_gspb_post_css":""},"product_brand":[],"product_cat":[21],"product_tag":[],"class_list":["post-8746","product","type-product","status-publish","has-post-thumbnail","product_cat-c-z-u-w-purlin-machine","first","instock","shipping-taxable","product-type-simple"],"_links":{"self":[{"href":"https:\/\/zhongtuomachine.com\/ar\/wp-json\/wp\/v2\/product\/8746","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/zhongtuomachine.com\/ar\/wp-json\/wp\/v2\/product"}],"about":[{"href":"https:\/\/zhongtuomachine.com\/ar\/wp-json\/wp\/v2\/types\/product"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/zhongtuomachine.com\/ar\/wp-json\/wp\/v2\/media\/8747"}],"wp:attachment":[{"href":"https:\/\/zhongtuomachine.com\/ar\/wp-json\/wp\/v2\/media?parent=8746"}],"wp:term":[{"taxonomy":"product_brand","embeddable":true,"href":"https:\/\/zhongtuomachine.com\/ar\/wp-json\/wp\/v2\/product_brand?post=8746"},{"taxonomy":"product_cat","embeddable":true,"href":"https:\/\/zhongtuomachine.com\/ar\/wp-json\/wp\/v2\/product_cat?post=8746"},{"taxonomy":"product_tag","embeddable":true,"href":"https:\/\/zhongtuomachine.com\/ar\/wp-json\/wp\/v2\/product_tag?post=8746"}],"curies":[{"name":"\u062f\u0628\u0644\u064a\u0648 \u0628\u064a","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}