The rolled-edge sealing machine is the core and key equipment for the production line of metal cans and food empty cans packaging. It achieves the double rolled-edge sealing of the can body and the can lid through the cooperation of the first and second rollers and the pressing head, the supporting base plate directly determining the sealing performance, preservation period, and factory qualification rate of the packaged products. During continuous industrial production, multiple factors such as the long-term high-speed operation of the equipment, continuous wear of components, operational personnel's deviation in adjustment, fluctuations in the incoming quality of the can body and can lid, and inadequate lubrication and cleaning are prone to cause batch quality problems such as excessive double rolled-edge dimensions, appearance damage, sealing failure, and leakage of cans. This not only increases material loss but also causes production line shutdown and rising maintenance costs.
To facilitate the quick identification of faults by the company's internal production operators, equipment maintenance technicians, and quality control personnel, and to standardize equipment maintenance, this article, based on the actual operating conditions of the equipment, comprehensively sorts out the full range of fault phenomena, deep-seated causes, and simple troubleshooting ideas of the rolled-edge sealing machine. At the same time, it formulates a complete and implementable standardized operation and hierarchical maintenance system. The content is both based on a theoretical basis and has practicality in the field, and can be used for internal training, official website knowledge popularization, and workshop boards.
Abnormal lengths of the rolled edge hooks and the cover hooks
The body hooks and the cover hooks overlap to form a sealing barrier. An imbalance in their lengths will directly reduce the sealing strength of the seal.
(1). Excessively long body hooks
Main causes: Excessive pressure adjustment of the support base; Insufficient vertical distance between the press head and the support base; Loosening of the gap of the first roller.
Additional risks: Excessively long body hooks will cause sharp edges on the inner side of the rolled edge, resulting in "fast leaks", and after sterilization, leakage and fluid loss are very likely to occur.
(2). Excessively short body hooks
Main causes: Excessive spacing between the press head and the support base; Insufficient support pressure of the support base; Loosening of the gap of the first roller, excessive gap of the second roller; Loose support base of the support base, malfunction of the spring; Defects at the front end of the canning, insufficient width of the rolled edge of the can body, and too small radius of the rolled edge arc; The installation position of the rolled edge roller is too high.
(3). Excessively long cover hooks
Main causes: Excessive pressing force of the first roller; Insufficient thickness specification of the press head.
Optimization plan: Moderately widen the gap of the first roller, and replace the standard press head with the matching thickness to quickly improve the situation.
(4). Excessively short cover hooks
Main causes: Excessive installation position of the rollers, too low installation position of the press head; Excessive pressure of the support base, too small spacing between the press head support base; Loosening of the gap of the first roller; Small arc radius of the groove of the first roller, wear of the groove, and shaking of the upper and lower supports of the rollers; Excessive outer diameter of the press head, and excessive thickness.
Edge curling damage, sharp edges, waves, insufficient tightness
(1). Damage on the edge surface, scratches, indentations
Causes: Incorrect sequence of roller opening and closing; excessive installation height of the roller; burrs on the conveying track of the lid, conveyor jamming; loose upper and lower supports of the roller; wear of the groove; wear of the pressure head surface; excessive pressing force of the second roller.
(2). Double-edge curling "sharp edge"
Criteria: A sharp cutting sensation can be felt when touching the inner side of the edge with fingers, mostly concentrated at the joint of the container body; severe cases may result in cracking and leakage of the sheet metal.
Causes: Excessive installation height of the roller relative to the pressure head; low installation position of the pressure head, excessive spring pressure of the second roller; excessive soldering on the joint; excessive pressure on the base plate; excessive pressing of the roller, wear of the groove, shaking of the support; loose fastening nut of the bearing; long-term wear and deformation of the pressure head.
(3). Large waves on the edge surface
Causes: Excessive gap between the second roller; excessive gap between the first roller; wear of the groove; turning jamming; deviation in the sequence of roller opening and closing; wear of the groove of the second roller; poor operation; poor edge forming of the lid.
(4). Insufficient edge tightness, loose interlayer
Causes: Inappropriate curve design of the groove of the first roller after edge curling; too deep groove of the second roller, poor compaction effect; excessive adjustment of the overall gap of the second roller; too thin thickness of the lid sheet metal, poor forming performance; excessive die-cutting size of the lid; failure of the spring of the second roller, abnormal clearance with the pressure head; wear of the pressure head; poor edge flanging processing of the container body; excessive coating of the sealing rubber layer of the lid.
Standardized Usage Management Specification for Rolled Edge Sealing Machines
Production Process Operation Control
Safety Regulations: Strictly follow the safety warning signs posted on the machine body. During equipment operation, it is prohibited to insert hands into the sealing machine head, vacuum chamber, conveying track, and other moving areas; during equipment debugging and cleaning, the emergency stop switch must be pressed to cut off the power supply;
Precise Component Protection: The parts in the vacuum chamber, the pressing head, and the first and second sealing rollers are high-precision, wear-prone components. During operation and transportation, impacts and hard object scratches are strictly prohibited. Once scratches occur, they will continuously scratch the tank, causing batch rolled edge damage;
Real-time Inspection: During the production process, samples are taken every half hour to dissect and test the rolled edge indicators. In case of size deviation or appearance defects, the machine should be stopped immediately for fine adjustment to prevent the continuous production of defective products;
Material Control: Control the filling volume to avoid material overflow and sticking to the tank opening, getting caught in the rolled edge, and cleaning the stuck material promptly before sealing the tank to prevent the residue from wearing down the roller grooves.
Maintenance Details for Grading Equipment
(1) Daily Post-Shift Basic Maintenance (Required after each production shift)
Whole Machine Cleaning: Thoroughly clean the machine body, conveying track, vacuum chamber, sealing machine head, residual soup, food residues, iron scraps, and sealant stains. Use soft-bristled brushes and special cleaners to wipe. Do not use hard steel wire brushes to polish the roller and press head surfaces;
Lubrication Maintenance: Uniformly apply lubricating grease or anti-rust oil to all transmission bearings, roller support seats, chains, adjusting screw rods, and other moving friction parts. After application, run the equipment unloaded for 3-5 minutes to allow the grease to fully penetrate the joint gaps of the parts and eliminate dry friction losses;
Simple Inspection: Check the wear of the roller grooves, whether there are scratches on the press head surface, and whether the spring is deformed or loose. Mark any damaged parts and replace them uniformly before the next day's startup.
(2) Short-Term Shutdown Maintenance (Shutdown for 1-7 days)
On the basis of daily post-shift cleaning and lubrication, add rust protection: Thinly apply a layer of rust inhibitor to the metal precision parts such as the machine head roller, press head, and support base. Turn off the equipment power, cover with a dust cover, and isolate the workshop from water vapor and dust to prevent metal surface oxidation and rusting.