5 Frequent Faults of Double-Knife Paper Sheeter Machine: Cause Analysis & Solutions
Double rotary paper sheeter machine are widely used for cutting white cardboard, kraft board, coated paper, laminated cardboard and other heavy-grammage paper. During long-term continuous production, various quality defects and unexpected shutdowns may occur due to improper operation parameters, wear of consumable parts, mechanical aging and faulty electrical detection components.
This article sorts out typical frequent faults encountered on-site, analyzes their root causes, and provides three categories of practical solutions including remote commissioning, on-site maintenance and structural upgrading, helping equipment operators quickly carry out troubleshooting.
1: Failure to cut white cardboard/kraft board above 200gsm, excessive paper fuzz on cutting edges
Symptom: Cardboard delamination, abundant fibrous residues on edges; finished paper cannot be fed directly to printing machines. Root Causes: Excessive knife clearance caused by long-term wear of rotary shear knives; Incomplete cleaning of paper roll surfaces, sand and hard impurities mixed in paper leading to chipping of tungsten carbide blades; High brittleness of tungsten carbide blades (standard regrinding cycle: 8~12 months; 24-hour non-stop production will further shorten service life).
Solutions: On-site fine-tuning: Our engineers calibrate the clearance between upper and lower rotary shear knives on site, controlling the gap within 0.01~0.03 mm. Knife adjustment follows a progressive principle: test cutting on thick paper until complete separation, then conduct repeated tests with thinner paper and ultra-thin paper in sequence. Experienced technicians usually need 2~3 adjustments to achieve optimal cutting effect. The precision of knife adjustment directly determines the regrinding cycle of rotary knives. Proper adjustment enables one year of operation without blade replacement; poor adjustment may require blade replacement within 3 to 5 months. Spare parts replacement: Select alloy steel rotary shear knives dedicated for heavy board; adopt tungsten carbide blade grades with balanced high hardness, wear resistance and toughness.
2: Imprinted light spots on paper during 2 rolls cutting at the same time
Symptom: Belt or pressure roller marks appear in the middle of paper, resulting in scrapped finished products. Such marks are particularly obvious on gold card, silver card and coated paper, causing prominent color difference after printing.
Root Cause: Extrusion and friction at the overlapping section of high-speed and low-speed conveying belts during synchronous dual-web feeding.
Solutions: Production process optimization: Dual-web slitting is available for thin paper; single-web production is recommended for paper above 250gsm, as dual-web slitting easily triggers web breakage for heavy board. Structural installation: Install star wheels and independent pressure belts to shorten the overlapping conveying distance of paper. Star wheels are available in rubber, flannel and brush materials; original PE conveyor belts can be replaced with flannel belts to reduce surface indentation. Complete machine upgrading: Install pressure-roller-free vacuum adsorption device arranged between high-speed and low-speed conveying sections. It removes the upper pressure rollers and eliminates paper indentation caused by contact friction of star wheels.
3: Severe curling at paper roll tail, production speed cannot be increased
Symptom: Serious bending deformation of paper near the core; the machine can only run at low speed, restricting overall production capacity.
Solutions: Parameter adjustment: Activate the automatic deceleration buffer program for roll tail via remote or on-site commissioning. The machine runs at rated speed (e.g. 300 m/min) for large roll diameters and automatically slows down for slitting when the roll diameter decreases. Hardware upgrading: Replace with widened dual bowed spreader rollers equipped with independent air pressure regulating valves; alternatively upgrade to bowed roller assembly with rubber shafts.
4: Dust accumulation on ultrasonic sensor, fixed tension reading without adjustment
Symptom: Unwinding tension loses automatic regulation, leading to continuous fluctuation of paper tightness. Root Causes: Dust covers the probe of the ultrasonic sensor, which fails to identify the real-time outer diameter of paper rolls (ultrasonic sensors judge roll size by distance measurement; partial or full dust coverage of the probe will interfere with signals); Out-of-round paper rolls caused by moisture deformation lead to frequent fluctuation of detection distance and unstable tension; Loose wiring terminals and cable joints.
Solutions: Clean the sensing surface of the sensor on site; Replace the ultrasonic sensor directly once damaged; Comprehensively inspect and fasten all cable joints and terminals.
5Chain skipping of lifting platform, uneven stacked paper after delivery
Symptom: Lifting chain skips teeth and disengages, paper stack tilts left and right; there is a risk of chain breakage under extreme conditions.
Root Causes: Long-term meshing wear of chains, rusted and stuck chain links; Loose chain pressure auxiliary device reduces chain wrap angle and causes disengagement; Insufficient counterweight for the lifting mechanism;
Stable operation of double-knife paper sheeter relies on standardized daily maintenance and standardized operation. Reasonable setting of process parameters and regular inspection of wearing parts can effectively reduce various quality faults and sustain stable production capacity.
If you encounter the above problems during the operation of double rotary sheeter machine please feel free to contact our technical team. We provide one-stop technical support including remote parameter commissioning, on-site maintenance and machine structural upgrading. We also supply full sets of original spare parts such as rotary knives, bearings, sensors and pneumatic components. Please contact us for any technical inquiries.
Our address
Dongguan city,Guangdong province
Phone Number
＋8617371066702
chm007@szchm.com
