1.Introduction of Tungsten Carbide Corrugating rolls

Corrugating roll, as the most important part of corrugated cardboard production line, whose abrasion resistance and service life is the main technical index for measuring its quality and economical efficiency, directly influences the economic benefits of manufacturer for corrugated cardboard. As low-profit times approaching, control of production cost matters manufacturers’ competition and survival ability.

2. Merits of Tungsten Carbide corrugating roll

 

  • Strong combination between coating and matrix ensuring long service life of coating without any peeling.
  • With higher hardness of coating, abrasion resistance will be increased by manyfold and service life of it will be prolonged linearly.
  • Thickess of coating could be even and accurately controlled, ensuring the precision of rolls.
  • Surface roughness of coating will reach to Ra0.4~0.6 after special fine polishing, pretty suitable for high-speed corrugated cardboard making machine.
  • Matching with flute designs of UV and UVV type, increase efficiently hardness of cardboard and deduct wastage of paste and medium paper.
  • Theoretically, flute in service life will be never worn and take up ratio will be never changed.
  • By using tungsten carbide corrugating rolls, cardboard will be maintained at certain thickness and printed always flat for stable quality of cardboard and carton.
  • Used coating could be removed by special process and the rolls could be refurbished for reuse.
  • Advancement in service life deducts frequencies of changing, saving expenditures of manpower and material resources。

    3. Comparison tungsten carbide corrugating rolls 
    with hard chrome corrugating roll

 

 

 

Compare Item
Hard chrome corrugating rolls
Tungsten carbide corrugating rolls
Comparison on flute type and take up ratio For weak abrasion resistance of hard chrome coating, the original height of its flute will be designed more higher, which accordingly increased its take up ratio; ②Usually the top of flute will designed more blunt for ensuring its service life and meanwhile its’ take up ratio accordingly increased. For high hardness and abrasion resistance of tungsten carbide coating, its flute height could be designed more lower for decreasing take up ratio and accordingly saved medium paper; ② its top of flute could be designed more sharp to save wastage of paste and medium paper without considering its abrasion which might cause reduction of compressive strength and quality of cardboard.
Comparison on thickness of cardboard Thickness of cardboard produced by hard chrome corrugating rolls will be correspondingly lowered due to abrasion of flute during use and will be continuously lowing. Theoretically, flutes of tungsten carbide corrugating rolls will be never worn, so thickness of cardboard will be always even for sustainable good quality.
Comparison on Service life of corrugating rolls Service life of hard chrome corrugating rolls is usually during 6 million to 8 million. Service life of tungsten carbide corrugating rolls could be reach to at least more than 30 million, which deducts frequencies of changing and saves expenditures of manpower and material resources.
Comparison on usability of matrix For severe abrasion, diameter and hardness of hard chrome corrugating rolls will be certainly deduced every time during refurbishment and so does for its times of refurbishment. For tungsten carbide corrugating rolls, used coating could be removed by special process and the rolls could be refurbished for reuse more times.

APPENDIX: T. U. R Introduction

 

  • You have not noted maybe that during your machine working in high-speed, you didn’t get high profit rates of return and then you could consider the direct effect to your profit from T. U. R of your corrugating rolls.
  • T. U. R (Take up ratio) means when corrugated paper be taken shape, its ratio of medium paper to liner paper. (For example, cardboard of length 300mm, whose medium paper be extended to 450mm, then it’s T.U.R is 1.5 by 300 divide 450) 
  • Under the same condition of corrugated paper taken shape, if you could choose corrugating roll with T.U.R lower 3% than what you used now, then…
    Supposing your corrugating rolls run 120000 meter per day, then you could save 3600 meter of medium paper per day by calculation method of 120000 meter multiply 3%. And accordingly you could save 108000 meter every month by 3600 meter multiply 30 days.
  • The wider your machine is, the bigger you lose. For instance, if your machine with width 2.5 meter, 150g medium paper, and using medium paper of 2100mm wide (appr. 83〃), then you will lose 1.134 ton per day; on the analogy of this, if your have machine of 2.5 meter wide by using medium paper of 1500mm wide (appr. 59〃), then you will lose 0.81 ton per day. So, the new competitive T.U.R of corrugating roll will help you recover cost within two month and the remained all is profit.

Current T.U.R in Southeast Asia area

Flute Type Nos. of tooth within 300mm Height of Flute T.U.R
A Flute 34 plus or minus 2 4.6mm plus or minus 0.2mm 1.43~1.62
C Flute 40 plus or minus 2 3.6mm plus or minus 0.2mm 1.38~1.55
B Flute 48 plus or minus 2 2.8mm plus or minus 0.2mm 1.33~1.51
E Flute 78 plus or minus 2 1.5mm plus or minus 0.15mm 1.25~1.41
F Flute 126 plus or minus 4 0.7mm plus or minus 0.1mm 1.13~1.27
G Flute 166 plus or minus 4 0.5mm plus or minus 0.1mm 1.10~1.26

 

Pressure Rolls' characteristic

Material: SC45 seamless steel tube

Straightnessaccuracy: less than or equal to φ0.02MM

Circular run-out:  less than or equal to 0.02MM

Hardness: more than or equal to HRC45°

Spec.: φ50-φ800mm *L100~5000 MM
CNC cylindrical grinder external grinded, dynamic balancing corrected, hard chrome electroplated and polished

 

 

Glue Rolls' characteristic 
Material: SC45 seamless steel tube

Size of mesh: concave
convex flower: 0.8mm;1.0mm;1.2mm;1.4mm;1.6mm 

concave flower: 1.0mm;1.5mm; 2.0mm

Spec.: φ50-φ800mm *L100~5000 MM

Straightnessaccuracy: less than or equal to φ0.02MM

Circular run-out:  less than or equal to 0.02MM

Treated by hardening and tempering after rough machining by lathe,

Grinded by CNC cylindrical grinder, knurling processed and dynamic balancing corrected

 

Doctor Rolls' characteristic
Material: No. 45solid round steel

Hardness: more than or equal to HRC45°

Spec.: φ50-φ800mm *L100~5000 MM

Treated by hardening and tempering after rough machining by lathe,

Grinded by CNC cylindrical grinder, hard chrome electroplated and polished.