CMT-30_Improvement technique case study on paper machine

CMT-30_Improvement technique

1. Technical Report: CMT-30 Improvement on Fluting Grade
Objective
To increase the Concora Medium Test (CMT-30) value of fluting grade paper through process and chemical
parameter optimization across the wet end, forming, press, drying, and size press sections.
1. Headbox Horizontal Slice - Increase
Action: Open the horizontal slice width.
Justification: Increases fiber delivery across the web width, enhancing sheet thickness and CD fiber
distribution. This results in improved fiber bonding and higher CMT.
2. Headbox Vertical Slice - Reduce
Action: Narrow the vertical slice opening.
Justification: Minimizes turbulence at the slice, leading to improved jet stability and uniform fiber
orientation-essential for strong CD strength and high CMT.
3. Headbox Dilution - Increase
Action: Raise dilution water ratio.
Justification: Enhances fiber dispersion and reduces flocculation, leading to a more uniform sheet formation.
Improved formation correlates directly with better mechanical strength and higher CMT values.
4. Low Vacuum - Increase
Action: Boost low vacuum (forming section).
Justification: Enhances initial water removal and fiber mat formation, contributing to better sheet consolidation
and fiber bonding, thereby increasing CMT strength.
5. Wire Turbulence - Reduce by Adjusting I-Table
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2. Technical Report: CMT-30 Improvement on Fluting Grade
Action: Optimize I-table positioning to reduce turbulence.
Justification: Less turbulence ensures better fiber orientation and less fiber loss. Results in a well-bonded,
uniformly formed sheet with higher internal strength (CMT).
6. Jet/Wire Ratio - Maintain at 1.02 to 1.05
Action: Set jet velocity slightly above wire speed.
Justification: Provides optimal fiber alignment and moderate shear, enhancing fiber bonding and structure
while maintaining formation quality-important for CMT improvement.
7. Top Wire Speed - Slightly Faster than Bottom Wire
Action: Increase top wire speed marginally.
Justification: Improves drainage balance in twin-wire systems and fiber alignment, reducing two-sidedness
and enhancing strength properties like CMT.
8. Press and Dryer Part Slide - Reduce
Action: Minimize sheet slide or shrinkage in MD.
Justification: Reduces fiber misalignment and preserves orientation through the drying process, maintaining
bonding and strength integrity.
9. Starch Viscosity - Increase to 50-60 cP by Reducing Enzyme
Action: Decrease enzyme dosage in starch preparation.
Justification: Higher starch viscosity provides more solids and better fiber binding. Strengthening the paper's
internal bond directly improves CMT.
10. Improve Retention
Action: Optimize retention aids and system chemistry.
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3. Technical Report: CMT-30 Improvement on Fluting Grade
Justification: Retaining more fibers and fines enhances bonding, sheet density, and formation. Improved
retention also ensures better starch and chemical efficiency, leading to higher CMT.
Summary Table of Adjustments
| No. | Parameter | Action | Justification |
|-----|---------------------|----------------------|----------------------------------------|
| 1 | Horizontal Slice | Increase | More fiber mass, better CD strength |
| 2 | Vertical Slice | Reduce | Less turbulence, improved formation |
| 3 | Headbox Dilution | Increase | Better fiber dispersion |
| 4 | Low Vacuum | Increase | Faster dewatering, improved bonding |
| 5 | Wire Turbulence | Reduce via I-table | Improved fiber orientation |
| 6 | Jet/Wire Ratio | 1.02 - 1.05 | Balanced shear and orientation |
| 7 | Top Wire Speed | Slightly higher | Better drainage balance |
| 8 | Press/Dryer Slide | Reduce | Maintains fiber alignment |
| 9 | Starch Viscosity | 50-60 cP | Stronger bonding |
| 10 | Retention | Improve | Better fines/fiber bonding & strength |
Recommendations for Monitoring:
- CMT testing every 2-4 hours during production.
- Retention monitoring via white water solids and first-pass retention tests.
- Jet/wire ratio and slice adjustments to be trialed incrementally.
- Starch viscosity checks before every shift application.
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