Paper & Tissue
Bed Knives and Top Blades for Tissue Converting
Long-life tooling for tissue converting lines running 600â2,400 m/min. Optimised cutting angles reduce dust and extend service intervals â typically 8â14 weeks uncoated, 14â22 weeks PVD-coated on 2-ply stock.
Cutting mechanics
How tissue lines cut 2-ply without dusting
At 1,800 m/min the cut is happening 30 times per second across the bed-knife length. Dust, edge wear and ply separation are symptoms of bed-knife geometry drifting out of spec.
Tissue cutting is a controlled shear between a stationary bed knife and a rotating top blade. The two blades meet at a precise angle, with a precise clearance, and the ply stack passes between them. The cut is so fast that any geometry drift shows up as dust within minutes, not shifts.
The two failure modes we see most often â dust generation and ply separation â both trace back to the same root cause: the bed-knife shear angle drifted outside the 20°â24° window, or the top-blade clearance drifted outside 0.5°â1.5°.
Shear angle and clearance
Bed-knife shear angle 20°â24°, top-blade clearance 0.5°â1.5° per OEM. Correct angles reduce dust generation by 30â60 % and extend regrind interval over generic tooling.
Bed-knife flatness
Bed-knife flatness âĪ 0.02 mm across the full cutting length (typically 2,000 â 4,200 mm). Granite-plate-verified before dispatch.
Hardness pair for impact loading
D2 / SKD11 bed knives at HRC 58â62; M2 HSS top blades at HRC 60â64 where impact loading is high. TiN or CrN PVD coating on abrasive furnish.
Engineering scope
Six specification levers for tissue converting
Tissue lines punish generic knives. Each variable below is specified as a number against an international standard, then verified on the part before it leaves the shop.
Tissue grammage range
Validated on 1-ply, 2-ply and 3-ply tissue at 13â40 gsm per ply, including through-air-dried (TAD) and conventional pressed sheets. Bed-knife / top-blade pair geometry tuned to ply count and bonding pattern.
Line speed envelope
Production-validated on tissue lines running 600 â 2,400 m/min. Higher speeds require tighter angular control on the bed-knife seat and stricter flatness on the top blade â both verified on the CMM before dispatch.
Cutting angle optimisation
Bed-knife shear angle and top-blade clearance optimised per OEM (typically 20°â24° shear, 0.5°â1.5° clearance). Correct angles reduce dust generation and extend regrind interval by 30â60 % versus generic tooling.
Material grades
D2 (1.2379) and SKD11 for bed knives; M2 high-speed steel (1.3343) for top blades where impact loading is high. Hardness HRC 58â62 bed, HRC 60â64 top. Optional TiN or CrN PVD coating on abrasive furnish.
Tolerances and flatness
Bed-knife flatness âĪ 0.02 mm across the full cutting length (typically 2,000 â 4,200 mm). Top-blade thickness Âą 0.005 mm, parallel within 0.01 mm. CMM reports available with every shipment.
Service interval extension
Common service interval on premium uncoated D2 bed knives is 8â14 weeks on 2-ply tissue. PVD-coated sets typically run 14â22 weeks on the same lines. Intervals quoted against a reference substrate and shift count.
Documented 1200 m/min 4-ply case study
See how a 15 Ξm micro-hone combined with an 18° clearance angle extended bed-knife service life from 11 days to 34 days at 1200 m/min on 4-ply tissue â with the D2 grade and HRC 60 unchanged.
Need tissue bed-knife or top-blade tooling?
Send the OEM machine model, current knife geometry and target service interval. We will return a written quotation with material grade, hardness, tolerance and lead time within one business day.