Edge chipping
Looks like: small notches torn out of the cutting edge, often within the first shift.
Likely cause: clearance angle too small, shock load on startup, or contaminated feedstock.
KAIPU Industrial Blades
Precision Engineered Machine Knives
Looking for a manufacturer who can quote on your drawing within one business day? Industrial cutting tools for printing, packaging, paper, food, plastics recycling and metalworking lines. Manufactured in-house from D2, SKD11, M2 HSS and tungsten carbide.
ISO 9001 certified since 2001. Last reviewed 2026.Every batch ships with a mill certificate, hardness chart and CMM dimensional report. Critical dimensions run at Cpk ≥ 1.33, first-pass yield above 99%, scrap rate below 0.4%. See our QC process →
Product Range
Six Blade Families for Industrial Cutting
Standard SKUs and custom builds, all manufactured under one roof. Click a category for details, or send us a drawing for a quote against your application.
Circular Blades
Slitting knives for paper, film, foil and tape. OD 60–600 mm, ground to ≤ 0.01 mm parallel.
Straight Blades
Top blades for slitting, sheeting and converting lines. Length up to 3 m, single or double-bevel.
Serrated Blades
Toothed blades for tear-strips, perforations and cut-to-length. 6–32 TPI, custom tooth profiles.
Shear Blades
Industrial shear blades for guillotine, swing-beam and plate cutting up to 12 mm mild / 8 mm SS.
Granulator Knives
Rotor and stator knives for plastics granulators and shredders. M2 HSS, four-edge reversible.
Custom Blades
Reverse-engineered from your sample or drawing. Co-developed geometry, material and tolerance.
Material Decision Matrix
Pick the right steel before you pick the geometry
Four workhorse grades cover roughly 90% of industrial cutting applications. This is the shortlist our engineering team uses during RFQ review.
| Attribute | D2 (1.2379 / SKD11) | SKD11 / DC53 | M2 HSS (W6Mo5Cr4V2) | Tungsten Carbide (YG8 / YG6X) |
|---|---|---|---|---|
| Typical hardness | HRC 58–62 | HRC 58–62 (DC53 up to 64) | HRC 60–65 | HRA 88–92 (carbide body) |
| Best for | paper, film, foil, thin sheet | slitter, shear, packaging lines | plastics granulator, wood, abrasive non-woven | corrugated, battery foil, abrasive non-woven |
| Limit / Avoid | continuous service above 200 °C | corrosion-sensitive without coating | cost roughly 2× D2 | brittle — avoid impact loading |
| Description | High-carbon, high-chromium cold-work tool steel. Air-hardening, deep through-hardening to 62 HRC. Workhorse grade for most converting lines. | Japanese-grade equivalent of D2 with tighter impurity control. DC53 variant offers higher toughness at the same hardness for impact-loaded cutting. | Molybdenum high-speed steel. Retains hardness at elevated temperatures; standard for granulator rotors running hot against contaminated feedstock. | Sintered WC-Co tips brazed onto a hardened steel body. For abrasive or high-volume production runs where steel edges fail in hours. |
Not sure which grade fits? Send a sample and a process description — engineering will recommend within one business day.
Failure Diagnostic Atlas
Eight failure modes, eight root-cause directions
If your blade is failing prematurely, match the visible failure pattern against this atlas first — roughly half of these fixes do not require a new tool.
Abrasive wear
Looks like: uniform edge recession, polished contact zone, gradual loss of cut quality.
Likely cause: glass-fibre, mineral fillers, or recycled feedstock. PVD coating (TiN / TiCN / CrN) or grade upgrade to M2 / carbide.
Adhesive build-up
Looks like: material welded onto the edge, tearing rather than clean shearing of film or paper.
Likely cause: low hardness combined with tacky or warm material. DLC coating or higher HRC, plus verify blade temperature.
Plastic deformation
Looks like: edge rolled or bent over, edge radius increased instead of cut depth.
Likely cause: cutting temperature exceeded the tempering point of the grade. Reduce RPM, add coolant, or step up to M2 HSS.
Cracking (heat-check)
Looks like: fine perpendicular cracks across the cutting edge, sometimes hairline, sometimes visible.
Likely cause: thermal cycling — hot cut, cool cut, hot cut. Stellite overlay or M2 HSS with PVD extends life 3–5×.
Corrosion pitting
Looks like: orange or dark spots on the blade body, pitting near edges, premature dulling.
Likely cause: wet environment (food, paper mill, outdoor) combined with insufficient surface protection. CrN or DLC coating is the fix.
Edge rounding
Looks like: cut quality drifts over weeks, then hours — edge becomes visibly rounded under magnification.
Likely cause: correct material but insufficient hardness, or micro-chipping masked by re-sharpening. Audit HRC and re-grind schedule.
Tooth breakage (serrated)
Looks like: one or two missing teeth on an otherwise intact disc, often on the lead tooth.
Likely cause: TPI too fine for the material, tooth root radius too sharp, or side-load misalignment. Coarser pitch and larger root radius is the fix.
Cannot match the failure to a card? Send a photo and 50 mm of the failed blade — failure analysis is part of our engineering support.
Manufacturing Process
From Drawing to Dispatch
Step 1: RFQ review
Drawing or sample in, written spec out. Engineering responds within one business day.
Step 2: Quotation
Material, hardness, tolerance, lead time and tooling cost — no hidden charges.
Step 3: Drawing approval
For custom parts, 2D / 3D drawing sent for written sign-off before any steel is ordered.
Step 4: Material procurement
Steel from audited mills with mill certificates. Buffer stock for common grades.
Step 5: Heat treatment
Vacuum hardening and tempering to specified HRC. Hardness verified per batch.
Step 6: CNC grinding
5-axis CNC profile grinding, surface grinding to Ra 0.2 µm, EDM for carbide.
Step 7: PVD coating
Optional TiN / TiCN / CrN / DLC coating applied in-house. ±2 µm uniformity.
Step 8: Final QA & dispatch
CMM dimensional report, hardness and surface records shipped with the goods.
By the numbers
25+
Years manufacturing
40+
Countries served
600+
Standard SKUs
120K
Annual capacity (parts)
Quality & Traceability
Every blade is traceable back to the heat and the mill heat
Five inspection gates between raw stock and dispatch. The records travel with the part.
01
Incoming steel
Mill certificate (MTC) verified against PO. Grade, heat number, batch dimensions logged.
Tolerance check: bar OD / width ±0.1 mm vs. nominal.
02
Pre-HT machining
Rough CNC profiling in annealed state. Stress-relief between roughing and heat treatment.
Tolerance check: profile ±0.5 mm before HT.
03
Heat treatment
Vacuum furnace, recorded time-temperature curve per batch. Triple temper for D2 / SKD11.
Tolerance check: HRC ±1 vs. spec, three points per part.
04
Finish grinding
5-axis CNC profile and surface grinding. Optional PVD coating (TiN / TiCN / CrN / DLC).
Tolerance check: flatness ≤0.01 mm, parallelism ≤0.01 mm, Ra 0.2–0.4 µm.
05
Final QA & dispatch
CMM dimensional report, hardness chart, surface record, visual inspection, serial-number engraving.
Tolerance check: CMM against signed-off drawing.
Full documentation on request: ISO 9001 certificate, QC flowchart, sample CMM report.
Total Cost of Ownership
The cheapest blade is rarely the lowest cost per cut
Three pricing schemes we see in the field. Pick the one that matches how your operation measures downtime.
Scheme A — Piece price
Fixed price per blade. Re-sharpening and freight are not included.
- Best for: low-volume production, prototype runs, spare-parts inventory.
- Risk: unit price looks attractive but lifetime cost per cut is hidden.
- Verdict: use only when downtime cost is low and material is uniform.
Most common
Scheme B — Re-sharpening included
Unit price covers 3–5 re-grind cycles. We collect, regrind, certify, return.
- Best for: continuous converting lines, 24/7 packaging operations.
- Risk: requires disciplined blade rotation; logistics cadence matters.
- Verdict: lowest cost-per-cut in 80% of cases we have measured.
Scheme C — Managed blade pool
Monthly fee covers a blade pool on-site, scheduled regrinds, and lifetime replacement.
- Best for: multi-site operations, customers without blade-management staff.
- Risk: contract terms must clearly cap re-sharp cycle count.
- Verdict: best when downtime cost exceeds USD 5 000 per hour.
Numbers above are typical. vs Typical job-shop piece-price schemes: an alternative to per-piece pricing, KAIPU's re-sharpening-included model usually lands 30–45% lower cost-per-cut once downtime is priced in. Ask for a TCO worksheet with your volumes, shift pattern and material mix.
Industry Case Studies
Four applications, four engineering decisions
Anonymised examples from the field. Customer names and tonnages available under NDA.
Case 01 · BOPP film slitting
From 4 hours to 11 days between re-grinds
Problem: 20 µm BOPP film, line running 600 m/min, customer was re-grinding D2 top blades every 4 hours.
Change: upgraded to SKD11 with CrN PVD coating, refined clearance angle from 1.5° to 2.5°.
Result: 65× longer interval between re-grinds (4 h → 11 days), annual saving roughly USD 90 000 in downtime.
Case 02 · Plastics granulator
Rotor knife life doubled on 30 % glass-filled PA
Problem: granulator processing 30 % glass-filled polyamide was wearing D2 rotor knives every 5 days.
Change: stepped up to M2 HSS (62 HRC) plus TiCN coating, reduced clearance angle to optimise bite.
Result: knife life extended from 5 to 11 days; regrind cost per kg of throughput fell 38 %.
Case 03 · Corrugated slitter-scorer
Eliminating edge chipping on B-flute cardboard
Problem: thin B-flute corrugated was chipping within the first 200 m of every shift.
Change: replaced straight D2 knives with tungsten-carbide-tipped blades (YG6X), refined grind profile.
Result: chipping eliminated; blade change interval extended from 8 h to 72 h.
Case 04 · Stainless plate shear
6 mm SS304 cut clean for 18 000 cycles
Problem: swing-beam shear cutting 6 mm SS304 was showing burr above 0.15 mm after 5 000 cycles.
Change: replaced standard shear blades with H13 tool-steel pair, hardened to 56 HRC, re-engineered gap.
Result: burr held below 0.10 mm for 18 000 cycles before re-sharpening; QC reject rate halved.
Frequently Asked Questions
What is the minimum order quantity?
For stocked SKUs we ship from 1 piece. For custom builds the MOQ is typically 10 pieces — below that the engineering and setup cost dominates the unit price.
What is the typical lead time?
Stocked sizes ship in 5–10 working days. Custom builds are 20–35 working days from drawing approval, depending on material, heat treatment and any PVD coating.
Do you offer re-sharpening service?
Yes. Send us the worn blade and we will measure the original geometry before grinding, so the re-sharpened part fits back into your line without re-tooling.
Can you match an existing OEM blade?
Yes. Send the part or a drawing and we will reverse-engineer the geometry and propose a material upgrade if the original blade is failing prematurely.
What materials can you work in?
D2, SKD11, DC53, M2 HSS, M4 HSS, H13, 6CrW2Si, tungsten carbide tipped, plus PVD coatings (TiN / TiCN / CrN / DLC). Mill certificates provided on request.
What is the typical payment terms?
30% T/T deposit with order, 70% balance against B/L copy for new customers. Open-account terms available after one year of trading.
Ready to put a real manufacturer on your RFQ list?
Send a drawing, a sample or a written specification. Engineering responds within one business day.