1 Introduction
2 Tool manufacturing
2.1 Tool grinding
Operation | Cutting speed vC (m/s) | Feed rate vf (mm/min) | Depth of cut ae (mm) |
---|---|---|---|
Cylindrical grinding | 17 | 25 | 0.05 |
Flute grinding | 17 | 25 | 1.00 |
Peripheral grinding | 40 | 25 | 0.02 |
Face grinding | 40 | 15 | 0.80 |
Specification | Diameter as (mm) | Width bs (mm) | Grain mean Diameter dk (µm) | Grain concentration c (ct/cm3) | Bonding |
---|---|---|---|---|---|
1A1 | 80 | 20 | 64 | 4.4 | Hybrid bond |
11V9 | 40 | 40 | 64 | 4.4 | Resin bond |
2.2 Cutting edge preparation
Milling tools | Cutting edge radius rβ (µm) | Form-factor K |
---|---|---|
Cemented carbide (sharp) | 4.2 ± 0.9 | –a |
Cemented carbide (rounded) | 16.2 ± 1.6 | 0.76 ± 0.15 |
Ceramic (sharp) | 5.6 ± 3.5 | –a |
Ceramic (rounded) | 16.9 ± 1.9 | 0.83 ± 0.06 |
3 Experimental procedure
Tool specifications | Values |
---|---|
Materials | Cemented carbide “Ihle cki10” Ceramic “Ceramtec SiAlON SL506” |
Diameter | D6 Z4 40° |
Teeth | 4 |
Helix angle δ | 40° |
Wedge angle β | 90° |
Tool orthogonal rake angle γ | − 5° |
Tool orthogonal clearance angle α | 5° |
Cutting edge | Sharp Rounded (radius rβ, see Table 3) |
Workpiece specifications | Values |
Material | Grey cast iron with lamellar graphite EN-GJL-200 |
Hardness HV30 | 210 |
Geometry | 100 × 50 × 4 mm |
Process parameters | Values |
Cutting speed vc | 195/390 m/min |
Feed rate vf | 3360 mm/min |
Depth of cut ap | 0.3 mm/cut |
Width of cut ae | 4 mm |
Number of cuts per tool | 300 (≙ VW = 18,000 mm3) |
Direction | Up-milling |
Lubricant | None |
4 Results
4.1 Process forces
4.2 Cumulative energy demand
Carbide (rounded) | Carbide (sharp) | Ceramic (rounded) | Ceramic (sharp) | |
---|---|---|---|---|
Material | Cemented carbide | Cemented carbide | Ceramics SiAlON | Ceramics SiAlON |
Weight of blank | 24.45 g | 24.45 g | 4.58 g | 4.58 g |
Weight of end mill | 22.2 g | 22.2 g | 4.21 g | 4.21 g |
Length of end mill | 58 mm | 58 mm | 50 mm | 50 mm |
Preparation of cutting edges | Yes | No | Yes | No |
Number of cutting edges | 4 | 4 | 4 | 4 |
Carbide (rounded) | Carbide (sharp) | Ceramic (rounded) | Ceramic (sharp) | |
---|---|---|---|---|
Production | ||||
Primary product | 14.16 MJ | 14.16 MJ | 0.50 MJ | 0.50 MJ |
Metal/ceramic powder forming | 0.61 MJ | 0.61 MJ | 0.12 MJ | 0.12 MJ |
Grinding | 2.52 MJ | 2.52 MJ | 2.6 MJ | 2.6 MJ |
Preparation of cutting edges | 0.47 MJ | – | 0.47 MJ | – |
Usage | ||||
Milling | 0.151 MJ | 0.145 MJ | 0.221 MJ | 0.217 MJ |
Disposal | ||||
Landfill | 0.002 MJ | 0.002 MJ | 0.0004 MJ | 0.0004 MJ |
Amount (first life) | 17.91 MJ | 17.44 MJ | 3.91 MJ | 3.44 MJ |
Recycling credit | − 12.47 MJ | − 12.47 MJ | – | – |
Total | 5.44 MJ | 4.97 MJ | 3.91 MJ | 3.44 MJ |
4.3 Surface quality
4.4 Tool wear
5 Summary and outlook
- The additional hardness of high performance ceramics leads to less tool wear in comparison to cemented carbide tools.
- The surface roughness could be decreased by ceramic end mills, both with prepared and unprepared cutting edges.
- The use of ceramic end mills contributes to an ecological and economic production by saving energy resources, measured by cumulative energy demand.
- The rounded cutting edges lead to higher feed normal forces but do not decrease surface roughness significantly for both tool materials. Cumulative energy demand is slightly higher for tools with prepared cutting edges, but the advantages of lower tool wear overcome this drawback.