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Ceramic machiningApplications
Ceramic grades can be applied in a broad range of applications and materials; most often in high speed turning operations but also in grooving and milling operations. The specific properties of each ceramic grade enable high productivity, when applied correctly. Knowledge of when and how to use ceramic grades is important for success.
All ceramic cutting tools have excellent heat and wear resistance at high cutting speeds. Below you can find the most common types of ceramics used in hard and/or difficult to machine materials.
Super alloy materials
Sialon (SiAlON) grades combine the strength of a self-reinforced silicon nitride network with enhanced chemical stability. Sialon grades are ideal for machining heat resistant super alloys (HRSA). CC6060, CC6065
Whisker-reinforced ceramics use silicon carbide whiskers (SiCw) to dramatically increase toughness and enable the use of coolant. Whisker-reinforced ceram-ics are ideal for machining Ni-based alloys. CC670
Other materials
Mixed ceramics are particle reinforced through the addition of cubic carbides or carbonitrides (TiC, Ti(C,N)). This improves toughness and thermal conductivity. CC6050
Silicon nitride ceramics (Si3N4) represent another group of ceramic materials. Their elongated crystals form a self-reinforced material with high toughness. Silicon nitride grades are successful in grey cast iron, but a lack of chemical stability limits their use in other workpiece materials. CC6190, CC6090
Oxide ceramics are aluminium oxide based (Al2O3), with added zirconia (ZrO2) for crack inhibition. This generates a material that is chemically very stable, but which lacks thermal shock resistance. CC620
General limitations of ceramics include their thermal shock resistance and fracture toughness.
Ceramic grades
vc
hex
CC6065
CC6060
CC670
400
300
200
100
00.05 0.1 0.15 0.2
CC670
CC6060CC6065
3
Bulk toughness
Programmed direct into corner/plunging
Programmed with roll-in, roll-out of corner
Skin, scale, ovalityHigh quality forging
Pre-machined material
First stage machining – 26 HRC
Intermediate stage machining – 46 HRC
Short tool life – too high cutting temperature
Edge line frittering – too low cutting temperature
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CC670 200 to 300 m/min 2 mm 0.1 to 0.15 mm/rCC6065 200 to 250 m/min 2 mm 0.15 to 0.2 mm/rCC6060 250 to 300 m/min 2 to 3 mm 0.15 to 0.2 mm/r
Grade Cutting speed, vc Cutting depth, ap Feed, fn
Start cutting data recommendations (RNGN 12, RCGX 12) – Inconel 718 (38 to 46 HRC)
Cutting parameters
The speed should be balanced to create enough heat in the cut-ting zone to plasticise the chip but not too high to unbalance the ceramic.
The feed should be selected to give a chip thickness which is high enough to not work-harden the material but not be too high to cause edge frittering.
Higher feeds and depths of cut require a reduction of the cutting speed.
These boundaries will change depending upon the component material hardness and grain size.
Cutting data for turning
Stable conditions and correctly applied application methods and coolant supply are important for best results.
Notch wear resistance
Programming consideration
Material consideration Forging
Application areas for HRSA grades
Ceramic turning
vc
hex
1200
900
600
300
0.025 0.05 0.075 0.1
6060 700 to 1000 m/min 2 mm 0.07 to 0.11 mm/r
Grade Cutting speed, vc Cutting depth, ap Feed, fn
Cutting data for milling
• Grade CC6060 best - no coolant• Conventional milling - zero chip thickness on entry into component• Radial immersion, ae - >70% to give smoothest exit from component
Ceramic milling
Ceramic inserts cutter for roughing super alloys
• Ceramic milling typically runs at 20 to 30 times the speed of carbide, although at lower feed rates (~0.1 mm/tooth), which results in high productivity gains. Due to intermittent cutting, it is a much cooler operation than turning. For this reason, speeds of 700-1000 m/min when milling are adapted, compared with 200–300 m/min for turning.
• Ceramics have a high tendency for notching, which is why round inserts are primarily used to ensure a low entering angle.
• Never use coolant.
• Ceramics have a negative effect on the surface integrity and topography, and are therefore not used when machining close to the finished component shape.
• The primary application for grade CC6060 (sialon) is milling Inconel 718 engine castings and oil drilling equipment, in both cases due to the high metal removal rates.
• Maximum flank wear when using ceramic inserts in HRSA is 1 mm.
Short tool life – too high cutting temperature
Edge line frittering – too low cutting temperature
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application
Negative inserts require up-milling
Please observe that negative inserts require up-milling while positive inserts prefer down-milling
Programming considerations when using turn milling technique – the center line of the insert must be on the centre line of the component.
4
Ceramic milling
Tool: Competitor, Sandvik Coromant high-feed cutter S-R120R-051C6-12X4Insert: Competitor, Sandvik Coromant carbide RNGN 12 07 00-E
Cutting speed vc (m/min): 38 800Feed per tooth fz (mm): 0.71 0.13Table feed vf (mm/min): 600 2000Cutting depth ap (mm): 0.7 1.5Cutting width ae (mm): 46 44.1Metal removal rate Q (cm3/min): 19.3 132.3
Results:A total of 42 hours of cutting time was saved per year, and the productivity increased by 469%.
Sandvik Coromant’s Sialon grades CC6060 and CC6065 and the whisker ceramic CC670 complement a strong ceramic insert programme both for turning and milling.
Tool: Competitor, Sandvik Coromant Solid holder Adaptor: C8-SL70-LF-051 Holder: SL70-CRDCL-50-12Insert: RC… RCGX 12 07 00E Coated carbide Ceramic grade CC6060
Cutting speed vc (m/min): 50 275Feed per tooth fz (mm): 0.2 0.25Cutting depth ap (mm): 2.5 2.5Metal removal rate Q (cm3/min): 25 172Tool life per insert edge (min): 10 5
Results:By using the ceramic insert grade CC6060 in combination with trochoidal turning the machining time for the pocketing operation was reduced from 63 hours down to 13 hours i.e. a saving of 50 hours machining time per component! Additional the No of insert edges used is reduced from 380 to 160 per component.
Ceramic turning
5
Cases
Product offer for super alloys
CNGN
DNGN
RNGN
SNGN
TNGN
RPGN
RCGX
RPGX
TPGN
General inserts turning/ milling
12
15
9, 12, 15, 19, 25
9, 12, 15, 19
16, 22
6, 9, 12
6, 9, 12
6, 9, 12
11, 16
ISO
4
4
3, 4, 5, 6, 8
3, 4, 5, 6
3, 4
2, 3, 4
2, 3, 4
2, 3, 4
2, 3
ANSI
CSGX
150.23
Grooving
6, 9, 12
X
ISO
2, 3, 4
X
ANSI
6060 6065 670
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
6
CNGN
DNGN
SNGN
TNGN
RNGN
CNGN
DNGN
SNGN
TNGN
RCGN
RNGN
CSGX
RCGX
150.23 RPGN
RNGN
Cor
oman
t Cap
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SL7
0
Sha
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ools
Dam
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blad
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r tu
rnin
g/ g
roov
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For round T-Max P ceramic inserts with positive or negative basic-shape and without hole.
Internal turning T-M
ax®
boring
bar
s
Gauge inserts
For T-Max P ceramic and CBN inserts with negative basic-shape, without hole.
External turning
Applications
Holders for inserts with hole
Turning
7
Dia 40 mm
Dia 50 mm
Dia 50 - 80 mm
Dia 36 - 44 mm
Dia 36 - 54 mm
Dia 20 - 32 mm
Dia 25 - 40 mm
Dia 32 - 50 mm
RNGN 12
RPGN 06
RPGN 09
RPGN 12
Cyl
indr
ical
sha
nk
Cor
oman
t Cap
to®
Arb
or
Applications
Milling
Head office: AB Sandvik Coromant SE-811 81 Sandviken, Swedenwww.sandvik.coromant.com E-mail: [email protected]
C-2929:61 ENG/01 © AB Sandvik Coromant 2010.12
Sandvik Coromant Total ceramic grade offer
CC650
CC6050
GC1690
CC6060
CC6190 CC6090
CC620
CC6065
CC670
Oxide ceramic for high speed finishing of grey cast iron in stable and dry conditions.
Mixed ceramic for light, continuous finishing in hardened materials.
Mixed ceramic for high speed finishing of grey cast irons and hardened materials, and for semi-finishing operations in HRSA with low toughness demands.
Whisker ceramic with excellent toughness for turning, grooving and milling of Ni-based alloys. Can also be used for hard part turning in unfavourable conditions.
Silicon nitride grade for rough to finish turning and high speed dry milling of cast iron, perlitic nodular cast irons and hardened cast irons.
Coated silicon nitride grade for light roughing to finish turning of cast iron.
Sialon grade for optimized performance when turning pre-machined HRSA in stable conditions. Predictable wear due to good notch wear resistance.
Particle reinforced Sialon for turning operations in HRSA that demand tough inserts.
www.sandvik.coromant.com, www.aero-knowledge.com