si3 n4 application guidelines web

Ceramic Application Guidelines

A Guide for Success

Whisker Ceramics

Developed for machining high temp alloys

Primary target Inconel

Primary Markets Aerospace Energy Military

Nickel Based Materials

Geometry Strongest possible

#1 - Round #2 - 100º corner of 80º diamond #3 - Square #4 - 80º diamond #5 - Triangle #6 - 55º diamond

Edge Preparation Finishing

Hone Roughing

T Land Severe Roughing or Scale

T Land with Hone


Lead Angle Longest tool life with

45º Lead Angle #1 45º Best #2 30º #3 15º #4 0º #5 -5º Worst

Percentage of Strength by Shape

100%80%

40% 10%35%

90%

70%

Clearance Improves Tool Life

11°6°

.005“ Wear .003“ Wear

*Both inserts have .025" flank wear

Strength by Thickness

5/16"

1/4"

3/16"

1/8"

0%

Weakest

25% 50% 75% 100%

Strongest

Insert Thickness

Strength by Nose Radius

.062"

.047"

.031"

.015"

100%75%50%30%

Strength

Nose

Radius

SFM & IPR % Adjustment

0.000

0.050

0.100

0.150

0.200

0.250

50 75 100 125 150 175 200 225

SFM & IPR %

SFM & IPR % Versus DOC

75°

60°

45°

30°15°

Centerline

Insert Diameter

.250 .375 .500

.125 .188

.100. .150

.075 .113

.050 .075

.025 .038

D

O

C

0.000

0.050

0.100

0.150

0.200

0.250

50 75 100 125 150 175 200 225

SFM & IPR %


75°

60°

45°

30°15°

Centerline

Insert Diameter

.250 .375 .500

.125 .188

.100. .150

.075 .113

.050 .075

.025 .038

D

O

C

0.000

0.050

0.100

0.150

0.200

0.250

50 75 100 125 150 175 200 225

SFM & IPR %


75°

60°

45°

30°15°

Centerline

Insert Diameter

.250 .375 .500

.125 .188

.100. .150

.075 .113

.050 .075

.025 .038

D

O

C

0.000

0.050

0.100

0.150

0.200

0.250

50 75 100 125 150 175 200 225

SFM & IPR %


75°

60°

45°

30°15°

Centerline

Insert Diameter

.250 .375 .500

.125 .188

.100. .150

.075 .113

.050 .075

.025 .038

D

O

C

Above 100% increase SFM & IPR

Below 100% decrease SFM & IPR

Chamfering

Feed Direction

Poor Tool Life

*Multiple passes at the same depth of cut increase notch wear which is the primary failure for this grade

Ramping

Alternate cut paths

One angled pass and one straight pass

Spreads notch wear over a bigger area and increases tool life


Lead Angle Effect of Round Insert

45º

25% of insert diameter

Produces 45º lead angle

Feed Direction


Speeds & FeedsHardness Cutting Speed Feed 30 HRC 800-2000 SFM .008 - .015 IPR 35 HRC 600-1400 SFM .008 - .012 IPR 40 HRC 500-900 SFM .007 - .009 IPR 45 HRC 450-750 SFM .006 - .007 IPR 50 HRC 450-650 SFM .005 - .006 IPR


Guidelines for success Chamfer parts before machining

This prevents burrs on exit and creates smooth entrance and exit of cuts preventing chipping

Feed at 90º to chamfer to avoid notching

Use largest lead angle possible (45° preferred) Use strongest geometry possible Vary the D.O.C. (reduces notching) Ramp the cuts on a slight angle (reduces notching) Increase speed (reduce BUE)


Guidelines for success continued Edge preps are very important (See charts) When testing start at low feed and increase

.001" per pass. Try slightly higher SFM than competition Honed edge should provide longest life in

clean cuts Increase SFM for interrupted cuts Using coolant will increase notching but

reduce BUE

Guidelines for success Round inserts

Do not exceed 25% of the insert diameter DOC equal to 5% to 15% of diameter is optimum

Never double notch inserts by cutting in both directions (DNGA or CNGA profile cuts)

Flank wear Reduce speed Increase feed


Countermeasures - Edge Chipping

Cause Speed too low Feed too high Incorrect Edge

prep Vibration

Countermeasure See chart for correct speed Reduce Feed See Chart Check Chucking, reduce tool

overhang. Change direction of cut. Reduce lead angle or nose radius to reduce tool pressure

Countermeasures - Edge Chipping

Cause Interrupted Cut

Countermeasure Increase SFM Reduce Feed IPR Increase insert thickness Decrease tool overhang Increase number of passes Check spindle bearings,

ways, chucking, fixturing.

Troubleshooting Wear

Use correct SFM. Too high or too low can both cause wear.

Check feed (IPR) Maybe too high. Check for correct edge prep Vibration and micro chipping. Your machine

and setup must be very rigid.

Troubleshooting Insert Breakage

Cause Scale

Breakage on entering or exiting.

Countermeasure Increase width of

land and add hone. Increase insert

thickness, increase edge prep, check shim seat.

T Land

Measure the width of the T Land across insert

not perpendicular to T Land

W

Honed Insert

A hone .0005 to .001 used for finishing and with a T Land for roughing

B hone = .002 to .003 used for severest roughing.

Honed Edge

Ceramic & Whisker CeramicEdge Preparations

T Lands .008" x 20° (standard edge prep)

Turning & Milling Clean Materials Nickel Materials

.008" x 20° + A Hone General Purpose Cobalt and Iron Based Alloys

.008" x 20° (use a lighter feed & higher speed) .008" x 20° + A Hone

Scale Applications, Overlay Welds, Lightly Interrupted Cuts, Hardened Material Finish Turn & Mill

.008" to .015" x 30° +B Hone The Severest Roughing Applications

Gray Iron Application Guideline

Si3N4

Developed for machining gray cast irons

Primary Markets Automotive Truck Tractor

Primary Applications Diesel Engines

Cylinder Heads Liners Blocks

Brakes Rotors Drums

Gray Cast Irons

Speeds & Feeds Cutting Speed

2000 to 3400 Start at 2300

Feed .005” to .030”

As Required

Edge Preparations

T Lands .008" – .016" x 20°

Turning & Milling .008" – .016 “ x 20° + A Hone General Purpose Cobalt and Iron Based Alloys

.008" x 20° standard edge prep .008" to .016” x 20° + A Hone

Scale Applications, Overlay Welds, Lightly Interrupted Cuts, Hardened Material Finish Turn & Mill

.013" to .015" x 30° +B Hone The Severest Roughing Applications

Turning, max feed is 1.5 times the width of the T land Milling the max feed must be less than the T land