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Frequently asked questions about Turning

Some of the questions we are often asked about turning are listed here. You can find the corresponding products here.

How do you calculate Power Requirement?

The following formula explains how to calculate the power requirement. Values such as cutting speed, feed rate (mm/rev), cutting depth (mm), machine efficiency and specific cutting force should be available in order to be able to calculate the net power requirement and then also the required power.

Mechanical

No./Name of failure

Cause of failure

1-5 Flank Wear

Due to the scratching effect of hard grains contained in the work material.

6 Chipping

Fine breakages caused by high cutting loads or chattering.

7 Fracture

Due to the impact of an excessive mechanical force acting on the cutting edge.

Chemical

No./Name of failure

Cause of failure

8 Crater Wear

Swaft chips removing tool material as it flow over the top face at high temperatures.

9 Plastic Deformation

Cutting edge is depressed due to softening at high temperatures.

10 Thermal Crack

Fatigue from rapid, repeated heating and cooling cycles during machining.

11 Built-up Edge

Work material is pressure welded on the top face of the cutting edge.

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Excessive flank wear

Cause:

  • Grade lacks wear resistance.
  • Cutting speed ist too fast.
  • Feed rate ist far too slow.

Countermeasures:

  • Select a wear-resistant grade.
    P30 ⇒ P20 ⇒ P10
    K20 ⇒ K10 ⇒ K01
  • Use an insert with a larger rake angle.
  • Decrease the cutting speed.
  • Increase feed rates.

Excessive crater wear

Cause:

  • Grade lacks crater wear resistance.
  • Rake angle is too small.
  • Cutting speed is too fast.
  • Feed rate and depth of cut are too large.

Countermeasures:

  • Select a more crater-resistant grade.
  • Use an insert with a larger rake angle.
  • Select an appropriate chipbreaker.
  • Decrease the cutting speed.
  • Decrease the D.O.C. and feed rate.

Cutting edge chipping

Cause:

  • Grade lacks toughness.
  • Insert falls off due to chip build-up.
  • Cutting edge lacks toughness.
  • Feed rate and depth of cut are too large.

Countermeasures:

  • Change to tougher grades.
    P10 ⇒ P20 ⇒ P30
    K01 ⇒ K10 ⇒ K20
  • Increase amount of honing on cutting edge.
  • Reduce rake angle.
  • Reduce feed rates and depth of cut.

Cutting edge fracture

Cause:

  • Grade lacks toughness.
  • Insert falls off due to chip build-up.
  • Cutting edge lacks toughness.
  • Feed rate and depth of cut are too large.

Countermeasures:

  • Change to tougher grades

    P10 ⇒ P20 ⇒ P30
    K01 ⇒ K10 ⇒ K20
  • Increase amount of honing on cutting edge.
  • Reduce rake angle.
  • Reduce feed rates and depth of cut.

Build-up edge

Cause:

  • Inappropriate grade selection.
  • Dull cutting edge.
  • Cutting speed is too slow.
  • Feed rate is too slow.

Countermeasures:

  • Select a grade with less affinity to the work material. Coated carbide or cermet grades.
  • Select a grade with a smooth coating.
  • Use an insert with a larger rake angle.
  • Reduce amount of honing.
  • Increase cutting speeds.
  • Increase feed rates.

Plastic deformation

Cause:

  • Grade lacks thermal resistance.
  • Cutting speed is too fast.
  • Feed rate is too fast.
  • Depth of cut is too large.
  • Not enough cutting fluid.

Countermeasures:

  • Select a more crater-wear-resistant grade.
  • Use an insert with a larger rake angle.
  • Decrease the cutting speed.
  • Reduce feed rates and depth of cut.
  • Supply a sufficient amount of coolant.

Notch wear

Cause:

  • Grade lacks wear resistance.
  • Rake angle is too small.
  • Cutting speed is too fast.

Gegenmaßnahmen:

  • Select a wear-resistant grade.
    P30 ⇒ P20 ⇒ P10
    K20 ⇒ K10 ⇒ K01
  • Use an insert with a larger rake angle.
  • Alter depth of cutto shift the notch location.

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Frequently asked questions about Milling

Some of the questions we are often asked about milling are listed here. You can find the corresponding products here.

What are the parts of a milling cutter?

Here is an overview drawing showing the components of a milling head:

Functions of the Various Cutting Angles and Influences

Description/Code

Functions/Influences

1. Axial rake angle γy

2. Radial rake angle γx

Controls chip removal direction, effects adhesion of the chips and thrust force etc. Rake angles can vary from positive to negative (large to small) with typical combinations of positive and negative, positive and positive or negative and negative configurations.

3. Approach angle κ

Controls chip thickness and chip removal direction.

4. True rake angle (Effective rake angle) γ

Controls cutting performance and ability to retain a cutting edge. With a positive (large) angle, cutting ability and adhesion resistance are improved but the strength of the cutting edge is weakened. - With a negative (small) angle, the strength of the cutting edge is improved but chips will tend to adhere more easily.

5. Inclination angle λ

Controls chip removal direction. With a positive (large) angle, the chip removal is satisfactory with less cutting resistance but the strength of the corner is weaker.

6. Wiper flat clearance angle αf

Controls surface finish. A smaller clearance angle will produce a better surface finish.

7. Clearance angle α

Controls edge strength, tool life and chattering, etc.

Trouble Shooting Guide for Milling

Basic Remedies

  • Select a more wear resistant grade. Carbide.
    P30 ⇒ P20, K20 ⇒ K10 ⇒ Coated/Cermet
  • Cutting Conditions: Reduce cutting speeds. - Increase feed rate.

Recommended insert grades

 

Steel

Cast Iron

Non-Ferrous Alloy

Finishing

T250A (Cermet)

ACK200 (Coated Carbide) BN700 (SUMIBORON)

 DA1000 (SUMIDIA)

Roughing

ACP100 (Coated Carbide)

ACK200 (Coated Carbide)

DL1000 (Coated Carbide)

Basic Remedies

  • Select a crater-resistant grade.
  • Reduce cutting speeds.
  • Reduce depth-of-cut and feed rate.

Recommended insert grades

 

Steel

Cast Iron

Non-Ferrous Alloy

Finishing

 T250A (Cermet)

ACK200 (Coated Carbide) BN700 (SUMIBORON)

 DA1000 (SUMIDIA)

Roughing

ACP100 (Coated Carbide)

ACK200 (Coated Carbide)

DL1000 (Coated Carbide)

Basic Remedies

  • Select tougher grade.
    P10 ⇒ P20 ⇒ P30
    K01 ⇒ K10 ⇒ K20

  • Reduce feed rates.

  • Select a negative-positive cutter configuration with a large approach angle.
  • Reinforce the cutting edge (Honing).
  • Select a strong edge insert (G ⇒ H).

Recommended insert grades

 

Steel

Cast Iron

Finishing

ACP200

(Coated Carbide)

ACK200 (Coated Carbide)

Roughing

ACP300 (Coated Carbide)

ACK300 (Coated Carbide)

Recommended cutter: WaveMill WGX type.

Cutting conditions: Refer to recommended conditions listed in the general catalogue.