Cylinder head

When it comes to cars, the cylinder head is cast from aluminium alloys. The configuration and features for machining vary according to the engine fuel. The cylinder head is fitted on the cylinder crankcase and is responsible for the fuel and fresh air supply. Due to its stringent requirements for quality and tolerance, it is the most demanding component for machining in engine manufacture. Through precise valve control and minimal friction losses in the camshaft bearings, fuel consumption and emissions are already reduced before the combustion process.
„Cylinder head with valve train, injector bores and camshaft bearing bores structure

Key features

  1. Valve Train
  2. Injector bore
  3. Camshaft bearing bore
  4. Core plug bore

  • The tool carries out the pre-machining of the base bore in the internal combustion engine.

    1. Pre-machining – blind bore

    High feeds and large chip quantities require sturdy, PCD-tipped boring tools with efficient chip removal. Machining forms the foundation for all subsequent process steps in the valve train.

  • The tool carries out the finishing of the blind bore in the internal combustion engine

    2. Finishing – blind bore

    Multi-blade, PCD-tipped boring tools ensure dimensional accuracy and surface quality. In this machining step, precision is crucial so that the valve seat rings and valve guides can be pressed in later.

  • “The tool carries out the pre-machining of the valve seat in the internal combustion engine.”

    3. Pre-machining – valve seat and valve guide

    Once the valve seat ring and valve guide are pressed in, machining of the hard workpiece materials takes place. Extremely tight tolerances and wear-resistant cutting materials are required.

  • The tool carries out the finishing of the valve seat in the internal combustion engine.

    4. Finishing – valve seat and valve guide

    Fine boring or reaming tools are used for precise sealing surfaces. These ensure high process reliability and long tool lives.

1. Valve train

PROCESS CONDITIONS
  • High-precision requirements for form and position tolerance
  • Cylindricity 10 μm 
  • Diameter tolerance 15 μm
  • Coaxiality from valve seat to valve guide
  • Circularities < 8 μm
  • Angle tolerances on the valve seat ring in the μm range
  • Materials with high resistance to wear on valve seat ring
  • Maximum process reliability and accuracy of repetition
PCD fine‑boring tools for machining the valve train pilot bore in the cylinder head

Blind Bore

1. Pre-machining
PCD boring tool

  • Short and stable tool design for maximum positional accuracy.

2. Finishing
PCD boring tool
 
  • Multi-blade tool concept for short processing times.

Werkzeuge zur Bearbeitung vom Zylinderkopf: Ventilsitz und Ventilführung

Valve Seat / Valve Guide

3. Pre-machining
Pilot tool

  • Short, stable tool ensures maximum positional accuracy for the subsequent finishing tool.

4. Finishing
Finishing tool

  • High-precision fine machining with adjustable fine boring tool with EA system and quick-change valve guide reamer.

2. Injector bore

PROCESS CONDITIONS
  • Very large step changes > 10 mm
  • Critical chip removal due to component contour
  • Fluctuating casting situations
  • Surface requirements of up to Rz 4
  • Diameter tolerances in H7 range
  • Wide range of contour designs with multiple tight-tolerance
  • radii and chamfers (± 0.1 mm)
Three tools for machining the cylinder head via the injector bore using a three‑stage process

プロセス信頼性 を最大限に高める 3段階プロセス

1.前加工
PCDステップ貫通穴用ドリル
  • ろう付けされたPCD切削刃と最適な切り屑 排出のための特殊な切り屑排出スペースを 備えた、多段式ソリッドボーリングツール。

2.中仕上げ加工
超硬ソリッド・ステップドリル
  • 最適な切り屑破砕と切り屑排出を実現する、特殊な刃先形状と螺旋状設計。

3.仕上げ加工
PCDステップリーマ

  • ろう付けされたPCD切削刃、特殊な切削刃形 状、および最適な切り屑排出のための拡張され た切り屑スペースを備えた多刃ステップリーマ。

Two tools for machining the cylinder head via the injector bore using a two‑stage process

生産性を最大限

1.前加工
交換可能なソリッド超硬ドリルを備 えたPCDボーリングツール
  • 個別に交換可能なフルボーリング・ステージにより、PCD 切削刃の工具寿命を最大限に延ばすことができます。

2.仕上げ加工
PCDステップリーマ

  • ろう付けされたPCD切削刃と、最適な切り屑排出を実現 する拡大研磨された切り屑排出スペースを備えた多刃ス テップリーマ。

3. カムシャフトベアリングボア

プロセス条件
  • Cylindricity (15 μm over 100 mm)
  • Circularity < 5 μm
  • Diameter tolerances of 15 – 20 μm
  • Surface qualities of < Rz 5 μm
  • Repeated cutting due to the interrupted cut
  • Tools with very high length–diameter ratio
Large tool, also known as a line boring bar

ワンショットソ リューションで 生産性を 最大化

1.前加工および仕上げ加工
ラインボーリングバー
  • 転がり軸受または滑り軸受による追加 支持により、非常に優れた穴の真直度で ワンショット加工が可能です。

Two fine boring tools for machining the internal combustion engine

2段階プロセ スによる最大 限のプロセス 信頼性

1.前加工
ファインボーリングツール
  • 調整が容易なHXインサート付きの バーガイド式ファインボーリングツール。

2.仕上げ加工
ファインボーリングツール

  • インサートを備えたバーガイド式ファインボーリングツール- 切削 刃の調整が容易で、最高品質要件を満たすための追加の予備切削 工程も備えています。

3. ウォータープラグボア

プロセス条件
  • Surface quality Ra < 16 μm
  • Circularity 0.05 mm
  • Diameter tolerance H7
  • Positional accuracy
Tool for machining the core plug bore on an internal combustion engine

4. ウォータープラグボア

1. Semi-finishing
PCD step boring tool

  • Short, compact tool design for maximum tool stability.