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. Foro dell’iniettore

CONDIZIONI DI PROCESSO
  • 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

Processo in 3 fasi per la massima sicurezza

1. Prelavorazione
Punta a gradini in PCD per foratura dal pieno

  • Utensile a più gradini per foratura dal pieno e barenatura, dotato di taglienti in PCD saldobrasati e speciali vani trucioli per garantire un’ottima asportazione dei trucioli.


2. Semifinitura
Punta a gradino in metallo duro integrale

  • Speciale geometria dei taglienti in elica per garantire la migliore rottura e asportazione dei trucioli.


3. Finitura
Alesatore a gradini in PCD

  • Alesatore a gradini multitagliente con taglienti in PCD saldobrasati, geometria speciale dei taglienti e vani truciolo ampliati per un’ottima asportazione dei trucioli.

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

Processo in 2 fasi per la massima produttività

1. Prelavorazione
Utensile di barenatura in PCD con punta in metallo duro integrale intercambiabile
  • Massima resa utile dei taglienti in PCD grazie alla possibilità di sostituire separatamente il gradino di foratura dal pieno.

2. Finitura
Alesatore a gradini in PCD

  • Alesatore a gradini multitagliente con taglienti in PCD saldobrasati e vani truciolo ampliati e levigati, per un’ottima asportazione dei trucioli.

3. Foro del cuscinetto dell’albero a camme

CONDIZIONI DI PROCESSO
  • 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

Massima produttività grazie alla soluzione one-shot

1. Prelavorazione e finitura
Bareno per lavorazione in linea
  • Lavorazione one-shot con eccellente rettilineità del foro mediante supporto supplementare con cuscinetti a rotolamento o a strisciamento.

Two fine boring tools for machining the internal combustion engine

Massima sicurezza grazie al processo in 2 fasi

1. Prelavorazione
Bareno di precisione

  • Bareno di precisione con pattini di guida e inserti a fissaggio meccanico HX facilmente regolabili.

2. Finitura
Bareno di precisione

  • Bareno di precisione con pattini di guida e inserti a fissaggio meccanico – con semplice regolazione dei taglienti e semifinitura supplementare per soddisfare i più elevati requisiti di qualità.

4. FORO DEL TAPPO DELL’ACQUA

CONDIZIONI DI PROCESSO
  • 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. FORO DEL TAPPO DELL’ACQUA

1. Semi-finishing
PCD step boring tool

  • Short, compact tool design for maximum tool stability.