Connecting rod

Tool for precision machining of connecting rods at the small and big end

Key features

  1. Small end 
  2. Big end
  3. Bolt locating Surface / 4. Bolt hole bore

  • Tool for pre-machining the small end of a connecting rod

    1. Pre-machining

    Various connecting rod forms require flexible tool solutions. A special solid drill combines drilling, boring and chamfering on both sides. The challenge: stable processes despite varying geometries.

  • Tool for semi-finishing the small end of a connecting rod

    2. Semi-finishing

    Radially adjustable ISO inserts compensate for shape deviations and prepare the bore for the sleeve. Dimensional accuracy and even material distribution are crucial for subsequent fitting.

  • Fine boring tool for finish machining of the small end of a connecting rod

    3. Finishing

    Fine boring tools with PCD guide pads create the best surface qualities and circularities under 10 μm.

1. Small end

PROCESS CONDITIONS
  • Spot drilling and boring due to different connecting rod shapes
  • Surface requirements of maximum Ra 0.8 μm
  • Diameter tolerances of 6 μm
  • Circularities of 5 – 10 μm
  • Partly specified bore shapes such as the bell-mouthed shape
WP solid carbide drill for connecting rod machining

The right solution for every requirement

1. Pre-machining
WP solid drill
 
  • Short, sturdy tool design enables drilling from solid, boring and chamfering on both sides with just one tool.

Two tools for machining the connecting rod: semi-finishing and finishing operations

2. Semi-finishing and finishing machining
Fine boring tool

  • Pre-machining stage for maximum tool life and for the stringent quality requirements of the fine boring stage.

or


HPR replaceable head reamer

  • Multi-blade, regrindable replaceable head for short processing times and long tool lives.

Two tools for finishing the connecting rod in cylindrical and trumpet-shaped form

The right solution for every contour

3. Finishing
Fine boring tool

  • Pre-machining stage and adjustable WP fine machining stage for the most stringent quality requirements and maximum tool life.
     

or


Actuating tool

  • Additional U axis for semi-finishing and finishing machining for big and small end. Maximum contour flexibility and simple wear contour.

2. Big end

PROCESS CONDITIONS
  • Wear-resistant carbide on the crack notch
  • Different stock removal situations
  • Highest quality requirements for bore geometry
  • Circularities of 5 – 8 μm
  • Diameter tolerances of 10 μm
  • Defined surface values of ~ Rz 6 μm to Rz 11 μm
Two tools for machining the big end of the connecting rod: roughing and finishing operations

1. Pre-machining
Roughing tool

  • Stable, multi-blade tool design for the combination of multiple process steps (roughing, boring, chamfering
     

2. Finishing
Fine boring tool

  • Boring and fine boring for defined stock removal, maximum tool life and the most stringent quality requirements.

3. Bolt locating surface / Bolt hole bore

PROCESS CONDITIONS
  • Positional accuracy of +/- 0.10 mm
  • Surface finish requirement Ra 3.2 μm
  • Concentricity 0.20 mm
  • Diameter tolerances 0.05 mm to 0.10 mm
  • Bore design with multiple step changes
  • Materials difficult to machine with additional hard-forged outer skin
Connecting rod bolt head seating surface / bolt hole

1. Grooving/milling
Solid carbide milling tool

  • Face geometry that cuts across the centre for milling and grooving contact surfaces.

2. Pre- and finishing machining
Solid carbide step drill

  • Multi-stage one-shot design with Optimum chip breaking at boring stages.