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Honing process of connecting rods

Example machining: Bike connecting rods - honing of big eyes, allowance of 25µm

Requirements: Rz=8±3µm, Rpc>170 peaks per cm, honing angle 40-50°, diameter 37.00 +12µm  roundness lt. 5μm, parallelism lt. 8μm, straightness lt. 8μm, reversal line free hash pattern

The machining is done on pre-machined parts (after fine spindle operation), which are inserted into a floating fixture (allows the center of the eye to move and center itself towards the tool axis). This fixture applies no clamping force into the part and reduces common roundness problems. Big advantages are the ease in loading and the avoidance of clamping forces.

Example machining: PV connecting rods - honing of big eyes, allowance of 30µm

Requirements: Rz=8±3µm, Rpc>170 peaks per cm, honing angle 40-50°, diameter 41.00 +12µm,  roundness lt. 5μm, parallelism lt. 8μm, straightness lt. 8μm, no reversal lines in hash pattern

The machining is done on raw parts, fine spindle operation on a KOMET KomTronic facing head followed by a CNC-controlled honing operation with Xstep honing tools on another KomTronic unit.

Connecting rod - large and small eye

Honing of connecting rod - large and small eye- with a two-stage honing operation with Xstep® honing tool:

  • Part: Connecting rod
  • Diameter: 14 mm and 19 mm
  • Material: Steel, hardened
  • Machine manufacturer: Hermle
  • Machine: C40 U dynamic
  • Holding fixture: DAH81 for UAS115/HSK-A63

The task was successfully implemented with the KomTronic® U-axis from KOMET® and the Xstep® honing tool technology.

Honing of racing car connecting rods in a Hermle C40U Dynamic machining centre

In cooperation with our customers we developed a honing operation on connecting rods for racing cars (material: 300M) in a machining centr. The solution for the task was a 1-stage honing operation with coolEX®-honing tool technology to achieve Ra<0,4 μm on a Hermle C40U Dynamic machining centre without technical modifications. 

The task was successfully completed using coolEX® Honing tool technology.

Connecting rod, large eye

One-step coolEX® honing operation - connecting rod, large eye, process control according to time or vi

  • Part: Connecting rod
  • Diameter: 51mm
  • Material: 34CrNiMo6
  • Machine manufacturer: MAKINO
  • Machine: a61NX
  • Holding fixture: HSK-C63

The task was successfully completed using the since 2008 proven coolEX® Honing tool technology.