The Project: "Hard turning of "Gear-Satellite" part"

Gear-satellite in the operating position 

KSM specialists created a technological process, selected tools and developed the technology within the project  «Hard turning parts "Gear-Sat 11.5016"» on Monforts CNC lathe RNC 500. The project aim is replacing the grinding operations by hard turning to give bases for subsequent tooth-grinding, processing of gear ring (hard turning), radial facing and boring grooves.

The results of our work are reflected in this project.

Blank data

Part: Gear-Satellite №11.5016
Material: 12Х2Н4А-Ш
Hardness: 59...61 HRC

Requirements

1. Surface roughness:
   1. Ø105.4(+0.01) mm (max Ra~0.63 µm);
   2. Ø166.42(-0.05) mm (max Ra~1.25 µm);
   3. End face (max Ra~2.5 µm);
2. Providing minimal bore run-out  Ø105.4 max 0.004 mm;
3. Providing minimal face parallelism tolerance failure 0.01 mm.

THE FIRST BLOCK

At the first stage of preparation for gear-satellite machining a special device (Fig. 1) was designed and manufactured. This device balances tooth profile run-out of  Ø105.4 not more than 0.05 mm. According to the characteristics of the processed material, the hardness and the target roughness, a tool for hard turning was chosen, as well as processing modes, that allow the surface roughness Ra = 0.29 µm.  

Figure 1 A device for locating details on the ring gear (Pendulum cams)

Testing

1. Radial turning L = 75 +0.3 mm and boring Ø105.3 mm;
2. Finished boring the flute Ø110.5 (+0.07) mm final;
3. Finished pruning the end face L = 75 + 0.3 mm and boring Ø105.3 mm 

1. 

 Figure 2 Cut-map

2.

 Figure 3 Cut-map

Tests are carried out in two stages. At the first stage the workpiece was mounted in three-jaw chuck using a special tool (see Fig. 1), which allowed to machine face and bore hole Ø105. 4 mm (see Fig. 4).

3.

 Figure 4 Cut-map

Machining was carried out using a compressed air on tool without coolant. Machining was carried out in two passes: roughing and finishing.

Test data

Hard turning provided the surface roughness within Ra = 0.25 – 0.32 µm with machining by plate with root radius of 0.8 mm.

THE SECOND BLOCK

At the second stage of preparation for gear-satellite machining a special device (Fig. 5) was designed and manufactured. This device balances tooth profile run-out relating to Ø105.4 not more than 0.05 mm. According to the processed material characteristics, the hardness and the target roughness, a tool for hard turning was chosen, as well as processing modes, that allow the surface roughness Ra = 0.3 µm.

Figure 5 Based device for details on internal diameter 105.4 mm (collet chuck)