Case Study 1306 - Machining Process Optimization

Machining of the casting is one of the neglected areas as far as simulation is concerned, though a lot of tools have been available for a long time.

This case study describes the effective use of the same in the real life situation, whereas the throughput needs to be increased without much of an investment. The subject part is a compressor housing bracket and the throughput was already increased for the casting in the HPDC process by the help of flow simulation. Now, the machining has become a bottleneck and this challenge was faced with the help of the CAM solution specializing in this field.

Originally the part was run on a 4-cavity fixture with manual clamping and later on decreased to only 2 cavities to optimize the cycle time (Figure 6.1).

Figure 6.1 - The existing fixture loaded with the parts for machining

The machining involves a 4th Axis index table and the machining optimization was taken up starting with mod­eling of the fixture, clamps, part, tools, tool holders etc.

Figure 6.2 - Machining optimization through virtual simulation

The machining optimization (Figure6.3) was done through

  • optimizing the sequence of operation viz., tool based, position based
  • optimizing the speed and feed
  • reducing the safe movement thresholds
  • reducing the air cutting time
  • reducing repeated motion of table, tools
  • reducing the tool indexing, etc.

Figure 6.3 - Tool Paths, Axis movements, Tool Changes, Rapid and Feed movements

The original takt time of 161 secs was reduced to 125 secs. No improvement is final hence the design and implementation of a hydraulic fixture was taken up and the machining optimization was applied over it. After simple­ mentation (Figure 6.3) the takt time was reduced to 64 secs. A phenomenal throughput improvement

Figure 6.4 - Optimized Hydraulic Fixture Simulation and Actual Photograph

The other tangible benefits of the machining optimization include:

  • Elimination of programming errors.
  • Automatic NC code generation and Process Planning Reports.
  • Quick fixture proving.
  • Avoiding accidents.
  • Continuous program optimization through virtual simulation.
  • Consistent approach to machining techniques through standardization and horizontal deployment
  • Mundane programming of parts is reduced.
  • Change of job to Any Controller / Machine is easy.
  • Computation of exact cycle time for machining.

The most intangible and invaluable benefit being the time and effort of the process engineers.

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