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Circular Die "FCR" Gear Burnishing
What is Forced Controlled Rolling (FCR)?
FCR is a newly developed cold forming technology, that via CNC control is able to define and accurately control the application of material displacement forces and time required to roll splines, threads, grooves, ball tracks or many other symmetrical forms on a circular part.
FCR Rolling Applications
Any medium to high volume circular cold forming automotive applications such as:
Automatic transmission sun and planetary gears
Steering pinions
Transmission shafts
CV Joints
Stud shafts
Circular "FCR" (RADIAL) Die Rolling Process
CNC Force Controlled Rolling
Using advanced FCR technology, the rolling process can also be used to finish burnish gear teeth as an alternative to traditional shave cutting or other rolling processes, while in many cases providing higher qualities, faster production and lower tool costs.
Productivity Benefits
High productivity - 9 seconds per part (19-tooth planetary pinions ).
Very stable process.
Incoming part compliant using adaptive CNC force controlled process.
CNC process surveillance ( rejects out of toler. or bad parts ).
Geometry Benefits
Force controlled rolling using CNC controls and limits, giving uniform material displacement within MOB tolerances.
Uniform Compressive Stresses and gears are more stable through heat treatment.
Can be combined with Syncroll workholding (3rd) drive axis for improved toothspacing where exceptional accuracy is needed.
Performance Benefits
High surface finishes ( .025 - .25 Ra or 2-10 Rms).
High compressive residual stresses ( similar to shot peening ).
Reduced tooth pitting and improved wear characteristics.
Noise suppressing characteristics ( from geometry and finish).
FCR for Automatic Transmission Applications
Used as an alternative to conventional green (soft) finishing processes i.e.:
Shaving
Finish hobbing
Shaping
Pot Broaching
Rack Rolling
FCR Process Comparisons for typical automotive applications:
Conventional Circular Die or Rack Rolling
Rolls to a positive stop.
Does not compensate for incoming size variations.
Varied material displacement.
Higher tool costs and shorter tool life.
No process controls.
Shaving
Cuts to specific size.
Does not compensate for part variations.
5 -10 times higher tool costs.
Complex, costly & more frequent resharpening.
1/5 tool life.
Fragile tools .
Finish Hobbing
One carbide cutter is responsible for complete rough and finish quality.
Size varies over life of cutter and machine warm up.
Very high tool costs.
Varied part quality and performance due to resharpening and coating variants.
Contact Ray Mackowsky at Great Lakes Gear Technologies for more information.
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