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Deep Fillet Rolling Solutions

Crankshaft Fillet Rolling Tools Engineered for Superior Automotive Manufacturing

Lonero Engineering remains the industry leader in the development of deep rolling machine tool applications. We provide innovation and expertise in the total design, engineering, and manufacturing of crankshaft fillet rolling tool solutions.

Since 1971, Lonero Engineering has remained the industry leader in the development of specialized crankshaft fillet rolling tools for the automotive sector. Our precision tooling solutions have served many of the industry’s premier crankshaft manufacturers including: Ford, General Motors, Stellantis (FCA / Chrysler), Renault-Nissan, and Hyundai-Kia.

Twist Tool – The Industry Standard Fillet Rolling Tool

Our patented Twist Tool for fillet rolling crankshaft applications sets the industry standard in production speed, reliability, and consistency.

  • Patented two-piece housing design offers maximum strength and rigidity.
  • Constructed with hardened steel double-sided blade cages.
  • Durable, high-strength heat-treated housing material with armor clad coating.
  • Standardization perishable components for easier maintenance.

The Advantage of Lonero’s Innovative Twist Tool

  • Lower initial cost of investment compared to alternative tooling options.
  • Fewer components per assembly for maximum reliability and easier maintenance.
  • Highly accurate work roll positioning.
  • No manual adjustment required to set proper clearance.
  • Double-sided blade cages = double the life of each cage.
  • Minimum training required for tool setter.
  • Blade cages and work rolls can be changed out in seconds.
  • Identical blade cage used on all tools / all positions.
Deep Rolling Tools

Crankshaft Tooling Applications

Deep rolling is an automotive manufacturing technology that utilizes high-pressure rolling forces concentrated in the undercuts (or fillet areas) of a crankshaft. The rough machining processes can weaken the crankshaft by inducing internal machining stresses. These stresses reduce the fatigue strength of the crankshaft, thereby reducing its lifetime.

A compressive stress is rolled into this weak overlap area between the pin journal and the main journal. The deep rolling process leaves a new compressive residual stress in the undercut area strengthening this area. The process involves applying a specific load to a rotating crankshaft utilizing small “work rolls” that have the desired shape and size of the finished undercut. This machining operation is not a metal removal process.

Deep rolling results when the work rollers are worked against the crankshaft fillet exceeding the yield point of the material using area pressures from 250,000 to 750,000 psi (1725 to 1570 MPa).

The Benefits of Deep Rolling

The primary advantage of deep fillet rolling is an increase in the overall fatigue strength of the crankshaft by up to 300%. Additional benefits include:

  • Relieves internal residual stress
  • Generates internal compressive stress
  • Improves surface finish
  • Increases surface hardness
  • Maximizes both the strength and lifetime of the crankshaft

A Look Inside the Deep Fillet Rolling Process

  1. The crankshaft is placed into the machine and is held by a chuck and supported by a center.
  2. The machine utilizes hydraulically actuated jaws. One arm of the jaw holds the upper “deep rolling” tool. The other arm holds the lower “steady rest” tool. Each journal will have its own set of jaws and tools.
  3. When the cycle begins, the jaws close and pressure is increased as the crankshaft rotates. The rotating crankshaft consequently rotates the work rolls, and they in turn, drive the bearing-loaded back-up roll.
  4. The work rolls are held in the proper position by pocketed blade cages. The machine cycles for a predetermined number of revolutions and then ramps down. The rolling process is usually lubricated with a light oil applied by flood or mist.
  5. Finally, the crankshaft stops rotating and the jaw opens. The deep rolling process is complete, efficiently producing a stronger, more reliable crankshaft.

If you want to work with the industry leader
in the development of deep rolling machine tool applications,
call Lonero at 248-689-9120.