Crankshaft Web Laser Cladding for Crack Repair Durability

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Solution Overview

Problem

Crankshafts in internal combustion engines suffer from cracks due to intense mechanical stresses and fluctuating temperatures, leading to potential failure, and existing repair methods are inadequate.

Innovation Solution

A method involving laser cladding of a metal additive onto a prepared undercut region of the crankshaft to form a cladding deposit, which fills and strengthens the damaged area, using a powdered metal alloy and a U-shaped undercut design to ensure a strong bond.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If traditional repair methods are used on crankshafts, then the repair process is simpler, but the repaired crankshaft lacks sufficient strength and durability

Engineering Contradiction:

Improvestrength and durability of repaired crankshaftVSAvoidcomplexity of repair process

Core Design Contradiction:

StrengthVSDevice complexity

Solution Approach 1:

The repair process is segmented into distinct stages: surface preparation (grit blasting, heating to 200-400°F, applying bonding agent), undercut machining with specific geometric parameters, laser cladding deposition, and post-processing. Each stage addresses specific requirements for achieving strong repairs while maintaining process manageability through clear procedural breakdown.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention specifies precise parameter ranges for optimal repair outcomes: heating temperature of 200-400°F, undercut depth of 0.01-0.10 inches, undercut width of 0.02-0.04 inches, laser power settings, and deposition rates. These controlled parameter changes ensure sufficient bond strength and durability while managing process complexity through standardized specifications.

Inventive Principle:

Principle #35Parameter changes

2Strength

If a shallow undercut is used for cladding, then the repair process is faster and simpler, but the bond strength between cladding deposit and crankshaft is insufficient

Engineering Contradiction:

Improvebond strength of cladding depositVSAvoidtime for undercut machining

Core Design Contradiction:

StrengthVSLoss of time

Solution Approach 1:

Surface preparation actions (grit blasting, heating to 200-400°F, applying bonding agent) are performed before undercut machining to optimize surface receptivity. This preliminary treatment reduces the required undercut depth by improving chemical and mechanical bonding characteristics, thereby achieving sufficient bond strength with less material removal and reduced machining time.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The repair creates a composite structure consisting of the original crankshaft material, the bonding agent layer, and the laser-clad metal deposit. This composite construction achieves superior bond strength through material compatibility and interfacial bonding, allowing for optimized undercut dimensions that balance strength requirements with machining efficiency.

Inventive Principle:

Principle #40Composite materials

3Reliability

If excessive heating and rapid quenching occur during operation, then the crankshaft experiences thermal stress, but this leads to surface cracks and reduced reliability

Engineering Contradiction:

Improvereliability of crankshaftVSAvoidthermal stress from heating and quenching

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The laser cladding process incorporates controlled heating (maintaining crankshaft temperature at 200-400°F during deposition) and gradual cooling procedures to prevent thermal shock. This beforehand cushioning of thermal effects prevents the formation of new cracks during repair while the strengthened cladding deposit provides resistance against future thermal cycling damage, thereby improving reliability.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The repair process converts the harmful effect of thermal cycling (which caused original cracks) into a beneficial strengthening mechanism. The controlled thermal process of laser cladding, when properly managed within 200-400°F temperature ranges, creates a heat-affected zone that strengthens the surrounding material while the cladding deposit itself provides a crack-resistant barrier against future thermal stress damage.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The method effectively repairs cracks by forming a harder cladding deposit that enhances the mechanical properties of the crankshaft, providing improved strength and durability compared to traditional repair methods.

Implementation Method 1

a cladding deposit is fused to the machined undercut on the crankshaft to repair a defect or crack

Methodology Applied

Scientific EffectLaser heating and melting: Laser

Implementation Method 2

laser metal deposition. Suitable deposition methods may include laser cladding a metal additive onto a surface of a crankshaft

Methodology Applied

Scientific EffectMetal deposition: Deposition (physical)

Data Source

PatentUS12097582B2Crankshaft repair system and method

Publication Date: 2024.09.24 TRANSPORTATION IP HOLDINGS LLC

AI summary

A crankshaft for an internal combustion engine is provided and may include crank pins, crank journals, and webs extending between the crank pins and the crank journals. Each web further may include a web surface on each side of the web. On the web surface, a repair region is provided with an undercut formed in the web. Included in the crankshaft is a cladding deposit that is fused to the web surface in the repair region of the crankshaft.