Compare and contrast additive manufacturing to forging – in terms of strength, part integrity, inspection requirements, ease of technical assistance, and production rates and economy.

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Additive Manufacturing

Forging

Strength: No established standards or property data exist for the additive process, and the property results are unknown or uncertain. Expensive materials are required to upgrade properties to meet performance requirements. Forgings are made from well known, widely used and reliable materials with established, predictable properties.
Part integrity: New additive techniques and processes must be developed for each new design. Full density of AM metal parts is not possible without subsequent Hot Isostatic Pressing (HIP). Ongoing incremental improvements to the forging process, such as computer simulation and modeling techniques, provide reliable and positive results in service performance.
 Inspection requirements: No solid standards exist for the inspection of AM components. Inspection techniques must be established for each unique configuration and material, as defect types are only partially known and process variables demand 100% inspection. PStandards exist to inspect forgings, as well as components machined from forgings, at every stage of processing. Defect types are known and understood. The consistency of the process allows for a reduced frequency of inspection.
Technical assistance: AM techniques vary widely between machine builders. No guarantees are offered, and warranties may be voided if proprietary materials and techniques specific to individual builders are used. Forging technology is well known and processes are rarely proprietary. Providers rely on efficient operations or specialized machinery to provide economy, rather than secret programming or material formulas.
Production rates and economy: AM production rates remain relatively slow, and their best use is with small, complex, and low volume components. Volumes of powdered metal for input may be limited in desired alloys, jeopardizing production and raising cost. Forging offers economy of scale with the capability for high production rates when volume production is required. Increases in volume drive the costs down, rather than up.

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Cost of materials:


Reinforced Plastics and Composites (RP/C)

High costs are incurred with advanced composite materials like graphite, aramid, S-glass and less common matrix resins.


Forging

A typical forging application uses materials that are readily available and comparatively inexpensive.

Production rates:


Reinforced Plastics and Composites (RP/C)

New advanced-composite part designs may often require long lead times and substantial development costs.


Forging

The forging process had high production rates that have yet  to be matched or achieved in reinforced plastics and composites.

 Established documentation:


Reinforced Plastics and Composites (RP/C)

RP/C physical property data is scarce, and data from material suppliers lack consistency.


Forging

Parts as advanced as aerospace components are well-established as forging applications, with well-documented physical, mechanical and performance data.

Service temperature range:


Reinforced Plastics and Composites (RP/C)

RP/C service temperatures are limited, and effects of temperature are often complex.


Forging

Forgings maintain their quality of performance over a wider temperature range.

Reliability of service performance:


Reinforced Plastics and Composites (RP/C)

Deterioration and unpredictable service performance can result, requiring continuous reinforcing of RP/C fibers.


Forging

Forging materials out-perform composites in almost all physical and mechanical property areas, especially in impact resistance and compression strength.

For more information on forgings compared to reinforced plastics and composites, visit the Forging Industry Association (FIA) website