Austenitic Stainless Steel: Grades, Properties & CNC Machining

Austenitic stainless steel is one of the most widely used stainless steel families in engineering and manufacturing. Common grades such as 304, 316 and 303 are used for precision machined parts, food-processing equipment, medical devices, chemical systems, automotive components and industrial machinery. Other grades, including 321, 310, 347 and 904L, are designed for more demanding temperature or corrosion conditions.

What makes austenitic stainless steel attractive is its combination of corrosion resistance, ductility, formability, weldability and toughness. However, these advantages do not mean every grade behaves the same way during CNC machining. Work hardening, poor heat dissipation, chip control and tool wear can significantly affect machining cost and dimensional stability.

For engineers choosing stainless steel for a CNC part, the important question is therefore not simply whether austenitic stainless steel is suitable, but which grade provides the right balance between corrosion resistance, machinability, temperature capability, surface finish and cost.

What Is Austenitic Stainless Steel?

Austenitic stainless steel is a family of chromium-containing stainless steels whose microstructure is predominantly austenite at room temperature. Austenite has a face-centered cubic, or FCC, crystal structure that contributes to the material’s ductility, toughness and forming capability.

Chromium provides stainless steel with its fundamental corrosion resistance by forming a thin passive chromium-rich oxide layer on the surface. Nickel is commonly added to stabilize the austenitic structure, while manganese and nitrogen may also contribute to austenite stability in certain grades.

Unlike martensitic stainless steels, conventional austenitic stainless steels cannot normally be significantly hardened through standard quenching heat treatment. They can, however, become considerably stronger and harder through cold working.

Annealed austenitic stainless steel is normally non-magnetic or only weakly magnetic. This should not be interpreted as an absolute rule. Forming, bending, drawing and machining may change part of the microstructure, particularly in grades such as 304, resulting in a measurable magnetic response.

History of Austenitic Stainless Steel

The development of stainless steel accelerated during the early twentieth century as metallurgists investigated iron-chromium alloys with improved corrosion resistance. Harry Brearley is closely associated with early stainless steel development in Britain around 1913, while German metallurgical development also contributed significantly to chromium-nickel stainless steels.

In Germany, the term V2A became historically associated with “Versuchsschmelze 2 Austenit,” referring to an early austenitic stainless steel development. V2A remains a familiar informal term in Germany for common chromium-nickel stainless steels, while V4A is frequently used when referring to molybdenum-containing grades with improved corrosion resistance.

Modern engineering specifications should nevertheless rely on actual EN, DIN, AISI or material-number designations rather than V2A or V4A alone because the informal terms may cover more than one specific grade.

Austenitic Stainless Steel Composition

Austenitic stainless steels are primarily iron-based alloys, but relatively small changes in alloying elements can substantially change their corrosion resistance, machinability and temperature performance.

Chrome

Chromium is the essential alloying element responsible for stainless behavior. It reacts with oxygen to create a very thin passive surface layer that helps protect the underlying material against further oxidation and corrosion.

Nickel

Nickel helps stabilize the austenitic crystal structure and contributes to ductility, toughness and corrosion resistance. Grades intended for severe environments may contain substantially more nickel than general-purpose 304 stainless steel.

Molybdène

Molybdenum improves resistance to localized corrosion, particularly pitting and crevice corrosion in chloride-containing environments. This is one of the main reasons 316 stainless steel is generally preferred over 304 for many marine, chemical and chloride-exposed applications.

Carbone

Carbon influences strength but may also contribute to chromium carbide formation at elevated temperatures. Low-carbon versions such as 304L and 316L are commonly selected when welding or sensitization resistance is important.

Soufre

Controlled sulfur additions are used in grades such as 303 to improve machinability. Sulfur helps chips break more easily during cutting, making 303 attractive for high-volume turned parts. The trade-off is reduced corrosion resistance and generally poorer welding suitability compared with 304.

Titanium and Niobium

Titanium and niobium may be added to stabilized grades such as 321 and 347. These elements help control carbide-related problems and improve resistance to intergranular corrosion after exposure to certain elevated-temperature conditions.

How Is Austenitic Stainless Steel Made?

Industrial stainless steel production starts with iron-bearing materials, stainless scrap and selected alloy additions. The charge is melted, commonly using an electric arc furnace, and the composition is refined to control carbon and alloy content.

Processes such as argon oxygen decarburization may then be used to refine the steel efficiently while maintaining chromium content. After refining, the steel is cast into slabs, blooms or billets.

Depending on the required product form, the material may then undergo hot rolling, annealing, pickling and cold rolling before becoming plate, sheet, bar, tube or coil.

This steelmaking process should be distinguished from CNC manufacturing. A CNC machine shop normally purchases certified stainless steel bar, plate or other stock and removes material through milling, turning, drilling, boring, threading and related operations to create the finished component.

Key Characteristics of Austenitic Stainless Steel

The popularity of austenitic stainless steel comes from a combination of properties rather than one single advantage.

• Corrosion resistance: Chromium creates a passive surface that protects the underlying steel in many industrial environments.
• Ductilité : Austenitic grades can generally tolerate substantial deformation before fracture.
• Formabilité : Many grades are well suited to bending, drawing and forming.
• Soudabilité : Common grades such as 304 and 316 are widely used in welded assemblies.
• Low-temperature toughness: Austenitic stainless steels retain useful toughness at very low temperatures.
• Temperature capability: Certain highly alloyed grades are suitable for elevated-temperature service.
• Cleanability: Smooth stainless surfaces are valuable in food, medical and pharmaceutical applications.
• Work hardening: Strength can increase significantly after cold deformation, although this behavior also creates CNC machining challenges.

Common Austenitic Stainless Steel Grades

Acier inoxydable 304

304 is one of the most commonly specified austenitic stainless steels. It is often associated with the term 18-8 stainless steel because common compositions contain approximately 18% chromium and 8% nickel, although actual composition is controlled by the applicable material specification.

304 offers a useful balance of corrosion resistance, forming ability, weldability, availability and cost. Typical applications include food-processing components, housings, brackets, fittings, equipment panels, fasteners and general industrial components.

For CNC machining, 304 is workable but not especially free-cutting. It tends to work harden quickly if the tool rubs instead of cutting efficiently. Its chips can also remain long and stringy, increasing the importance of suitable cutting geometry and chip evacuation.

Acier inoxydable 316

316 stainless steel contains molybdenum in addition to chromium and nickel. The molybdenum significantly improves resistance to localized corrosion in many chloride-containing environments.

This makes 316 a common choice for marine equipment, chemical-processing systems, pharmaceutical equipment, food-processing machinery and precision components exposed to corrosive media.

For CNC machining, 316 requires careful control of heat, tool engagement and chip formation. It can work harden rapidly, and its combination of toughness and low thermal conductivity may increase cutting-tool demands.

316 is not automatically a better choice than 304 for every part. When chloride resistance is unnecessary, 304 may provide sufficient corrosion performance at lower material and machining cost.

303 Stainless Steel

303 is particularly important in CNC machining because it was developed with improved machinability in mind. Sulfur additions encourage more manageable chip formation and make the material easier to turn, drill and machine than many general-purpose austenitic grades.

Typical 303 CNC components include:

• Shafts
• Pins
• Bagues
• Entretoises
• Fasteners
• Fittings
• Composants de vannes
• Precision turned parts

The improved machinability comes with trade-offs. 303 normally provides lower corrosion resistance than 304, particularly in more aggressive environments, and it is generally a less attractive choice for welded structures.

When machining productivity and chip control are the main priorities, 303 can be an excellent option. When corrosion resistance, forming or welding is more important, 304 will often be preferable.

321 Stainless Steel

321 stainless steel is a titanium-stabilized austenitic grade. Titanium helps reduce susceptibility to chromium carbide-related problems after certain elevated-temperature exposures.

It is commonly considered for aircraft exhaust systems, heat exchangers, high-temperature tubing and components exposed to repeated heating cycles.

310 Stainless Steel

310 stainless steel contains relatively high levels of chromium and nickel and is primarily selected for oxidation resistance and elevated-temperature applications.

Typical uses include furnace equipment, burners, heat-treatment fixtures and other components exposed to prolonged high temperatures.

347 Stainless Steel

347 is stabilized with niobium and is used where resistance to sensitization and stable performance after elevated-temperature exposure are required.

Applications can include aerospace equipment, petrochemical systems, high-temperature piping, exhaust components and heat exchangers.

904L Stainless Steel

904L is a highly alloyed austenitic stainless steel containing high nickel and molybdenum levels. It was developed for substantially more aggressive corrosive environments than typical 304 or 316 applications.

It may be used in chemical processing, seawater systems, pharmaceutical equipment and other environments involving challenging acids or chlorides.

However, 904L should not be selected simply because it offers higher corrosion resistance. Material price, cutting-tool demand and machining cost are considerably more important considerations than with common grades such as 304.

Austenitic Stainless Steel Grade Comparison

There is no universally best austenitic stainless steel grade. A better material is the one that provides sufficient environmental resistance without creating unnecessary material, machining or fabrication cost.

Physical Properties of Austenitic Stainless Steel

Austenitic stainless steels are generally dense, tough and ductile materials with relatively low thermal conductivity compared with many carbon steels. Their exact strength, hardness, thermal conductivity and expansion behavior depend on grade, product form, temperature and material condition.

This is important in engineering design because values for 303, 304, 316 and 310 should not be treated as interchangeable.

Another important characteristic is their relatively high thermal expansion. For precision CNC parts, temperature variation during machining and inspection may therefore need to be controlled when tight tolerances are required.

Chemical and Corrosion Properties

The corrosion resistance of austenitic stainless steel originates primarily from its chromium-rich passive surface layer. If the surface is clean and exposed to sufficient oxygen, this passive film can regenerate after minor damage.

However, stainless steel is not immune to corrosion. Depending on the grade and environment, possible failure modes include:

• Pitting corrosion
• Crevice corrosion
• Intergranular corrosion
• Stress corrosion cracking
• Surface staining
• Corrosion caused by carbon-steel contamination

Chloride concentration, temperature, acidity, oxygen availability, component geometry and surface condition all influence corrosion behavior.

Can Austenitic Stainless Steel Rust?

Yes. Austenitic stainless steel can corrode or develop visible rust staining under unfavorable conditions.

The term “stainless” means the material has substantially better corrosion resistance than ordinary carbon steel, not that corrosion is impossible.

Problems can occur when components are exposed to seawater, concentrated chlorides, aggressive chemicals, stagnant liquid or surface contamination. Iron particles transferred from carbon-steel tooling or handling equipment may also produce rust-colored contamination on an otherwise stainless component.

This is one reason proper cleaning and passivation are important for high-specification CNC stainless steel parts.

Is Austenitic Stainless Steel Magnetic?

Annealed austenitic stainless steels are generally non-magnetic or only weakly magnetic. Their FCC austenitic structure differs from the strongly magnetic structures found in many ferritic and martensitic stainless steels.

However, machining or cold forming can create microstructural changes. A heavily machined or cold-worked 304 stainless steel component may therefore show a noticeable magnetic response even though the original annealed bar stock was almost non-magnetic.

This behavior does not automatically indicate that the material is incorrect.

CNC Machining Austenitic Stainless Steel

Austenitic stainless steel can be machined to tight tolerances and high-quality finishes, but it usually requires more process control than free-machining carbon steel or aluminum.

From a CNC machining perspective, four characteristics are especially important:

• Rapid work hardening
• Faible conductivité thermique
• Tough, ductile chip formation
• Tendency toward built-up edge and galling

Because stainless steel does not transfer cutting heat away from the cutting zone as efficiently as some other metals, a significant amount of heat can remain near the tool tip. This accelerates tool wear if speed, feed, tool geometry and coolant strategy are poorly selected.

Work hardening creates an additional problem. If the cutting edge rubs across the surface without removing an adequate chip, the local surface can become harder. The next tool pass must then cut through material that is harder than the original stock.

This is why stable tool engagement is essential when machining 304, 316 and similar grades.

CNC Milling Austenitic Stainless Steel

Successful stainless steel milling begins with machine rigidity and a stable setup. Tool deflection or vibration can worsen work hardening and reduce surface quality.

Sharp carbide cutting tools with suitable positive geometry are frequently used because they help reduce cutting forces and maintain a clean shearing action.

Important milling considerations include:

• Maintaining positive cutting engagement
• Avoiding unnecessary tool rubbing
• Using sufficient feed per tooth
• Managing cutting temperature
• Removing chips from pockets and slots
• Controlling tool deflection
• Managing thin-wall distortion

Deep pockets and narrow slots can be particularly demanding because cutting heat and chips are trapped inside the feature. Tool reach and cutter rigidity become increasingly important as depth-to-width ratio increases.

Typical CNC-milled austenitic stainless steel parts include valve bodies, brackets, medical-device components, manifolds, housings, precision plates and aerospace fittings.

CNC Turning Austenitic Stainless Steel

Turning performance varies considerably by grade.

303 is normally much easier to turn because sulfur promotes chip breaking. This makes it useful for automatic turning and larger production quantities of shafts, pins, bushings and threaded parts.

304 typically forms longer chips and requires more attention to insert geometry and chip-breaker selection.

316 may be even more demanding in some machining conditions because of heat generation, work hardening and chip-control requirements.

During precision turning, the manufacturer must balance cutting speed, feed, insert geometry and coolant delivery while maintaining dimensional stability and surface-finish requirements.

Drilling Austenitic Stainless Steel

Drilling is another operation where work hardening can quickly create problems.

A drill that dwells against the bottom of a hole without cutting may harden the local material. Subsequent penetration then becomes considerably more difficult.

Sharp drills, sufficient feed, rigid workholding and good coolant delivery help maintain a consistent cutting action.

Deep holes may also require controlled peck drilling or other chip-management strategies depending on diameter and depth.

Threading and Tapping Austenitic Stainless Steel

Threading stainless steel requires additional attention because the material combines toughness with a tendency to gall.

Internal tapping is particularly demanding in small blind holes because the tap must cut material while chips and heat are confined inside the hole.

Manufacturers may consider suitable tap geometry, lubrication, thread milling or other strategies depending on thread size, depth, tolerance and production volume.

Blind-hole designs should also provide sufficient clearance beyond the required full thread depth whenever possible.

Why Does Austenitic Stainless Steel Gall?

Galling is a form of severe adhesive wear that can occur when stainless steel surfaces slide against each other under pressure.

The protective surface layer may locally break down, allowing microscopic regions of the mating components to adhere. Continued movement can tear material from the surface and progressively damage the interface.

Galling is particularly relevant to:

• Stainless steel bolts and nuts
• Threaded assemblies
• Sliding shafts
• Composants de vannes
• Bearing surfaces

Possible strategies include suitable lubrication, improved surface finish, careful fit selection, coatings or using dissimilar mating materials where the application allows.

Surface Finishes for Austenitic Stainless Steel CNC Parts

As-Machined Finish

An as-machined surface is often sufficient for internal industrial components where appearance and exceptional cleanliness are not required. Tool marks remain visible and achievable roughness depends on the machining operation and specified requirement.

Brossage

Brushing creates a controlled directional texture and is common on visible stainless components where a uniform appearance is required.

Polissage mécanique

Mechanical polishing reduces surface roughness and can improve appearance, cleanability and contact characteristics.

Polissage miroir

Mirror polishing produces a highly reflective finish and may be used on decorative components as well as certain hygienic equipment surfaces.

Passivation

Passivation is especially important for CNC-machined stainless steel components.

Machining, handling or grinding can introduce free iron and other contaminants onto the surface. A properly controlled passivation treatment removes suitable surface contaminants and supports development of the natural chromium-rich passive condition.

Passivation should not be confused with applying a conventional paint or thick protective coating. The dimensional effect is generally negligible compared with deposited coating processes.

Électropolissage

Electropolishing removes a controlled microscopic layer from the stainless steel surface through an electrochemical process. Microscopic peaks are preferentially reduced, producing a smoother and more uniform surface.

It is commonly considered for medical, pharmaceutical, food-processing and high-cleanliness equipment because improved smoothness can aid cleaning and reduce surface irregularities.

Applications of Austenitic Stainless Steel

Medical Equipment

Austenitic stainless steels are used for instrument components, equipment housings, fittings, fasteners and various precision medical parts.

However, not every 304 or 316 alloy is automatically suitable for implant applications. Medical implants require appropriate implant-grade material specifications, traceability and manufacturing controls.

Aérospatial

Aerospace applications may include exhaust components, fluid-system fittings, structural hardware and high-temperature parts. Stabilized or heat-resistant grades such as 321 and 347 may be considered where thermal exposure is important.

Automobile

Automotive stainless components include exhaust-system parts, sensor housings, fittings, valve parts, brackets and hardware exposed to moisture or temperature cycling.

Traitement chimique

Chemical equipment frequently relies on 316 or more highly alloyed stainless steels for pumps, valves, manifolds, fittings, heat exchangers and fluid-handling parts.

Marine Equipment

316 is widely considered for marine-related components because its molybdenum content provides improved resistance to chloride-related corrosion compared with 304.

Severe seawater service may still require more resistant alloys depending on temperature, oxygen level, crevice geometry and chloride exposure.

Food and Pharmaceutical Equipment

304 and 316 are common because they combine corrosion resistance with cleanability and compatibility with polishing and electropolishing processes.

Machinerie industrielle

Industrial CNC components manufactured from austenitic stainless steel include shafts, bushings, manifolds, valve components, fasteners, fittings, equipment housings and precision machine parts.

Advantages of Austenitic Stainless Steel

• Strong corrosion resistance across many environments
• Excellent ductility and formability
• Good weldability in common grades
• Good low-temperature toughness
• Wide selection of specialized grades
• Good surface appearance
• Compatibility with polishing and passivation
• Useful high-temperature performance in selected grades

Limitations of Austenitic Stainless Steel

Austenitic stainless steel also presents several engineering trade-offs:

• Higher material cost than many carbon steels
• Rapid work hardening during machining
• Relatively poor thermal conductivity
• Higher tool wear in demanding machining
• Long and difficult-to-control chips
• Galling risk in sliding or threaded assemblies
• Susceptibility to chloride stress corrosion cracking in some conditions
• Potential pitting and crevice corrosion
• No conventional quench-hardening response

These factors can make a nominally inexpensive material choice more expensive after machining. Material selection should therefore consider total part cost rather than raw material price alone.

How to Choose an Austenitic Stainless Steel Grade

Grade selection is most effective when the engineering requirement is defined first.

Choose 304 when you need a general-purpose stainless steel with good corrosion resistance, good fabrication characteristics and broad availability.

Choose 316 when improved resistance to chloride-containing, marine or chemical environments justifies the additional material and machining cost.

Choose 303 when machining efficiency, chip control and production speed are more important than maximum corrosion resistance or welding performance.

Choose 321 or 347 when elevated-temperature exposure and resistance to sensitization are important design requirements.

Choose 310 when oxidation resistance at high operating temperatures is a central requirement.

Choose 904L only when a highly aggressive corrosive environment genuinely requires its increased alloy content and corrosion performance.

For CNC parts, engineers should evaluate the material together with tolerance, geometry, surface finish, welding requirements, annual production quantity and total machining cost.

At Tuofa CNC Germany, stainless steel material selection can be evaluated together with part geometry and machining requirements rather than treating the alloy designation as an isolated decision. This is particularly useful when comparing 303, 304 and 316 for precision milled or turned components.

Austenitic vs Ferritic vs Martensitic vs Duplex Stainless Steel

Austenitic stainless steel is only one category of stainless steel.

Acier inoxydable austénitique generally provides excellent corrosion resistance, ductility, weldability and forming characteristics.

Ferritic stainless steel has a ferritic microstructure, is normally magnetic and usually contains little or no nickel compared with common austenitic grades.

Acier inoxydable martensitique can be heat treated to achieve substantially higher hardness and is common in cutting tools, shafts and wear-related applications where hardness is important.

Duplex stainless steel combines austenitic and ferritic microstructures and is valued for high strength and excellent resistance to certain chloride-related corrosion mechanisms.

Austenitic Stainless Steel vs Carbon Steel

Carbon steel normally costs less and many grades are easier to machine. It can also be heat treated to achieve a broad range of mechanical properties.

Austenitic stainless steel provides substantially better natural corrosion resistance and often avoids the need for paint, plating or other corrosion-protection systems.

The correct choice depends on environment, service life, strength, machining cost and maintenance requirements rather than assuming stainless steel is always superior.

How Long Does Austenitic Stainless Steel Last?

There is no meaningful universal lifespan for austenitic stainless steel.

A component may remain in service for decades in a mild environment while a poorly selected stainless grade can suffer localized corrosion much sooner in an aggressive chloride or chemical environment.

Service life depends on grade, temperature, stress, surface finish, chloride concentration, component geometry, cleaning procedures and maintenance.

Correct grade selection is therefore more useful than asking for a fixed number of service years.

Frequently Asked Questions About Austenitic Stainless Steel

What is austenitic stainless steel?

Austenitic stainless steel is a family of stainless steels with a predominantly austenitic FCC crystal structure at room temperature. Common grades combine chromium with nickel and other alloying elements to provide corrosion resistance, ductility and good fabrication characteristics.

What are examples of austenitic stainless steel?

Common examples include 303, 304, 304L, 316, 316L, 310, 321, 347 and 904L stainless steel.

Is 304 stainless steel austenitic?

Yes. 304 is one of the most widely used austenitic stainless steel grades and is common in food equipment, industrial machinery, fabricated products and CNC components.

Is 316 stainless steel austenitic?

Yes. 316 is an austenitic stainless steel containing molybdenum, which provides improved resistance to localized corrosion in many chloride-containing environments compared with 304.

Is austenitic stainless steel magnetic?

In the annealed condition, most conventional austenitic stainless steels are non-magnetic or only weakly magnetic. Cold working or machining may increase magnetic response in some grades.

Can austenitic stainless steel rust?

Yes. Austenitic stainless steel can suffer staining, pitting, crevice corrosion or other forms of corrosion when exposed to unsuitable environments or surface contamination.

Can austenitic stainless steel be hardened?

Conventional austenitic grades cannot normally be hardened through standard quench-and-temper heat treatment in the same way as martensitic steel. Their strength and hardness can increase considerably through cold working.

Which austenitic stainless steel is easiest to machine?

303 is one of the easiest common austenitic stainless steels to machine because sulfur additions improve chip breaking and cutting behavior.

Is 303 easier to machine than 304?

Generally, yes. 303 was specifically modified for improved machinability. However, the trade-off is lower corrosion resistance and poorer welding suitability compared with 304.

Is 316 harder to machine than 304?

Both grades require careful machining because they work harden and retain heat near the cutting zone. Depending on condition and operation, 316 may require additional attention to heat control, tool life and chip management.

Why does stainless steel work harden during CNC machining?

Plastic deformation can increase the local strength and hardness of austenitic stainless steel. If a cutting tool rubs rather than cutting cleanly, the next pass may encounter a harder surface, increasing tool wear and machining difficulty.

What is the best surface finish for stainless steel CNC parts?

There is no single best finish. As-machined surfaces may be adequate for internal industrial parts, while polishing, passivation or electropolishing may be preferred for corrosion-sensitive, hygienic or appearance-critical applications.

What is the difference between passivation and electropolishing?

Passivation is a chemical treatment primarily used to remove suitable surface contaminants and support the natural passive condition of stainless steel. Electropolishing electrochemically removes a controlled microscopic surface layer and produces a smoother finish.

Which stainless steel is best for marine environments?

316 is frequently selected instead of 304 for marine-related applications because molybdenum improves resistance to chloride-related localized corrosion. Severe seawater environments may require duplex or higher-alloy materials.

What is V2A stainless steel?

V2A is a traditional German term historically associated with austenitic chromium-nickel stainless steel. Today it is commonly used informally for stainless grades such as 304-type materials, but an exact EN or material-number specification should be used when ordering parts.

What is V4A stainless steel?

V4A is a commonly used German term for molybdenum-containing corrosion-resistant stainless steels, frequently associated with 316-type materials. The exact grade should still be defined by a formal material designation.

What is the difference between austenitic and martensitic stainless steel?

Austenitic stainless steel emphasizes corrosion resistance, ductility and fabrication performance, while martensitic stainless steel can generally be heat treated to substantially higher hardness and is often selected for wear-resistant or high-hardness components.

Conclusion

Austenitic stainless steel is not a single material but a broad family of alloys designed for different combinations of corrosion resistance, machinability and temperature performance.

304 remains a strong general-purpose choice, 316 provides additional chloride resistance, and 303 offers a major machining advantage when corrosion requirements allow it. Grades such as 321, 347, 310 and 904L address more specialized thermal or corrosive environments.

For CNC components, material selection should also consider work hardening, cutting heat, tool wear, tolerance, surface finish, thread design and total production cost.

Tuofa CNC Germany provides CNC milling and CNC turning for custom stainless steel components, including prototypes and production parts. If you already have a STEP, STP or technical drawing, material grade, tolerance requirements, surface finish and expected production quantity can be reviewed together to identify a practical manufacturing approach.