Case Study: Additive + HIP + Machining

Engineers and procurement teams often struggle to evaluate “end-to-end” additive manufacturing (AM) suppliers because a part is rarely just printed. In defense and aerospace programs, a part built by powder bed fusion (PBF) is typically stress-relieved, support-removed, densified via HIP (or PM-HIP), heat treated, precision CNC machined, finished, inspected, and delivered with a full certification pack—under AS9100 controls, with ITAR/DFARS compliance, and traceable back to the powder lot.

This article provides a structured case study template so you can build your own reference for evaluating AM suppliers. Fill in your part’s details or use it to prompt the right questions before issuing an RFQ or during a supplier qualification visit.

Why a case study matters

A case study is not just marketing. For the buyer, it is a compact record of how a problem was solved: what was built, under what process controls, with what results, and with what documentation to prove it. For the supplier, a well-structured case study serves as evidence that they can repeat the workflow.

In regulated manufacturing, the best case studies are built from objective evidence: material certifications, inspection data, process travelers, and compliance records. That is exactly what procurement needs to evaluate capability and risk before committing to a purchase order.

Template structure: The template below follows the typical process route from design intent through delivery. Each step includes what to record, what to look for, and what questions to ask.

Part overview

Part / component name: [Describe the component, e.g., “titanium structural bracket for missile airframe section”]
Function: [Primary loads/role: structural support, thermal management, fluid passage, etc.]
Industry / application: [e.g., defense—airframe structural hardware, Class II flight-critical, ITAR-controlled]
Why AM? [What drove the selection of additive manufacturing over conventional methods?]

Examples of drivers: geometry (internal channels, weight reduction, part consolidation), schedule (lead time shorter than forging or casting tooling), performance (lattice structures, conformal cooling), or lifecycle (low volume, spare parts, obsolescence mitigation).

Questions to ask

• Was AM the optimal choice, or was it selected out of convenience? Understanding the trade study behind process selection builds confidence that the supplier evaluated alternatives.
• What design-for-AM adaptations were made? Orientation, support strategy, machining stock, and build-to-size considerations should be documented early.

Material and powder control

Alloy: [e.g., Ti-6Al-4V, AlSi10Mg, Inconel 625, C-103, etc.]
Powder specification: [Internal spec or industry standard, e.g., AMS 4998 for Ti-6Al-4V]
Powder supplier(s): [Name(s), with any approved source requirements]
Powder traceability: [Lot number, chemistry cert, PSD and morphology data, virgin/recycled ratio or limit]
Reuse strategy: [How is powder reused? Sieving? Blending? How many cycles? Is reuse documented per lot?]

What to look for: The powder is the raw material. If the supplier cannot produce a controlled, traceable powder record tied to each build, every downstream step is built on uncertain ground. For defense/aerospace parts, expect chemistry and PSD certificates per lot, a controlled reuse policy, and clean storage and handling procedures.

Questions to ask

• Can the supplier trace each finished part back to a specific powder lot? This is critical when DFARS specialty metals clauses apply.
• Is powder purchased from an approved source? Some programs require specific mill certifications or powder supplier approvals.
• How is cross-contamination prevented? Especially for multi-alloy shops.

Build parameters and process control

AM process: [e.g., PBF (DMLS/SLM), EBM, DED, binder jetting]
Machine platform: [Make/model, and whether the parameter set is locked or open]
Build orientation: [How the part was oriented in the build chamber, and the rationale for that choice]
Support strategy: [Where supports were placed, type of supports, and how they will be removed]
Layer thickness: [e.g., 30 µm, 60 µm—and whether this was the same for all features or if variable parameters were used]
Scan strategy: [Controlled? Is it tied to a build recipe revision?]
Witness coupons: [Were coupons included in the build, and what were they used for (tensile, fatigue, microstructure)?]

What to look for: Process stability and configuration management. A case study that shows “we printed this successfully once” is not the same as one that shows “we can reproduce this build reliably under controlled conditions.” Ask how build recipes are revision-controlled, what happens when a machine is serviced or a laser replaced, and how you verify the process window hasn’t drifted between builds.

Questions to ask

• How does the supplier manage build recipe revision control? If the recipe changes, does it trigger re-qualification?
• What monitoring data is available? Some platforms offer in-situ monitoring (melt pool, photodiode, layer imaging). If used, how is it stored and reviewed?
• What is the failure/anomaly response plan? What happens if a build anomaly is detected mid-print (e.g., recoater strike)?

Stress relief and support removal

Stress relief process: [Furnace type, atmosphere, temperature/time/cooling rate, documentation]
Support removal method: [Wire EDM, hand grinding, CNC, break-away, etc.]
Inspection after support removal: [Visual, dimensional spot-check, surface condition verification]

What to look for: Stress relief timing and documentation. This step is often rushed, but the sequence matters—if supports are removed before stress relief, the part can distort. Documentation should include furnace charts and confirmation that the part was stress-relieved before significant material removal.

Questions to ask

• Was stress relief done before or after the part was removed from the build plate? The answer affects distortion risk.
• How is support removal documented? Especially for surfaces where support contact could affect fatigue or sealing.
• Was any intermediate inspection done to confirm geometry and stock allowance before committing to further processing?

HIP / PM-HIP densification

Step 5: HIP / PM-HIP densification (when required)
HIP is often included in defense/aerospace workflows when the part is fatigue-critical, pressure-containing, or when internal porosity is a service risk. PM-HIP parts (powder consolidated in a can) follow a different path but converge on the same downstream machining and inspection expectations.

HIP parameters: [Temperature, pressure, time, atmosphere, ramp rates if controlled]
HIP provider: [In-house or outsourced? If outsourced, is the provider NADCAP-accredited for HIP where required?]
Post-HIP condition: [What is the material state after HIP? Dimensional change allowance? Is there a post-HIP inspection gate?]

What to look for: Evidence that HIP parameters match the alloy and application, not just a default cycle. For Ti-6Al-4V, HIP is well-documented and widely applied; for other alloys, the cycle may be less standardized, and the case study should show that cycle development or qualification was performed. If HIP is outsourced, chain-of-custody and documentation control should be traceable.

Questions to ask

• Was porosity or density measured before and after HIP? (This is especially useful during qualification.)
• Is the HIP cycle part of the locked process route, or is it a variable?
• How is dimensional change from HIP managed? Is stock allowance planned before HIP?

Heat treatment

Heat treatment specification: [Governing spec, target condition (e.g., solution + age)]
Sequence: [Where in the route does heat treatment occur—before or after HIP, before or after machining?]
Documentation: [Furnace chart, load thermocouple placement, hardness verification if required]

What to look for: Sequencing matters. Some alloys are heat-treated after HIP; some undergo combined HIP + heat treat cycles. The case study should clearly define the thermal sequence and show that it produces the required mechanical properties. If the heat treat is a special process under the quality system, confirm NADCAP accreditation where required.

Questions to ask

• What mechanical property targets did the heat treatment achieve? (Ideally verified by witness coupons from the same build.)
• How was distortion managed during heat treatment? Quenching thin-wall parts can cause movement.
• Is the furnace load controlled to prevent part-to-part interaction or temperature gradients?

CNC machining and finishing

Step 7: Precision CNC machining (including 5-axis)
This is where “additive + machining” delivers procurement-ready parts. Many AM components require CNC machining for mating surfaces, datums, precision bores, sealing lands, and bolt patterns. The case study should show not just “we machined it,” but how the machining was planned around AM and post-processing realities.

Machining scope: [Which features are machined, and to what tolerances?]
Setup and fixturing: [Custom soft jaws, datum strategy, sacrificial features?]
Equipment: [3-axis, 5-axis, mill-turn? Why was that capability needed?]
Surface finish: [Ra requirements and how achieved—fine finishing, peening, coating?]

What to look for: Good case studies describe the fixturing and datum strategy (not just machine capability), because AM parts often have irregular shapes that require creative workholding. They also show that machining stock was planned upfront (not discovered to be insufficient after HIP).

Questions to ask

• Was machining stock sufficient after HIP and heat treat? Or did any features go out-of-stock?
• How was as-built geometry translated into machining programs? (Was the part scanned or probed before machining?)
• Are machining programs revision-controlled? What happens if the design changes?

Inspection and NDE

Dimensional inspection: [CMM, laser scan, structured light—tied to drawing datums?]
Surface NDE: [Penetrant (PT), visual, other?]
Volumetric NDE: [CT scanning—when was it performed, what was measured, what criteria?]
First article inspection (FAI): [Was AS9102 FAI performed? Ballooned drawing? Full measurement?]

What to look for: Inspection should be connected to the process route, not bolted on at the end. For AM hardware, in-process inspection gates (post-stress relief, post-HIP, post-machining) can catch problems early. CT scanning of critical internal features should have documented acceptance criteria, not open-ended “scan and report.”

Questions to ask

• Were in-process inspections performed, or was inspection only at the end?
• How are CT results evaluated? (Minimum reportable indication size, acceptance criteria, and who is the qualified analyst?)
• What does the inspection report include? Is it traceable to a specific part serial/lot and build ID?

Documentation and certification

Certificate of Conformance (CoC): [Does it reference the drawing revision, material cert, inspection data, and special process certs?]
Material certifications: [Chemistry, mechanical properties, powder lot traceability]
Special process certifications: [HIP, heat treat, NDE—NADCAP where required?]
Traceability records: [Full traveler linking part serial to powder lot, build ID, thermal processing batch, machining program, and inspection?]

What to look for: A complete cert pack that a quality auditor can trace from finished part back to raw material without gaps. For defense/aerospace, this often includes: CoC, material cert with powder lot trace, HIP/heat treat furnace records, NDE certs, CMM report (with datums), FAI (if first article), and any ITAR/DFARS compliance declarations.

Questions to ask

• Can the supplier produce a complete cert pack for every delivered lot?
• Are records retained for the required period per program flowdowns and AS9100 record retention requirements?
• How are nonconformances documented and dispositioned? (MRB process, engineering deviation requests, customer notification.)

Compliance and quality system

Quality management system: [AS9100 registration status]
ITAR compliance: [Registered with DDTC? Controlled access to technical data and hardware?]
DFARS compliance: [Specialty metals clauses, country-of-origin controls, cybersecurity (CMMC where applicable)?]
NADCAP special processes: [Which processes require accreditation, and is it current?]

What to look for: Active certifications (not expired or lapsed), clear answers on ITAR handling, and willingness to accept flowdowns. If a supplier cannot show current certifications or clearly explain how they handle controlled technical data, it is a risk for the program.

Questions to ask

• Is the supplier AS9100-registered? Check OASIS or equivalent database.
• How is ITAR-controlled data handled? (Physical and digital access controls, personnel clearance, shipping/export.)
• What DFARS clauses does the supplier routinely accept?
• Does the supplier’s process chain require any outside processing? If so, are those processors approved and documented?

How to use this template

Fill in each section with data from an actual part or qualification project. Use the completed template to:

• Evaluate a supplier’s end-to-end capability before awarding a PO.
• Structure your own internal case study to document a successful production workflow.
• Prepare RFQ and quality requirements that reflect the full process chain, not just the print.
• Support qualification reviews by providing traceable evidence organized by process step.

A strong case study is not a marketing piece; it is a compact quality record that links design intent to delivered hardware through controlled, documented steps. When you can fill in every box with objective evidence, the workflow is real. When you can’t, that is where the risk lives.

Explore Our Capabilities

Learn more about how Metal Powder Supply supports aerospace and defense manufacturing:

• Additive Manufacturing
• PM-HIP
• CNC Machining & Finishing

Need a quote or have questions about your project? Request a quote or contact our team to discuss your requirements.