How Medical Titanium Implants Are Made: A Guide to Machining, Forging & Additive Manufacturing

Titanium implants do not begin their lives as implants. They begin as an ingot, a billet, a ground bar, a rolled plate, or a drawn wire — and the route that material takes from that form to a sterile, packaged device shapes almost everything about how the finished implant behaves inside the body. Two implants can be made from the same ASTM F136 chemistry, meet the same tensile requirements, and still differ by an order of magnitude in fatigue life, simply because one was machined from bar and the other was forged, or because one was built additively and never properly stress-relieved.

This guide walks through the three manufacturing routes that dominate medical titanium implant production — CNC machining, forging, and additive manufacturing — and explains how the choice of raw material form, metallurgical condition, and post-processing determines whether the device will survive twenty years of cyclic loading in a hip, or fail at the thread root in eighteen months. It is written for implant designers, process engineers, and sourcing teams who need to connect material specifications on a purchase order to real outcomes on a shop floor.

What Counts as a Medical Titanium Implant

A medical titanium implant is a device that is intentionally placed inside the body and left there for a defined period, manufactured from implant-grade titanium conforming to one of three dominant material standards: ASTM F67 for commercially pure titanium (Grades 1–4), ASTM F136 for Ti-6Al-4V ELI (Grade 23), and ASTM F1295 / ISO 5832-11 for Ti-6Al-7Nb. Everything else — the design, the process route, the inspection plan — sits on top of that material foundation.

Implants, Instruments, and Components Are Not the Same Thing

The distinction matters more than most procurement documents admit, because the three categories carry different material requirements and radically different documentation burdens.

• Implants are indwelling. They must satisfy long-term biocompatibility and, in load-bearing applications, fatigue endurance measured in tens of millions of cycles. ELI grades are the default here, because interstitial content governs toughness and crack propagation resistance.
• Instruments are reusable or single-use tools — forceps, retractors, drill guides, reamers. They are sterilized repeatedly and must resist wear and corrosion, but they are not implanted. Standard Grade 5 Ti-6Al-4V is often acceptable, and 420/431 stainless steel competes on cost.
• Components are subassemblies supplied to an OEM — a machined blank, a threaded insert, a laser-cut mesh. The component supplier inherits the implant's material requirements even though the part is never sold as a device.

If you are still working out which material grade fits which application, the full guide to titanium grades used in the medical industry covers the selection logic in more depth, and the breakdown of chemical composition and mechanical properties of medical titanium alloys gives the numbers behind each grade.

The Four Implant Families That Drive Titanium Demand

Roughly speaking, medical titanium consumption splits into four families, each with a distinct manufacturing signature:

• Orthopedic — hip stems, acetabular shells, knee femoral and tibial components, bone plates, cortical screws, intramedullary nails. Dominated by forging and heavy machining of large-diameter ELI bar.
• Spine and trauma — pedicle screws, rods, interbody cages, trauma plates. A hybrid of high-volume turning and additive manufacturing, with a growing share of porous and lattice structures.
• Dental and maxillofacial — root-form implants, abutments, mini-plates, reconstruction mesh. The highest-volume, tightest-tolerance segment, built almost entirely by Swiss-type turning from small bar and CAD/CAM milling from disc.
• Cardiovascular and soft tissue — guide wires, stents, suture anchors, staples, clips. Driven by fine wire drawing and laser cutting rather than machining.

The application pages for medical applications break these families down further, and the dedicated guides to dental applications and cardiovascular devices cover the device-specific constraints.

The Three Manufacturing Routes

Almost every titanium implant on the market is produced by one of three routes, or by a deliberate combination of them. The route is usually fixed early in design, because it determines the material form you must buy, the tolerances you can promise, and the cost curve as volume scales.

Route 1 — CNC Machining from Bar, Plate, and Disc

Machining is the default route for anything small, intricate, or produced in modest volumes. Swiss-type lathes turn dental implants, abutments, screws, and pins from ground bar; five-axis mills cut knee components, cages, and bone plates from plate or near-net forgings; gun drilling produces the through-lumen in cannulated screws and instruments.

The advantages are real: no tooling investment, sub-0.01 mm tolerances, excellent surface finish, and fast design iteration. The penalty is material yield. A dental implant turned from a 6 mm bar may remove 60–70% of the incoming mass as swarf, and titanium swarf is both expensive to buy and difficult to recycle back into implant-grade stock. Buy-to-fly ratio is the single most important cost lever in a machining-based implant program.

Route 2 — Closed-Die and Open-Die Forging

Load-bearing orthopedic implants — hip stems above all — are forged. Hot working produces a grain flow that follows the part contour rather than cutting across it, which is exactly what you want in a component that sees bending and torsional fatigue for decades.

Ti-6Al-4V has a beta transus around 995 °C. Conventional alpha-beta forging is carried out roughly 40–90 °C below that — typically 900–950 °C — producing an equiaxed or bimodal structure with a good balance of strength and ductility. Beta forging above the transus yields higher fracture toughness and better crack growth resistance but coarser, less ductile microstructures — a trade-off that is legitimate for some hip stem designs and unacceptable for others.

Forging is not a finishing operation. Dies are cut oversize, and the forging is subsequently machined to final geometry, so the tolerance chain includes both the die and the machining setup. Tooling cost and lead time are significant, which pushes forging toward higher volumes and larger parts.

Route 3 — Additive Manufacturing

Laser powder bed fusion (LPBF) and, less commonly, electron beam melting have moved from prototyping to serial production for porous acetabular cups, interbody cages, craniofacial mesh, and patient-specific osteotomy hardware. Layer thickness typically runs 30–60 µm, with laser power in the 200–400 W range.

The technology’s real value is not “complexity for its own sake.” It is the ability to build controlled porosity — pore sizes in the 300–800 µm range with interconnected struts — that cortical bone will grow into, achieving fixation without cement or hydroxyapatite coating. It also collapses a multi-part assembly into a single printed component.

Additive parts are not finished when they leave the machine. They require stress relief, support removal, hot isostatic pressing (commonly around 900–1000 °C at ~100 MPa) to close internal porosity, and machining of any articulating or mating surface, because as-built surfaces sit at Ra 8–20 µm — far too rough for a bearing interface. Powder chemistry must be controlled and powder reuse tracked, since oxygen and nitrogen pick up with each build cycle.

Choosing Between the Three

In practice, most implants are hybrids. A porous acetabular cup is printed, HIPed, then the taper and rim are machined. A hip stem is forged, machined, then shot-peened. The route question is really about where the geometry is created and where the precision is created — and those are often two different operations.

How Material Form Drives Process Choice

Because the manufacturing route is fixed by geometry, the material form you purchase is largely determined before the first purchase order is written. Specifying the wrong form — a plate where a disc was needed, or a bar with insufficient straightness for a Swiss lathe — shows up as scrap rate rather than as a specification failure.

Bar and Rod

Bar is the feedstock for turning, so the properties that matter are not just chemistry and tensile strength. Straightness, roundness, and surface condition determine whether a bar will run through a Swiss lathe at all. For small diameters, centerless grinding delivers the diameter consistency and surface finish that guide bushings require; for cannulated screws and drills, gun-drilled hollow bar removes the deep-hole drilling operation from the customer's process entirely.

Medical titanium bar is supplied across Grades 1–4 to ASTM F67, Grade 5 and Grade 23 to ASTM F136, and Ti-6Al-7Nb to ASTM F1295, in diameters from 3 mm to 150 mm depending on grade.

Sheet and Plate

Plate is the feedstock for milling and for cutting blanks. Thickness tolerance, flatness, and the absence of alpha case matter as much as mechanical properties — a plate that springs when clamped will not hold a flatness callout after machining. Trauma plates, craniofacial mesh, and cutting blanks for dental disc all start here.

See medical titanium sheet for the available thickness range and surface conditions.

Wire

Wire follows a different logic again. Guide wires, Kirschner wires, staples, cables, and suture anchors are drawn rather than machined, so surface defect control dominates: a single longitudinal scratch or inclusion on the surface becomes a crack initiation site under bending fatigue. Diameter consistency and straightness in the coil determine how the wire behaves on automated forming equipment.

Details are on the medical titanium wire page.

Cannulated Bar and Dental Disc

Two specialized forms deserve separate mention. Cannulated bar is gun-drilled with a concentric through-hole so that a screw or drill can pass over a guide pin — the concentricity of that hole to the outer diameter is the critical characteristic, and it is far easier to buy it drilled than to drill it yourself. Dental discs are supplied as round blanks sized for CAD/CAM mill tables, from which abutments and framework structures are cut.

If you are still deciding which form suits a given part, choosing between titanium bar, sheet, and wire for medical applications works through the decision directly.

Metallurgical Requirements Behind Each Route

Material that meets the certificate is not automatically material that will machine well, forge well, or print well. The metallurgical condition has to match the process.

Chemistry and Interstitial Control

The difference between standard Ti-6Al-4V and Ti-6Al-4V ELI is almost entirely about interstitials. ASTM F136 ELI caps oxygen at 0.13% against 0.20% for the standard grade, and adds tighter limits on nitrogen, hydrogen, and iron. Oxygen and nitrogen raise strength but reduce ductility and toughness — precisely the properties that govern fatigue crack growth in an implant. Hydrogen is held to 0.0125% maximum because above roughly 150 ppm titanium can precipitate brittle hydrides, a risk that also makes hydrogen-bearing cleaning and pickling processes worth controlling.

For commercially pure titanium, the grades are defined almost entirely by oxygen: roughly 0.18% for Grade 1 up to 0.40% for Grade 4. That is why Grade 4 can substitute for an alloy in some dental applications while Grade 1 cannot carry load at all.

Grain Size and Microstructure

Grain size is measured to ASTM E112 and is usually called out as No. 5 or finer for implant bar, though the exact requirement should be agreed on the purchase order rather than assumed. What matters is uniformity. A structure with isolated coarse grains, beta flecks, or a Widmanstätten colony will pass a tensile test and still fail in fatigue, because fatigue initiates at the weakest microstructural feature, not at the average.

Forging must stay below the beta transus to avoid exactly this. Additive manufacturing produces a fine acicular α′ martensite in the as-built condition, which is why HIP plus annealing is not optional for fatigue-critical printed implants.

Residual Stress and Dimensional Stability

Machining induces surface residual stress; printing induces bulk residual stress from steep thermal gradients. Both cause problems later — a thin-walled cup that goes oval after the last pass, a thread that drifts out of tolerance after sterilization, a plate that will not sit flat on a bone surface. Stress relief in the 700–800 °C range, applied at the right point in the sequence, is what prevents this. Applying it too early is as much a mistake as skipping it.

Texture and Anisotropy

Wrought titanium is anisotropic. Transverse ductility is lower than longitudinal, and forged components inherit a grain flow direction. Designers who assume isotropic properties from a handbook table are occasionally surprised by a transverse elongation result that sits just under the specification minimum. Buying material with a declared test direction, and specifying which direction the test should represent, closes that gap.

Why Machining Titanium Is Different

Titanium is not difficult to machine because it is hard — annealed Ti-6Al-4V sits around 30–35 HRC, well below many steels. It is difficult for a different set of reasons, only one of which is actually about cutting.

Heat, Tool Wear, and Cutting Parameters

Titanium's thermal conductivity is roughly 7 W/m·K, about one-sixth that of steel. Heat generated at the cutting edge cannot escape into the chip or the workpiece, so it concentrates in the tool. Combined with titanium's chemical affinity for tool materials at elevated temperature, this produces rapid crater and flank wear. The practical response is lower surface speed — commonly 30–60 m/min with carbide — higher feed per revolution to keep the cut below the work-hardened layer, generous high-pressure coolant, and sharp, dedicated tooling.

Spring-Back, Chatter, and Thin Walls

Titanium's elastic modulus is around 110 GPa, roughly half that of steel. Thin walls and slender features deflect away from the cutter, then spring back, producing taper, chatter, and inconsistent wall thickness. Trochoidal toolpaths, light radial engagement, and rigid fixturing that supports the workpiece rather than clamping it are the standard countermeasures. For dental implant walls in the 0.3–0.5 mm range, this is where most process development time is spent.

Threads, Cones, and Tolerance Stack-Up

Implant connections are unforgiving. The internal taper on a dental implant, the thread form on a cortical screw, and the mating surfaces of a Morse-type connection all concentrate stress at radii measured in tenths of a millimeter. Surface finish at the thread root is a fatigue variable, not a cosmetic one — Ra below 0.2 µm is common on fatigue-critical threads. Every operation in the chain, from bar straightness to final pass, contributes to whether that finish is achieved.

Coolant, Cleanliness, and Cross-Contamination

Embedded iron particles from tooling or from shared equipment become corrosion initiation sites on a titanium implant, and they are invisible until salt-spray or metallographic inspection. Dedicated titanium machining cells, non-ferrous tooling where possible, and validated cleaning between batches are the practical controls. Cleanliness requirements for orthopedic implants are addressed in ISO 19227, and the associated test methods in ASTM F3127.

Post-Processing: From Blank to Sterile Device

The machining or printing operation produces a shape. Post-processing produces a device.

Stress Relief and Heat Treatment

Annealing relieves residual stress and normalizes microstructure. For ELI alloys the thermal cycle must avoid contamination — oxygen pickup during an improperly controlled anneal will push interstitial content past the ELI limit and quietly convert certified material into non-conforming material. Vacuum furnaces and validated atmosphere control are the norm.

Surface Finishing and Osseointegration

Surface topography determines how bone responds. Machined surfaces suit some applications; blasted and dual acid-etched surfaces (the SLA family) create the micro-roughness that supports osseointegration in dental implants; plasma-sprayed hydroxyapatite adds a bioactive layer on orthopedic stems; anodizing produces a controlled oxide that can also serve as a color-code for identification.

Because surface state is a functional requirement rather than a finish callout, it deserves its own specification. The overview of surface treatment technologies for medical titanium implants covers the available processes and their clinical rationale.

Passivation and Cleaning Validation

Passivation removes free iron and foreign matter from the surface and restores the passive oxide layer. ASTM F86 covers surface preparation for implant materials; ASTM B600 covers descaling and passivation of titanium, and citric or nitric acid passivation per ASTM A967 is commonly specified alongside. Cleaning validation then confirms that residues from machining, polishing, and passivation are below the limits set in the device's biocompatibility assessment.

Sterilization and Packaging

Ethylene oxide (ISO 11135), gamma irradiation (ISO 11137), and moist heat (ISO 17665) are the three main routes, all targeting a sterility assurance level of 10⁻⁶. Packaging must maintain the sterile barrier through distribution, per ISO 11607. Sterilization does not change the metallurgy, but it can change the surface, and it must be validated on the actual device rather than on a representative coupon.

Inspection, Testing, and Traceability

An implant's quality record is as much a part of the product as the metal itself. In a regulatory audit, the documentation is what demonstrates control.

Incoming Material Verification

Every incoming lot should be verified against its material test certificate — typically an EN 10204 3.1 certificate — covering chemistry, mechanical properties, and heat number. Beyond the certificate, implant programs commonly require ultrasonic inspection for internal defects, grain size to ASTM E112, hardness, and a dimensional check. Ultrasonic testing of titanium bar is usually specified to a recognized standard such as AMS 2631, with the acceptance class agreed in advance.

In-Process and Final Inspection

Coordinate measuring machines handle prismatic geometry and form tolerances; optical and video measurement handles small features and thread profiles; industrial CT is increasingly used to verify internal lattice structures in additively manufactured parts where no other method reaches. Surface roughness, thread gauges, and dye penetrant inspection round out the routine plan.

Mechanical and Biocompatibility Testing

Tensile testing follows ASTM E8; fatigue testing for implant components typically follows ASTM E466 or E606 depending on whether the regime is load-controlled or strain-controlled. Biocompatibility is assessed under the ISO 10993 series, with ISO 10993-1 framing the evaluation. The guide to biocompatibility testing for titanium medical devices explains which tests apply to which contact category and duration.

Lot Traceability

Traceability must run from the finished device back to the heat number, and forward from the heat number to every device it entered. That requires lot control at every transformation step — melt, forge, roll, draw, machine, finish, sterilize. Under ISO 13485 and 21 CFR 820, and with UDI labeling now standard in major markets, a break anywhere in that chain is a finding.

How to Qualify a Titanium Supplier

Supplier qualification for implant material is not a price negotiation with a certificate attached. It is an assessment of whether the mill can hold a metallurgical specification, document it, and tell you when something changes.

The Documentation Package

A complete package for implant-grade titanium should include: ISO 13485 certification (with ISO 9001 alone being insufficient for device-grade supply), material test certificate to EN 10204 3.1, ultrasonic inspection report, grain size and microstructure report, full chemistry including interstitials, mechanical properties with test direction declared, a certificate of conformity, and declarations covering REACH, RoHS, and conflict minerals. For medical programs, a statement on scrap segregation and re-melt policy is also worth requesting.

Ten Questions Worth Asking in the Audit

1. Is the material single-melt, or double/triple vacuum-arc remelted, and can you show the melt records?
2. How is the beta transus controlled and verified on each heat?
3. Is titanium processed on dedicated lines, or shared with stainless and nickel alloys?
4. What ultrasonic inspection standard and acceptance class do you apply, and who performs it?
5. What is your demonstrated process capability (Cpk) on the critical diameter or thickness?
6. Can you supply a first article inspection report to AS9102 or an equivalent PPAP format?
7. What is your change control notification process, and what is the notice period?
8. How do you segregate and control titanium scrap to prevent cross-grade contamination?
9. What are your standard and custom lead times, and what inventory is held for standard sizes?
10. Can you trace a delivered bar back to the ingot and forward to every shipment it entered?

Cost structure is worth understanding at the same time, since grade, melt method, and testing scope drive price more than tonnage does. The analysis of cost factors that affect medical titanium pricing explains where the money actually goes.

Frequently Asked Questions

Is forged titanium always better than machined titanium for implants?

No — it is better where fatigue in a load-bearing, complex-shaped component matters, because grain flow follows the contour and the microstructure is refined by hot working. For small, intricate parts like dental implants or screws, machining from wrought bar is the correct route, and forging would add cost without adding performance.

Can additive manufacturing replace machining for implants entirely?

Not currently. Printed implants still require machining on articulating surfaces, tapers, and threads, because as-built surface roughness and dimensional tolerance are not adequate for bearing or mating interfaces. Additive manufacturing changes where the geometry is created; it does not remove the need for precision machining.

Why is Grade 23 preferred over Grade 5 for implants?

Grade 23 is Ti-6Al-4V ELI, with tighter interstitial limits — notably oxygen at 0.13% maximum versus 0.20%. The lower interstitial content improves ductility and fracture toughness, which translates into better fatigue crack growth resistance in long-term implants. The Grade 23 overview covers the trade-offs in detail.

How long does implant manufacturing take from raw material to finished device?

It depends heavily on the route. A machined dental implant from standard bar stock can move from material to finished device in a few weeks. A forged hip stem involves die production, forging, machining, coating, and validation, and is measured in months. Material lead time is usually a smaller share than process and validation time — standard bar sizes are commonly available in 2–4 weeks, with custom specifications running 4–6 weeks.

What determines how long a titanium implant lasts in the body?

Material grade, microstructure, surface treatment, implant design, surgical technique, and patient factors all contribute. Titanium's corrosion resistance and biocompatibility mean the material itself is rarely the limiting factor; mechanical failure modes such as fatigue, loosening, and wear debris are more common. The review of implant longevity in the human body sets out the evidence.

Conclusion

The route from titanium bar to finished implant is a chain of decisions, and each one constrains the next. Choose forging and you commit to die cost and a machining allowance; choose additive and you commit to powder control, HIP, and post-machining; choose machining and you commit to material yield as your dominant cost. None of these is wrong. What is wrong is selecting a route without matching the material form and metallurgical condition to it — because that mismatch does not announce itself at incoming inspection. It shows up two years later, in a fatigue test that comes in under specification, or in a field complaint.

Getting the material right at the front of that chain is the cheapest control available. JH supplies implant-grade titanium bar, sheet, wire, cannulated bar, and dental disc to ASTM F67, ASTM F136, and ASTM F1295 / ISO 5832-11, with full traceability and lot documentation from a production chain that has served orthopedic, trauma, spine, dental, and maxillofacial customers since 2009.

If you are specifying material for a new implant program, or re-qualifying a supplier for an existing one, our engineers can review your grade, form, tolerance, and documentation requirements against what is actually achievable — and tell you where the specification is buying performance and where it is only buying cost.