Invar Machining Guides
For engineers and buyers with a low-expansion part to make who want to know what to ask the shop. 96 guides in four sections, written to the editorial policy.
Low-expansion alloys explained: Invar 36, Super Invar, Kovar, Alloy 42
Material guides for Invar 36, Super Invar, Kovar and Alloy 42: CTE across temperature, specs, stock forms, magnetism, stability over time and where each alloy is used.
40 guidesProcessHow Invar is machined: sequence, parameters and heat treatment
Guides on the Invar machining process: rough, stress relieve, finish and stabilize, plus milling, turning, drilling, EDM, grinding and coolant choices that keep parts stable.
30 guidesCostWhat an Invar part costs and why
Cost guides for Invar machining: material price per kg, why quotes run above stainless, minimum order quantities, stock lead times and drawing changes that lower the number.
6 guidesChoosing a SupplierHow to choose and brief a shop that machines Invar
Guides for buyers choosing an Invar machine shop: what real Invar experience looks like, the RFQ checklist, NDA and IP, certs, inspection reports and second-source qualification.
20 guidesStart here: the Invar machining buyer's guide. Looking up a spec or a term? See the Invar specs reference and the glossary.
Latest and updated
- Materials
Nov 4, 2026Invar Parts for Electron Microscope Stages and Columns
Where Invar fits in electron microscope stages and frames, why its magnetism limits use near the beam and how drift, cleaning and baking shape the parts.
- Process
Nov 1, 2026How to Deburr Invar Without Adding Residual Stress
Invar makes stringy burrs. Compare hand, brush, vibratory, electrochemical and tool path deburring, and see where each fits in the stress relief sequence.
- Materials
Oct 27, 2026Measuring the CTE of a Machined Invar Part: Dilatometry Explained
How dilatometers measure the CTE of Invar 36, what sample and heating rate to expect, and how to write a CTE test requirement that a shop can price and meet.
- Choosing a Supplier
Oct 25, 2026Photonics and Precision Trade Shows 2027 for Low-Expansion Parts Buyers
Photonics West, LASER World of Photonics in Shanghai and Munich, SPIE Optics + Photonics, OPTATEC: dates for 2027 and 2028, and how to source Invar parts there.
- Nov 4, 2026
Invar Parts for Electron Microscope Stages and Columns
Where Invar fits in electron microscope stages and frames, why its magnetism limits use near the beam and how drift, cleaning and baking shape the parts.
- Oct 27, 2026
Measuring the CTE of a Machined Invar Part: Dilatometry Explained
How dilatometers measure the CTE of Invar 36, what sample and heating rate to expect, and how to write a CTE test requirement that a shop can price and meet.
- Oct 23, 2026
Elinvar and Constant-Modulus Alloys vs Invar: Which Stability Do You Need
Invar holds its length across temperature. Elinvar and Ni-Span-C type alloys hold their stiffness. Compare the two kinds of stability and when each one applies.
- Oct 13, 2026
ASTM F1684 Explained: The Specification Behind Invar 36 Stock
What ASTM F1684 controls for Invar 36 bar, plate and sheet: chemistry, CTE, condition, certification and how to quote the spec correctly on a purchase order.
- Oct 9, 2026
ASTM F15 for Kovar: What the Specification Actually Controls
ASTM F15 sets chemistry and expansion limits for Kovar sealing alloy. See what it covers, what it leaves out and how to write the order for glass seal parts.
- Oct 5, 2026
Alloy 39, 42, 46 and 48: Controlled-Expansion Grades Compared
Compare iron-nickel alloys 39, 42, 46 and 48 with Invar 36 and Kovar: nickel content, typical CTE ranges, what each is matched to and how to choose one.
- Sep 26, 2026
Machining Alloy 42 (ASTM F30): Thin Parts, Flatness and Alloy Choice
Alloy 42 machining: ASTM F30, typical CTE 4 to 6 ppm/°C, used in lead frames and ceramic packages. Thin part fixturing, stamping vs machining and alloy choice.
- Sep 26, 2026
Where Aerospace Programs Use Invar 36 Tooling and Fixtures
Invar 36 assembly jigs, drill templates and test fixtures in aerospace: why fixture growth shows up as measurement error, and when the alloy's cost is worth it.
- Sep 26, 2026
How the CTE of Invar 36 Changes With Temperature and Condition
Invar 36 CTE vs temperature: typical 1.2 to 1.6 ppm/°C from 20 to 100 °C, rising past 150 °C and near plain steel above the Curie point. Tables and an example.
- Sep 26, 2026
Invar Parts for Diagnostic and Lab Equipment Manufacturers
Invar 36 machining for diagnostic imaging, lab automation and analyzer components, where dimensional stability protects calibration accuracy over temperature.
- Sep 26, 2026
Invar and Super Invar parts for wafer stages and reference frames
Invar semiconductor lithography parts explained: stage bodies, metrology frames, why sub-micron drift matters, cleanliness, magnetics near motors and RFQ notes.
- Sep 26, 2026
Invar Parts for Particle Accelerators and Beamlines
Why accelerator facilities specify Invar 36 and Super Invar for magnet mounts and alignment fixtures, and how beamline scale changes the machining and sourcing conversation.
- Sep 26, 2026
Invar Machining for Spectrometer and Analytical Instrument Manufacturers
Why spectrometer and analytical instrument makers specify Invar 36 for grating mounts and optical benches, how thermal drift becomes calibration error and what to put on the RFQ.
- Sep 26, 2026
Invar is ferromagnetic: what that changes in the shop and in service
Is Invar magnetic? Yes, Invar 36 and Kovar are ferromagnetic below their Curie points. What it means for magnetic chucks, demagnetizing, sensors and the RFQ.
- Sep 26, 2026
Machining Invar Reference Standards and Gauge Blocks
Invar reference standards for metrology labs: why the low CTE cuts temperature-driven uncertainty versus steel gauge blocks, and the tolerances a lab specifies.
- Sep 26, 2026
Invar Optical Bench Machining for Spacecraft Instruments
Why a spacecraft optical bench drawing differs from a ground telescope one: launch vibration survival, on-orbit vacuum and thermal cycling, and the verification tests that follow.
- Sep 26, 2026
Kovar Hermetic Packages for Defense and Avionics Electronics
Kovar housings, connector bodies and headers for defense and avionics electronics: production volume, qualification expectations and thermal cycling in service.
- Sep 26, 2026
Machining Kovar for Glass to Metal Seals: What the Seal Needs
Kovar glass to metal seal machining: why ASTM F15 Kovar matches borosilicate glass, how it machines, the anneal and oxide steps before sealing and the RFQ.
- Sep 26, 2026
Kovar Feedthroughs for Implantable Medical Electronics
How Kovar hermetic feedthroughs seal pins into implantable electronics, what to specify on the drawing and why certification stays the device maker's job.
- Sep 26, 2026
Kovar Machining for RF and Microwave Hermetic Connectors
Custom Kovar machining for RF hermetic connector bodies, pins and bulkhead feedthroughs: when catalog connectors do not fit and what to put on the RFQ.
- Sep 26, 2026
Kovar Hermetic Packages for Telecom Electronics Manufacturers
Machining Kovar lids, headers and butterfly packages for telecom optoelectronics: seam weld ledges, pin counts and when to machine versus stamp at volume.
- Sep 26, 2026
Choosing Invar, Kovar or Alloy 42 for RF and Microwave Housings
Decision guide for RF and microwave housing designers: matching Invar 36, Kovar or Alloy 42 to ceramic substrate CTE, sealing needs, cost and machinability.
- Sep 26, 2026
Super Invar Sourcing for Photonics and Laser Manufacturers
When a temperature-stabilized photonics enclosure justifies Super Invar over Invar 36, what availability and lead time actually look like, and what to check before you specify it.
- Sep 26, 2026
Super Invar Machining for Satellite Instrument Mounts
When a satellite payload's temperature-controlled band makes Super Invar worth the added cost and lead time over Invar 36, and the schedule risk that decision creates.
- Sep 26, 2026
Super Invar: The Lower CTE Option, Its Limits and How Shops Machine It
Super Invar machining: typical CTE 0.3 to 0.6 ppm/°C over a narrow band, the transformation risk below about -60 °C, the stabilization cycle and an example.
- Sep 26, 2026
Invar 36 vs Kovar vs Super Invar: Which Alloy for Your Part
Invar 36 vs Kovar vs Super Invar: typical CTE bands, Curie point, specs and machining notes, with a decision table for mounts, glass seals and space parts.
- Sep 21, 2026
Invar for Antenna and RF Waveguide Structures
Why some antenna reflectors, waveguide structures and RF reference frames specify Invar to hold electrical performance stable across temperature.
- Sep 21, 2026
Free-Machining Invar 36: What the Added Sulfur Changes
How free-machining Invar 36 differs from standard Invar 36, the tradeoff it makes for easier cutting, and which applications should avoid it.
- Sep 21, 2026
Obsolescence and Long Lead Times: Planning Invar Stock Orders Around Mill Minimums
Why Invar bar and plate lead times can stretch to weeks or months for nonstandard sizes, and how to plan orders and drawings around mill minimums and stock cycles.
- Sep 21, 2026
Invar 36 by Other Names: Regional Trade Names and Specs
Why the same 36 percent nickel-iron alloy is called Invar 36, Pernifer 36, Nilo 36 or FeNi36 depending on the supplier and region, and how to match specs across them.
- Sep 21, 2026
Invar vs ALLVAR Alloys: Comparing Low-Expansion Metal Options
How newer ALLVAR controlled-expansion alloys compare with Invar 36 and Super Invar, and when the difference actually matters for a machined part.
- Sep 20, 2026
Machining Invar Layup Molds and Mandrels for Composite Parts
Why Invar is used for carbon fiber layup tools instead of steel or aluminum, and what that means for machining large molds and mandrels to hold dimensions through autoclave cycles.
- Sep 20, 2026
Machining Invar for Cryogenic and Vacuum Applications
How Invar 36 behaves at cryogenic temperature and in vacuum service, and what that means for machined tolerances, cleaning and outgassing on parts destined for those environments.
- Sep 20, 2026
Long-Term Dimensional Stability: Does Invar Age After Machining?
Whether machined Invar parts keep moving over months or years after stress relief, and what shops do to minimize long-term dimensional drift beyond the initial process.
- Sep 26, 2026
Invar Machining: What Buyers Need to Know Before Sending a Drawing
How Invar machining differs from stainless: why shops rough, stress relieve then finish, which tolerances are realistic and what to put on your Invar 36 RFQ.
- Sep 20, 2026
Invar for Optical Benches and Telescope Structures: Why CTE Stability Matters
Why optical and telescope designers specify Invar 36 or Super Invar for mounts and structural benches, and what that means for how the parts are machined.
- Sep 20, 2026
Machining Super Invar and Invar 36 for Semiconductor Equipment
Why semiconductor and metrology equipment makers specify Invar and Super Invar for frames and reference plates, and what that means for tolerance, cleanliness and process control.
- Sep 20, 2026
Choosing Invar Stock: Bar vs Plate vs Sheet
How Invar 36 stock form affects lead time, cost and grain orientation, and which form fits round, block and thin-section parts best.
- Sep 20, 2026
Invar vs Zerodur and ULE Glass: Choosing a Low-Expansion Material
How machined Invar compares with Zerodur and ULE glass ceramics for low-expansion optical structures, and which applications favor a metal over a glass ceramic.
- Sep 20, 2026
Why Invar Work-Hardens and How Shops Control It During Machining
The mechanism behind work hardening in Invar 36, why it shows up as tool wear and poor finish, and the cutting practices shops use to keep it from taking over a job.
- Nov 1, 2026
How to Deburr Invar Without Adding Residual Stress
Invar makes stringy burrs. Compare hand, brush, vibratory, electrochemical and tool path deburring, and see where each fits in the stress relief sequence.
- Oct 18, 2026
Joining Invar to Other Metals: Brazing, Bolting and Bonding
Brazing, bolting or bonding Invar to steel, aluminum or glass: what each joint does to dimensional stability, the CTE mismatch and the machining sequence.
- Sep 26, 2026
Heat Treating Invar 36: What Each Step Does and How to Specify It
Invar 36 heat treatment: anneal, quench, stress relief and stabilize, with typical temperatures and times, where it fits in machining and the drawing note.
- Sep 26, 2026
Invar Vacuum Chamber and Beamline Component Machining
Machining practice for Invar flanges, bellows interfaces and mounting hardware in beamline vacuum systems: seal-face finish, leak-tight technique and bakeout dimensional stability.
- Sep 26, 2026
Machining Invar CMM Calibration Bars and Reference Gauges
Machining Invar CMM step gauges, ball bars and length bars: the tolerances, finish and stabilization a reference artifact needs before a cal lab certifies it.
- Sep 26, 2026
Invar Hardness and Machinability: Why the Rating Understates the Job
Invar machinability: hardness about 70 to 80 HRB annealed, a rating of 40 to 50 % of B1112 next to 304, 4140, 6061 and titanium, plus the effect on cycle time.
- Sep 26, 2026
Invar Resonator Housings: What Laser Manufacturers Specify
The parallelism, bore concentricity and flatness callouts a laser resonator housing or cavity spacer drawing needs, and how the stress relief sequence protects them over the laser's service life.
- Sep 26, 2026
Prototype to Production: Invar Parts for Photonics Programs
How a photonics program plans the move from a hand-built Invar prototype at one shop to a qualified production run with incoming inspection and a documented process.
- Sep 26, 2026
Cutting and forming Invar 36 sheet without losing flatness
Invar 36 sheet cutting compared: laser, waterjet, wire EDM and shearing, with typical heat affected zone, edge stress, flatness after cutting and springback.
- Sep 26, 2026
Outgassing and Cleanliness Requirements on Invar Space Parts
What ASTM E595 outgassing testing measures, why it matters for Invar parts going into a vacuum optical or electronic system, and cleaning and handling practice after machining.
- Sep 26, 2026
Kovar Seal Rings for Medical Device Hermetic Packages
Machining and surface prep for Kovar seal rings and housings in medical packaging: cleanliness before sealing and the dimensional control that holds a seal.
- Sep 21, 2026
Reading an Invar CMM Inspection Report: What Each Number Means
How to read a CMM inspection report for a machined Invar part: measurement temperature, soak time, GD&T callouts and what to check before accepting parts.
- Sep 21, 2026
CNC Turning Invar 36: Live Tooling, Chip Control and Setup
What is different about turning Invar 36 on a lathe compared with milling it: chuck and collet fixturing, live tooling for cross features, and controlling long chips.
- Sep 21, 2026
Coolant Strategy for Invar: Flood, MQL or Dry Cutting
Why coolant delivery matters more on Invar than on steel, and how flood coolant, minimum quantity lubrication and dry cutting compare for tool life and part quality.
- Sep 21, 2026
Design for Machinability: Drawing Choices That Cut Invar Cost Without Losing Function
A practical checklist of drawing decisions that lower an Invar machining quote without compromising the tolerances and stability your part actually needs.
- Sep 21, 2026
Engineering Change Requests on an Invar Part Already in Production
Why a small drawing change on an Invar part already in production can affect more than the dimension you changed, and how to scope an ECR to avoid surprises.
- Sep 21, 2026
Investment Casting vs Machining Invar 36: Which Process Fits Your Part
When a cast-then-machined Invar 36 part makes more sense than machining from solid bar or plate, and what casting changes about cost, lead time and dimensional stability.
- Sep 21, 2026
Invar Milling Strategy: Toolpaths That Avoid Work Hardening
How toolpath choice, adaptive clearing and climb milling affect work hardening and surface finish when milling Invar 36, beyond basic speeds and feeds.
- Sep 21, 2026
Invar Passivation: What It Does and When It's Worth Specifying
What passivation actually does to a machined Invar or Kovar surface, how it differs from plating, and when it is worth specifying over leaving the part bare.
- Sep 21, 2026
Helicoil and Thread Insert Practices for Invar Threaded Holes
When a helical thread insert is worth specifying on an Invar part instead of tapping directly into the base material, and how to call it out on the drawing.
- Sep 26, 2026
Speeds, Feeds and Tool Life for Machining Invar 36
Typical Invar 36 machining parameters for milling, turning, drilling and tapping: tool material, speed, feed, coolant and a worked 12 mm end mill example.
- Sep 20, 2026
Invar Drilling and Tapping: Hole Quality and Thread Practices
Why drilled and tapped holes in Invar 36 need different practices than steel, and how shops avoid work-hardened hole walls and broken taps.
- Sep 20, 2026
Invar Fixturing and Workholding: Avoiding Distortion During Machining
Why workholding matters more on Invar parts than on steel or aluminum, and the fixturing practices shops use to avoid clamping distortion on thin or precision features.
- Sep 20, 2026
Invar Grinding: When Milling Isn't Precise Enough
When shops add a grinding step to a machined Invar part, what it achieves that milling cannot, and how it fits into the rough, stress relieve, finish sequence.
- Sep 26, 2026
Invar Machining Tolerances: What a Shop Can Hold and What It Costs
Typical Invar machining tolerances by feature, why 20 °C inspection matters, which GD&T callouts count on Invar and how to turn a temperature band into a CTE.
- Sep 26, 2026
Stress Relief for Invar Machined Parts: When and How Shops Do It
Why Invar parts move after roughing, typical stress relief and stabilization cycles, where they sit in the machining sequence and how to write the drawing note.
- Sep 20, 2026
Surface Finish and Coating Options for Machined Invar Parts
Typical achievable surface finish on machined Invar 36, why work hardening affects it, and which coatings are used for corrosion protection or emissivity control.
- Sep 20, 2026
Thin-Wall Invar Parts: Machining Without Warping
Why thin Invar walls and webs are prone to distortion during machining, and the fixturing, sequencing and stress relief practices shops use to keep them flat.
- Sep 20, 2026
Machining Invar vs Welding Invar: Choosing the Right Fabrication Path
When a welded and machined Invar assembly makes more sense than a part machined from solid, and how welding affects the dimensional stability the alloy is chosen for.
- Sep 20, 2026
Wire EDM and Invar: When to Use It Instead of Milling
When shops turn to wire or sinker EDM for Invar features that are hard to mill, and how the non-contact process affects stress and dimensional stability.
- Sep 26, 2026
How Invar 36 is priced per kilogram and how to buy it smarter
What sets the Invar cost per kg: 36 % nickel and the LME price, mill or distributor, bar, plate or sheet, yield and the material share of a part price.
- Sep 26, 2026
Invar Lead Time Planning for Semiconductor Fab Tool Programs
How to stack Invar material, machining, stress relief and inspection lead time against a multi-tool semiconductor fab build schedule and ramp volume, with a worked example.
- Sep 21, 2026
Minimum Order Quantities and Scrap Rates on Small Invar Batches
Why small Invar orders carry a minimum order consideration and a higher effective scrap allowance than larger runs, and how to plan a small batch around it.
- Sep 21, 2026
Invar 36 vs 304 Stainless: When the Extra Cost Is Worth It
How much more an Invar 36 part costs than the same part in 304 stainless, and a practical way to decide whether your application actually needs the difference.
- Sep 26, 2026
Why Invar 36 Parts Are Costly and How Shops Price Them
Where Invar machining cost comes from: material, slow cutting, stress relief, inspection at 20 °C and certs, with a worked quote breakdown and ways to cut it.
- Sep 20, 2026
Prototype vs Production Invar Machining: What Changes
How a single Invar prototype and a production run differ in cost per part, tooling, lead time and inspection, and how to plan an RFQ around which stage you are in.
Choosing a Supplier
- Oct 25, 2026
Photonics and Precision Trade Shows 2027 for Low-Expansion Parts Buyers
Photonics West, LASER World of Photonics in Shanghai and Munich, SPIE Optics + Photonics, OPTATEC: dates for 2027 and 2028, and how to source Invar parts there.
- Sep 26, 2026
ITAR, EAR and Invar or Kovar Parts: What Buyers Should Know
Plain-language guide to ITAR and EAR basics for buyers sourcing Invar or Kovar aerospace and defense parts. Educational only, not legal advice.
- Sep 26, 2026
Invar Machining for Aerospace Programs: What Buyers Actually Vet
What aerospace and defense buyers check in an Invar or Kovar machine shop beyond price: heat lot traceability, first article inspection and engineering change control.
- Sep 26, 2026
Sourcing Invar Parts as a Laser System OEM
What a laser system manufacturer needs from an Invar machining vendor beyond a single precise part: repeatability across a run, alignment that survives shipping and a documented process.
- Sep 26, 2026
Qualifying an Invar Machining Vendor as a Semiconductor Equipment OEM
How a semiconductor equipment OEM qualifies an Invar machining vendor at production scale: what changes past a one-off RFQ, second sourcing and ECR control across tool builds.
- Sep 26, 2026
Sourcing Invar 36, Kovar and Alloy 42: Mills, Distributors and What Your Shop Already Has
How Invar 36, Kovar and Alloy 42 bar, plate and strip reach a machine shop: mills vs distributors, mill certificates, typical lead times and MOQs, and why most buyers let the shop source it.
- Sep 26, 2026
Supplier Sourcing for Metrology Lab Invar Components
How a metrology lab sources machined Invar parts: low volume realities, what to put on the RFQ, and why the lab's own accreditation establishes traceability.
- Sep 26, 2026
A 300 by 200 mm optical bench in Invar, from alloy choice to quote
Hypothetical Invar optical bench machining example: 300 x 200 x 25 mm bench, mounts held to 5 µm at 20 ± 5 °C. Alloy choice, sequence, inspection and quote.
- Sep 26, 2026
Sourcing Custom Invar Parts for Research Lab Instruments
How university and national lab procurement differs from industrial buying, why research drawings are often informal, and how to write an RFQ that still gets a useful Invar quote.
- Sep 26, 2026
Supplier Qualification for Invar Satellite Structure Machining
What a satellite program checks in a machine shop beyond cutting ability: material traceability, first article inspection and second-source qualification for flight hardware.
- Sep 26, 2026
Should a Semiconductor Equipment Maker Machine Invar In-House?
Build-versus-buy analysis for a semiconductor equipment maker with an in-house machine shop: what Invar needs beyond general machining, capital cost and the volume where in-house starts to pay off.
- Sep 26, 2026
Specifying a dimensional stability test for Invar parts
How to specify an Invar thermal cycling test on a drawing or PO: 20 °C soak, cycle range and count, CMM before and after, acceptable drift and the report.
- Sep 26, 2026
Invar Waveguide Component Machining and Supplier Sourcing
How to write an RFQ for an Invar waveguide section or flange: surface finish and plating callouts, typical order quantities and what a supplier quote should cover.
- Sep 26, 2026
What Medical Device Buyers Should Require from a Machining Supplier
A verification checklist for medical device buyers sourcing Invar or Kovar parts: quality system documents, traceability and change control to check yourself.
- Sep 26, 2026
How to Find a Machine Shop That Has Really Machined Invar
How to qualify an Invar machine shop: which alloys it cut recently, where stress relief runs, whether it inspects at 20 °C and what paperwork comes with it.
- Sep 21, 2026
NDA and IP Protection When Sending an Invar Drawing Overseas
How buyers protect drawing IP when requesting Invar machining quotes internationally: preview-only sharing, NDA timing and what a matching service does and does not solve.
- Sep 21, 2026
Second-Source Qualification: Requalifying an Invar Part at a New Shop
What changes when you move an existing Invar part to a second machine shop: process differences to check, first article comparison and what to document.
- Sep 20, 2026
Invar Mill Certifications: What a Certified Material Report Should Show
What a standard Invar 36 or Kovar mill cert includes, when to ask for measured CTE data, and how to read a certified material test report before it reaches your shop.
- Sep 20, 2026
Shipping and Storing Invar Parts Without Losing Dimensional Stability
How to package, ship and store precision Invar parts so handling stress, corrosion or temperature shock does not undo the dimensional stability the alloy was chosen for.
- Sep 26, 2026
What to Include on an Invar RFQ: A Drawing Checklist
An Invar RFQ drawing checklist: alloy spec, heat treatment note, critical tolerances, 20 °C inspection, certs, quantity and files, with sample drawing notes.