Magnesium Machining and Fabrication in Oshkosh, WI

The defense programs tied to Oshkosh-area Tier 1 and Tier 2 suppliers place strict weight budgets on everything from cab structures to electronic housing assemblies. AZ31B sheet and plate is the go-to wrought grade for formed enclosures and brackets — it machines cleanly at surface speeds of 1,000–2,000 SFM with sharp carbide tooling, produces tight tolerances down to ±0.002 inch, and accepts chemical-film (Alodine-equivalent) or anodize finishes that satisfy MIL-spec corrosion requirements. For structural castings, AZ91D die casting alloy offers a tensile strength around 230 MPa with yield near 150 MPa — adequate for non-primary structure where weight savings justify the trade-off against steel weldments. Aerial work platform frames and outrigger components benefit from magnesium's vibration damping, which is roughly 10 times better than aluminum. When equipment runs rough terrain — the operational reality for defense and utility vehicles built in this region — damping translates directly to longer fatigue life on welded sub-assemblies. Shops in the Fox Valley that already hold ITAR registration can process AZ31B and AZ91D without additional export-control overhead, which shortens the vendor qualification cycle for defense prime contractors. WE43, a rare-earth-strengthened grade (zirconium plus yttrium), extends service temperature to around 250°C and is the correct choice when a component lives near a powertrain or hydraulic circuit rather than in ambient structure. Its machinability is similar to AZ91D, but tool life drops roughly 20–30 percent, so job cost estimates should account for higher insert consumption and slower feed rates on deep pockets.

Magnesium's chip ignition temperature is approximately 650°C — well above what normal dry machining reaches with proper parameters, but a real hazard if chips accumulate or dull tooling generates frictional heat. Reputable Fox Valley shops running magnesium maintain Class D fire extinguishers (dry sand), dedicated chip drums with tight lids, and strict housekeeping protocols. Buyers specifying magnesium should ask suppliers for their written magnesium machining procedure and proof of Class D suppression during RFQ — not as a formality but because it directly signals process discipline. Typical CNC parameters for AZ31B: spindle speed 3,000–6,000 RPM on a 0.5-inch carbide end mill, feed 0.003–0.005 IPT, axial depth 0.25–0.5 inch, dry or with compressed air evacuation. Through-spindle coolant is not recommended; flood coolant that contains water reacts with magnesium swarf and generates hydrogen gas. Shops without dry-machining experience will quote magnesium but should be screened carefully. Minimum lot sizes in the region typically run 5–25 pieces for prototype and 100+ for production, with lead times of 3–6 weeks for first articles from drawing. Surface finishing options relevant to Oshkosh defense buyers include Dow 17 anodize for moderate corrosion protection, chrome-free conversion coating for RoHS-compliant programs, and epoxy primer plus topcoat systems to MIL-PRF-23377 or MIL-PRF-85582. Dimensional inspection to AS9100 rev D quality plans is standard among shops serving Oshkosh-area prime contractors.

AZ31B (3% aluminum, 1% zinc) is the dominant wrought grade. It comes in sheet, plate, bar, and extrusion. Use it for formed brackets, weldments, sheet-metal enclosures, and any component requiring bending or rolling. Weld with AZ61A filler using TIG; post-weld stress relief at 260°C for one hour prevents residual-stress cracking. Density is 1.77 g/cm³, elastic modulus 44 GPa. AZ91D is die-cast grade. It cannot be wrought-processed — specify it only for cast parts. Die-cast AZ91D offers better corrosion resistance than AZ31B and is the most widely cast magnesium alloy globally. Local die casters serving the Fox Valley automotive and equipment sector have the tooling infrastructure. Expect porosity rates below 0.5 percent from qualified suppliers using vacuum-assist dies; porosity above that threshold compromises pressure-tight housings for hydraulic or pneumatic circuits. WE43 (yttrium 4%, rare earth 3%, zirconium 0.4%) is the premium elevated-temperature grade. It was originally developed for aerospace gearbox housings and has seen adoption in defense electronics and satellite structures. Procurement teams should expect a 3–4x material cost premium over AZ31B and limited regional stock — most WE43 bar and billet ships from specialty distributors in Chicago or Minneapolis with 2–4 week lead times into Oshkosh.

ManufacturingBase connects procurement engineers at Oshkosh-area defense contractors and equipment OEMs with qualified magnesium fabricators across the Fox Valley and the broader Midwest manufacturing corridor. When you post an RFQ, the platform routes your inquiry to shops that have self-identified magnesium capability, ITAR registration status, and relevant certifications — filtering out shops that will simply accept the job and subcontract it without telling you. For high-mix, low-volume defense programs, the ability to find a single qualified shop handling rough machining, finish machining, conversion coating, and CMM inspection under one roof shortens lead time and removes inter-supplier handling risk. ManufacturingBase supplier profiles show actual capabilities, not marketing language, so your sourcing team can evaluate fitness before sending drawings. Co-founder Tony Gunn brings 20-plus years and 80-plus countries of machining experience to the vetting standards baked into every supplier profile on the platform.