A weldment is a single part created by welding multiple pieces of metal together—plates, bars, tubes and machined details fused into one component. Machine bases, frames, brackets, hoppers and housings are all typically weldments. For low and medium volumes, a weldment usually beats a casting on cost, lead time and design flexibility.
How is a weldment different from a casting?
A casting is poured as one piece into a mold that costs real money and time to create; a weldment is cut and joined from standard mill shapes with no tooling investment. Castings win at high volumes where the mold cost spreads thin. Weldments win when you need ten, five or one—which describes most industrial equipment.
Why do weldments dominate machine frames and bases?
Because plate and structural shapes are strong, available and easy to modify. A welded base can be designed this week, built next week and revised next year—try that with a pattern and a foundry queue. Critical surfaces are machined after welding, giving cast-level precision exactly where it is needed.
Can a weldment replace an obsolete casting?
Frequently, yes. When a cast part breaks and the pattern no longer exists, a fabricated equivalent—reverse-engineered from the original—can restore the machine, often in a stronger or more repairable form. It is one of the most common rescues in our replacement parts work.
What makes a good weldment drawing?
Overall geometry, weld requirements where they matter, materials, and clear callouts for the surfaces that get machined after welding. State the functional requirements and let the fabricator plan the joint details—our RFQ guide covers the package.
How do machining and weldments work together?
Weld first, machine second. Welding moves metal; machining afterward puts bores, pads and mounting faces exactly where the drawing wants them. Shops that do both under one roof—as we do—control that sequence without trucking parts between vendors.
Frequently asked questions
Properly designed, yes for most industrial duty—strength comes from the design and materials, not the label. Each approach suits different load cases and volumes.
When quantities climb high enough that tooling cost per part becomes small—typically hundreds to thousands of identical parts.
Yes—that is the standard way weldments get precision surfaces, and our CNC machining department does it in-house.
A weldment is permanently joined by welding; an assembly is joined by fasteners and can be taken apart. Many machines are assemblies of weldments.
Turn the broken casting into a better weldment
A & P Fabricating Solutions, LLC designs and builds weldments—and machines them—at our Appleton, Wisconsin shop. Send the part or the problem to the quote request page.
