Where multi-process builds actually go wrong
Most multi-process manufacturing builds don’t fail because of the hardest features. Problems usually show up in the coordination between one step and the next, not inside any single process.
Take a part that needs machining, casting, welding, and finishing. Each of these steps is complex on its own, but most shops handle their piece of a manufacturing project well. The machinist and the plating house both meet their specs. The real trouble comes from managing multiple manufacturing vendors at once, since each one is focused only on its own job, its own timeline, its own piece of the drawing.
A real example
Not long ago, we had a build where plating was scheduled a day before final inspection confirmed a key feature was correct. On paper, everyone did their job. The plater met their deadline. The problem was that the plating and inspection schedules weren’t connected.
This happens a lot. Sometimes, an assembly is built using an old fit because the assembler never heard about a change from two revisions ago. A finishing vendor might only see the part they’re working on, not the full drawing, so a finish meant for one surface gets applied everywhere. These aren’t machining problems. They happen when no one is watching the handoffs between vendors.
We’ve seen the same thing on a build that combined an additive prototype with a production tool. The additive vendor hit their spec. The tooling shop hit theirs. But nobody had flagged that the transition itself needed its own check, since the additive part was never meant to carry the same tolerance as the molded version that followed it. That’s not a materials problem. It’s a coordination gap between two vendors who never talked to each other.
The quality on the print has to survive the whole trip.
A drawing starts out clear, with a tolerance callout, a finish spec, and an inspection requirement already built in. The real question is whether that same scope, the actual intent behind the print, survives four separate handoffs before the part ships: engineer review, vendor selection, production, and inspection. Each one is a place where the original intent can quietly shift.
This happens more than most people realize, and it’s rarely anyone’s fault outright. An engineer reviewing the print might read a note slightly differently than the person selecting the vendor. The vendor selected might interpret a tolerance differently than the shop actually running it. By the time a part reaches inspection, the standard it’s checked against isn’t always the one the customer specified in the first place. Someone has to own that scope from the first review to the last inspection, or it drifts a little at every stop until the final part isn’t exactly what was originally drawn.
How we handle it
Managing multiple manufacturing vendors on one build takes more than a spreadsheet of due dates. Our engineers review the entire build package before we even send a quote, not just the individual items. If there’s a transition from additive to molding, a machined feature that needs to survive plating, or a tolerance stack across several vendors, we want to spot it early in the drawings. It’s much cheaper to find these issues now than during final inspection.
We have a trusted network of vendors for CNC machining, sheet metal fabrication, injection molding, additive, finishing, and assembly. Each process is matched to a shop with proven experience. Capability and tolerance claims come from our network, tracked for each shop. You get one number, one timeline, and one contact. We inspect all parts in San Clemente before shipping, so the final check is always ours.
Common questions about multi-vendor manufacturing projects
How do you manage a manufacturing project across multiple vendors? One point of contact reviews the entire drawing package before quoting, then owns every handoff between vendors until the part ships.
What causes most multi-process manufacturing delays? Rarely a single hard feature. Delays usually come from vendors working off different revisions, different schedules, or incomplete visibility into the rest of the build.
Can one supplier really manage machining, molding, and finishing together? Yes, through a vetted vendor network where each process is matched to a shop proven on that specific step, coordinated by one team.
What we need from you
Send the whole package. Prints or models for every step, finish and inspection requirements for each one, and some sense of how it’s all supposed to come together at the end. Let us know if something’s already sourced or already underway. The more we can see up front, the faster we can tell you where the real risk sits, before it turns into a missed date.
ISO 9001:2015. AS9100 Compliant. ITAR Registered.
You shouldn’t have to manage five vendors on your own project. Send us the drawings.
