How to Consolidate 40 Machined Parts Into One 3D-Printed Assembly

A Practical Engineering Guide to Part Consolidation with MJF and SLS

Forty parts become one.

On paper, that sounds like an easy manufacturing win. Forty drawings become one. Dozens of fasteners disappear. Assembly labor drops. Purchasing gets easier.

Sometimes that's exactly what happens.

But part consolidation is not really about achieving the lowest possible part count. The better objective is to eliminate unnecessary interfaces, manufacturing operations, tolerance-stack contributors, and failure points without creating a new part that's difficult to print, clean, inspect, qualify, or service.

That's an important distinction when you're considering Multi Jet Fusion (MJF) or Selective Laser Sintering (SLS) for a previously machined assembly.

A good consolidation project doesn't take 40 existing CAD bodies and perform a heroic Boolean union. It goes back to the function of the assembly and asks a more useful question:

If we weren't constrained by the original manufacturing process, how would we design this assembly today?

Start With Why Those 40 Parts Exist

Before opening the master CAD model, look at the assembly drawing and BOM.

Why are there 40 parts in the first place?

Some probably need to remain separate. Bearings, wear components, seals, motors, sensors, and parts requiring different materials have obvious reasons to exist independently.

Others may exist primarily because of manufacturing constraints.

A machined bracket might be separate because a cutter couldn't reach the feature from the primary setup. A manifold may consist of several plates because internal passages had to be drilled from different directions. A spacer might do nothing except establish an offset between two other components. Several screws may exist solely because those separately manufactured pieces need to be held together.

Those are the components worth investigating.

This is also why purchase price alone doesn't tell you much about the opportunity. The true cost of a 40-part assembly includes machining setups, purchased hardware, finishing, inspection, assembly labor, alignment, fixtures, inventory, supplier coordination, rework, and engineering-change management.

A cheap component can be surprisingly expensive once the entire organization has to keep track of it.

SICAM saw a version of this with Teledyne LeCroy Test Services. A rugged battery chassis contained deep-pocket geometry that was relatively slow and expensive to CNC machine. After evaluating several additive approaches, the application transitioned to MJF PA 12 production. The resulting manufacturing workflow also incorporated threaded inserts and vapor smoothing.

The lesson isn't simply that MJF is cheaper than CNC. It isn't universally.

The geometry, production quantity, required finishing, secondary operations, and assembly burden changed the economics enough to make MJF the better production process for that application.

Redesign the Function, Not the Existing Components

Once you've identified what each component actually does, resist the urge to simply merge the existing geometry.

That's usually how you end up with an additive part that looks suspiciously like several machined parts welded together.

Instead, rebuild the assembly around its load paths and functional interfaces.

Two overlapping plates might become a ribbed shell. A separate gusset can become a continuous structural transition. Cable clips can become integral routing features. Alignment hardware may become printed locating geometry where the tolerance and wear requirements allow it. Several manifold components may become one body containing internal passages.

This is where additive manufacturing starts earning its keep.

You're no longer asking the printer to reproduce geometry designed for a mill. You're removing geometry and interfaces that existed because the mill needed them.

There is a mechanical catch, of course.

If the original assembly was aluminum and the consolidated design is PA 12, deleting the fasteners doesn't magically make the two structures equivalent.

HP reports approximately 50 MPa tensile strength and 1,900 MPa tensile modulus for MJF PA 12 produced on its Jet Fusion 5200 platform under the specified test conditions. Those numbers are useful for material selection and early calculations, but the modulus difference compared with metals should immediately get a designer's attention.

If stiffness controls the application, simply copying the aluminum wall thickness into PA 12 is unlikely to produce the same behavior.

The geometry has to start doing more work.

Increasing section depth, adding ribs, closing open sections, introducing curvature, and placing material along the actual load path can improve stiffness far more efficiently than globally thickening the part. This is one reason consolidation works best when you're willing to redesign rather than translate.

Part Consolidation Can Also Eliminate Tolerance Problems

The dimensional side of consolidation is just as interesting as the structural side.

Imagine an alignment feature whose final position depends on three machined components, two locating pins, a spacer, and four fasteners. Each individual component may be perfectly within tolerance while the final assembly still accumulates variation through the stack.

Integrating those features into one body can eliminate several contributors to that stack entirely.

That's a legitimate advantage.

But it doesn't mean every resulting feature should receive a ±0.1 mm tolerance because someone found that number on an MJF capability chart.

A production drawing still needs to distinguish between features that are critical to function and features that simply need to exist in roughly the right place.

Bearing seats, sealing surfaces, datums, precision bores, shaft interfaces, connector positions, and critical locating features deserve special attention. Depending on the requirement, some may print directly to an acceptable condition. Others may need stock for secondary machining. Still others may reveal that the original drawing tolerance was tighter than the function ever required.

SICAM's production qualification workflow is built around this distinction. The drawing and critical dimensions are reviewed against normal process capability first. When geometry-specific performance needs to be demonstrated, a pilot run can be inspected before committing to production requirements.

If a tighter tolerance is genuinely required, additional process development or tolerance compensation can be considered.

That's a much safer way to design a production additive part than treating a generic machine specification as a promise.

For production work, demonstrated capability on the actual geometry matters more than brochure accuracy.

The Most Interesting Geometry Is Usually Inside the Part

Part consolidation gets much more compelling when the assembly contains internal routing.

A conventionally manufactured manifold, for example, may require several drilled passages, plugs, fittings, seals, and separate components simply because a cutting tool needs straight-line access.

With MJF or SLS, some of those passages can potentially be produced directly inside the component. The same applies to cable routing, air passages, hollow structural sections, internal stiffening, and weight-reduction cavities.

But there's a manufacturing constraint that is very easy to overlook while rotating a beautiful section view in CAD:

The powder has to come out.

MJF and SLS parts are built surrounded by powder. Any enclosed cavity or internal channel therefore needs a realistic depowdering strategy.

A short cavity with large openings on accessible faces is one thing. A narrow serpentine passage buried deep inside a housing is something else entirely. Length, cross-sectional area, bends, restrictions, dead ends, opening location, and cleaning orientation all influence whether powder can actually be removed.

This is why specifying one universal "minimum escape hole" is misleading. An opening that works perfectly for one cavity can be useless for another.

A simple DfAM rule is more reliable:

If you can't explain how the powder gets out, the internal geometry isn't finished.

And if residual powder would create a functional problem—fluid contamination, blocked airflow, moving-component interference, or cleanliness issues—the cleaning strategy deserves even more scrutiny.

Not Every Lightweight Part Needs a Lattice

Once engineers start redesigning for additive, lattices tend to appear remarkably quickly.

Sometimes they are exactly the right solution.

Sometimes they're what happens when somebody discovers the lattice button.

An internal lattice can reduce mass while retaining useful stiffness or energy absorption, but its performance depends on cell topology, cell size, strut dimensions, load direction, boundary conditions, manufacturing variation, and how the lattice transitions into solid geometry.

It also creates another question: how are you going to inspect it?

A CMM can characterize an external datum or bore. Verifying the geometry of thousands of inaccessible internal struts is considerably less straightforward.

For many production components, a hollow structure with intelligently placed ribs may accomplish the lightweighting objective while remaining easier to model, clean, inspect, and qualify.

Complexity should earn its way onto the drawing.

"No Supports" Doesn't Mean "No Manufacturing Constraints"

One of the major advantages of MJF and SLS is that the surrounding powder supports the part during the build. That makes geometries possible that would be painful or impossible with processes requiring conventional sacrificial supports.

But design freedom isn't the same thing as process immunity.

Build orientation and geometry still influence dimensional behavior, thermal distortion, feature accuracy, surface condition, cleaning, nesting efficiency, and ultimately cost.

Large planar surfaces deserve attention. So do abrupt thick-to-thin transitions and large concentrations of material. A feature that looks harmless in CAD can behave differently once the thermal history of the build is involved.

This is where it helps to design one manufacturing step ahead.

Don't stop at, "Can we print it?"

Ask whether the technician can depowder it without damaging thin features. Ask whether blasting can reach the surfaces that need finishing. Ask whether a machinist can fixture the part if several critical bores need secondary operations. Ask whether a CMM probe can reach the features on the inspection plan and whether the datum structure can be established repeatably.

If inspection requires an elaborate custom fixture and interpretive dance, you've probably moved complexity rather than eliminated it.

A consolidated component is successful when it can be repeatedly printed, cleaned, finished, inspected, assembled, and released.

So, Does Consolidation Actually Save Money?

Sometimes dramatically.

Sometimes not at all.

Consider two hypothetical 40-part assemblies.

The first consists mostly of laser-cut plates, simple bent sheet-metal parts, and commodity fasteners. Turning all of that into one large additive component could easily increase the unit cost.

The second contains multiple multi-setup machined parts, deep pockets, custom spacers, precision alignment operations, internal routing, substantial inspection, and several hours of manual assembly.

Now the calculation looks very different.

This is why percentage-saving claims without a real project behind them aren't particularly useful. The comparison needs to include the total manufacturing system.

For the existing assembly, that means component manufacturing, hardware, finishing, inspection, fixtures, assembly, rework, inventory, and supplier management.

For the consolidated design, it means additive manufacturing, depowdering, finishing, inserts, secondary machining, inspection, qualification, and whatever assembly operations remain.

Then include the one-time engineering and qualification cost and amortize it across the expected production quantity.

That's the comparison worth bringing into a design review.

The Bigger Win May Not Be Piece Price

Part consolidation can still make sense when the piece-price comparison is relatively close because removing interfaces has effects elsewhere in the product.

Tolerance stacks get shorter. Purchasing manages fewer part numbers. Engineering changes affect fewer drawings. Assembly technicians perform fewer operations. There are fewer fasteners to loosen and fewer opportunities to assemble something incorrectly.

Mass can also fall substantially when material is placed around the load path instead of around machining access. In robotics, drones, automation equipment, and other moving systems, reducing mass can improve more than the component itself. Lower inertia can reduce actuator loads, increase acceleration, increase payload capacity, or reduce energy consumption.

The engineering-change advantage is also easy to underestimate during early product development. Changing one digitally manufactured component can be considerably simpler than coordinating revisions across several machined parts, purchased components, assembly fixtures, and suppliers.

That's particularly useful during bridge production when the design isn't completely frozen.

Sometimes 40 Parts Should Stay 40 Parts

Or perhaps the right answer is 17.

Part consolidation is a trade study, not a competition.

A wear component that costs $5 and takes thirty seconds to replace probably shouldn't become an integral feature of a $600 housing. Components that require different materials have an obvious reason to remain separate. Moving interfaces, bearings, seals, serviceable components, and highly loaded metallic features may also argue against full consolidation.

Production volume matters as well. A stable high-volume design may eventually belong in injection molding or another production process even if additive manufacturing made perfect sense during prototype and bridge-production stages.

And sometimes a machined component is simply cheap, robust, accurate, and easy to source.

Leave it alone.

The strongest consolidation projects aren't the ones that eliminate the most parts. They're the ones that eliminate the right parts.

Getting From "It Printed" to Production

There is one final distinction that matters if the consolidated component is headed into a real product.

A successful prototype demonstrates that the geometry can be manufactured and may prove that the design functions.

It does not automatically demonstrate repeatable production capability.

Before production release, critical-to-function dimensions need to be identified and validated against the actual manufacturing process and actual geometry.

SICAM's qualification approach can include pilot-run inspection, CMM measurement, First Article Inspection (FAI), and, where tighter dimensional control is required, a Tolerance Compensation Process (TCP).

With TCP, sample parts are serialized and positioned through the build chamber so dimensional behavior can be measured. The resulting data can be used to identify systematic shrinkage or distortion and make compensating adjustments to the CAD geometry. A verification lot is then produced and remeasured, with the resulting production geometry controlled for subsequent builds.

That takes the project from:

"We printed one and it fit."

to:

"We've characterized how this geometry behaves in this process and established how we're going to manufacture and inspect it repeatedly."

For a mechanical design engineer responsible for production release, those are very different statements.

The Real Goal Isn't One Part

Part consolidation gets presented as a before-and-after exercise: forty components on the left, one elegant printed component on the right.

That's visually satisfying, but it misses the engineering point.

The best consolidation projects remove components because those components no longer need to exist. They eliminate fasteners because the joint itself has disappeared. They shorten tolerance stacks by eliminating interfaces. They integrate passages because drilling, plugging, sealing, and assembling those passages no longer make sense.

And they deliberately keep components separate when wear, serviceability, material selection, precision, inspection, or economics demand it.

So if you're considering converting a machined assembly to MJF or SLS, don't begin with:

"How many parts can we combine?"

Start with the assembly drawing, BOM, functional requirements, and load paths.

Then ask:

"If we designed this assembly around what it needs to do instead of how we've historically manufactured it, what would we build?"

That's where part consolidation becomes engineering rather than just part-count reduction.