Design for Additive Manufacturing (DfAM) isn’t just for engineers designing parts from scratch. Even if you’re sending us an existing CAD file, understanding these five principles can cut your per-part cost significantly — sometimes by 50% or more — without changing what the part does.

Every dollar saved in print time, material usage, and post-processing comes directly from how the part is designed. Here are the five rules that have the biggest impact.

Rule 1: Wall Thickness — Thicker Isn’t Always Stronger

Minimum guidelines:

Structural walls: 1.2mm minimum (3 perimeters at 0.4mm nozzle)
Non-structural walls: 0.8mm minimum (2 perimeters)
Maximum useful wall thickness: 3-4mm for most applications

There’s a common instinct to make walls as thick as possible for strength. The problem is that past about 3mm, additional wall thickness adds weight and print time without meaningful strength gains. The part’s overall geometry — ribs, gussets, curves — matters more than raw wall mass.

Before: A mounting bracket with 5mm uniform walls. Print time: 4.5 hours. Material: 120g. After: Same bracket redesigned with 2mm walls and internal ribs. Print time: 2.2 hours. Material: 65g. Same load capacity.

If you need maximum strength, the answer is usually reinforced material (CF-nylon) at 2mm walls, not standard nylon at 5mm walls.

Rule 2: Print Orientation — Plan for It

Every FDM part has a “grain” — layer lines run perpendicular to the build direction. A part is strongest along the layer plane and weakest across layers (the Z-axis). This means orientation determines where your part is strongest and where it’s most likely to fail.

Key tradeoffs:

Strength axis: Orient so primary loads run along layers, not across them. A hook loaded in tension should be printed on its side, not standing up.
Surface finish: Vertical walls are smoothest. Angled surfaces show stair-stepping. Top surfaces get the best cosmetic finish.
Support material: Overhangs over 45° need supports, which add time, cost, and cleanup. Orienting to minimize overhangs directly reduces cost.

How to communicate preferences: If your part has a critical load direction or a cosmetic face, note it in your file submission. “This face is visible” or “load is applied here” tells us exactly how to orient for the best result. If you don’t specify, we’ll optimize for strength by default.

Rule 3: Infill Strategy — Less Is Usually More

Infill is the internal structure that fills the space between walls. Most people default to high infill percentages without realizing how little it changes part performance in many applications.

Guidelines:

15-20% infill: Sufficient for non-structural parts, enclosures, covers
30-40% infill: Good general-purpose range for moderate loads
60-80% infill: High-load applications, attachment points for fasteners
100% infill: Rarely needed. Solid parts are heavy, slow to print, and prone to warping.

Infill pattern matters too:

Gyroid: Best all-around. Good in every direction, handles compression and shear. Our default for most production parts.
Grid/rectilinear: Strong in two axes but weak diagonally. Fast to print.
Triangular: Good for lateral loads. Common in aerospace applications.

Before: An enclosure printed at 80% infill. Print time: 6 hours. Weight: 340g. After: Same enclosure at 25% gyroid infill. Print time: 3.5 hours. Weight: 180g. Identical performance for its actual use case (protecting electronics from impact).

We’ll recommend an infill strategy based on your part’s actual loads. If you’re not sure, tell us what forces the part needs to handle and we’ll spec it.

Rule 4: Minimize Supports — Design Them Out

Support structures are scaffolding printed under overhangs and bridges, then removed after printing. They cost time twice: once to print, once to remove. And they leave surface marks that may need finishing.

Self-supporting design principles:

45° rule: Overhangs up to 45° from vertical print without supports. Design angles at 45° or steeper to avoid support needs entirely.
Bridging: Horizontal spans up to ~10mm can bridge without supports. Beyond that, add a slight arch or chamfer.
Chamfers over fillets: On bottom-facing edges, a 45° chamfer is self-supporting. A fillet (radius) creates a gradual overhang that needs support.
Split and rotate: A part that needs heavy supports in one orientation may need zero supports if split into two pieces and printed flat.

Before: A C-shaped bracket printed standing up. 45 minutes of support material. 20 minutes of cleanup. Surface marks on inner radius. After: Same bracket split into two halves, printed flat, bonded together. Zero supports. Clean finish everywhere. Net time saved: 50 minutes per part.

This doesn’t mean avoiding all supports — some geometries require them. But every support you design out saves material, time, and post-processing labor.

Rule 5: Consolidate Parts — Print as One

This is where 3D printing fundamentally changes design thinking. If your assembly has three parts bolted together, ask whether they could be one printed piece.

Benefits of consolidation:

Fewer parts to manufacture, track, and assemble
No fastener costs or assembly labor
Eliminated joint failures — bolted joints are the most common failure point
Reduced weight (no overlap material at joints)

Before: A sensor mount made of three machined aluminum pieces + 6 fasteners. Three purchase orders, assembly time, potential for loose bolts. After: Same sensor mount printed as one piece in CF-nylon. Same stiffness, 60% less weight, zero assembly, one part number.

Not everything should be consolidated — parts that need to be serviced or replaced independently should stay separate. But most assemblies have at least one opportunity to merge components.

The Payoff

These five rules compound. A part that uses thinner walls (Rule 1), proper orientation (Rule 2), appropriate infill (Rule 3), minimal supports (Rule 4), and consolidated assembly (Rule 5) can easily cost half what the naive design costs — with equivalent or better performance.

You don’t need to apply all five to every part. Even one or two rules can make a meaningful difference. And if your design is already locked, we can often suggest orientation and infill changes that save 20-30% without any CAD modifications.

Send us your files. If we see an opportunity to save you money through better DfAM, we’ll tell you before we print.