3D Printing Guide: Materials, Strength & Cost

THE SHORT ANSWER

What matters before you order

FDM is the practical choice for most functional plastic parts, prototypes and short production runs.
Material, orientation and wall count usually matter more to strength than pushing infill toward 100%.
Upload an STL or 3MF for a calculated estimate; a human should still review printability before production.

Start with the path you are actually on

People arrive at 3D printing with three different problems. Choosing the correct path first prevents wasted hours learning software you may not need.

YOU HAVE A FILE

Prepare and print it

Check scale, walls, overhangs and intended use; then slice the STL or 3MF and review material, orientation and price.

YOU NEED AN OBJECT

Find or design the model

Search model libraries using the object name and device model. If nothing suitable exists, create it in CAD or commission the model.

SOMETHING BROKE

Reverse-engineer the part

Preserve every fragment, photograph the assembly and measure the interfaces. The useful geometry can often be reconstructed without an original file.

How FDM printing works

FDM (Fused Deposition Modeling) is the most widespread 3D printing technology. A machine melts a thin plastic filament and draws your object layer by layer, from the bottom up — each layer typically 0.1–0.3 mm thick. The result is a real, usable plastic part: not a mock-up, but something you can screw, snap, load and use daily.

Because the part is built from layers, geometry matters: holes print cleaner vertically, large flat surfaces may warp on cheap machines, and overhangs need support material. Good print services (that's us) check every model before it hits the machine and tell you if something should change.

Other technologies exist — resin (SLA) for jewelry-grade detail, powder (SLS/MJF) for industrial nylon parts — but FDM is the workhorse: the best strength, size and price per dinar for functional plastic parts. It's what our farm runs, and what this guide covers.

01
Model
A watertight 3D file describes the outer surfaces of the object at real scale.
02
Slice
The slicer divides the model into layers and calculates walls, infill, supports, material and machine time.
03
Build
The printer places molten filament along each toolpath. Every new line bonds to the line below it.
04
Inspect
Supports are removed and the part is checked for dimensions, surface defects and the features that actually have to fit.

Which material should you pick?

Material choice matters more than any slicer setting. The question is never 'which plastic is best' — it's where will the part live, and what will try to destroy it there.

FDM materials: choose by the job the part must do
Material	Useful for	Watch out for
PLA	Indoor models, prototypes and fit checks	Heat and sustained load; avoid a hot car
PETG	Tough brackets, housings and everyday parts	Can creep under load; outdoor performance depends on grade
TPU	Feet, grips, bumpers and flexible covers	Hardness and geometry control flexibility
ABS	Rigid enclosures and parts used near heat	Warping and sunlight; needs controlled printing
ASA	Outdoor housings and parts exposed to sunlight	Warping; needs an enclosure and suitable extraction

Material properties vary by grade, print settings and load. Use the filament supplier's data sheet and test the finished part in its intended conditions.

PLA

STIFF / INDOOR

A useful starting point for stiff indoor models, prototypes, organisers and fit checks. PLA prints cleanly, but can soften in a hot car and deform under a sustained load. Check the specific grade before choosing it for a functional part.

PETG

TOUGH / GENERAL USE

A practical choice for tough brackets, housings and everyday functional parts. PETG is less brittle than typical PLA and tolerates moisture well. It can still creep under sustained load; heat, chemical and outdoor performance depend on the formulation.

TPU

FLEXIBLE / IMPACT

For feet, bumpers, grips, protective covers and parts that need to bend. TPU is available in different hardnesses, so a thin wall and a thick solid section can behave very differently. Flexible does not mean indestructible.

ABS

RIGID / HEAT

For rigid enclosures and functional parts that need better heat resistance than ordinary PLA. ABS shrinks as it cools, so a controlled printing environment matters. Standard ABS is a poor choice for prolonged direct sunlight.

ASA

UV / OUTDOOR

For outdoor housings and functional parts exposed to sunlight. ASA combines useful heat resistance with better UV stability than standard ABS. It still needs controlled printing, suitable ventilation and a design that accounts for shrinkage.

The letters on the spool are a starting point. For a part that must survive heat, chemicals or repeated loading, compare the exact filament data sheet and test a printed sample. Geometry and layer orientation change the result too.

Layer height: speed vs. beauty

FDM parts are built from layers, and layer height is the single biggest quality-versus-price lever you control. Thick layers print fast and show visible ridges; thin layers look almost molded but multiply machine time.

0.28 mm (draft) — fastest and cheapest. Perfect for prototypes, fit checks, and parts nobody will ever look at.
0.20 mm (standard) — the sweet spot. Good surfaces, sane print times; our recommendation for most functional parts.
0.12 mm (fine) — display-quality surfaces and crisp small details, at roughly double the machine time of standard.

What makes a printed part strong

Printed parts are anisotropic: strong along the layers, weaker between them — like wood along versus across the grain. Four decisions set the strength:

Walls — the solid perimeters carry most of the load. Three is our minimum for functional parts; four to six for brackets, hooks and levers.
Infill — the internal lattice. 15% is fine for decorative pieces, 30% is a strong default, 60%+ approaches solid for heavily loaded parts.
Orientation — layers should run along the stress, not across it. A hook printed lying flat is many times stronger than the same hook printed upright. We check this on every order.
Material — PETG bends where PLA snaps. For anything that takes impacts or sustained load, tougher plastic beats more infill.

What decides the price?

Two things dominate: material weight and machine time. Our slicer computes both from your actual model — the price you see is calculated from a real slicing pass, not estimated from a photo. Settings you control directly move the price:

Infill — the internal lattice. 30% is a strong default; 15% is fine for decorative pieces; 60%+ only for seriously loaded parts.
Walls — 3 is our recommended minimum for strength; 2 walls saves money on display pieces.
Layer height — 0.28 mm prints fast and cheap, 0.12 mm looks beautiful but takes much longer.
Ironing — the nozzle polishes top surfaces glass-smooth. Adds machine time, worth it for visible faces.

That's also why 'how much does 3D printing cost?' has no honest one-number answer: a phone stand is a couple of coffees, a helmet-sized prop is a serious print job. Upload the model and the slicer answers precisely, for free, in seconds.

Designing parts that print well

If you model your own parts, a handful of rules prevent 90% of printing problems:

Walls ≥ 1.2 mm — thinner features may not survive printing, let alone daily use.
Overhangs beyond ~50° need support material. Chamfer or reorient where you can; supports cost material and leave marks.
Holes print slightly undersized — design +0.2 mm on the diameter, or tell us the target fit and we'll compensate.
Clearance between mating or moving parts: 0.3 mm minimum, 0.5 mm for a comfortable fit.
Large flat bases can warp — round the corners, add brims, or split the part. ABS is the most warp-prone.

Post-processing: from printed to finished

A raw print is rarely the end state. What can be done after the printer stops:

Ironing — the hot nozzle re-melts top surfaces glass-smooth. Ordered with one click in our slicer.
Threaded inserts — brass inserts heat-set into the plastic give real machine threads that survive repeated assembly.
Sanding & painting — PLA and ABS sand and paint well; primer-filler hides layer lines completely.
Joining — large objects printed in sections join with epoxy or plastic welding; a designed joint is stronger than the plastic around it.

Preparing and exporting a model

We accept STL and 3MF files. If you found a model online, our Discover page pulls it straight into the slicer. If you designed it yourself: keep wall thickness above 1.2 mm, avoid giant unsupported overhangs, and export at fine resolution. And if you have no model at all — just an idea or a broken part — that's exactly what the 3D modeling half of our printing service is for.

BROKEN OR DISCONTINUED PART

No file exists? Start with the physical evidence.

Our replacement-parts guide explains what to photograph, what to measure, how reverse engineering works and when a printed substitute is the wrong answer.

OPEN THE REPLACEMENT-PARTS GUIDE

Vase mode: printing vases the right way

Search any model site for 'vase' and you'll find solid-looking cylinders — those models are DESIGNED to be sliced in vase mode: the printer draws only the outer wall in one continuous spiral, turning a solid shape into a hollow, elegant vessel. Sliced normally, they come out as expensive solid blocks.

Classic vase mode uses a single wall, which looks stunning but cracks easily and can seep water. Our slicer offers both: a reinforced vase mode with 3 fused walls (watertight, survives being knocked over — our default) and the classic single-wall spiral for purists. Models with 'vase' in the name switch to vase mode automatically when you pull them in from Discover.

Tolerances and fit

FDM does not have one universal tolerance: machine, material, feature size, orientation and cooling all change the result. Exact CAD dimensions still need designed clearance and, for a critical fit, a small calibration coupon. These are useful starting ranges, not substitutes for testing:

Press fit (bearings, inserts): calibrate the exact hole with a coupon. A few tenths of a millimetre can change assembly from loose to impossible.
Snug fit (lids, caps): start around 0.2–0.3 mm designed clearance, then adjust for the machine, material and length of engagement.
Free fit (hinges, sliders): start around 0.4–0.6 mm clearance when movement matters more than a tight seam.
Threads: printed threads work well from M8 upward; below that, use heat-set brass inserts — we install them as a finishing option.

Why first layers (and beds) matter

Nearly every failed print fails at the first layer. If it doesn't bond to the bed, the part detaches mid-print and becomes spaghetti; if it bonds too close, the bottom flares out ('elephant foot'). Print farms live and die by first-layer discipline: leveled beds, measured nozzle offsets, the right bed temperature per material, and adhesion helpers (brims) on tall or thin parts. It's also why the first layer is printed slower and thicker than everything above it — when you see a quote where the first centimeter costs disproportionately more time, that's the machine being careful on purpose.

Diagnosing common print failures

A failed print is evidence. The location and shape of the defect usually point to a small number of causes; changing five settings at once only destroys that evidence.

FIRST LAYER

Corners lifting or part detaching

Check bed cleanliness, nozzle offset and bed temperature. Use a brim for narrow contact areas and control drafts for warp-prone materials.

EXTRUSION

Gaps, clicking or weak lines

Look for a partial nozzle clog, tangled filament, unsuitable temperature or a feed path that is slipping.

SURFACE

Strings between features

Dry the filament first, then inspect temperature and retraction. Wet material often makes tuning look worse than it is.

GEOMETRY

Sagging bridges or overhangs

Change orientation, add support, reduce the unsupported angle or redesign the feature with a chamfer.

DIMENSIONS

Holes too tight

Measure the result rather than guessing. Compensate the model or calibrate the feature with a small test coupon before printing the whole part.

STRUCTURE

Part splits along a layer

Reorient the load, increase walls, improve layer bonding or choose a tougher material. More infill alone may not fix the failure.

Before you order or press Print

A final two-minute review catches the expensive mistakes before the printer spends hours making them.

PRE-FLIGHT CHECK

The model is at the intended real-world scale and uses millimetres.
Every wall and small feature is thick enough for the selected nozzle.
The strongest layer direction follows the real load.
Overhangs and bridges are supported or intentionally designed.
Mating parts include clearance appropriate to the required fit.
Material matches heat, sunlight, chemicals, impact and flexibility.
Visible faces and support scars are oriented deliberately.
Safety-critical use has been identified instead of treated as an ordinary print.

Glossary

FDM: Fused Deposition Modeling — printing by extruding melted filament layer by layer. The most widespread 3D printing technology.
Slicer: Software that converts a 3D model into machine instructions and computes exactly how much material and time it needs. Ours runs in your browser and prices your part live.
Infill: The internal lattice of a print. More infill = stronger, heavier, more expensive.
Walls / perimeters: The solid outer shells of a part — the main carriers of strength.
Supports: Temporary printed scaffolding under overhangs, removed after printing.
Brim / raft: Sacrificial first-layer aids that keep warp-prone parts stuck to the plate.
STL / 3MF: The two file formats we accept. STL is the classic mesh format; 3MF is newer and carries units, colors and metadata.
G-code: The low-level instruction list a printer executes: move here, extrude this much, at this temperature.

Frequent questions

How long does an order take?

Most single-part orders ship within 2–4 working days. Large or multi-part orders get a delivery date with the invoice.

How strong are printed parts?

With 3+ walls and 30%+ infill in PETG, printed parts routinely replace injection-molded originals. Strength is directional (layers matter) — we orient your part for the load it carries.

Can you print in color X?

The slicer shows colors we stock right now. Need something specific — a brand color, silk finish, glow-in-the-dark? Message us, we can usually source it in days.

What's the biggest part you can print?

250 × 250 × 250 mm in one piece. Bigger objects get split, printed in sections and joined — done properly, the seam is stronger than the plastic around it.

Is 3D printing strong enough to replace 'real' plastic parts?

For the vast majority of household and machine parts — yes, when printed correctly. PETG at four-plus walls routinely outlives injection-molded originals, because we reinforce exactly where the original failed. What FDM can't match is glass-filled nylon or metal — and we'll say so when that's the case.

Can I order without any file at all?

Yes — that's the 3D modeling half of the service. Photos with a ruler in frame, a few key measurements, or the broken part in a shipping box are all workable starting points.

Are printed parts food safe?

We don't advertise them as food safe: layer grooves harbor bacteria and our lines aren't food-dedicated. For dry, brief contact (a cookie cutter on dough) many people accept the risk; for anything more, ask and we'll be straight about it.

Do you print in resin or metal?

Not in-house. FDM covers the overwhelming majority of functional plastic parts; for resin-level detail or metal we'll say so honestly and point you to the right process.

What is vase mode?

A slicing technique where the printer draws only the outer wall of a model in one continuous spiral — no infill, no top, no seams. It turns solid decorative models into hollow vessels, prints fast and uses little material. See the vase-mode section above; our slicer supports both classic single-wall and a reinforced 3-wall variant.

Why did my downloaded vase print as a solid block?

The model was designed for vase mode but got sliced with normal settings. Vase models are drawn solid on purpose — the vase-mode toggle (in our slicer, on the right) is what hollows them out. Ours also switches on automatically when the model title contains 'vase'.

How accurate are printed dimensions?

There is no honest universal number: accuracy changes with machine, material, geometry, orientation and feature size. Mating parts need designed clearance, and critical holes should be checked with a small coupon or first article. Tell us the intended fit so it can be reviewed before production.

Can you print threads, hinges and moving parts?

Yes. Threads from M8 up print directly; smaller sizes get brass inserts. Hinges and print-in-place mechanisms work with 0.3–0.5 mm designed clearance. Fully assembled mechanisms printed in one piece are one of FDM's party tricks.