FDM AND SLA
Compare FDM and SLA 3D printing. We explain thermoplastic deposition and resin printing, along with layer height and infill choices.
A 3D printer builds an object layer by layer from a digital model. FDM and SLA differ mainly in their materials and how those layers are formed. The right choice depends on what your part needs to do.
Send us your model and describe its purpose. We will review it and recommend the technology, material and production approach.
01 / CHOOSING A TECHNOLOGY
One goal, two different processes.
FDM / FILAMENT PRINTING
Filament is a plastic strand supplied on a spool. The printer heats it and deposits it precisely through a nozzle. The part gradually grows from the bottom up.
SLA / RESIN PRINTING
Light cures selected areas of liquid resin, layer by layer. We then clean and post-cure the printed part using the process required for the selected material.
| What we compare | FDM | SLA |
|---|---|---|
| Surface and fine detail | Visible layer lines; a good choice for many functional products. | Generally less visible layers and better reproduction of fine detail. |
| Material selection | PLA, PETG, ABS, ASA, TPU, PA, PC and composites. | Standard, tough, flexible and other engineering resins. |
| Mechanical applications | We adapt the material, layer orientation and walls to the loads. | We select a resin with suitable properties; a smooth surface alone does not mean greater strength. |
| Inside the part | Can contain a lattice infill and multiple outer walls. | Solid or hollow; hollow parts require drainage openings. |
| Support structures | Used under overhangs where needed; removal may leave marks. | Often needed during printing; contact points may require finishing. |
| Price and lead time | Depend on size, material, printing time and finishing. | Depend on resin, geometry, supports, washing and curing. |
Appearance may matter most for a display model, load capacity for a bracket, and temperature and fit for an enclosure. We prepare a quote after reviewing these requirements.
02 / SURFACE APPEARANCE
It is the thickness of one printed layer. On curved or sloped surfaces, layers look like small steps. Thinner layers make those steps smaller.
For smoother slopes and curves. Printing usually takes longer.
250 layers at a height of 30 mmOften a practical starting point for functional parts where very fine detail is not the priority.
150 layers at a height of 30 mmFor simpler shapes where visible layers are acceptable. Also depends on the nozzle.
Approximately 107 layers at a height of 30 mmEnlarged schematic sections of the same shape. The dashed curve shows the intended shape. Layer counts are simplified calculations; these are not surface photographs or quality guarantees.
When visible detail, curves or presentation quality matter. On flat vertical walls the difference may be less noticeable. For a part hidden inside a machine, the right construction may matter more.
For SLA, we choose layer height after reviewing the model, resin and desired appearance. Leave that setting to our advice in the form. Bambu Studio settings apply to FDM printing.
Layer height describes a printed layer; tolerance is the permitted deviation from a finished dimension. Tell us separately if a hole needs to fit a screw or two parts need to mate.
03 / INSIDE THE PART
An FDM part does not have to be completely solid. The outer shell forms the surface, while the inside may contain a lattice. Infill percentage describes the interior fill, excluding outer walls.
For visual models and parts under low loads.
More material inside. We assess its value against the type of load.
Greater weight and material use. On its own, it does not guarantee adequate strength.
Schematic interior view. We adapt the actual pattern, density and wall count to the part.
Outer walls carry a substantial share of the load. More appropriately positioned walls can be more useful than simply increasing infill. We also consider screws, clamping and local reinforcement.
We can print the part solid or hollow it appropriately. Hollow parts need resin drainage and access for cleaning. We decide this after reviewing the model.
04 / PREPARING FOR PRODUCTION
The same part can be printed flat or upright. This changes layer direction, supports and surface appearance. For FDM, we consider the direction of the load.
Overhangs sometimes need temporary supports. Removing them can leave marks. Tell us which surfaces will be visible and what finish you expect.
Mark critical holes, threads and mating surfaces on a drawing. We can agree on a test piece where needed. Dimensional requirements are confirmed separately.
AT A GLANCE
Compare the benefits of PLA, PETG, ASA, TPU, engineering filaments and resins.
Further technical reading: Formlabs – technology comparison, Prusa – layers and walls and Prusa – infill.
LET'S DISCUSS YOUR PROJECT
Send your file and describe its use. We will review your requirements and prepare a quote.
No obligation to order.
