Stereolithography vs Fused Deposition Modeling (SLA vs FDM) in 3D Printing Technology

3D printing, one of the seven disruptive technologies of this century, is also among the top 10 technologies that are expected to transform the coming decades. The technology finds application in several industries, such as:

However, more than 70% of the market is currently dominated by 3D printing of polymer-based materials due to the ease of process, availability of material and low cost.

To print 3D parts, various technologies have been developed till date, such as:



Of these, FDM and SLA are the most used. SLA was developed by 3D Systems in 1986 and FDM by Stratasys in 1988. The key reason for their adoption is that they were the early entrants in the market.

Let's find out which out of the two accounts for major market share...

Comparison of FDM AND SLA 3D Printing Technology

Over time, many technologies were developed in parallel, including several incremental innovations in FDM and SLA 3D printing technology. Today, FDM and SLA remain the leader in 3D printing of plastic materials. The two have been compared below:

Parameters		FDM	SLA
Material details	Base material	Typical thermoplastic materials used: PLA, ABS, PETG, Nylon, PEI (ULTEM), ASA, TPU	Photopolymers: Epoxy or acrylate-based resins
	Material distribution method	Extrusion	Vat (tank, vessel)
	Binding technique	Heat	Light (laser)
Dimensional details	Layer thickness	0.05–0.127mm	0.05–0.015 mm
	Wall thickness	1 mm	5 mm
	Print volume	200 x 200 x 200 mm – Desktop 1000 x 1000 x 1000 mm – Industrial	145 x 145 x 175 mm – Desktop 1500 x 750 x 550 mm – Industrial
	Support	Not always required (dissolvable available)	Larger support required
	Smallest possible detail	140 micron	250–800 micron
Quality	Printed product quality	Low to medium	High
	Surface texture	Rough (“staircase” effect) but can be polished	Smooth; often shiny
	Accuracy	Lowest	Highest
	Mechanical failure	Gradual deformation until fracture	Almost no deformation until sudden fracture
Compatibility	Food compatibility	Leakage due to micro-gaps	Only with special resins (can be expensive)
	Chemical compatibility	Leakage due to micro-gaps	Yet to be defined
Post processing	Object removal from bed after printing	Easy	Difficult
	Applications	Low-cost rapid prototyping; basic proof-of-concept models; low-volume production of complex end-use parts	Functional prototyping; dental applications; jewellery prototyping and casting; model-making
	Pros	Fast; low-cost consumer machines and materials	High value; high accuracy; smooth surface finish; range of functional applications
	Cons	Warping; misalignment of layers; shrinking of lower parts; low accuracy; low details; limited design compatibility	Average build volume; sensitive to long exposure to UV light
Overall rating of the technology based on various parameters		★★★★☆	★★★☆☆

From the above analysis, it is evident that FDM has more benefits over SLA and, hence, is widely used. Even from the latest market share perspective, FDM commands around 69% in the 3D printing market, whereas SLA has less than 15%.



A study by Wohlers Associates in 2013 revealed that around 10,000 industrial units were sold in 2013. It also showed that of the overall units sold, Stratasys, which is mainly into FDM 3D printing, had the highest market share. As per Aranca research, in 2016, of the 255,000 units estimated to have been sold that year, FDM-based 3D printers (industrial + desktop) totaled 235,000 units (Industrial + Desktop). Hence, it can be firmly concluded that currently FDM is a highly adopted 3D printing technology for both industrial and desktop units.

FDM-based 3D printers would remain the industry standard for the next few years, given the advantages the technology has over others. Also, due to the low cost (of FDM printers as well as filament material), these printers are in huge demand in schools and universities for educational and research purposes.


 » Continue reading to explore the recent developments in SLA and FDM 3D Printing technologies along with the challenges involved!