SLA White Resin 3D Printing

Stereolithography (SLA) is an additive manufacturing process that belongs to the Vat Photopolymerization family. In SLA, an object is created by selectively curing a polymer resin layer-by-layer using an ultraviolet (UV) laser beam. The materials used in SLA are photosensitive thermoset polymers that come in a liquid form.

SLA is famous for being the first 3D Printing technology: its inventor patented the technology back in 1986. If parts of very high accuracy or smooth surface finish are needed, SLA is the most cost-effective 3D printing technology available. Best results are achieved when the designer takes advantage of the benefits and limitations of the manufacturing process.

SLA has many common characteristics with Direct Light Processing (DLP), another Vat Photopolymerization 3D printing technology. For simplicity, the two technologies can be treated as equals.

How does SLA work?

Here is how the SLA fabrication process works:

I. The build platform is first positioned in the tank of liquid photopolymer, at a distance of one layer height for the surface of the liquid.

II. Then a UV laser creates the next layer by selectively curing and solidifying the photopolymer resin. The laser beam is focused in the predetermined path using a set of mirrors, called galvos. The whole cross sectional area of the model is scanned, so the produced part is fully solid.

III. When a layer is finished, the platform moves at a safe distance and the sweeper blade re-coats the surface. The process then repeats until the part is complete.

IV. After printing, the part is in a green, no-fully-cured state and requires further post processing under UV light if very high mechanical and thermal properties are required.

The liquid resin is solidified through a process called photopolymerization: during solidification, the monomer carbon chains that compose the liquid resin are activated by the light of the UV laser and become solid, creating strong unbreakable bonds between each other. The photopolymerization process is irreversible and there is no way to convert the SLA parts back to their liquid form: when heated, they will burn instead of melting. This is because the materials that are produced with SLA are made of thermoset polymers, as opposed to the thermoplastics that FDM uses.

Support Structure

Support structure is always required in SLA. Support structures are printed in the same material as the part and must be manually removed after printing. The orientation of the part determines the location and amount of support. It is recommended that the part is oriented so that so visually critical surfaces do not come in contact with the support structures.

Bottom-up and top-down SLA printers use support differently:

In top-down SLA printers, support requirements are similar to FDM. They are needed to print accurately overhangs and bridges (the critical overhang angle is usually 30o). The part can be oriented in any position and they are usually printed flat, to minimize the amount of support and the total number of layers.

In bottom-up SLA printers, things are more complicated. Overhangs and bridges still need to be supported, but minimizing the cross-sectional area of each layer is the most crucial criterion: the forces applied to the part during the peeling step may cause it to detach from the build platform. These forces are proportional to the cross-sectional area of each layer. For this reason, parts are oriented in an angle and the reduction of support is not a primary concern.

Post Processing

SLA parts can be finished to a very high standard using various post processing methods, such as sanding and polishing, spray coating and finishing with a mineral oil. An extensive article on post processing of SLA parts can be found here.

Bast Post Processiong: Removing the support structure from an SLA part

Special Material Post Processing: PMMA Transparent or Semi Transparent or Acrylic Material

When we print this kind of material, Post Processing take more procedure.

Transparent resin electronic housing cover with a range of post processing finishes. From left to right: basic support removal, wet sanding, UV protective acrylic and polished

Design guidelines for SLA

Common SLA Materials

SLA materials come in the form of a liquid resin. The price per liter of the resin varies greatly, from about $50 for the standard material, upwards to $400 for the specialty materials, such as the castable or dental resin. Industrial systems offer a wider range of materials than desktop SLA printers, that give the designer a closer control over the mechanical properties of the printed part.

To meet Customer needs of Cost control in Galaxy3DM, both Chinese original Industrial Resin or Somos Resin are avaliable in SLA 3D printing.

The following table summarizes the advantages and disadvantages of the most commonly used resins:

Galaxy3DM SLA 3D Printing Service FAQS 

1.What is SLA 3d printing?
Stereolithography (SLA) is an additive manufacturing - commonly referred to as 3D printing - technology that converts liquid materials into solid parts, layer by layer, by selectively curing them using a light source in a process called photopolymerization.

2.How does SLA 3d printing work?
Stereolithography (SLA) printing was first invented in the 1980's and works by curing resin with light. The light solidifies a liquid resin via a process called photo-polymerization and builds objects layer by layer.

3.Is SLA 3d printing expensive?
In general, you could say that 3D printing small objects is cheap and 3D printinglarge objects is expensive. Prices go up exponentially as the object size increases. ... And although precious metals are even more expensive, jewelry production is very suitable for 3D printing.

4.How to control SLA 3D Printing cost?

A. Choose right resin Material

B.  Adjust wall thickness

C.  Choose right SLA 3D printing service provider, Galaxy3DM's printing cost is much less than any other 3D printing company in China.

D.  Choose right Cooperation relationship with right SLA 3D printing service provider. Galaxy3DM provide special discount policy with VIP 3D printing partner.

5.What is the difference between SLA and SLS?
There are some common denominators, for example, both use a laser to trace out and build individual layers. For SLA a liquid resin is cured, whereas in SLS powder is selectively fused together.

6.How long can i receive the prototype by 3D Printing?

Usually it take 1-3days if material is not special. If it is PMMA material, since its post process take longer time, it will take about 1-5days to finish.

The delivery time is about 7-10days via DHL Carrier.

7.When we need to ajust the design file?

A. If the design file is not standard format. We need to adjust the file.

B. When we input original design file into Magics, if printing programmer found some structure error, we will remind the designer to fix it.

C. When the 3D model size exceed the Maxium printing size, for example 2m, we need to slipt the 3d model into 2parts.

8.Who adjust the design file?

Usually the designer may adjust the design file. 

Sometimes, Galaxy3DM printing programmer may adjust the design file if this is approved by the design or our customer.

9.What is SLA resin made of?
SLA uses a UV laser to cure liquid resin into hardened plastic in a process called photopolymerization. Different combinations of the monomers, oligomers, photoinitiators, and various other additives that comprise a resin result in different material properties. SLA produces parts from thermoset polymers.

10.What is 3d printer resin?
Instead of using powder or filament, Stereolithography technology uses a liquid resin to produce 3D prints. ... The 3D printing process takes place in a large tank filled with liquid resin. To start the process, a layer of UV-sensitive liquid polymer is spread over a platform.
Who adopt 3d printing service?
Companies like Ford, Volvo, and BMW really uses 3D printing for rapid prototyping, experimental parts, and creating jigs and fixtures for manufacturing. Mercedes-Benz which is currently pioneering this niche among other truck producers, and makes more than 100 000 printed prototypes each year.

11.What is 3d slicing?
There are two major types of software that will allow printing a (good read-to-print) 3Dmodel file: A so-called slicer takes a3D drawing (most often in .STL format) and translates this model into individual layers. It then generates the machine code that the printer will use for printing. ... 3D printing.
What is SLA stereo?

12.Stereolithography (SLA or SL; also known as stereolithography apparatus, optical fabrication, photo-solidification, or resin printing) is a form of 3D printing technology used for creating models, prototypes, patterns, and production parts in a layer by layer fashion using photopolymerization, a process by which light causes chains of molecules to link, forming polymers.[1] Those polymers then make up the body of a three-dimensional solid. Research in the area had been conducted during the 1970s, but the term was coined by Chuck Hull in 1984 when he applied for a patent on the process, which was granted in 1986.[citation needed]Stereolithography can be used to create things such as prototypes for products in development, medical models, and computer hardware, as well as in many other applications. While stereolithography is fast and can produce almost any design, it can be expensive.

13.What 3d printing can do?
3D printing or additive manufacturing is a process of making three dimensional solid objects from a digital file. The creation of a 3D printed object is achieved using additive processes. In an additive process an object is created by laying down successive layers of material until the object is created.

14.What file formats are used in 3D Printing?
The most common and universal file formats for 3D printing are STL

Optional file format: STP,OBJ,IGS,etc.

15.Why 3d printing is the future?
3D printing, or additive manufacturing, has the potential to democratize the production of goods, from food to medical supplies, to great coral reefs. In the future, 3D printingmachines could make their way into homes, businesses, disaster sites, and even outer space.

16.Can I make money with a 3d printer?
One of the easiest ways to make money with a 3D printer is to offer the printer as a commercial service or to sell items that are made with it. Businesses and individuals often want objects produced through 3D printing, but don’t have the equipment. Additionally, as a skilled designer, you can make items and sell them. For both approaches, you can find robust marketplace communities that help to facilitate your services.