Stereo-lithography (SLA) | Xcentric Mold & Engineering

Stereo-lithography (SLA)

Stereolithography (SLA) uses a UV laser to photo-cure, large vats of epoxy-based resin to form a part.  During the process a laser moves along the vat curing the epoxy layer by layer.  A program instructs the laser based on the 3d cad model loaded into the software.

Once the parts have been completely built they are removed from the tray and placed in a post-curing chamber for final photo-curing.

There are a variety of finishes that can be done to SLA parts.  Parts can be sanded, primed, painted, or plated.  This requires manual labor as the product that comes out of the machine is not smooth enough.

After 20 years of stereo-lithography being on the market, there is a wide range of materials with varying mechanical properties that allow SLA  parts to further try to mimic engineered grade plastics.  However, there are still limitation and other processes seem to have left the SLA process behind.

Standard Tolerances for an SLA is: +/- 0.005″ for the first inch, +/- 0.002” on every inch thereafter

Although 3-d printing has become the big buzz over the past few years, the technology is over 30 years old. Given the limitations on quality and speed to make an individual part, 3d printing still lags behind in traditional methods such as injection molding and cnc machining.  However, when proving concept and fit with some functionality requirements, 3d printing can be a good choice.

Consider the following chart when deciding which Rapid Manufacturing service is best for your project;

  Process Type     Function     Fit     Testing     Proof of  
concept
  Tolerance  
<.005 in
Visual
   Quality   
Plastic  Material  
  Selection  
Metal  Material  
  Selection  
  Per Piece  
Price
  Tooling  
Cost
Tooling Life
Expectancy
3d Printing

Limited

Yes

no

Yes

Limited

Limited

Limited

Limited

High

N/A N/A
Injection Molding  

Yes

Yes

Yes

Yes

Yes

Yes

Unlimited

Limited

Low

Low-

Mid

Unlimited

CNC Machining

Yes

Yes

Yes

Yes

Yes

Yes

Limited

Unlimited

High

N/A N/A
Cast Urethane

Yes

Yes

Yes

Yes

Limited

Limited

Limited

N/A

High

High

< 50

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