Tuesday, March 11, 2014

3D Printing - testing size and colour

We have been running the 3D printer through its paces, working with scaling the printed objects, and with different processes and products for post-printing infiltration. 

Our test object was a small red projectile point. The point was first scanned in 2012 by the Sustainable Archaeology Animation Unit using the macro white light scanner.  

The untextured (left) and textured (right) scans of the point
In order to see how the printer was handling the detail captured in the original scans of the projectile point, we decided to print not only an original sized replica, but also one that was 2x larger, and one that was 3x larger.

Print in progress in the build bed

By scaling the model, we are able to better see with the naked eye the detail that was captured in the scan. Depending on the end user need, printing scaled versions of the scanned object may prove beneficial - for example, if there is detail not easily seen by the naked eye, or where we wish to isolate and print one segment of the object at a larger size in order to examine a specific feature of the original. For example, with our print, we are able to better see each flake scar on the point by examining the larger model, and could use the larger model to take measurements (converting to account for the size difference).

Scaled 3D prints (left to right): 3x larger; 2x larger; original size

Back side of the three printed points

In addition to testing scale, we were interested in testing how different infiltration products and methods affect the end product. We printed several copies of the point at its original size, and used the 3D Systems infiltrant Z-bond, as well as Paraloid B-72 resin, and the salt water infiltration we had previously used for our first print test.

Infiltrating the prints (left to right): Z-bond infiltrant; Paraloid B-72; salt water

Back of prints with different infiltrants (left to right): Z-bond; Paraloid B-72; salt water

As you can see from the images, the print infiltrated with the Z-bond demonstrates the most robust colour. The Paraloid resin offers a significant improvement over the salt water, and we plan to explore its use further, using different concentrations of the acrylic resin in acetone. As with scale, the end user need will help determine what infiltration product will be used with a print - for example if the user is interested in a print as a replication, or whether they simply wish to have a physical copy of the scanned object to handle and examine.

Comparison of the original artifact (left) with the Paraloid (center) and Z-bond (right) infiltrants

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