Thursday, 25 May 2017

A Step-by-step guide to post-processing a thingiverse Darth Vader without any sanding or acetone Part 1

EQUIPMENT USED:

  • Plastic plate
  • Soft Paint brush
  • Clean water
  • Methylated spirits
  • Soft, clean cloth
  • Hair dryer or fan.

PRODUCTS USED:

  • Poly-clean Plastic Cleaner
  • Proto-fill Liquid Plastic (Jet black Ultra-matte finish)



3D Printed Part - Before Post-Processing


METHOD:
First clean your object’s surface with Poly-clean Plastic Cleaner.

Before using Proto-fill, be sure to stir the contents thoroughly before you start, as the ingredients tend to settle on the bottom. The product may be sprayed if you have the equipment. Use a disposable plastic plate to place your model on, which are made from a type of plastic, that Proto-fill won’t stick to. Some take-away containers and lids are also suitable.

Brush the first coat of Proto-fill, in a horizontal direction, or in the direction of the grooves. The product goes on like a liquid plastic and is shiny when it’s wet and dries to a matte finish. Because of the rich nature of the resin-system, allow the product time to self-level and even out before applying low heat from a hairdryer or air movement from a fan.


After First Coat - Drying Process
DRYING:
Depending on your environment and how thickly you apply the coating, it takes around 20-30 minutes to air dry. A hair dryer (only ever on a low setting) or a fan can be used to speed up the drying process. Movement of air over your model is more important than applying heat. Too much heat will dry the top layer, but because there is still liquid underneath, it can cause the coating to craze slightly. This is easily rectified, however.

Once the coating is touch-dry, use a brush or soft smooth cloth, dipped in methylated spirits to re-soften and smooth the coating. Never sand the coating at this early stage, as you may tear the coating film. This “smoothing” technique will also fix any dried runs or drips. Being water-based, there is virtually no smell when applying or after drying; great for students or people who don’t have dedicated post-processing areas. Spills can be cleaned up with water or methylated spirits.

As the Proto-fill dries, it reduces by around 25%. Two coats seem to be sufficient to fill most fine print lines. Some deeper print lines may require additional coats. Although the product is viscous, it is still a very thin coating and intricate details are retained, just one coat of the matte finish makes most printed objects appear less “plasticky” and more like a moulded object. It is a good practice to address any runs or bubbles, in between coats.

Applying the second coat


Final result after drying

"ADJUSTING” THE COATING:
Once the products is touch-dry, use methylated spirits on a cloth or your paint brush to soften and “re-distribute” the product and even out areas which may have been over-filled. After a few coats, there is no need to apply more product, instead re-distribute the product from where there is too much, to areas which need more coverage. This technique is almost like, being able to pause time and resume when you’re ready. Making fine adjustment is like photo editing, you can add detail in, or take detail out. When you start sanding or vapour smoothing an object, there’s no going back.

Up next: We will be applying a colour coat to the same part. Stay tuned for PART 2.

For more information or to buy Poly-Clean and Proto-Fill, visit https://www.objective3d.com.au/coating-systems/

Monday, 22 May 2017

ARTEC Eva 3D scans its first submarine

Who can tell how much heritage has been destroyed by time, man and nature? Countless monuments and artefacts have been lost forever, leaving traces only in manuscripts, books, photos and memories of the lucky ones to have seen them. But things have changed with the advent of 3D scanning as more and more institutes and museums have started to embrace the technology to save precious and fragile legacy in 3D.

Artec 3D scanners have been used extensively to digitize museum collections and historical sites, from scanning Assyrian reliefs at the British Museum to 3D capturing excavation sites with fossilized bones of prehistoric animals and hominids in Kenya.

The extent of heritage preservation is not confined to antiques and fossils, though. Artefacts of more recent history also need to be conserved. One of the examples of such artefacts is this Biber mini-submarine that has been 3D scanned by Artec’s Dutch partner Erwin Kanters, the head of the 3D tech company Miniyours.


The Biber, the German for beaver, was the smallest, one-man submarine in the Kriegsmarine, the navy of Nazi Germany. It could carry mines and two torpedoes attached to each side of the hull and was used to attack ships off the Belgian and Dutch coasts during World War II.

The submarine was developed in less than six weeks in February 1944 with the view to helping repel the imminent invasion of the Allies. The haste resulted in some serious construction flaws, which meant that pilots operating the Biber were virtually on a death mission. Between January and April 1945, 109 Bibers were sent on operations and only 32 survived.

The Biber scanned with Artec Eva sank before it saw action. The submarine was discovered buried deep in the silt of a river in the Netherlands a few years ago, and the Dutch maritime heritage foundation Stichting Maritiem Erfgoed K-Verband asked Erwin Kanters to 3D scan it in order to capture its measurements for restoration and preservation.

“Because all the metal was old and dented, it was quite easy to scan as we had enough features on the surface of the metal,” Erwin says.


Using Eva connected to a battery pack, which ensures stable scanning in places where there is no source of electricity, Erwin scanned the hull, the propeller and the torpedoes. Even though the Biber is a mini-submarine, it was quite a large object for the scanner, and taking into account all the ribs and gaps that needed to be captured, scanning took one full day, generating 10 files of raw data 3GB each.


“I found it useful to make multiple files and scan the submarine in sections to get maximum accuracy, as each section took quite a number of scans,” Erwin says. “I find Artec Studio very fast and easy to use. Although I prefer to do post-processing manually, the automated post-processing is simply amazing! Artec Studio algorithms help a lot in processing. I especially like constrained alignment with loop closure.”



Erwin processed the propeller and parts of the hull, and the larger part of processing was done by the foundation’s staff. They are now reconstructing the Biber, planning to put it on display in the future, which may take some time as it was badly damaged.

Artec3D Scanners are available from Objective3D. For more information, contact us at 03-9785 2333 (AUS), 09-801 0380 (NZ) or email us at enquiries@objective3d.com.au