Mister shark started out on a simple premiss. Don was taking his usual morning swim in the ocean while thinking of the next model to build for fun (not for a client) he wanted to get away from the mechanical things he’s been building and wanted to do something organic. When swimming by himself he eventually thinks “hmm, I wonder if there’s a shark out here.” A local great white shark had been tagged last year and it reportedly left our area, went to party in Key West and is reportedly heading to Texas. A shark! Of course!
For this build detail, we’ll spend a little more focus on the modeling process.
Mister shark isÂ modeled in Lightwave 3D 11.6. To do organic shapes Don often uses theÂ Lightwave subpatch tool. Here, the shark startsÂ out as a cube, Don then divides the cube into several sections with a knife toolÂ and then pushes around the points of the cube to generally reflect the area of a shark.
When the subpatch tool is applied, itÂ smooths out the shape, but still gives Don the same control points, which he uses to push and pull until his sharkÂ form is where he wants it to be. After that he ‘freezes’ the sub patch and the shape becomesÂ a mesh.
With the mesh done, Don adds details. For this shark he stenciled an oval shape for the dorsal finÂ and simply extruded the faces many times, slowly forming the shape of the fin. Since this wouldn’t print well, he designed it so he could later removeÂ it and print it separately. He used the same technique for all the fins. Like the dorsal, the pectoral fins would be separated and printed separately. A biscuit would be printed to fit into a slot to hold them on. The other fins were angled enough that they would print OK.
With the details done, the shark was cut in half. Lightwave’s thicken tool (actually used earlier in the process) would be used to create the shell of the shark. Mr. shark would be hollow, attached together by 3 pegs. The shark parts were assembled in Lightwave in the manner they would be printed and then exported as an STL file. This file was brought into Simplify3D, printer settings were then adjusted.
Mr. Shark in Simplify3D, where the printer settings are input
The back fins and tail of the shark may present a printing challenge because of their overhang. Like all of Don’s models, Mr Shark is designed to print without rafts and without supports. If you print with a raft, the parts won’t fit together very well until ALL the raft material has been removed. To avoid supports, Don recommends you print your shark at a slow speed (he used 250o mm per minute) and at a low temperature, this was printed in PLA at 190Â° with no temp on the plate. These settings allowed the tail to be printed without any support. If you have a fan on your print head, use it. Don uses a stock machine and did not have a fan on the nozzle.
The print starts with a brim
The resulting file from Simplify3D is an .x3g document which Don puts on an SD card and inserts into his printer, a Wanhao Duplicator 4. To make sure the build starts right, Don uses a brim 3 lines wide around the print. This is set up to print at 25% of the speed of the rest of the layers and allows Don to make adjustments to the bed level as needed before the real print begins. Above you can see the brim with the print beginning on the upper portion. The print is done on a sheet of glass covered with Scotch brand painters tape.
Mr. Shark is a vertical print, so it’s possible you could set up 3 or 4 sharks in a single print. With the above settings, a single Mr. Shark takes about 8 hours.
The final proof of Mr. Shark is printing right now. If the proof looks good, it’ll be photographed and placed here tonight (Wednesday, June 25th)
Photo of the final print
The print separated easily off the bed. The biscuits and pegs are broken off their platforms and inserted (if desired, you can glue it without them) and then a little Ultra Control Gel Superglue is applied and a minute later…a shark is born!
Photo of the final build
Diagram for Mr. Shark
Mr. Shark is Don’s small shark, designed to fit into most 3D printers. Don is currently Developing Mrs. Shark for his new large format printer. Mrs. Shark will be about 34 inches long when assembled and will be offered to those with large vertical printers. Mrs. shark will be an entirely new construction than Mr. Shark.
To purchase the STL file to print your own shark, CLICK ON THIS LINK to go to the store.
See full post here: donfoley.com2014-06-25.