art and fl ight hardware. Consult the sidebar
“Direct Metal Part Produc- tion” for details on each of the major methods of direct part fabrication available today.
Indirect Part Fabrication
Another method of cre-
ating a metal part from AM is to create a pattern or tool that can be inserted into the standard metalcasting workfl ow. In the last few years, several new/updated technologies have become available, each of which can be used to differing advantages. The choice of which path to use for a given part depends on factors such as the size of the casting, complexity, number of castings to be made from each tool, and accuracy requirements. Improvements in software, systems and materials have increased the accuracy, surface fi nish, usability and fi t into the metalcasting workfl ow. The latest generations of new systems and materials are offering lower cost approaches, though performance of these systems remains unproven. Consult the sidebar “Indirect Metal Part Production”
for details on each of the major methods of indirect part fabrication. Sand Molds, Cores, Patterns and Inserts—Patterns for sand
casting tools can be created by the majority of the AM technol- ogy available today. Stereolithography (SLA), selective laser sintering (SLS), 3D printing, jet printing, digital light processing (DLP) and fused deposition modeling (FDM) technologies are available at prices ranging from $3,000 to more than $1 million.
This full axle assembly was built using a fused deposition modeling system from Stratasys.
All of these options provide a means to create a positive tool that can be bolted to a squeeze board, whether powder- or resin-based. Printing a squeeze board pattern can be faster and cheaper than CNC milling the same part, especially as complexity increases. Molds and cores also
can be printed directly on 3D printing systems, as well as a few of the laser sintering stations. For many geometry types at low volume, the speed of
fabrication and elimination of tooling can make this option favorable. Sands molds are typically silica sand with an or- ganic binder, but the options for refractory and metal choice continues to expand.
METAL Online Resource
For more industry data provided by Wholers Associates, visit
www.wholersassociates.com.
About the Author
William Shambley, who has spent 10 years in materials development for additive manufacturing, is president of Viridis3D LLC, Tyngsboro, Mass.
Fig. 1. Shown is a basic overview of the solidifi cation mechanisms used in additive manufacturing. (Note: This fi gure omits some post-processing steps that can change or improve the original part properties, such as post fi ring or infi ltration with molten metal or resin.)
JULY/AUGUST 2010 METAL CASTING DESIGN AND PURCHASING 37
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60