Table 1. Variations in the Small Elbow Casting: (6) Pieces Total Section
A-A Elevation
Largest Deviation (-) Average Deviation (-) Largest Deviation (+) Average Deviation (+)
-0.11
-0.06 0.18 0.12
-0.16 -0.06 0.11
0.09
Table 2. Variations in the Lerge Elbow Casting: (10 Pieces Total) Section
A-A Elevation
Largest Deviation (-) Average Deviation (-) Largest Deviation (+) Average Deviation (+)
Figure (k): Dimensional Variation
various industries. For the metalcast- ing industry in particular, the tech- nology can be a tremendous tool in verifying a pattern’s dimension and inspecting a fi rst-article casting for shrinkage and warpage. From a machining standpoint,
especially in large format jobbing op- erations, 3-D scanning technology can be used to qualify castings for rough or fi nish machining with an additional purpose of optimizing a machining strategy. T is allows for “level machin- ing,” which means that CNC milling equipment can be programmed based on a part’s scanned geometry. As a result, less spindle time is spent cut- ting “air” during the rough machining process, which potentially increases throughput and reduces costs. In this case of the two diff erent elbow castings, the data from 3-D
scanning provided general insight into the metalcasting process with respect to dimensional repeatability of unusual geometries utilizing polystyrene pat- tern equipment. By casting these components, and ensuring they met re- quired tolerances via 3-D scanning, the customer eliminated complex layout
and assembly processes at its facility. T e scan data provided proof that the component met its required shape. ■
This article is based on the paper, “Prac- tical Application of 3-D Scanning in a Jobbing Foundry,” presented at the Steel Founders’ Society of America’s 2014 Technical & Operating Conference.
-0.09 -0.04 0.20 0.10
A-A Curvature (6 places)
-0.19 -0.09 0.19 0.10
A-A Curvature (4 places)
B-B Elevation
-0.13 -0.10 0.04 0.02
B-B Curvature (4 places)
-0.15 -0.05 0.13
0.06
C-C Elevation
-0.20 -0.13 0.10 0.10
C-C Curvature (4 places)
-0.22 -0.09 0.16
0.08
B-B Elevation -0.15
-0.06 0.20 0.06
B-B Curvature (6 places)
-0.25 -0.08 0.17
0.09
C-C Elevation
-0.25 -0.14 0.25 0.12
C-C Curvature (4 places)
-0.20 -0.09 0.18
0.08
Fig. 4. Tie bars were added to the casting to maintain dimensional stability through heat treatment.
Sept/Oct 2015 | METAL CASTING DESIGN & PURCHASING | 33
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