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40 Cards in this Set
- Front
- Back
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Acurracy of automatic bending equipment |
+- 0.005" |
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Applying force great enough to go beyond elastic limit but not so far as to exceed the ultimate strength |
Plastic deformation |
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Critical mechanical property when selecting material to bend |
% of ductility |
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Bending on easy plane is |
Bending on narrower plane or dimension |
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Bending on hard plane |
Bend on wider plane or dimension |
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If tube is bent too close to the end |
Edge distortion on pipe |
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Recommended min. Radius when bending round tubing |
2.5x outside diameter |
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Min bend radius when bending square tube |
4x OD |
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Stretch out length for pipe bending calculated on 90° bend by |
1.57 x mean bend die radius |
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Most versatile and accurate method of Bending |
Draw bending |
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Obtains 2 simultanious compression bends with each bend being .5 of desired bend angle |
Press bending |
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Workpiece clamped against bending die, die and clamp rotated moving workpiece through a pressure tool. Uses mandrel |
Draw bending |
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Tube is clamped to a stationary bending form and wrapped around it |
Compression bending |
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Similar to plate rolling. Limited to heavy wall tube |
Roll bending |
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Tube stretched longitudinally past elastic limit by pulling both ends then wrapping tube around a form. Used for irregular shapes |
Stretch bending |
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Primary tool around which workpiece is formed |
Bend die |
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Matching half of bend die to form true circle when closed |
Clamp die |
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Contains tube in bend die groove during bend cycle |
Pressure die |
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Prevents flattening, wrinkling or tube collapse during bending |
Mandrel |
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4 factors to consider when selecting bending lubricant |
•Provide physical barrier to protect mandrel and inside of tube • Lube film must remain intact and not dry from heat of forming • Overcome frictional drag of tube over mandrel • Compatible with tooling and workpiece material |
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Ability of material to deform plastically without fracture |
Ductility |
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Line between compression and tensile forces |
Neutral axis |
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Material length should extend how far past bend to prevent distortion |
2x diameter |
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Type of bender capable of both draw and compression bends |
Hossfield benders |
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What are diacro benders |
Compression benders |
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Type of tube bending produces full circles and coils |
Roll bending |
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Inserted into tube to prevent collapse |
Mandrel |
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3 common types of mandrel |
Plug, form and ball |
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3 roll pinch type |
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3 roll pyramid type |
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2 roll machine |
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3 types of rolls for sheet metal |
3 roll pinch, 3 roll pyramid, 2 roll |
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3 roll pinch pyramid type |
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Double pinch four roll |
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Types of rolls for plate rolling |
3 roll pinch, 3 roll pinch pyramid, double pinch 4 roll |
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Min diameter achievable with 3 roll pyramid style |
Top roll diameter plus 2 inches |
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Max material thickness for 2 roll urethane rolls |
1/4" |
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Plate roller choice of most fabricators and produces most accurate curvatures |
3 roll pinch |
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Signed for 1 entry 1 pass forming |
Double pinch 4 roll |
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When pipe bending round or square tubing, how is lube used |
Square tubing lubricated forming die. Round tubing never lubricated forming die |
