Metal extrusion. Metal stamping

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Kathleen Peters
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1 Metal extrusion Answer the following questions 1. In which of the following extrusion operation is friction a factor in determining the extrusion force (one best answer): (a) direct extrusion or (b) indirect extrusion? 2. Hot extrusion involves prior heating of billet to a temperature above its. 3. A standard method of measuring capacity of maximum size of extrudable cross section is in terms of. 4. The ratio of length to thickness of any extrudable segment should not exceed. 5. Symmetrical cross sections are preferable to non-symmetrical designs to avoid. Metal stamping Answers the following questions: 1. Write the name of four operation which are used in sheet metal stamping? 2. Name the operation in which cutting of sheet takes place? 3. Cup shaped parts are made by which process? 4. Why shaving allowance is provided? Choose the best answer: Fine blanked parts 1) The triple action for clamping material during blanking provides a) V-ring pressure b) Counter pressure c) all of the above d) none of these

2 2) Which of the following is false regarding blanking a) better surface finish b) squared sheared edges c) low dimensional accuracy d) better flatness or appearance 3) Which of the following materials cannot be blanked? a) steel with carbon content of 0.08 to 0.35 % b) brass with lead content c) copper d) aluminium 4) Which of the following is false regarding design recommendation for blanking? a) corners for fine blanked parts must be rounded b) hole diameter should be approximately 20 to 25% of the material thickness c) pitch circle radius for tooth form is 60% of material thickness d) maximum depth to which semi piercing are to be pierced is 70% of material thickness 5) The flatness obtained for piece-part in production varies widely with respect to a) part size b) part configuration and quality c) thickness of material d) all of the above Rolled formed section Answer the following questions 1. The starting work piece in steel hot rolling of plate and sheet stock is which of the following (one best answer): (a) Bar stock, (b) billet, (c) bloom, (d) slab, or (e) wire stock?

3 2. The maximum possible draft in a rolling operation depends on which of the following parameters (two correct answers): (a) Coefficient of friction between roll and work, (b) roll diameter, (c) roll velocity, (d) stock thickness, (e) strain, and (f) strength coefficient of the work metal? 3. Which of the following stress or strength parameters is used in the computation of rolling force (one best answer): (a) Average flow stress, (b) compression strength, (c) final flow stress, (d) tensile strength, or (e) yield strength? 4. steels are the most frequently processed roll-forming materials. 5. The thickness of the sheet stock which can be processed varies between. Impact or cold extrusion Multiple choice questions (1). In the impact extruded products are of material. a) Aluminum b) Al alloys c) Ferrous d) Nonferrous (2). In the Impact extrusion process, base must be to/than the sidewalls. a) Thicker b) Equal c) Thinner d) Thicker or thinner (3). Impact extruded parts should be symmetrical in order to. a) minimize tooling deflection b) maintain unequal wall thickness c) both a & b d) Neither a nor b

4 (4). what is the maximum recommended height of internal ribs in the extruded part? a) ½ of the wall thickness b) 2 times the wall thickness c) 3 times the wall thickness d) Same as the wall thickness (5). Inclined bottom surfaces, with a desired inclination of, near the sidewalls assist metal flow in backward extrusion. a) 80 o b) 75 o c) 120 o d) 50 o Forward extrusion Multiple choice questions (1). At what length-diameter ratio, Forward extrusions can be made? a) 25:1 b) 50:1 c) 75:1 d) 100:1 (2). Side wall can be made with zero draft. a) True b) False (3). Flange should be placed of the part for forward extrusion a) At the start b) At the middle c) At the end d) Anywhere (4). For a forward extruded part fillet is required at the junction between

5 a) Flange and sidewall b) Bottom and the side wall c) Both a and b d) None of the above (5). For forward extrusion sidewalls has to be a) Straight b) Tapered c) Either a or b Design for Forging Answer the following questions 1. Based on temperature, forging operations are classified into:,, and forging. 2. In forging, the work is completely constrained within the die. 3. The projection made by filling parallel to the die motion is called a. 4. Grain flow must be aligned with the direction of (highest/lowest) principal stress. 5. Under ideal condition, the parting line should lie on plane to the axis of the die motion. 6. Die impressions are generally made tapered for easy withdrawal of the forgings. The taper provided is called. 7. Forging is the oldest metal forming operation. True/False 8. Magnesium alloys are suitable for Forging. True/False Metal Injection Molded Parts Answer the following questions 1. The metal powder used in MIM is than that used in conventional powder metallurgy.

6 2. After debinding, the part is called a part. 3. Densities of parts produced via MIM are normally (higher/lower) than those produced by conventional powder metallurgy. 4. If the part has a heavy section, should be added to reduce the cross-section. 5. MIM gives a (high/low) degree of precision. 6. Bosses and Ribs are unfeasible in MIM parts. True/False 7. Copper alloys are suitable for MIM parts. True/False 8. Typical MIM parts are small and complex in nature. True/False Metal extrusion Answers: 1. (a) 2. Crystallization temperature. 3. Circumscribing circle-diameter (CCD) :1 5. Unbalanced stresses and warpage. Metal stamping 1. Blanking, forming shaving, drawing. 2. Blanking and trimming. 3. Drawing process. 4. To produce smooth parts. Fine blanked parts (1). c (2). c (3). b (4). b

7 (5). d Rolled formed section (1). d (2). a and b (3). a (4). Low-carbon (5) mm to 25 mm Impact or cold extrusion (1). Nonferrous (2). Thicker (3). both a & b (4). 3 times the wall thickness (5). 120 o Forward extrusion (1). 100:1 (2). True (3). At the end (4). Flange and sidewall (5). either a or b

8 Design for Forging (1). Hot, warm, cold (2). Flashless (3). Boss (4). Highest (5). Perpendicular (6). Draft (7). True (8). True Metal Injection Molded Parts 1. finer 2. brown 3. higher 4. cores 5. high 6. False 7. True 8. True

Design for Forging. Forging processes. Typical characteristics and applications

Design for Forging. Forging processes. Typical characteristics and applications Design for Forging Forging processes Forging is a controlled plastic deformation process in which the work material is compressed between two dies using either impact or gradual pressure to form the part.