Safety Hazards Material Processing Laboratory Room 232

HAZARD: Rotating Equipment / Machine Tools

Be aware of pinch points and possible entanglement

Personal Protective Equipment: Safety Goggles; Standing Shields, Sturdy Shoes No: Loose clothing; Neck Ties/Scarves; Jewelry (remove); Long Hair (tie back)

HAZARD: Projectiles / Ejected Parts

Articles in motion may dislodge and become airborne.

Personal Protective Equipment: Safety Goggles; Standing Shields

HAZARD: Heating - Burn

Be aware of hot surfaces

Personal Protective Equipment: Safety Goggles; High Temperature Gloves; Apron, Welding Jacket, Boot Gauntlets, Face Shield

HAZARD: Chemical - Burn / Fume

Use Adequate Ventilation and/or Rated Fume Hood. Make note of Safety Shower and Eyewash Station Locations.

Personal Protective Equipment: Safety Goggles; Chemically Rated Gloves; Chemically Rated Apron

HAZARD: Electrical - Burn / Shock

Care with electrical connections, particularly with grounding and not Using frayed electrical cords, can reduce hazard. Use GFCI receptacles near water.

HAZARD: High Pressure Air-Fluid / Gas Cylinders / Vacuum

Inspect before using any pressure / vacuum equipment. Gas cylinders must be secured at all times.

Personal Protective Equipment: Safety Goggles; Standing Shields

HAZARD: Water / Slip Hazard

Clean any spills immediately. R. Dubrovsky Mechanical Engineering Department, NJIT ME 215, Engineering Materials & Processes Experiment # 6

EXPERIMENT # 6:

METAL CUTTING PROCESSES AND TOOL GEOMETRY

Goal: To familiarize the students with main metal cutting processes, cutting machines and cutting tool geometry. Objectives: To learn principles of , chip formation approach, cutting parameters, tool geometry and its influence on cutting process, surface finishing and accuracy.

Equipment Lathe, milling machine, optical comparator, protractor, carbide lathe tools, & Tools: high speed steel cutters: spiral-point drill and .

Materials: Steel shaft.

Each group of students must complete tool geometry investigation of minimum one cutter per student, sketch its geometry and all necessary cross sections, label all defined cutting edge angles, make partial cutting of the shaft, produce the Data Sheet, and give the answers on the Set of Questions.

A report has to be prepared according to the requirements of the General Instruction.

LABORATORY ASSIGNMENT:

In carrying out your assignment, follow the sequence given below:

1. Learn the mechanics of metal cutting. 2. Study the metal cutting theory and chip process. 3. Learn tool terminology. 4. Learn the principles of turning and milling. Define the difference in motions of work piece and cutter on the lathe and milling machine. Read the related chapter from the suggested literature. 5. Learn the names of the different parts of the lathe and milling machine and their functions when the instructor operates them. Also use the related diagrams on the bulletin board. 6. Learn what are cutting force, cutting speed, feed and depth of cutting. 7. Learn the classification of cutting tools. 8. Learn how to use the optical comparator and protractor. 9. Measure different tool angles of the suggested tools and prepare the sketches of the tool showing all the angles you have measured. Use a top view, side view and end view to show all the angles. 10. Learn the influence of tool geometry on the process of metal cutting. 11. Give the answers to the set of questions.

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DATA SHEET FOR LAB. # 6

GROUP MEMBERS Weeks:

1

2 s ’ 3 r o t c

4 u r t

5 s n I 6 Approval 7 DATE: 8 GROUP: Group Leader:

SKETCHES:

Tool # 1 Tool # 2

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Tool # 3 Tool # 4

Tool # 5 Tool # 6

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Fig. 1. Turning cutters and tool geometry A- Tool geometry for threading cutter; B & C-Tool geometry for right & left hand cutters.

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SET OF QUESTIONS

1. Calculate the revolutions per minute for a lathe to cut a rough finish 5" (127mm) diameter of a gray cast iron shaft with a high-speed steel cutter. Use the supporting Table 6-1.

2. Name the factor, which causes the tool to lose its hardness.

3. List the properties of materials used to make cutting tools.

4. What are the effects of a large frictional force on a cutting tool and how can they be reduced?

5. What is the function of each of the following lathe parts? a. Face Plate b. Lead Screw c. Back Gears d. Tail Stock

6. Name four methods for turning a taper on a lathe.

7. A bar of steel 3 in. (76.2mm) in diameter is to be machined at 90 fpm (0.5 m/sec). What spindle speed should be used?

8. Assuming a 0.020 “ (0.508 mm) feed per revolution and 0.062 in. (1.575 mm) depth of cut to machine a 2 in. (50.8mm) diameter bar of SAE 1020 low carbon content plain carbon steel, calculate the metal removal rate on cubic inches per minute (mm2/sec) as a function of the cutting speed. If necessary, make an additional assumption. Use the Table 6-1.

9. What type of machining should be used to make a shaft?

10. A 2." (50.8 mm) diameter rod turning at 120 rpm is to be cut off by a tool having a feed of 0.004 in. per revolution (0.l mm/rev). Calculate the cutting time.

11. What is the cutting speed in fpm of a 4 in. (101.6 mm) cutter rotating at 50 rpm?

12. Explain the difference between up-milling and down-milling from the figure shown below.

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Fig.6-2 Climb and Conventional Milling Approach

SUGGESTED LITERATURE:

1. E. Paul De Garmo, J. Temple Black, Ronald A. Kosher, Materials and Processes in Manufacturing, Macmillan, 8th Edition, New York, 1997.

2. L.E. Doyle, Manufacturing Processes and Materials for Engineers, Prentice Hall, Inc., Second Edition, Englewood, 1969.

3. R. Dubrovsky. Laboratory Manual. Engineering Materials & Processes. ME Department, NJIT. 2001

4. A Treatise on Milling and Milling Machines, 3rd Edition, The Cincinnati Milling Machine Co., Cincinnati, Ohio, 1946.

5. Woldman, Norman Emme, Machinability and Machining of Metals, McGraw-Hill, New York, 1951.

6. Catalog of Advanced Precision Tools and Gages. The L.S. Starrett Co. 5nd Edition, 1995

7. Selection Guide, First Edition, Cahners Publishing, Boston, 1965.

8. B. Mills, A.H. Redford, Machinability of Engineering Materials, Applied Science Publishers, New York, 1983.

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