In a surface grinding operation performed on a 6150 steel workpart (annealed,approximately 200 BHN), the designation on the grinding wheel is C-24-D-5-V.Wheel diameter =178 mm and its width= 25 mm. Rotational speed = 3000 rev/min.Infeed = 0.05 mm per pass, crossfeed = 12.5 mm, and workpiece speed = 6 m/min.This operation has been a source of trouble right from the beginning. The surfacefinish is not as good as the 0.4 µm specified on the part print, and there are signs ofmetallurgical damage on the surface. In addition, the wheel seems to becomeclogged almost as soon as the operation begins. In short, nearly everything that cango wrong with the job has gone wrong. (a) Determine the rate of metal removalwhen the wheel is engaged in the work. (b) If the number of active grits per cm? =30, determine the average chip length and the number of chips formed per time. (c)What changes would you recommend in the grinding wheel to help solve theproblems encountered? Explain why you made each recommendation.

we are given a problem whwere we are to find the MRR , chip length , number of chips and recommend…

go wrong with the job has gone wrong. (a) Determine the rate of metal removal when the wheel is engaged in the work. (b) If the number of active grits per cm? = 30, determine the average chip length and the number of chips formed per time. (c) What changes would you recommend in the grinding wheel to help solve the problems encountered? Explain why you made each recommendation.

go wrong with the job has gone wrong. (a) Determine the rate of metal removal when the wheel is engaged in the work. (b) If the number of active grits per cm? = 30, determine the average chip length and the number of chips formed per time. (c) What changes would you recommend in the grinding wheel to help solve the problems encountered? Explain why you made each recommendation.

Precision Machining Technology (MindTap Course List)

2nd Edition

ISBN:9781285444543

Author:Peter J. Hoffman, Eric S. Hopewell, Brian Janes

Publisher:Peter J. Hoffman, Eric S. Hopewell, Brian Janes

Chapter7: Grinding

Section7.3: Surface Grinding Operations

Problem 8RQ: Depth-of-cut range for surface grinding is: a. 0.010"0.100" b. 0.0001"0.0002" c. 0.0001"0.003" d....

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Depth-of-cut range for surface grinding is: a. 0.010"0.100" b. 0.0001"0.0002" c. 0.0001"0.003" d. 0.00001"0.00005"
c) It is planned to carry out the grinding operation using a grinding wheel of diameter 15 cm and width 2 cm, and using successive depths of cut of 0.02 mm, with two final cuts of 0.01 mm each. Wheel speed is 1450 m/min, work speed is 0.25 m/s and the cross feed is 0.4 mm. The number of active grits per area of the wheel surface is 0.75 grits/mm? with a grain aspect ratio of 20. i) Determine the Material Removal Rates for both depths of cut. ii) If the cycle time for one forward/return stroke of the work during grinding is 5 sec., estimate the total time taken to complete the job. ii) Considering a constant of proportionality K2 of 40,000, determine the maximum surface temperature of the work. iv) What recommendations would you give to reduce any surface damage owing to high work temperatures?
Why Centerless Grinding machine uses two grinding wheels during grinding? Type your Answer here:-
1/ Belt grinding is an example of primary shaping process. Select one: True False
Answer the following questions by circling True or False. 1. Creep feed grinding is an operation used for large material as compared to the conventional grinding operation, and it uses hard grinding wheels and small depths of cut. 2. For sawing softer materials, fine pitch blades are used since they produce long chips, while coarse pitch blades are used for sawing harder materials. 3. The machined surface with high finish should be used as the clamping surface to guarantee machining accuracy 4. Since the fixture elements are reusable, the overall cost for modular fixturing is less. 5. Using the slip gauges can obtain the exact value of the part dimensions. ( ) ()
11) Name 2 adverse effects of allowing the workpiece to become too hot in grinding. 12) Name 2 reasons coolant is used in grinding
11) An internal bore is ground to 100 mm, removing 0.3 mm stock. To accomplish this, a grinding wheel 80% of the finished size is used. The wheel is dressed every 15 cycles because it is observed that the radial wheel wear is 0.05 mm on average. Assume wheel and part widths are equal. a. What dressing depth would you recommend and why? b. Calculate the G-ratio of this operation.
Problem 4. (Grinding) (SI units) Wheel diameter = 160 mm, and infeed = 0.03 mm in a surface grinding operation. Wheel speed = 1500 m/min, work speed = 0.25 m/s, and crossfeed = 4 mm. The number of active grits per area of wheel surface = 35 grits/cm². When the wheel is engaged in the work, determine: a. average length per chip, b. metal removal rate, and C. number of chips formed per unit time for the portion of the operation Equations used V = TDN R MR lc rg = √ Dd = U = Vwwd nc = vwC w' t GR Fev vwwd rgvw d F'. = K₁ (TW) 0.5 (1) 0.25 vC D Ts = K₂d0.75 = V fr = TD,N, sin I w Vg 0.5 20.75 ( TO CU) OD D rg Cv บ D0.25 ▶
1) The specification of a grinding wheel is given as follows: 32A 40 L10 B Give the complete interpretation of the underlined segments in the grinding wheel specification. 2) Explain briefly how the dressing operation is performed prior to grinding on a surface grinding machine. 3) As the manager of a large machining workshop you are required to prepare the specifications of a lathe machine to be purchased to replace an old one which has been used for the last 25 years. Outline the main specifications that you deem important to suit the requirements of the workshop. 4) Outline the principle of Electro Discharge Machining (EDM) and its scope of use in industry. 5) Outline the principle of Ultra Sonic testing for checking deeply imbedded defects in a welded joint.
(Grinding) (SI units) Wheel diameter = 160 mm, and infeed = 0.03 mm in a surface grinding operation. Wheel speed = 1500 m/min, work speed = 0.25 m/s, and crossfeed = 4 mm. The number of active grits per area of wheel surface = 35 grits/cm². When the wheel is engaged in the work, determine: a. average length per chip, b. metal removal rate, and C. number of chips formed per unit time for the portion of the operation equations used; lc = √Dd RMR = vwwd U = Fev vwwd
13) Manufacturers are designing grinding spindles to turn at higher and higher speeds. What is the main reason for this, and what is one drawback of increasing speed? 14) Name 2 reasons why cost increases as finish allowances decrease (See Figure 9.40).
In grinding certain tools the linear velocity of the grinding surface should not exceed 6000fts/s. Find the maximum number of revolutions per second (a) 12 in (diameter) (b) 8-in wheel.