metrology and quality control (17530) 2017-18 · web viewmetrology and quality control (17530)...

Metrology and Quality Control (17530) 2017-18

Rayat Shikshan Sanstha’sKarmaveer Bhaurao Patil Polytechnic, Satara

Test Paper 1Course: Mechanical Engineering Course Code: ME-5-G

Semester: Fifth Marks: 25 Subject: Metrology & Quality Control Subject Code: 17530

Date:- 11/08/2017 Time:- 2:30 to 3:30 pm

Instructions: 1.All questions are compulsory.2. Illustrate your answers with neat sketches wherever necessary.3. Figures to the right indicate full marks.4. Assume suitable data if necessary.5. Preferably, write the answers in sequential order.

Q. 1 Attempt any THREE of the following 9

a) Define Metrology. State objectives of metrologyb) State the characteristics of the end standards.c) What is the meaning of 35 H8f6? State meaning of each term.d) Draw a labeled diagram showing the working mechanism of dial indicator.

Q. 2 Attempt any TWO of the following. 8

a) Explain the term selective assembly.

b) List the minimum no. of slip gauges to be wrung together to produce an

Overall dimension of 73.975 mm using a set of 87 pieces. The set contain

Range ( mm) Step Pieces1.005 - 1

1.001 to 1.009 0.001 91.01 to 1.49 0.01 490.5 to 9.5 0.5 1910 to 90 10 9

Total 87c) State the essential characteristics of the good comparator.

Q. 3 Attempt any TWO of the following. 8

a) State the Taylor’s principle of gauge design.

b) Design a general type plug gauge for checking a hole dimension 30−0.03+.0.05consider both wear

allowance and gauge tolerance as 10% of work tolerance

c) Draw the conventional diagram of limits and fits and define the terms 1) Basic size 2) Fundamental deviation.

Karmaveer Bhaurao Patil Polytechnic Satara

Roll No.


Rayat Shikshan Sanstha’sKarmaveer Bhaurao Patil Polytechnic, Satara

MODEL ANSWER PAPER

CLASS TEST - 1

Sub: - Metrology and Quality Control Paper Code :- 17530

Q.No.1 Attempt any three of the following Marks( 3*3 = 9)

a) Definition:“It is a science of measurement which deals with the measuring instruments, measuring technique and measuring standards”Objectives:1. To ensure that the product is as per quality standard.2. To enhance total customer satisfaction.3. To reduce rework and rejections.4. To increase profitability of organization.5. It helps in manufacture of interchangeable parts.6. Overcome the short coming in the production process

01 Marks For Definition 1/2

mark each4 points

b)Characteristics of End Standard : 1. End standards are having accuracy up to 0.001 mm. 2. Measurement by End standard is time consuming. 3. Environmental errors can occur in end standard. 4. Manufacturing of end standards is complex. 5. End standards are used for calibration purpose.

Any 6 Points ½ mark each

c) 35 H8 means an H-hole of basic size 35mm having tolerance grade IT8.35 f8 means an f-shaft of basic size 35 mm having tolerance grade IT8.35 H8 f8 is fit indicated by its basic size 35mm followed by symbols representing the limits of hole and shaft, the hole being stated first. The type of fit is clearance fit.

2 marks for correct

description 1 mark for type of fit



d)

2 Marks forFigure and 1

mark for labeling

Q.No.2 Attempt any two of the following Marks ( 4*2 = 8)

a) 1. The consumer not only wants quality, precision and trouble free products but also he wants them at attractive prices. 2. This has become possible only by adopting automatic gauging for selective assembly whereby parts manufactured to rather wide tolerances fit and function as though they were precisely manufactured in precision laboratory to very close tolerances. 3. This is a concept which does away with old idea of inspection in which part in identified as ‘good’ or ‘bad’; good part being used for assembly and bad used to be scraped. 4. In selective assembly the components produced by a machine are classified into several groups according to size. 5. This is done both for hole and shaft and then the corresponding groups will match properly. 6. If some parts (shaft and holes) to be assembled are manufactured to normal tolerances of 0.01 mm (and both are within the curve of normal distribution).7. An automatic gauge can segregate them into ten different groups with a 0.001 mm limit for selective assembly of the individual parts.

Any Eight points with explanation 04 marks



b) Minimum no. of slip gauges required =04 no. are as follows.73.975mm‐1.005…………………i)72.97‐1.47………………….i)71.50‐1.5……………………i)70.00‐70.00………………i)0OR1.005……………..i)+1.470……………i)+1.500…………..i)+70.000………..i) (04M)73.975mm

04 marks for correct steps

c) Essential characteristics of good comparator are 1. Easy to operate 2. Output must be easily readable and

understandable. 3. Easy availability. 4. Low in cost. 5. Robust in design. 6. Useable by unskilled labour. 7. Quick response to input. 8. Less maintenance.

Any Eight points with explanation ½ mark each



Q.No.3 Attempt any two of the following Marks ( 8*1 = 8)

a Taylor’s principle of gauge design states that. 1. GO gauges should be designed to check the maximum material limit, while the NO-GO gauges should be designed to check the minimum material limit.

The plug gauges are used to check the hole, therefore the size of the GO plug gauge should correspond to the low limit of hole, while that of NO-GO plug gauge corresponding to the high limit of hole.

Similarly, the GO snap gauge on the other hand corresponds to the high limit of shaft, while NO-GO snap gauge corresponds to the low limit of shaft.

2. Go gauges should check all the related dimensions (roundness, size, location etc). Simultaneously whereas NO-GO gauge should check only one element of the dimension at a time.

Go plug gauge should have a full circular section and be full length of the hole it has to check. This ensures that any lack of straightness, or roundness of the hole will prevent the entry of full length GO plug gauge. If this condition is not fulfilled, the inspection of the part with the gauge may give wrong result.

(Fig 2 Marks and Description 2 Marks )

b) Design Of GO and NO-GO Gauge: 04 Marks for Karmaveer Bhaurao Patil Polytechnic Satara


correct steps

c) 2 Marks for



Basic size:-It is the standard size of a part, with reference to which all the limits of variations of size are determined.

Fundamental Deviation:-The algebraic difference between size and corresponding basic size is known as deviation.

sketch2 Marks for

correct Definition


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