SHEET 2 FLATNESS 1. A table of upright drilling machines 550x 550 mm was tested for flatness error. A mesh consists of 4 similar squares of 250 mm side length is drawn on the table. A sensitive level of constant 0.04 mm/m is used to measure the level of each point relative to the preceding one as listed on the following table. Using SEMI- ANALYTICAL method, determine the maximum out of flatness. Position ba cb ed fe Reading (div) -3 2 4 1 Position hg ih da gd Reading (div) l 2 2 4 = 0.04 mm/m = 0.01 mm/250mm 1- Reading 2- Accumulative
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SHEET 2
FLATNESS
1. A table of upright drilling machines 550x 550 mm was tested for flatness error. A
mesh consists of 4 similar squares of 250 mm side length is drawn on the table.
A sensitive level of constant 0.04 mm/m is used to measure the level of each
point relative to the preceding one as listed on the following table. Using SEMI-
ANALYTICAL method, determine the maximum out of flatness.
Position ba cb ed fe
Reading (div) -3 2 4 1
Position hg ih da gd Reading (div) l 2 2 4
π = 0.04 mm/m = 0.01 mm/250mm
1- Reading
2- Accumulative
3-make the lower left corner =0
4-make the upper right corner =0
5-rotate about the diagonal
Maximum out of flatness = (3.5+1.5)Γ 0.01=0.05 mm = 50 microns
2. A Rotchdal arm tester having 200 mm leg distance was calibrated on three
points x, y, z on a line. Their reading at point Z was 0.1 mm. The same line is
divided into 4 equal distances to be checked using a sensitive level. The
readings were 1 and 3 ΞΌm respectively on the line xy and were -1 and -3 ΞΌm
respectively on the line yz
The calibrated Rotchdal arm is used to check the flatness of a surface shown in Fig.
The readings
Line abc Afe edc Bdh ehk bcl hjl cjk
Readings(ΞΌm) 15 -6 5 -10 -3 106 116 -83
Find the height readings relative to the plane abf, then find the out of flatness.
position x x1 y y1 z
reading relative to the preceding one 0 1 3 -1 -3
Accumulative (mm) 0 1 4 3 0
π = 2π β π + π¦
Where:
R: level of the point under the dial indicator plunger
Maximum out of flatness = |0.385962| + |β0.34512| = 0.73108ππ
7. A Rotchdal arm tester having 200 mm leg distance was calibrated on three points x, y, z on a line. Its readings at point Z was 0.1 mm. The reading of a sensitive level on the same line needs to divide the line into parts as shown. The readings were 1 and 3 ΞΌm respectively on the line xy and were -1 and -3 ΞΌm respectively on the line yz
x____ xl _____ y ____ yl _____ z
The calibrated Rotchdal arm is used to check the flatness of a surface shown in Fig. The readings were:
Line a be afe edc Bdh ehk bcl hjl cjk
Readings(ΞΌm) 15 -6 5 -10 -3 106 116 -83
Find the height readings relative to the plane abf, then find the out of flatness.
8. A Rotchdal arm tester having 200 mm leg distance was calibrated on a reference
straight edge and its reading was 45 ΞΌm .The calibrated Rotchdal arm is used to
check the flatness of a surface shown in Fig. The readings were:
Line abc Afe edc Bdh ehk bcl hjl cjk
Readings(ΞΌm) 15 -6 5 -10 -3 106 116 -83
Find the height readings relative to the plane abf.