TEST

1.  a) Define roughness

    roughness is the surface that occured on the object wether it is in  high  or low roughnes



     b) list 4 elements for surface roughness

•  flaw
• lay direction
• roughness height
• roughness width
• walviness width
• walviness height
• roughness-width cut off             

    


  c) explain effect of surface roughness on functional   properties:

        The surface roughness influence the functional properties if the roughness of object is highher, the energy to push the object on something is higher. The roughness on an object that stop  the surface to continue to move. so it stop the functional of the object to ware resistance
     
        


2. a) label screw structure part

• pitch diameter
• thread angle
• minor diameter
• crest
• pitch
• root
• helix angle

   b) explain what is major diamter 

      Major diameter is the diameter of an imaginary co-axial cylinder which is touches the crest of an internal thread or the roots of an internal thread


    c) list the mearement instrutment for each mearurement
         

• major and minor diameter: ruler, vernier caliper,profile projection,tool microscope
• pitch length: ruler and screw thread diameter and profile projector

• pitch angle : screw thread micrometer, profile projection

• thread angle : profile projection

3.a) Name the geometrical properties

• roughness or circularity
• flatness
• straightness
• paralellism
• perpendicularity
• symmetry
• angular
• cylindricity

    b) state which is the part of geometrical dimensional and tolerances based on the diagram.

MY OWN SIMPLE NOTE CHAPTER 1 : INTRODUCTION TO ENGINEERING METROLOGY

LEARNING OBJECTIVES OF THE CHAPTER: 

1.         Provide a basic understanding on Metrology principles.

2.         Provide knowledge on international measuring units; the SI unit.

3.         Expose the measurement standard, measurement processes and measurement errors.

1.1 DEFINATION

•            In general, Metrology is a scientific study of measurement.

Metrology is a very broad field and may be divided into three subfields:

·         Scientific or fundamental metrology

       concerns the establishment of measurement units, unit systems, the development of new measurement methods, realisation of measurement standards and the transfer of traceability from these standards to users in industry. 

·         Applied or industrial metrology

      concerns the application of measurement science to manufacturing and other processes and their use in society, ensuring the suitability of measurement instruments, their calibration and quality control of measurements. 

·         Legal metrology 

      concerns regulatory requirements of measurements and measuring instruments for the protection of health, public safety, the environment, enabling taxation, protection of consumers and fair trade.