A protractor is a measuring instrument , typically made of transparent plastic or glass, for measuring angles. Radian-scale protractors measure angles in radians. Most protractors are divided into equal parts. Some precision protractors further divide degrees into arcminutes. They are used for a variety of mechanical and engineering-related applications.
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In experiment, we have to measure an angle of the block using the instrument bevel vernier protractor and optical comparator. We must measure the sample follows method to measure 3 times for each sample.
The data of the measure reading must be tables in Microsoft excel or word. The table is calibration form to find any error in measuring the samples. From the error we use to search perfectness, that we must using in industrial job. In this lab each student must practice the method using instrument tool and know the measure reading technics for each instrument tool used.
Lastly, the experience is importance in the technologies study where their students practice since at the institution. Student practicing the handling of basic measuring equipments for angle measurement; sine plate, sine bar, angle Dekkor, tool microscope and optical comparator. Learn technics using bevel vernier protractor and optical comparator not only know theory of this instrument. Know the suitable instrument uses according to condition measure whether angle or length. Perform measurement system analysis by calculating Repeatability and Reproducibility.
Demonstrate the proper method in using and taking care of the instrument. To familiarize the student with the types applications of bevel vernier protractor and optical comparator.
To take angle measurements with a certain accuracy depending on the instrument being used. To understand the types of error in the measurement each type of instruments. To study and understand about function of bevel vernier protractor and optical comparator.
Students are able to know how to measure and calculate the data by using statistics measures. The work piece was placed to the measuring equipment base part of bevel vernier protractor. The bevel vernier protractor was lock iii. The number of full degrees was count. The number of full degrees was count between the 0 degree mark on the degrees scale and the 0 minute mark on the vernier scale.
The number of minutes was count. The number of minutes was count on the vernier scale until reach minute mark which matches. The data was recorded. HB Horizontal Optical Comparator. Repeatability is variation in measurements obtained with one measurement instrument when used several times by one appraiser while measuring identical characteristics on the same part.
Optical comparator have a good repeatability because the data from experiment recorded closed with the real value while the bevel vernier protector have a poor repeatability. Reproducibility is variation in average of the measurement made by different appraiser using the same measurement instrument when measuring identical characteristic on the same part.
From this experiment the result show that bevel vernier protector have poor reproducibility because the result that recorded from this lab show a big different value among each appraiser while the optical comparator have a good reproducibility. Factor that have effected to repeatability, EV, and reproducibility , AV between appraiser is training , technique, skills, and experience.
Between part sample average different when measuring types of part A,B,C etc. Between instrument average different using instrument A,B,C etc. Measurement System Analysis MSA is the complete study of the measurement system to determine and understand the source of variation that can influence the result measured or produced by the system. Measurement System Analysis assesses the adequacy of a measurement system for a given application.
The perfect measurement system only the correct measurement and its having statistical property of zero variance, zero bias, and zero chances of misclassification of product measured. Related Papers. By Vishnu Chandran. Engineering Metrology and Measurements. Basic Engineering Technology. By Ste Naz. LAB reports. By Ashkan Renovation. Download file. Remember me on this computer. Enter the email address you signed up with and we'll email you a reset link. Need an account? Click here to sign up.
The bevel protractor is used to establish and test angles to very close tolerances. A circle can be divided into equal angles. Each angle is called degree. So a circle is degrees o. For calculation a degree is divided into 60 parts called minutes and a minute is sub-divided into 60 parts called seconds. When the edges of the beam and blade are parallel, a small line on the swivel plate coincides with the zero line on the graduated dial, and when any measurement of an angle between the beam and the blade of 90 degrees or under is desired, the reading may be obtained direct from the position of the line on the swivel plate with regard to the graduation numbers on the dial. But remember this: To obtain the measurement of the angle between the beam and the blade of over 90 degrees subtract the number of degrees as indicated on the dial from degrees.