The objectives of this research are to design the load cell tolerance testing machine and demonstrate the tolerance of load cell with a tolerance test that has a beam length of 90 cm. It can create the compressed force at the load cell more than 1 kN The experiment cam be divided into 2 stages; 1.) verification of load range and 2.) linearity test. Both stages are tested at a temperature at 25°C using 10 to 30 kg of mass in the lowest compressed force condition of 0.091 kN and the maximum compressed force condition of 1.12kN As a result the linearity performance of the tolerance of the load cell test kit between calculated force and displayed value force are different 0.354 percentage only while the standard deviation of displayed value force and voltage signal output are 0.0013 and 0.0022 respectively. It reveals that the experimental result is reliable because of less than 1. In addition the tolerance of the load cell tolerance testing machine is 0.00300 (0.3 percent) which was calculated from the comparison of the tolerance specification of two main equipment that specified by manufacturer.

This research aims to study and compare the test results obtained from the rolling resistance tester of automobile tires based on force method and torque method system. The four newly manufactured tires were sampled from two tire classes namely passenger car tires (Class C1) and light truck tires (Class C2). The tire rolling resistance test according to the international standard UN ECE Regulation No.117 was used as an important research process. The experimental work discovers that the rolling resistance of the same tire obtained from the test between the two different methods of testing machines was not more than 6 percent different. The testing results that used the torque method system calculation are high reliability because of the principle of calculation from the measurement value directly results in. and suitable for research testing. However the force method tester can perform more than a tire simultaneous test which is suitable for working in industrial applications where time is limited.

The objectives of this research is to study the relationship between tolerance and measurement range of load cells. Tolerance test kit length of mass beam 90 cm was used. It can create the compressed force at the load cell more than 1 kN. The experiment cam be divided into 2 stages; 1.) verification of load range and 2.) linearity test. Both stages are tested at a temperature at 25°C using 10 to 30 kg of mass in the lowest compressed force condition of 0.091 kN and the maximum compressed force condition of 1.12kN As a result the linearity performance of the tolerance of the load cell test kit between calculated force and displayed value force are different 0.354 percentage only while the standard deviation of displayed value force and voltage signal output are 0.0013 and 0.0022 respectively. It reveals that the experimental result is reliable because of less than 1. In addition the tolerance of the load cell tolerance testing machine is 0.00300 (0.3 percent) which was calculated from the comparison of the tolerance specification of two main equipment that specified by manufacturer.

The objectives of this research are to study the rate of deterioration of tyre friction coefficient and investigate the quality of new and old tyres that are currently in use. A set of the rolling resistance testing was designed and set up to work with the single dynamometer according to speed 80 km/h tire load 4660 N and inflation pressure 30 psi. There were three tire samples new tire one year used tire and two year used tire to find the rolling resistance coefficients. The finding shows that the rolling resistance was inverse variation with tire aging. For instance the new tire (1st sample) had the highest rolling resistance on the other hand the two year used tire (3th sample) had the lowest rolling resistance. Moreover the rolling resistance coefficients were inverses variation with tire aging. Besides the one year used tire had the average of the decreasing rate of the rolling resistance coefficient at 0.03689 N/kN per a week while the two year had the average of the decreasing rate of the rolling resistance coefficient at 0.03671 N/kN per a week. Furthermore the result also revealed that the rolling resistance coefficients nonlinearly decreased comparing to the tire aging.

Currently the automotive industry plays an important role on the economic growth in Thailand. As the same time the waste of automotive parts has increased as well. As a results the automotive parts made from three different natural fiber parts was studied consisting of hyacinths sugarcane and pineapple leaf fiber. By of 50 x 250 x 20 mm of mold dimension the specimens were produced under 700 W of heating stick and measured temperature by a K type of thermometer. There were 3 same proportion specimens made from: 1) sugar cane fiber: husk: latex adhesive 2) water hyacinth fiber: husk: latex adhesive 3) pineapple fiber: husk: latex adhesive in the ratio of 25:25:50 by weight which were formed under temperature between 100GC and 105°C at 5 MPa of pressure and leading to find out the bending moment ability. The test results show that the specimen made from sugar cane fiber has the highest value 5482.5 Nand 4061.11 N/mm2 of bending moment and bending stress respectively. It was more than specimen made of water hyacinth 29.84 % and pineapple fiber 65.01 %.