Problem-solving step analysis for increasing tire static balance levels: a case study

One of the company's efforts in implementing the commitment to customer satisfaction is carried out through continuous improvement activities. All indicators are evaluated to determine the level of quality stability against process variations that will impact non-compliance with predetermined product specifications. One of the quality problems found in the tire manufacture industry is the out-percentage of tire uniformity, which suddenly increases, one of which is the value of static balance. This study analyses the process variation factors that occur to take corrective and preventive actions through a series of Root Cause Analysis (RCA), Fault Tree Analysis (FTA), and Failure Mode and Effect Analysis (FMEA). Refers to the analysis result, it was found that there was a problem with the rubber film gauge variation at the manufacturing step of the steel breaker, one of the material components in the tire construction. Two main factors cause rubber film thickness variation: rubber sticky with roll calendar, Radial Run Out (RRO) Roll Calendar out standard, and viscosity compound variation with 12 root problems found. The results of the improvements that have been made can effectively improve rubber film thickness variation, increase the Cpk level of steel breaker material from 0.82 to 1.91 and reduce the out percentage ratio of static balance by 54.65%.

Behavior of bladder-type inflatable anchors in sand: Physical modeling

This paper describes an investigation into the performance and pull-out capacity of a bladder-type inflatable anchor. The inflatable anchor is a type of support member used in foundation pit support engineering. Based on improvements and innovations, the multi-bladder-type inflatable anchor consists of two or more hydraulically inflated rubber membranes that are embedded in unconsolidated earth and then inflated to provide pull-out capacity. The primary objective of this study was to investigate the impact of inflation pressure, embedment depth, number of bladders, bladder length, and rubber film thickness on the pull-out capacity and displacement of the inflatable anchor. The tests were carried out in a cylindrical steel test chamber filled with medium coarse sand. The pull-out behavior of the bladder-type inflatable anchor and the five variables was investigated, and the benchmark values for all tests are determined by similarity ratio. Compared with the single bladder inflatable anchor, under the same conditions, the ultimate pull-out capacity of the two bladder-type inflatable anchor is 1.2 times higher, with ultimate displacement only 37.5% of the former, the ultimate pull-out capacity of the three bladder-type inflatable anchor is 1.7 times higher, with ultimate displacement only 32.3% of the former. The two bladder-type inflatable anchor is superior to the single bladder inflatable anchor and the multi-bladder-type has higher ultimate pull-out capacity and greater stiffness. The inflation pressure and the rubber film thickness have a significant influence on the bearing capacity. The number of bladders effectively controls the ultimate displacement.

Xanthan Gum-Incorporated Natural Rubber Film Casted with Solvent Evaporation

Xanthan gum (X)-incorporated natural rubber (NR) cast films were fabricated from blocked NR by solvent casting method using dichloromethane as the solvent. The rather smooth films were obtained. X markedly promoted both of water sorption and erosion in phosphate buffer pH 7.4 of these composite films. With increasing X amount also significantly enhanced the film tensile strength, Young’s modulus and area under the curve while did not affect contact angle of water/formamide and surface free energy. 30%X-loaded NR films exhibited the highest durability with apparently high water sorption and erosion for further using such as wound dressing.

Deproteinized natural rubber film reinforced with silane-modified silica nanoparticles

Mechanical properties and morphology of the deproteinized natural rubber (NR) films reinforced with modified silica (SiO2) nanoparticles were studied in this research. In the step of deproteinization, a chemical method followed by centrifugation was used to reduce the amount of protein from 0.42 wt% to 0.11 wt%. Structure-modified nanosilica with Silane A174 was used as an additive to reinforce the deproteinized films. The addition of 1 phr of the modified nanosilica exhibited better tensile strength, tensile force at break, modulus at 500% and elongation at break which were improved significantly compared to those of bare films. The modified nanosilica dispersed uniformly in the rubber matrix with the nanoparticle size less than 100 nm observed from the scanning electron microscope. The prepared rubber films containing the modified SiO2 nanoparticles have great potential to produce the NR gloves having very tiny amounts of protein for medical use which still provide the good mechanical strength compared to the standard ones.