Root Cause Analysis for Warming Delay of Resilient Solid Tire Heel Compound on Warming Mill During Manufacturing
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Date
2020
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Publisher
Uva Wellassa University of Sri Lanka
Abstract
Solid tires used in heavy-duty applications consist of three distinct parts: heel, cushion,
and thread. The heel is the innermost layer which provides the resistance to air
permeation while ensuring excellent adhesion to the rim and cushion. More fiber
reinforced compounds are used in heel production. But a warming delay for about 8-10
minutes which is more than the specified time limits to warm the compounds before
production has been observed when warm the compounds using warming mill. Therefore,
this research focused to analyse the root causes of the warming delay of compounds
during the warming operation. Minimum torque (ML) and Mooney viscosity (MV) of the
heel compound, nip size of the warming mill, thickness, and maturity of the incoming
compound sheets were selected as key factors for the warming delay. Multiple regressions
analysis and simple linear regression were applied to predict the relationships of these
factors with the warming time while using cubic regression to find the effect of nip size
on the warming time. According to the results, there is a significant effect of these factors
on warming time. Improper mixing of the compounds tends to show high values for MV,
ML, and thickness of incoming compounds. The maturity of the compounds and the nip
size of the warming mill was selected for further study. According to the two-way
ANOVA, there is an interaction between maturity and nip size on warming time. The nip
size (mm) was varied from 7 to 10 at 1mm interval and the maturity time of the
compounds was varied as 6, 12, 24, and 48 hours. Results revealed that warming time can
reduce using 9mm nip size and 48 hours maturity time of compounds at warming mill in
the manufacturing process.
Keywords: Minimum torque, Mooney viscosity, Nip size, Solid tire heel, Warming delay
Description
Keywords
Materials Sciences, Mineral Sciences, Rubber Technology