Caterpillar Inc is also reworking its manufacturing practices to minimise disruptions. The machinery maker said Friday that changes to its assembly-line processes and alterations to material specifications for hard-to-find resins meant that availability for the majority of its products remained within normal ranges in the second quarter. But Caterpillar expects the bottlenecks to last through the end of the year. The supply-chain challenges it's facing now are much broader than the one-off component shortages or metal-casting logjams that might normally be expected in an economic upturn, CEO Jim Umpleby said on a call to discuss the results. The company reported better-than-expected sales and earnings for the second quarter amid booming demand for heavy-duty equipment but also warned that rising employee compensation and manufacturing costs would weigh on operating margins in the current period.