Improved productivity and wear life for a large Muck Spreader OEM
Overview
Chapmans was contacted by a major OEM of muck spreaders to assist with improving the wear life of the auger flights and other wear parts coming into contact with frozen muck, abrasive granite material and heavy type boulders on their machines working in continental North America.
Issue
Contractor-type, heavy users were experiencing accelerated wear on their auger flights and paddles due to the harsh winter weather conditions in the USA and Canada.
The cold-formed, mild steel parts were susceptible to the extreme temperatures and would, at best, wear out after only 2-300 hectares of spreading, or more worryingly, crack under impact from any rocks or solid abrasive lumps in the muck.
Design Brief
Chapmans was tasked with finding improvements in wear life by using hardened boron steel for the auger flights, spreader tips, paddles, and wear rings.
We felt that having watched the fabrication and assembly processes in action, there were also opportunities for productivity improvements at the factory.
Our Proposal
Chapmans developed an innovative process to hot form and harden auger flights in a single operation with consistent and repeatable tolerances of only ±1.5mm on the overall pitch of the auger flights.
The combination of wear resistance – hardness – from the boron additions and the natural toughness of medium carbon steel would make the Chapmans’ products ideal for coping with the harsh conditions experienced by the end users in North America.
The other associated auger parts were also formed and hardened in a similar way to improve wear resistance and increase product life.
The Result
The use of single-piece, hardened auger flights in boron steel dramatically increased the wear life of the assemblies and reduced the number of failures due to cracking and breakages to almost zero in the ten years following their introduction. The wear life of the replaceable spreader tips and paddles was also extended by using hardened boron steel, with the benefit of reduced downtime and running costs.
In addition, the improved consistency of form with tighter tolerances achieved using the novel production process resulted in a 25% improvement in welding productivity at the customer. Their welders were able to fit the auger flights to the assembly in a shorter time with minimal adjustment and clamping when joining flights together, enabling them to concentrate on the welding operation itself.
