Case History: On-Site/Portable Machining Saves Small Fortune For Paper Mill
A paper mill in upstate NY has a very large machine that removes bark from logs. This is an initial phase in the papermaking process where raw logs go in one end of the process and finished paper goes out the other. ….Remarkably, this machine is called a de-barker.
The de-barker has 3 large rotating shafts that are timed together with sprockets and chains.
Unfortunately, the sprockets & bushings had spun on one of the shafts. The original sprocket mounting was a B-Lock keyless bushing design. It was determined that a direct keyed, interference fit sprocket mounting design would be more durable. However, to disassemble the de-barker, remove the large shaft and ship it to a qualified machine shop was definitely cost prohibitive.
The mill was desperate for an alternative solution. They found us online when searching for a company who had On-Site/Portable Machining capabilities.
Knowing their desperate situation, we responded almost immediately. Once on site, we first machined the shaft in-place to remove the scoring damage caused by the spun bushing. The shaft was originally 8” diameter. We machined it to a clean 7-7/8” diameter. This was accomplished with our portable lathe that mounts to and swings about the axis of the stationary shaft. Following the machining of the damaged shaft, we mounted a portable key mill onto the shaft and cut two keyways: 2” wide x 5/8” deep x 8” long. Keyway alignment was critical to maintain the appropriate sprocket position. The new sprockets were then machined to accommodate the required shrink fit onto the newly machined shaft.
The entire machining and re-assembly process was accomplished in one weekend, allowing the de-barker to go back into operation on Monday morning, definitely ahead of schedule.
The savings realized by eliminating the de-barker disassembly and associated downtime is likely in the seven figure range.
On-Site/Portable Machining is a dream come true. It can eliminate very costly machine disassembly.
Our many portable machining capabilities include:
- Machining full face, raised face, back face and grooved flanges; internal and external mounted machines available; to 120″ O.D.
- Applications include cutting ‘O’ Ring grooves, vertical grooves, V grooves, pipelines and reactor vessel flanges.
Pipe Cutting / Weld Preparation
- Applications include all types of vessels, pipes, valves and tubes.
Shaft & Journal Machining
- Repair of worn or damaged shafts and journals up to 11″ in diameter, including stepped profiles, ring grooves and parallel shafts; weld build-up if necessary; polishing available.
- Applications include mixer journals, roll journals, alternator and ventilator shafts, crank pins, presses, turbine rotor journals, fan shafts and pumps, and more.
- Sizes include 1- 36″ in diameter and in excess of 60″; to 12′ distance between bores. Inquire about larger bores and the alignment that is always necessary to ensure accuracy.
- Applications include industrial equipment and machinery including mining & earth- moving equipment, excavator buckets, printing presses, pump housings, valve bodies, valve seats, turbine casings, diesel engines, crank and cam shaft housings.
- Applications include milling and fly-cutting pump and motor bedplates, milling heat exchanger division plates, external and internal keyways in shafts and bores, crane pedestals and tracks, bedplates, steel rolling mills, hatch covers and square flange machining, blast and oxygen furnaces, concast units, sinter plants, iron ore terminals and mill stands, joint faces on fin/fan coolers and intercoolers.
Keep your Plant Up and Running.