RPM has used laser cladding technology to repair a wide variety of shafts since 2004. From out-of-tolerance ash crusher shafts to galled drag line swing shafts, laser cladding has proven itself to be the most timely and reliable solution to shaft wear problems. Unlike spray repair, laser cladding provides a metallurgical bond that won’t lift or spall under tough operating conditions. Our engineers will choose the best alloy for your specific wear environment.
Some shaft repairs that have been completed by RPM & Associates include Trunion Shafts, Coal Pulverizer Journal Shafts, PA Fan Shafts, Atomizer Shafts used in Flue Gas Desulfurization Systems, and Pump Shafts. Following are a number of specific case studies of shaft repairs RPM & Associates has completed.
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A high-speed 4340 drive shaft was repaired using a conventional spray process. Note the severe spalling in the repaired tapered area of the shaft. The user tolerated this recurring problem due to lack of other options for repair. The LCT process was introduced to the customer and now several of these shafts have been successfully repaired using 420 stainless.
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Bearing and seal diameters, tapers and treads may all be repaired!!!
 Atomizer Shaft as Received Failed Spray Repair |
 Atomizer Shaft with Laser Deposit |
 Atomizer Shaft with Final Machining |
An HP 1103 Journal Shaft from a coal pulverizer system was brought into our shop for repair. The shaft was worn on three surfaces and one face. RPM & Associates has since repaired a number of these shafts.
 Shaft During Deposit |
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 Shaft Post Deposit |
 Shaft Post Deposit |
 Shaft After Final Machining |
RPM & Associates performed a repair of a spindle sleeve for a horizontal boring mill using Laser Cladding Technology (LCT). The cladding for this part, due to its size, was performed in open atomosphere. Distortion was kept to a minimum by running the laser at 465 watts and using a 1 mm spot size. 420 LC SS powder was used to give the part better wear resistance.
 Spindle Sleeve As Received |
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 Wear Surface Pre-deposit |
 Wear Surface Post-deposit |
 Spindle Sleeve Post-machine |
This example Trunion Shaft had two sections that had worn out. The shaft was machined to minimum cleanup. A process was developed to deposit 420 SS (stainless steel) to build up both surfaces of the Trunion Shaft. The 420 SS material improved the wear resistance of the part to future wear. After material was built up, the Trunion Shaft was then machined to its final dimensions.
 Trunion Shaft Wear Surface Before Repair |
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 Trunion Shaft Before Repair |
 Trunion Shaft Final Machined |
 Trunion Shaft Wear Surface Final Machined |
The following repair was done on a 4340 Swing Shaft used on a drag line in a coal mine. The 4340 Swing Shaft is 16 1/2 ft. long and weighs 25,000 pounds. Conventional repairs on this type of shaft were not possible due to high heat input.
RPM & Associates developed a repair process for the bearing surfaces of the 4340 Swing Shaft using 420 SS (stainless steel) and the Laser Cladding Technology process.
The repair cost is approximatley 65% less than new and extends the operational life of the shaft compared to new due to the materials used. A number of these shafts ranging in various sizes have been repaired.
 Worn Bearing Surface |
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 Shaft During Deposition |
 Shaft Final Machined |
 Shaft Final Machined |
A 1035 PA Fan Shaft was knocked out of tolerance due to a crash that occurred while in service. The shaft is a precision shaft that runs at 1,725 RPM and 3,500 horsepower in an ambient condition. Diametrical tolerances are within 0.0005" and run out tolerances are also within 0.0005".
RPM & Associates developed a repair process using Laser Cladding Technology (LCT) that added material to the shaft and allowed the shaft to be machined back into specified tolerances.
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 During Laser Deposition |
 After Laser Deposition |
 After Final Machining |
While overhauling a CE11003 journal, we found the shaft had a prior spray on bronze repair at bearing fit location that was failing. Bronze debris was contaminating the oil. RPM pre-machined to remove failed repair, Laser Clad with 420 SS, and post machined to correct tolerances.
 CE1003 Pulverizer Journal Shaft |
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 After Laser Deposition |
 After Final Machining |
RPM engineers and manufactures specialty parts for many industrial needs such as these upgraded soot blower front support rollers.
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