Inspection and repair of EISENBEISS ZSE 130 gearbox

Scope of work:

We performed an inspection and repair on a gearbox EISENBEISS ZSE 130.

GBS Gearbox Services International was approached by a customer in the plastic industry, they were planning to assemble a spare extruder gearbox and wanted a professional to check and assist with the assembling. The scope contained: checking assembly of the gearbox which is done by the customer, checking the bearings and alignment of the gears, alignment of the two gears and adjusting the position of the two keyways, providing recommendations.

So one of our service engineers travelled to Moscow, Russia to provide advises and check the assembly.
After opening the gearbox we found a lot of oil residue that was exposed to a lot of heat and had turned black, there also were some bits and pieces of broken gears. The new gear had only been milled and had no surface finishing after the heat treatment only the outside diameter had been turned. Therefor the quality of the gear was according to the customer 7-C, after measuring and aligning the gear it had a gap between the two gears, this gap was too large and was not acceptable. We reused the big axial bearing because there was no spare bearing but it had a lot of pitting on the surface. Then we assembled the two shafts and gears and when we tried to turn the shaft but it didn’t turn, it only scratched the opposite gear. So we had to grind the gear several times by hand in order to make it turn. Unfortunately the surface of the tooth was too rough to get a good blueprint.

We recommended that the gearbox would be shipped to our workshop in order to get the best result. But that was not possible for the customer so we made some recommendations:

• Cleaning the gearbox and oil systems
• Machining the gears after heat treatment for a better quality
• Grinding of the tip of the tooth to avoid that it will scratch the opposite tooth surface
• Repositioning of the keyways
• Outlining the new holes in the gearbox
• Renew the big axial bearing