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Pull broaching solutions

Pull broaching is one of the most productive precision machining processes. It is a high-production, metal removal process that can be applied in the powergeneration equipment manufacturing industry to make one-of-a-kind parts. It is at its best when machining simple surfaces or complex contours.

The strong demand for new powergeneration equipment, most prominently gas turbines, has lead to substantial productivity improvement requirement with equipment manufactureres in order to keep up with the booming market.
Correctly applied, broaching provides massive productivity increases, holds tight tolerances and produces precision surface finishes.

Tooling
Tooling is at the heart of any broaching process. The broaching tool is based on a concept unique to the process - rough, semi-finish, and finish cutting teeth combined in one tool or string of tools. A broach tool frequently can finish-machine a rough surface in a single stroke.

In its simplest form, a broach tool resembles a wood rasp. It is a slightly tapering flat bar with rows of cutting teeth located along the tool axis. In advanced forms, extremely complex cross-sections and tooth designs may be found, However, the basic axial, multi-toothed tool shape remains.

Steamturbine vs gasturbines
Most often, steam turbine rotors/shafts are made of solid monolithic steels and the blade root slots are milled with custom made fir tree tooling sets:

Turbine tooling solutions

Gasturbines on the other hand are often assembled through an array of  turbine discs and its blade root slots thus lend themselves perfectly well to pull-broaching applications.



Fir tree slot milling


Dove tail broaching



Indexable insert solutions vs HSS broaches
The majority of broaching tools today are still made of HSS (High Speed Steel). While these tools are suitable for small scale broaching volumes, HSS broaches are slow, providing only very low productivity. HSS broach maintenance costs at the same time are high as multiple sets need to be ordered and kept in stock to allow for safe regrining and reconditioning cycles.

New, innovative indexable carbide insert based broaching solutions pioneered by Seco are availabe. Cutting speeds with insert based pull broach sets can be as high as 4-5 times the data applied with HSS tooling and always lead to massive productivity gains. Production times of complete disks are most often reduced to less than half the time it takes to complete the same component with HSS broaches. Cost savings of up to 60% are possible.



Broach segment examples


Loaded broaches



We provide winning solutions for:

Gasturbine broaching
General Powergen broaching
Aerospace industry disk broaching

Talk to us today and discover why we are a key industrial partner.

Download related documents:

Powergeneration competence brochure

Powergen brochure pdf


Related links:

Holemaking
Milling

Tooling Systems
Turning and threading

Application links:

Turbine tooling solutions
Application examples