Manufacturing Processes (Electric Motors)

3.3.2
Cast Iron. The typical sequence of a cast iron operation is as follows:
1. Machine and drill the mounting feet to be used as a locator for further machining operations.
2. Bore the inner diameter (ID).
3. Turn the end frame registers (optional—sometimes done as a wound stator assembly).
4. Drill and tap for the end frame attachment.
5. Mill for the outlet box attachment.
These machining operations can be completed on either manual machines or CNC machining centers. Usually machine-tool cells are incorporated.
Rolled Steel. A coil is processed through a stamping press and the shape is a flat form. This piece is then formed around a mandrel and welded. In some cases, the weld is a straight butt weld. In other cases, the rolled end attachment is interlocked mechanically with several weld beads.
The housing is then machine-faced to length. Next, a stamped mounting base is welded to the housing.
There are both highly automated and semimanual machines for this process.
Wrapped Steel. The manufacturing processes are the same as for a rolled housing, except that the stator core is used as the mandrel.
Tube Steel. A drawn-over-mandrel (DOM) tube or a hot-rolled seamless tube is processed in the following manner.
DOM. Cut to length, machine end frame diameter (optional—may be done as a wound stator assembly), and weld mounting feet.
Seamless tubing. Cut to length, machine end frame diameter (optional—may be done as a wound stator assembly), and weld mounting feet. Depending on the condition of the bore, it may have to be machined.
Aluminum Castings. Most aluminum castings are produced as a complete housing with mounting feet. These are machined like cast iron and with the same type of equipment. Some, however, are cast over a stator core. This process requires machining like cast iron, except that the bore is not machined.
Aluminum Tubing. The material is cut to length. Sometimes the end housing diameter is machined prior to stator core assembly. The mounting feet are then welded or screwed to the housing.