Manufacturing Simulation Using Finite Element - Finite Element Analysis for Satellite Structures - page 300

Table 7.2 Selected milling cutting speeds for different materials. [ http://www.southbaymachine.
com/setups/cuttingspeeds.htm ]
Material Steel cutter, m/min Carbide cutter, m/min

Alloy steel 12-20 45-75

Aluminum 150-300 300-600

Bronze 20-35 60-120

Cast iron 15-25 40-60

Stainless steel 10-25 30-90

Tool steel 18-20 40-60

process due to discarded material. The high accuracy in tolerances and surface
finishes offered by the removal process makes it an attractive option for producing
small quantities. Satellite structure components are produced in small quantities with
high mounting accuracy requirements, which make material removal the perfect
option. Assembly process of aerospace assemblies requires that each subassembly
satisfies specific geometrical constraints. For example the aircraft wing assembly is
preceded by the shot peen process and the riveting assembly of the wing panels to the
stringers. These manufacturing processes sometimes produce unwanted deforma-
tions and require material removal to satisfy the geometrical tolerances, despite the
high cost involved. The conventional material removal processes are to cut away
small chips of material incrementally using a revolving cutting tool. Nonconven-
tional machining processes may apply chemical or thermal process to remove
material. Conventional machining processes are placed in three categories—single
point cutting, multipoint cutting, and abrasive machining. Single point cutting is to
use a stationary cutting tool with sharp edge to remove material from the work piece.
Turning process is rotating the work piece while the cutting tool feeds into it,
removing away material. Turning process is used for boring, grooving, or thread
cutting. Multipoint material removal is to use a cutting tool with many sharp teeth
that rotates against the work piece to remove material. Multipoint cutting processes
are milling and drilling. Milling is to feed the work piece into the rotating cutting tool
along defined paths to produce a variety of features. Milling process is used to create
slots, chamfers, pockets, flat surfaces, and complex shapes. Drilling is to feed the
rotating sharp tool vertically into the stationary work piece to create a hole. Drilling
processes such as counter boring, counter sinking, and reaming can be used to create
high accuracy holes, and threaded holes. Abrasive machining is to use a tool that has
small abrasive particles to remove material from a work piece. Abrasive machining
process is considered similar to milling or turning as each particle cuts into the work-
piece removing a small chip of material. Abrasive process is used to improve the
surface finish of a part, yet can still be used to form a work piece.
In this section, the milling process of metallic plates is simulated using finite
element and discussed in details. Yet, the technique that to be discussed in the
following section can be applied to simulate the other material removal processes.
More practical details can be found in Workbook for Machine Tool Applications,
Michael Bush [ 23 ]. Milling process is controlled by three parameters;