In
mechanical engineering
Mechanical engineering is the study of physical machines that may involve force and movement. It is an engineering branch that combines engineering physics and mathematics principles with materials science, to design, analyze, manufacture, ...
, a fillet is a rounding of an interior or exterior corner of a part design. An interior or exterior corner, with an angle or type of
bevel
A bevelled edge (UK) or beveled edge (US) is an edge of a structure that is not perpendicular to the faces of the piece. The words bevel and chamfer overlap in usage; in general usage they are often interchanged, while in technical usage they ...
, is called a "
chamfer". Fillet geometry, when on an interior corner is a line of
concave function
In mathematics, a concave function is the negative of a convex function. A concave function is also synonymously called concave downwards, concave down, convex upwards, convex cap, or upper convex.
Definition
A real-valued function f on an ...
, whereas a fillet on an exterior corner is a line of
convex function
In mathematics, a real-valued function is called convex if the line segment between any two points on the graph of the function lies above the graph between the two points. Equivalently, a function is convex if its epigraph (the set of poin ...
(in these cases, fillets are typically referred to as rounds). Fillets commonly appear on
welded,
soldered, or
brazed joints.
Applications
*
Stress concentration
In solid mechanics, a stress concentration (also called a stress raiser or a stress riser) is a location in an object where the stress is significantly greater than the surrounding region. Stress concentrations occur when there are irregularit ...
is a problem of load-bearing mechanical parts which is reduced by employing fillets on points and lines of expected high stress. The fillets distribute the stress over a broader area and effectively make the parts more durable and capable of bearing larger loads.
* For considerations in
aerodynamics
Aerodynamics, from grc, ἀήρ ''aero'' (air) + grc, δυναμική (dynamics), is the study of the motion of air, particularly when affected by a solid object, such as an airplane wing. It involves topics covered in the field of fluid dyn ...
, fillets are employed to reduce
interference drag where aircraft components such as wings, struts, and other surfaces meet one another.
* For manufacturing, concave corners are sometimes filleted to allow the use of round-tipped
end mill
An end mill is a type of milling cutter, a cutting tool used in industrial milling applications. It is distinguished from the drill bit in its application, geometry, and manufacture. While a drill bit can only cut in the axial direction, most mi ...
s to cut out an area of a material. This has a ''cycle time'' benefit if the round mill is simultaneously being used to mill complex curved surfaces.
* Radii are used to eliminate sharp edges that can be easily damaged or that can cause injury when the part is handled.
[Visualization, modeling, and graphics for engineering design
By Dennis Kenmon Lieu, Sheryl Sorby, Page 6-31]
Design process
Fillets can be quickly designed onto parts using
3D solid modeling engineering
CAD software by invoking the function and picking edges of interest. Smooth edges connecting two simple flat features are generally simple for a computer to create and fast for a human user to specify. Once these features are included in the CAD design of a part, they are often manufactured automatically using
computer-numerical control.
Terminology
Different design packages use different names for the same operations.
*
Autodesk Inventor,
AutoCAD
AutoCAD is a commercial computer-aided design (CAD) and drafting software application. Developed and marketed by Autodesk, AutoCAD was first released in December 1982 as a desktop app running on microcomputers with internal graphics controllers. ...
,
Rhino3D,
CATIA
CATIA (, an acronym of computer-aided three-dimensional interactive application) is a multi-platform software suite for computer-aided design (CAD), computer-aided manufacturing (CAM), computer-aided engineering (CAE), 3D modeling and Product ...
,
FreeCAD,
Solidworks
SolidWorks is a solid modeling computer-aided design (CAD) and computer-aided engineering (CAE) application published by Dassault Systèmes.
According to the publisher, over two million engineers and designers at more than 165,000 companies wer ...
and Vectorworks refer to both concave and convex rounded edges as ''fillets'', while referring to angled cuts of edges and concave corners as ''chamfers''.
*
CADKEY and
Unigraphics refer to concave and convex rounded edges as ''blends''.
*
PTC Creo Elements/Pro (formerly Pro/Engineer) refers to rounded edges simply as ''rounds''.
Other 3D solid modeling software programs outside of engineering, such as
gameSpace, have similar functions.
See also
*
Welding
Welding is a fabrication process that joins materials, usually metals or thermoplastics, by using high heat to melt the parts together and allowing them to cool, causing fusion. Welding is distinct from lower temperature techniques such as br ...
Notes
{{Reflist
External links
Welding filletsLink missing
Mechanical engineering