In
mechanical engineering
Mechanical engineering is the study of physical machines and mechanism (engineering), mechanisms that may involve force and movement. It is an engineering branch that combines engineering physics and engineering mathematics, mathematics principl ...
, a fillet (pronounced , like "fill it") is a rounding of an interior or exterior corner of a part. 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
A chamfer ( ) is a transitional edge between two faces of an object. Sometimes defined as a form of bevel, it is often created at a 45° angle between two adjoining right-angled faces.
Chamfers are frequently used in machining, carpentry, fur ...
". Fillet geometry, when on an interior corner is a line of
concave function
In mathematics, a concave function is one for which the function value at any convex combination of elements in the domain is greater than or equal to that convex combination of those domain elements. Equivalently, a concave function is any funct ...
, 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 distinct points on the graph of a function, graph of the function lies above or on the graph between the two points. Equivalently, a function is conve ...
(in these cases, fillets are typically referred to as rounds). Fillets commonly appear on
welded,
soldered, or
brazed joints.
Depending on a
geometric modelling kernel different CAD software products may provide different fillet functionality. Usually fillets can be quickly designed onto parts using
3D solid modeling engineering by picking edges of interest and invoking the function. 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.
Applications
*
Stress concentration
In solid mechanics, a stress concentration (also called a stress raiser or a stress riser or notch sensitivity) is a location in an object where the stress (mechanics), stress is significantly greater than the surrounding region. Stress concentra ...
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 () is the study of the motion of atmosphere of Earth, air, particularly when affected by a solid object, such as an airplane wing. It involves topics covered in the field of fluid dynamics and its subfield of gas dynamics, and is an ...
, 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. They can have several end configurations: round (ball), tapered, or straight are a few popular types. They are most commonly used in "milling machi ...
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]
Terminology
Different design packages use different names for the same operations.
*
Autodesk Inventor
Autodesk Inventor is a computer-aided design extension application for 3D mechanical design, simulation, visualization, and documentation developed by Autodesk.
Features
Inventor allows analyzing 2D and 3D CAD models by creating a virtual rep ...
,
AutoCAD
AutoCAD is a 2D and
3D computer-aided design (CAD) software application developed by Autodesk. It was first released in December 1982 for the CP/M and IBM PC platforms as a desktop app running on microcomputers with internal graphics control ...
,
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 li ...
,
FreeCAD
FreeCAD is a general-purpose Solid_modeling#Parametric_modeling, parametric 3D computer-aided design (CAD) modeler and a building information modeling (BIM) software application with finite element method (FEM) support. It is intended for mecha ...
,
Solidworks
SolidWorks (stylized as SOLIDWORKS) is a brand of software used for solid modeling computer-aided design (CAD) and computer-aided engineering (CAE). It was one of the first 3D CAD applications designed to run on a desktop PC.
The brand is owned ...
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
NX, formerly known as "Unigraphics", is Computer-aided design, CAD/Computer-aided manufacturing, CAM/Computer-aided engineering, CAE software, which has been owned since 2007 by Siemens Digital Industries Software. In 2000, Unigraphics purchased ...
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 (metal), fabrication process that joins materials, usually metals or thermoplastics, primarily by using high temperature to melting, melt the parts together and allow them to cool, causing Fusion welding, fusion. Co ...
Notes
{{Reflist
External links
Welding filletsLink missing
Mechanical engineering