We often say: "Everything is under control" in mechanical design, which has two meanings: First, all structural details have been carefully thought out and fully expressed, and the design intention cannot be guessed during the manufacturing process. Re-design or "free play"; second, all designs are based on grounds and cannot be played arbitrarily by "slapping the head". Many people disagree, thinking that it is impossible to do it. In fact, they did not master the design method and develop good habits.
There are also design principles for chamfering/rounding corners that are easily overlooked in design. Do you know where the corners should be, where the corners should be rounded, and how big the corners should be?
1 Overview
1.1 Definition
Chamfering and rounding refer to cutting the corners of the workpiece into a certain slope/round surface
1.2 Purpose
1.2.1 Remove the burrs on the parts due to machining, so that the product is not sharp and will not cut the user
1.2.2 Facilitate parts assembly
1.2.3 When the material is heat treated, it is conducive to the release of stress, and the chamfer is not easy to crack, which can reduce the deformation and solve the problem of stress concentration
2. Five Design Principles
2.1 Inner circle and outer square (machined parts) Principles:
1) Machined parts are machined with rotary tools, the inner corners of the workpiece are rounded, and the outer corners are squared
2) The outer square corner and inner fillet corner of a certain feature in the same workpiece should be as consistent as possible to reduce the number of tool changes
Editor's Note: The "square" here should mean chamfering.
2.2 Inner circle and outer circle (sheet metal parts) principle:
1) Sheet metal parts are laser processed, which is different from traditional cutting processing
2) Unified rounded corners inside and outside the workpiece
3) Fillet range R=2～5
2.3 Coordinate with neat and beautiful principles:
1) Chamfering ensures neat and beautiful assembly parts
2) No obvious sharp edges, protecting the body from handling, assembling and using
3) Default C0.5 if no chamfering is specified
As shown in the figure below, the ticked ones indicate neat assembly.
Editor's Note: Sometimes whether a part needs chamfering depends not only on the part itself, but also on the assembly relationship with other parts.
2.4 Relieve internal stress & increase strength principle:
1) There is internal stress concentration in the heat treatment of the material, and the transition fillet is added to eliminate the deformation and fracture caused by internal stress
2) For cantilever parts, adding rounded corners can increase the strength
2.5 Guiding principles:
1) To place the acupuncture points of the product, in order to facilitate the insertion, it is necessary to chamfer the angle to increase the guide
2) For the convenience of assembly, the matching of parts needs to be chamfered
The above are some basic knowledge about the chamfering of parts in non-standard mechanical design. Do you have any other insights and opinions?
