When using modern CNC machining equipment, the geometry of the part can be read from a 3D CAD file directly. Technical drawings are not required to obtain a quote, but they are nevertheless highly significant and commonly utilized in the business because they increase the communication between the designer/engineer and the machinist.
When and why should you include a technical drawing in your CNC order? We'll explain the anatomy of a drawing and provide you some basic and advanced ideas and guidelines for drafting one in this article.
Learn a selection of the best milling tools for CNC cutting.
What is it about technical drawings that makes them so valuable today?
When you have a 3D CAD model that includes the following features:
Pinning and Weaving (internal or external)
Features with tolerances that go beyond the norm Individually finished surfaces (surface roughness etc)
A 3D CAD model will not be able to represent these needs.
Any design that doesn't include the above should nevertheless include a sketch when it comes to placing an order for a CNC machine. Machining is usually done using programming for the CNC machine, and this drawing is utilized as a guide. There are a number of reasons why CNC service providers prefer to work with technical drawings over 3D CAD files:
From the 2D drawing, they are taught in the art of quickly deciphering a part's geometry.
It is much simpler to determine a part's primary size, functions, and essential characteristics.
The cost of producing the part can be more easily estimated.
In the world of technical drawing, there are numerous guidelines and best practices. Your technical drawing doesn't need to be drawn in any particular way if it properly communicates your project's specifications.
As an added bonus, the model in the illustration used to illustrate this essay is shown in its full scale. As long as the essential dimensions of the part are given in the 3D CAD file, this isn't required but is preferred. The threads and the most essential elements you want measured can be annotated in your technical drawing to save time.
a technical drawing's skeleton
In a typical technical drawing, the following elements are included:
In this section, we have the title block.
Name, material, finish and color requirements and the designer's and company's names are all included in the title block's information. It is critical to provide this basic information, as it explains the part's function to the manufacturer.
Besides the drawing's scale and the standard used for dimensioning and tolerancing, the title block offers further technical information.
The angle projection's title block is generally flanked by another element. The arrangement of the views in the drawing is determined by the angle projection of the image. While drafting designs according to ASME standards (such as in the United States and Australia), third angle projection is typically used; when using ISO/DIN standards (such as in Europe), first angle projection is typically used.
The isometric picture view
You should include at least one or two 3D views of the part in your drawing, as they make it easier to read at a glance.
Using isometric views, the feeling of depth is combined with the depiction of the parts geometry in an undistorted fashion (vertical lines remain vertical and horizontal lines are drawn at 30o).
The primary orthographic perspectives
Detailed information about the part's geometry can be gleaned from the orthographic views.
From the outside of a box, one side is shown at a time, with a two-dimensional representation of that side's three-dimensional object depicted. In order to communicate dimensions and features more clearly, only the borders of the sections are drawn in this manner
A few orthographic views are usually enough to convey the full geometry of an object.
Sections are viewed.
Using section views, the inside of a part may be seen in all its fine detail. Cutting lines in the main orthographic view indicate where the part is cross-sectioned, and the cross-hatch pattern in the section view indicates places where material has been removed.
In technical drawings, cutting lines can be linked to each section view by two letters (for example A-A, B-B and so on). There are cutting lines that point in different directions, and these arrows point in the same direction.
It is customary to arrange section views next to a corresponding orthographic view, however this does not always have to be the case. The portion can be divided into sections that span its entire width (as shown in the illustration), half of its breadth, or at an angle.
Section views provide a better visual representation of hidden interior structures than orthographic dashed lines.
Views on the finer points
Detail views are used to highlight areas of a main orthographic view that are difficult to measure.
Circular in shape, they are offset from the main drawing to minimize misunderstanding, and they are labeled with a single letter that identifies them as part of the main drawing (for example A, B and so on).
There are no restrictions on where and how you insert detail views on your drawing, as long as you make it apparent when you do so (like in the example).
Manufacturer's instructions
Notes to the manufacturer can be added to the technical drawing to convey additional information that wasn't included in the technical drawing.
Your technical drawing notes may include instructions to break (deburr) all sharp edges, specific surface finish requirements and references to other components that the part in the drawing interacts with.
As an alternative to text, symbols may be utilized. Symbols are often used to indicate surface roughness, for example.
Annotate the design rather than the notes if only one surface requires a specified surface roughness finish. An average of 3.2 m (125 inch) is the standard roughness of Hubs-machined items. Surface roughnesses of Ra 1.6 m (64 inch) and 0.8 m (32 inch) can also be achieved with special finishing techniques.