The part drawing is one of the most critical elements in custom tube bending and laser cutting. This file provides the key pieces of information needed to manufacture the part. The drawing shows all dimensions and measurements, material type, tolerances required, revision information, part number and relevant notes. These details are used to determine costs, to set up how a part will be manufactured, and in some cases, how the full order will be handled or shipped.
“Detailed parts drawings are the “language” between engineering and manufacturing and serve as the standard way of transmitting information about how the part will be created.”
The dimensional drawing, whether 2D or 3D, helps the manufacturer determine costs, understand what tooling may be required, how the machine will be set-up and even how long a part will take to bend or cut on a tube laser. Run times can be determined by looking at the 3D model file and in some cases running a simulation of the machine’s CNC program. This “digital twin” allows the engineer full visibility to the part within the software.
Whether square, rectangular, or round, one of the most important dimensions contained on the parts drawing is the material profile size or the OD (outside diameter). These dimensions will impact whether the part can be handled by the equipment and machinery available from the vendor. For example, our CNC tube bending and tube lasering equipment can handle material within the range of 0.25” to 6” OD.
Wall thickness is also important. The thinner the wall, the more challenges exist in tube bending or tube lasering. The ratio of tube OD to wall thickness must be known from the outset of the project, along with the material type. Tube will be shown as gauge, or wall thickness. Pipe wall thickness is specified by “Schedule” or Sch. For more information, click here.
Information such as tolerances, finishing specifications or packaging requirements may also be called out on the parts drawing.
Locating the information
Title block: Commonly located in the lower right side of the drawing, this area includes information such as the part name, part number and its description. Additionally, you’ll find the revision number or letter, the scale of the drawing, the specific type of material to be used for the part. The revision block is especially important as it helps the manufacturer know that they are working off the most recent version and what the revision may have been for.
On the part itself: dimensions, notes, callouts are a standard part of a drawing, with dimensions specified using numbers and symbols, per section of the part. For example, the tube outside diameter is normally shown as Ø 4.00 in. or 4.00” OD.
Notes section: Sometimes there is a set of notes listed near the dimensional drawing, calling out part characteristics or manufacturing steps or part requirements. Examples of this type of note include deburring, polishing, packing, additional treatments, cleaning requirements or cosmetic specifications.
File types and usage
Files can come in 2D and 3D file extensions. For example, a PDF and .dwg is a 2D file, showing two dimensions only. However, a .step file is a 3D file showing a CAD model of the part. This file allows an engineer to move the part around, zoom in to see measurements and detail, or add notes about part dimensions and descriptions. Click here for a video of a 3D model being analyzed.
“Run times are typically determined by looking at the 3D .step file and running a simulation. This “digital twin” allows the engineer full visibility to all dimensional detail of the part within the software.”
There are several types of engineering-based programs that can be used to assess what will be required to produce a part; the most common non-native file formats you’ll see are, .x_t, .stp or .igs. These can be opened in most 3D CAD software programs.
If you have questions about file requirements it is always best to consult with your engineering team or your vendor. For additional information on this topic, please feel free to contact us.
This blog was co-authored by Marshall Arndt, manufacturing engineer, and Chad Conroy, estimator, Sharpe Products.