When learning how to read a manufacturing drawing, it can seem quite daunting because there is so much information to take in. This blog post will break down a drawing and make it easier to understand. But, first thing is first! What is the purpose of a manufacturing drawing if there are 3D models? Manufacturing drawings show numerous features of a part that a 3D model doesn’t. For instance, drawings show the material type, the finish, dimensions, hardware, company information, and other specific requirements. The sole purpose of a drawing is to show all the details of a part. Imagine if you were looking at a single part in your hand, a drawing would essentially describe and illustrate all the details of how to place the part in your hand.
Manufacturing drawings can be referred to as manufacturing prints, dimensional prints, prints, drawings, manufacturing blueprints, blueprints, mechanical drawings, and more. Drawings are designed by engineers, so there is a lot of engineering lingo and symbols that are used to identify and describe certain aspects of a part. This is the “daunting” part of a drawing because unless you have experience with reading drawings or you’re an engineer, learning what everything means on a print can be a challenge. So let’s break down a print and make this easier! This blog post will specify the format, location, and type of information that should be included in drawings like blocks, notes, specifications, and symbols you may find on a drawing.
Engineers include a lot of critical information in the blocks in order to give the reader information about who the print belongs to, part number and description, and information about the material and finish. The information blocks are located in the bottom right-hand corner of the drawing. Occasionally, some blocks are left blank if the information in that block is not needed or hasn’t been decided. From a manufacturing point of view, the more information the better and all blocks should be filled in so there are no assumptions. The information blocks include the following:
The following information is located within the title block in the lower right hand corner of a blueprint as shown above:
- Name: company or agency who prepared or owns the drawing
- Address: location of the company or agency
- Name and date: responsible engineers who drew, checked, and approved the drawing
- Part name/description: describes what the part is
- Part/drawing number: assigned number to identify the part
- Revision: identifies the correct version of the drawing
- Scale (optional): ratio of actual size of the part compared to the size of the part on the drawing. It can be shown as 1:1 or 1=1. The first number represents the actual size of the part and the second number represents the print. In other words, 1:2 means the the print is double the actual size. Whereas 3:1 indicates the actual size is three times what is shown on the print. Note: even if the sale says 1:1, never measure the drawing, use the dimensions.
- Size: specifies the drawing sheet size; A = 8.5 x 11, B = 11 x 17, C = 17 x 22, D = 22 x 34, E = 34 x 44, F = 28 x 40 (inches)
In addition to the revision shown in the Title Block, there is a revision block that is located in the upper right hand corner. The Revision Block indicates the specifics in regards to the changes that were made to roll the revision. The Revision Block includes the revision, the description of what changes were made, the date of the revision, and approval of the revision.
Bill of Materials (BOM) Block
For parts that require assembly, require hardware to be added to the part, or there is a kit of parts, there is a Bill of Materials Block that contains a list of all the items that are needed for the assembly or project. Bill of Materials can also be referred to as a Parts List, Schedule, or for short BOM (pronounced either “be-oh-em” or “bomb”). The BOM includes the part number, the description/name of the part or item, the material specification (if any), and the quantity to be required of that item.
The BOM can be located in different areas on the print. The two most common are located right above the Title Block or in the upper left hand corner.
ZONE LETTERS AND NUMBERS
Prints contain a border around the entire print which include letters and numbers as shown in the above print between the red lines. These letters and numbers are used like a map in order to help locate and pinpoint certain areas of a print. The letters are in alphabetical order from the bottom up. The numbers are in numerical order from right to left. Therefore, you are to read the zones from right to left.
NOTES AND SPECIFICATIONS
Since the blueprint shows the part graphically and with dimensions, many times there are more specifics to the part that cannot be seen graphically which are described in the Notes and Specifications which are generally located in the upper left hand corner or lower left hand corner. Notes are additional information about the part. Whereas, Specifications are a reference to an actual document or statement that describes how the parts are to be manufactured, assembled, and maintained.
Now that all the different components of a print have been identified and described, the next step is learning how to read a manufacturing print. This blog post will help you to understand the lines of a part of a print in order to visualize the part correctly.
Thanks for reading along. Vista Industrial Products, Inc. has specialized in fabricating sheet metal for over 57 years. We provide CNC machining, sheet metal fabrication, and welding fabrication for the medical, defense, kiosk, commercial, and high technology industries who require high quality products. If you’re company requires these types of services and you are looking for a precision sheet metal company, please contact us today for a quote. We will require manufacturing drawings like those described above and quantities. We look forward to hearing from you!
For more information about manufacturing prints, check out these articles: