Why Weld Symbols Are Vital to Consistent Metal Fabrication Quality

August 8, 2016 | Mechanical Engineering, Welding

Weld symbols are an important part of engineering schematics.Careful preparation is key to ensuring high quality in any manufacturing endeavor. When preparation is lacking, it can have a significant negative impact on the final product.

This is why, when creating a custom metal form design, it’s important to make sure that weld symbols in the design document are clearly marked. Improperly-marked weld symbols can lead to bad welds or welds being made in the wrong spots.

Weld symbols are how the designer of a custom metal form communicates how objects should be welded to welders working the manufacturing line. Without clearly-marked weld symbols, the welder won’t know where to place a weld, what type of weld should be made, and the weld size.

Even in modern factories where automated welding machines are used to join metal instead of manual labor, weld symbols help the welding machine operator program the welding machine.

Anatomy of a Weld Symbol

Weld symbols can convey very complex welding instruction in a deceptively simple-looking format. In most weld symbols, there are a few basic components present:

  • An arrow to indicate where the weld is required.
  • The reference line, which is always horizontal. This line typically has a symbol attached to it to indicate the type of weld to be made.
  • A leader line that connects the arrow to the reference line.
  • The tail, which is an optional component used to relay special instructions.

Each and every weld symbol is a compact set of instructions written in a code that experienced welders can quickly interpret to determine how they should handle every weld in a custom metal form.

Interpreting Weld Symbols

In most weld symbols, the reference line will contain the majority of the information needed about the weld, including the type of weld to be made, length of weld, weld size, and required beveling of the weld area can all be communicated on one small line.

The reference line typically has a number on the left, a symbol in the center, and another number to the right. The first number on the left is the weld size, the symbol indicates the type of weld, and the final number denotes length of the weld. If there is no number indicating length, then the weld should follow the entire length of the joint.

For example, a reference line with a set of symbols reading 1/4 Right_Angle_Triangle_Flipped.png 4 below the line would indicate a quarter-inch-sized fillet-style weld that is four inches long to be placed on the same side of the joint that the arrow is on. If placed above the reference line, then the weld symbol would be indicating that the weld should be placed on the opposite side of the joint from where the arrow is pointing.

Sometimes, there will be markings on both the top and bottom of the reference line, indicating that there should be welds on both sides of the joint. If these symbols are staggered rather than aligned, then the welds on either side of the joint should be staggered rather than mirrored.

Why Weld Symbols Matter

The biggest reason why weld symbols matter for making custom metal forms is that they help to ensure consistent quality and production tolerances for custom metal forms. With clearly-marked weld symbols, welders know exactly where to place their welds, how large to make them, and what kind of weld to apply for the best overall quality.

Even welding machine operators who program welding sequences into an automated machine benefit from having weld symbols clearly marked on the design diagram. Using these symbols allows the operator programming the machine to ensure that every weld joint is executed to the exact standards outlined in the design document.

Getting details such as weld symbols in a design document right is what separates passable-quality custom metal forms from top-quality ones. When these details are ignored in the design document, welders won’t know exactly which spots need to be welded for best results, and the overall strength and quality of the metal form suffers.

Learn more about how Marlin Steel creates the perfect custom metal forms for different industries by checking out some of our other resources today!

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