Subject: Welding/Fabrication
1. Topic-
GMAW Welding Gun parts and changing liner for wire size
2. Content-
(1) Explain all safety precautions to be considered before any work on machine parts is to begin. Welding machine must be removed from its source of power.
(2) Demonstrate and lecture of parts that the MIG gun consists of and how to dissemble and replace all internal pieces. Show students what parts are considered to be consumables, such as contact tip, nozzle, and inner liner. Show students the identifying markings on contact tip and inner liner that determine what size wire they are designed to be used with.
(3) Install a new inner liner and show students how to size and cut new liner to the correct length if needed.
(4) Explain the reason why inner liners and consumables need to be changed and what are some of the signs or indicators to look for to determine when to change them.
3. Goals: Aims/Outcomes-
1. Convey the importance of safety, never work on a machine that is possibly still powered.
2.Students understand the parts and operation of the MIG gun, and understand the importance of the consumable parts.
3.Students understand the need for properly sized wire and consumables.
4. Objectives-
1.Given the task of replacing parts in the MIG gun the students will be able to identify the parts, remove and replace them correctly.
2.Students will be able to determine when consumables need to be replaced and what parts specifically are causing the problem.
5. Materials and Aids-
MIG gun and welder
New consumables, contact tips .023 and .035, inner liner for .023 and .035, and welding wire .023 and .035 mild steel


Allow students to change parts in the MIG gun and change the inner liner.

Checking for understanding-

Group question and answer time , clear up any issues or problems


Revisit the importance of safety.

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