pneumatic system. The good news is most controls sold today can easily interface with one. This baseline weld schedule will be used for the changed system. Let’s start with the new consumable by selecting a full-dome weld face. The radius of the weld face is the same as the radius of the body of the consumable; for example, for a 16-mmdiameter cap, it would be an 8-mm radius weld face. Figure 1 shows an example of a female 16-mm cap. The alloy of the new consumable, of course, should be from CDA1815, CuCrZr — Fig. 1. This scheme is meant for a finished weld nugget requirement of 10 mm or less, which covers a high percentage of the applications in the market. If you have a weld nugget requirement that is in excess of 10 mm, the rules are not as effective and the geometry of the consumable will need to change from a full dome. Now let’s start with the aluminum product as the first run on the equipment. Exchange the full-dome consumables for the ones you have been using and confirm the fitup with the tooling. We will change three common variables of your baseline weld parameters to generate a pulse schedule that precedes your baseline weld schedule as follows: 1. Take 10% of the weld time of your baseline weld schedule for the pulse time. This needs to be a minimum of 28 milliseconds for a 60-Hz primary, or two cycles for an AC/SCR weld control if your calculation produces a lower value. 2. Take 20% of the current and add that to your baseline current. In other words, multiply by 1.20%, and use this as the amperage for the pulse. 3. Take 30% of the weld force and subtract this from your boggy weld force. In other words, multiply your boggy weld force by 0.7 for the pulse force. With aluminum welding, you are constantly fighting oxygen combining with the aluminum, producing aluminum-oxide and adhering to the consumables’ surface, which interfaces with the product. We are going to limit the amount of buildup on the initial contact area of the full-dome consumable. MARCH 2016 / WELDING JOURNAL 21 Fig. 1 — A female 16mm cap. For info, go to www.aws.org/adindex
Welding Journal | March 2016
To see the actual publication please follow the link above