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Dialing in your welding settings can often feel like shooting at a target with a blindfold on while riding a merry-go-round. There are a million ways to miss, and you won’t always know how far off the mark you really are.
This is largely because many welders, both beginners and experts, don’t actually know what options will move them closer to their ideal weld settings. This is true even with an incredible machine like the Millermatic 252. In this article, we’ll show you the right way to dial in the correct parameters when using the Millermatic 252.
Understanding Wire Speed
While the Millermatic 252 does have an advanced timers menu, most of the parameter changes you’ll make will be limited to “Wire Speed” and “Voltage.” Those are the only two knobs present on the control panel for the Millermatic 252. It’s therefore critical to know what wire speed and voltage actually change.
Wire speed seems obvious at first: It changes how quickly the wire is propelled from the tip of your gun. However, wire speed also translates to how hot your weld will get. For instance, if you find that your welds are burning holes completely through your material, the problem is more likely that your wire speed is set too high.
But how does that make sense? Why would wire speed = heat?
Recall in your mind the hit 1985 movie, Back to the Future. Remember at the end of the movie when Doc Brown is trying to pull two electrical cords together before lightning strikes the clock tower? At the last second, he uses his own body to complete the circuit, which causes a lot of sparks and heat which blows Doc Brown backward.
That’s basically how most “short circuit” MIG machines work. You’re essentially creating a circuit between your welding machine and the metal you’re welding. When you pull the trigger on your MIG gun, it pushes the wire out to touch your material, completing the circuit and causing an electrical arc — just like when Doc Brown completed the circuit.
The faster you push wire into the material, the faster heat builds up in your welding area. So if your welds aren’t penetrating far enough into your piece, it often means your wire speed is too slow. And again, if you’re penetrating too far, your wire speed is generally too high.
As a quick note, it’s often easiest when dialing in your settings to think of wire speed as heat but many factors also relate to heat such as the size of your wire, etc. If you have followed all the steps in this article but are still having issues with burning through your material, refer to the troubleshooting section of your Millermatic 252 manual.
Understanding Voltage
For the sake of understanding how voltage affects your welds, it’s best to think of it as the “length of your arc.” Above, we mentioned that when your wire touches your material, it completes a circuit. When this happens, your wire heats up and melts. As the wire melts into your weld, an electrical arc is formed between your weld pool and the tip of your wire. The more voltage you have, the longer the weld arc can last before the distance is too great and the circuit is closed.
So if you begin welding and it feels like your wire is just pushing up against your weld piece without melting very much, your voltage is probably too low. In this case, the arc isn’t able to burn back far enough with your current settings.
If, however, you start to get a long arc and notice a lot of spatter shooting out, your voltage is probably too high. In this case, the wire is burned back so much that it’s causing melted metal droplets to shoot all over.
As a final note: If you’re really far away from the ideal weld settings for your material, voltage can affect penetration and wire speed can affect spatter. This is why it’s always important to start with the recommended weld settings (which we will show you how to do in the section below).
How to Set Your Millermatic 252
Now that we understand the science behind voltage and wire speed, we can set our parameters correctly. Luckily, Miller almost always includes a reference guide right on their machines that will give you a solid starting place to begin.
With the Millermatic 252, this reference guide is included right on the front of the machine under the control knobs.
When using the reference guide, first find the type of material you’re using. For this example, we’ll say we’re welding mild steel (step 1 in the image above). Then find the shielding gas you’re using. For this example, we’ll say we’re using 100% CO2 (step 2). Then find the diameter of your wire (step 3). In this case, we’re using 0.030 inch (0.8mm) wire. Finally, all we need to do is reference our material thickness. In this situation, we’ll say we’re welding on ⅛” steel (step 4). When we put those all together, we can see that the Millermatic 252 recommends setting the voltage to 20.1 and the wire speed to 190.
These starting parameters give you a strong beginning point for dialing in your settings. If you try to wing it, you’re really just taking shots in the dark. As mentioned, while heat often relates to wire speed and arc length relates to voltage, both of those settings work together to influence the way your machine reacts to your material.
Once you have your baseline settings from your reference guide, you can continue to refine your parameters. Different situations can affect how you want to alter your settings. For instance, when welding in the vertical or overhead positions, some welders will dial back their settings a little. Many other factors can affect your ideal weld parameters such as temperature or even altitude.
With these steps, you should be able to find the right parameters for any type of material that your Millermatic 252 can handle. If you’re experiencing any issues, the Millermatic 252 has an excellent troubleshooting section at the back of its manual. Of course, it’s critical to purchase your Millermatic 252 from a source you can trust. And with thousands of 5-star reviews, you won’t find a better place on the web than Welding Supplies from IOC.
