If you are welding or learning welding for a long, you might come to hear about polarity. And you may hear the name reverse polarity and straight polarity. These two terminologies are important to know in welding industry. Without the knowledge, you may not be able to weld perfectly and aesthetically.
In short DCEN is Straight polarity and DCEP is reverse polarity. Describing other way, DCEN is a setting where electrode is connected to negative and work piece clamp is connected to positive receptacle. But it is not the case in every welding technique.
With the welding process, the polarity may vary. We will discuss them here in deep. So let’s start-
Polarity
When you switch on the welder machine, an electric circuit with a positive and a negative pole is formed. These poles are polarity. It is very important to know about the polarity because quality weld depends on through understanding of polarity in different welding process.
There are two types of poles created in welding machine we know. These two poles are designated as (+) and (-) sign on the welder. Sometimes you may see simply ‘work’ and ‘torch’ as designation instead of (+) & (-) to reduce the possibility of confusion. In these two designation you need to connect either a torch or a work clamp to get the power to weld the metal. Variation of connecting the torch or electrode & clamp is termed in two different names DCEN (Straight polarity) and DCEP (reverse polarity).
What is DCEN?
DCEN is an abbreviated form of Direct Current Electrode negative. From the name you can easily understand that, in DCEN polarity torch or electrode is connected to negative receptacle on the welder. And in negative receptacle, work clamp is connected. The other part of the clamp cable is placed on work piece. It is also called reverse polarity.
Welders that produce AC power supply, may have torch and work designation on it. You need to be careful while connecting the electrode and clamp in the welder because wrong connection may lead to overheating of either clamp or electrode resulting in welding defects that may produce fragile weld.
What IS DCEP
DCEP means direct current electrode positive. From the name we can say that in DCEP electrode is connected to positive and clamp is connected to negative pole. With AC or DC current flow, you should follow the DCEP for some welding process. Otherwise it would produce a faulty weld.
Similarities Between DCEN & DCEP
- Both polarities generate heat in different spectrum in the form of Arc (electric arc)
- Both polarities can be used in combination in case of AC current supply. This is normally done to weld in Tig welding process. The variation of current supply provides strong weld in Tig.
- Both polarities have one common goal and that is to join two metals together. The results may be different in each case.
Differences Between DCEP & DCEN
| no. | DCEP (DCRP) | DCEN (DCSP) |
|---|---|---|
| 1. | Stands for Direct Current Electrode Positive | Stands for Direct Current Electrode Negative |
| 2. | Electrode is connected to positive and clamp at negative pole | Electrode is connected to negative and clamp at positive pole. |
| 3. | Suitable for welding thin plates | Not suitable for welding thin plates |
| 4. | Can clean oxide | Can’t clean oxide |
| 5. | Good for low melting point metal like aluminum and copper | Good for high melting pint metal like stainless steel and titanium |
| 6. | Low chance of distortion | High chance of distortion |
| 7. | Lower chance of inclusion for oxide cleaning action | There are chances of defects like inclusion if there are rust on surface |
| 8. | Have a chance of incomplete fusion | No chance of fusion defect |
| 9. | Filler metal deposition rate is high | Filler metal deposition rate is low |
| 10. | Most of the heat (2/3) generates in electrode tip | Most of the heat is generated near the base plate |
AC (Alternating Current)
Ac is not polarity. But you will need to know about AC in welding. With combination of DCEN and DCEP you can create variable current flow instead of direct one way dc current. This combination specially facilitates the Tig welding. With the back and forth in Tig, you will get better weld on aluminum. Because this frequent changing would drive away the oxide layer from aluminum surface and lead the welder to penetrate deep in the metal. Which in turn produce a strong and sustainable weld.
Applications of DCEN & DCEP
DCEN
Basically, you need to follow DCEN connection in Tig welding and Plasma cutting. While doing Tig welding, you should connect the torch to negative and clamp to positive in either DC or AC current flow. A reverse to that may lead to overheating of torch, instable arc and will ruin the project.
In case of Plasma cutting, you need to connect the cut torch to negative. If you connect that in reverse way, the torch may get damaged and electrode would be destroyed. In stick welding you can use DCEN polarity to weld with an aggressive electrode E6011. But in most of the case, stick welding is better with DCEP connection.
DCEP
You should connect the torch and clamp following DCEP (reverse polarity) in Mig welding and stick welding. For mig connect the torch or spool gun to the positive (+) receptacle and connect the work clamp to the negative.
If you accidentally do mig welding with DCEN, you may get worse weld with unstable arc. You must follow the same in case of stick welding. Because, in stick welding DCEP will direct the electron to positive electrode which in turn will help to deposit the metal in regular pace making the weld strong and efficient. You will have deep penetration also.
In stick welding with DCEP you may use Cr-Mo electrodes like
- E7015-B2L (CMB-95)
- E8015-B3L (CMB-105)
For DCEN you may use high cellulose electrodes like
- E6010 (KOBE-6010)
- E7010-P1 (KOBE-7010S)
- E8010-P1 (KOBE-8010S)
Safety Measures
You must follow the safety guide while you are welding. You must wear protective gears in both DCEN or DCEP welding connection. The following are some safety tips you should consider-
- Wear Safety Equipment’s: Wear helmet, thick clothes and gloves to protect yourself. Helmet will save your eyes from harmful rays and gloves would save you from getting electrocuted.
- Don’t work in dirty and wet area: Choose dry and clean place for welding. It would save you from getting electrocuted and also would ease your breath.
- Check the connection: Before starting the welding, check the connection of torch, clamp and welder power supply. Make sure there is no loose connection.
- Check the receptacle: Make sure electrode is attached to negative and clamp or workpiece to positive pole.
Lastly
Both professionals and newbies must understand the polarity and its use. For quality weld you must understand how to connect the torch and workpiece to welder. Hopefully you are clear about the DCEN & DCEP polarity from this post.
