Why Weld when you can Fold?
Folding metal? It’s not paper you know…
When developing something from metal, perhaps a casing or a display unit for example, there are a number of reasons why, when possible, it is better to fold the metal than welding.
How do you fold metal?
Obviously the answer is… very carefully. In reality, we have a sheet metal bending machine (see the image above) that allows us to bend sheets up to three metres long. It can make multiple bends, in both directions.
We simply move the metal sheets within the bending machine and apply hydraulic pressure when needed.
So let’s go through the reasons why it is better to fold, rather than bend.
1. Welds are less accurate that folds
The process of welding can move the metal by anything up to a couple of millimetres. If accuracy is critical, you are far better off folding.
2. Welds can deform
The process of heating metal changes its properties. The metal expands and increases in volume. Depending on how the metal is cooled afterwards, the metal may not return to the same size. If the welding sequence isn’t right you can end up with deformed metals.
Of course, there are times when you want to change the metal. The annealing process (where metal is heated and then cooled at a slow, controlled, rate) is often used to soften metal. This makes it easier to cut, stamp or form.
3. Welds can distort the part
Distortion can range from cracks (even tiny cracks have the potential to get larger over time) to spatter (droplets of molten metal that end up around the weld instead of part of the weld). The final product is not what is wanted, either because it is weaker than needed (may or may not be visible) or is disfigured.
4. Welds under load are more likely to break
The welding process joins two pieces of metal together by melting the metal. The melting is supposed to seal the join between them, but it is still, effectively, two pieces of metal. The welding process can also make the metal more brittle. Both can be considered a weakness and if loads are applied in the wrong direction, the weld can break.
A fold may move under the same load, but it is highly unlikely it will break because it is still one piece and has the inherent strength that comes with that fact.
5. Welding may need to be certified
Depending on where and how the end product is being used, welds may need to be certified to ensure they have the strength needed. For example, D1.8 Certification is for welds being used in seismic areas. Welds being used by the military will also have to be certified.
6. The natural bend looks better with a fold
As you bend metal, you get a perfect arc on both the inside and outside of the bend. If you want that symmetry from a weld, you have to build the corner back in, either with additional metal or with the flux being used.
So those are our 6 reasons why it is better to bend than fold. Of course, many products we make involved both processes. There are times when you need to weld after a series of bends. You cannot bend a bend, so more complex shapes and products will be bent where possible with welds used where necessary.
If we can help you with a project, give us a call or click here.