Tubing

How to decide which pneumatic tubing to consider?

When it comes to tubing, there are also some things to consider. Actually, they are almost the same questions as we had for the fittings:

• Which material?

• Which size?

• What pressure?

• What temperature?

• What fluid?

• and What environment?

Materials comes down to different plastics, but also in some cases we could need metal tubing.

How to specify the size of pneumatic tubing?

When we talk about the size, we need to know the inner diameter because this will depend on the flow of the fluid. And the outer diameter since this will depend on the size of the fitting. Actually, some fittings are depending on both inner and outer diameter, but we will cover the different types of fittings in a while.

Depending on the pressure we might have some materials or sizes that can not be used. The higher the pressure, the bigger the wall thickness needs to be, if using plastic. If that’s not enough, metal tubing could be used.

Same thing with the temperature, even if some plastics could cover a large temperature range, metal tubing might be better in extreme cold or warm places. Some applications may use some kind of gas, and we need to choose the right plastic for that gas (or metal tube once again). Even the environment can affect the choice of tubing, if the application is outside for example, the tube will be exposed to UV light and needs to withstand this.

How to choose pneumatic tube material?

The most common used plastic in pneumatic tubing, is polyamide, PA. But other types of plastic are also used, mainly polyurethan which is considered more flexible when dealing with small bending radiuses. The most cost effective tube is PE, and the one that can handle the highest pressure is PV. When used in an environment with a lot of chemicals, you should consider the PTFE tube. Have a look at the tube guide, these headlines are often the ones the customer needs to consider when choosing the tube material.

Why cutting pneumatic tube correctly is important?

One last thing to mention when we are talking about the tube is the importance of having a square cut at the end before putting it into a fitting. Watch the video below for examples. If the cut is not square then you could get either a leakage problem in the fitting, or the tube will simply come loose once it is pressurized. And that could be damaging for both machine and operators.

The best tool to use is a tube cutter, with a razor that cuts the tube without squeezing it like a nipper could.