Air assist

Yes, you can use air assist with your Mini Gerbil. Read on for background and how-to.

What is air assist?

Air assist is the use of artificial airflow to reduce the built up or smoke and residue on your optical lens and workpiece. This article has a more detailed description.

There are multiple ways to implement air assist:

  • Small fans and air-pumps – small fans or air pumps that run on low voltages are quiet enough to run continuously without being a disturbance. Awesome.Tech’s recommendation is that such devices be turned on manually from a separate supply, or run directly from the 5V or 24V output of the laser power if they don’t use much power. This is a lot simpler than operating via a controller!
Low voltage options: small air pump and small fan
  • Large fans, compressor or air pump – larger fans, compressors or air pumps are too noisy to leave on, or require lower duty cycles than smaller units. If the user doesn’t want to have these items on all the time, it is possible to switch them via the laser controller if a suitable relay system is used. This allows them to be turned on/off via g-code. Note it is binary – speed control is not supported.

History and availability of the Air Assist output

Due to a change in microcontroller design, Mini Gerbils versions v1.1 to v2 when using their original factory-supplied firmware didn’t support an Air Assist function.

The original design of the Mini Gerbil included a Fault output function, which sent a HIGH output signal in the event of the microcontroller or firmware error. However Awesome.Tech understands no users utilised this feature and it is redundant.

So to cater for interest in Air Assist, in Mini Gerbil firmware 12353 Awesome.Tech have changed the re-assigned the Fault output function to act as Air Assist. This explains why the relevant connection on the Mini Gerbil is labelled ‘Fault’.

How to setup air assist functionality

Connect your large fan, compressor or air pump to a solid state relay as shown in the circuit below. Before connecting to your Mini Gerbil, test the solid state relay by applying a 3.3V signal to the input terminals.

How to connect air assist to the Mini Gerbil

Choose a solid state relay capable of switching your air device with a 3.3V input from the Mini Gerbil, with absolute maximum 25mA control current. If the solid state relay draws more than 25mA the Mini Gerbil will be damaged, so please leave a safety margin by sourcing a suitable SSR requiring up to 20mA maximum control current.

Note that some solid state relay models are inverting (low input causes output to operate), which is generally unsuitable. To choose a solid state relay that is safe and suitable for your application, you’ll need some electrical engineering knowledge. As mains power is involved, do not choose a solid state relay or perform the wiring unless you are suitably qualified.

Older style coil-relays are unsuitable because they (pretty much always) require much more than 3.3V to toggle the output.

How to use air assist functionality

To turn on the air assist:

  • send a M8 command via the console, or
  • send g-code that includes a M8, or
  • toggle the Air button on in the Lightburn cuts/layers interface

To turn off the air assist:

  • send a M9 command via the console, or
  • send a M9 command via g-code, or
  • toggle the Air button off in the Lightburn cuts/layers interface

It is possible to configure Lightburn so that it automatically turns on air assist at the start of a g-code program and turns it off at the end of the g-code program.

2 thoughts on “Air assist”

Leave a Reply