Introduction

The air assist is critical for keeping flare-ups at bay, mitigating smoke, helping keep the lens cleaner and cooler (it really shouldn't get that hot if it is in proper order anyway), and, when cutting, catalyzing the ablation of material and evacuating the debris field through the bottom of the substrate and out the downdraft exhaust.

THIS ARTICLE IS MEANT ONLY FOR THOSE USING AN EXTERNAL AIR COMPRESSOR

STOCK AIR PUMPS WILL NOT OUTPUT A PRESSURE THAT WILL REGISTER WELL

Here is more on external air: Thunder Laser External Air Compressor Guidelines

The maximum recommended operating system pressure, according to Thunder China Engineering, is now 55 psi to help prevent premature air solenoid failures.

Other than sound, feel, and maybe little bit of napkin math, there is no real way to apply a metric without a gauge. You can monitor the pressure at any point in the air assist system... the question is, which point?

Well, the placement of the peripherials, as well as the components and methodologies used, can make pressures vary from user to user unless they were modified in exactly the same manner with exactly the same parts. But, at the end of the day as long as you set a constant reading, you will be able to replicate those outputs. The size of the orifice makes a difference too so your readings will likely be different across the different heads and/or nozzles. This article will cover our preferred method for installing the pressure monitor.

Parts Required

SMC ISE30A-01-N-L Pressure Switch

We have been using this pressure monitor for a long while now and it is the best pressure monitor we have seen. There are some on Amazon, etc... but many of them (especially the 'cheap' ones) are for vacuum and won't accurately read positive pressures. 

Overview

The ISE30A series high precision digital pressure switch (for positive pressure) with two color digital display allows you to choose the setpoint according to your application requirements. 4 different display settings are available.

You can find the OEM product page here: https://www.smcpneumatics.com/ISE30A-01-N-L.html

The Operation Manual and the product Series Catalog are attached at the end of this article. 

Specifications

The Series Catalog with full specifications is attached at the end of this article.

1/8" NPT Female to 1/4" (or 6mm) Quick Connect Airline Fitting

Type:1/4" Od x 1/8" NPT Female Push to Connect Fittings; Body Style: Female Straight 1/4 inch Tube Air Fittings Fluid Admitted: Air, Water (No Freezing)

Here is a link to a 5 pack: https://www.amazon.com/Female-Connect-Fittings-CEKER-Pneumatic/dp/B07VLLRWY5/

1/4" (or 6mm) 'Y' or 'Tee' Fitting

You will need to plumb the pressure monitor into the single airline that runs to the nozzle.

'Y' Fitting

Pneumatic PY1/4 Union Y 1/4" x 1/4" x 1/4" Tube OD Air Push to Connect Fitting

Here is a link to a pack of 10: https://www.amazon.com/dp/B07SRLLTVH/

'Tee' Fitting

Pneumatic PUT1/4 Union Tee 1/4" x 1/4" x 1/4" Tube OD Air Push to Connect Fitting

Here is a link to a pack of 10: https://www.amazon.com/MacCan-Pneumatic-Union-Connect-Fittings/dp/B08BKSJ5ZT/

Fitting Considerations

To give you an example of how sensitive pneumatics can be, here is some information that Chris Ankrom published regarding the pressure difference between a T and a Y quick release coupling:

Installing a T vs. a Y makes a pretty big difference. 1st pic shows gauge reading with T installed.  4th pic shows reading with Y installed. Last pic is pressure coming to laser. Noticed around 6 plus psi different with Y verse T.  The Y seems to be more accurate to my input air.  No picture posted for test but also tried rotating the T so that air from the air assist dials was connected to the leg of T and it had no change.
The installed T	Reading with T installed
The Installed Y	Reading with Y installed

Thanks for the great observation Chris!

1/4" (or 6mm) Airline

You will need a small section of 1/4" (6mm) blue airline to facilitate the installation. You can snip a bit off of the tubing you already have connecting the compressor to the machine, or you can get this kit on Amazon that makes a great mod/repair kit.

Here is the link to that kit: https://www.amazon.com/gp/product/B07RJ1BYKV/

Pressure Monitor Installation

Mounting Location

We drilled a hole that was close the the size of the larger threads on the input of the monitor and screwed it into the hole. You can mount it any way you wish, just be EXTREMELY careful with placement (especially on the left hand air control side) to make sure you are free from obstructions, wires, airlines, etc...

You do not have to permanently mount the monitor, you could us vhb to stick it to the machine or maybe cut out a box for it or something. you may want to put it inside so you dont have to drill holes.

WARNING: The mirror 2 assembly comes close to the air assist control area shown in the image below. USE EXTREME CAUTION when fitting, modifying, plumbing, etc... that area because the gantry could make contact with the peripherials. Keep wires and tubing neat and tidy, follow all factory routing, and use existing permanent anchors, strain reliefs, etc... 

Airline Connection

You want to plumb the monitor into airline 4. This is the line that goes to the nozzle:

Power Connection

You can get 24V DC for power at this connector. That is the power for the LED lamps inside the machine:

Operating The Monitor

Changing Unit of Measure

Changing Resolution

Program Window Output

Lock/Unlock

Output Alarm Connection (optional)

the alarm output can be run to the water protection/safety interlock system to prevent the laser from firing. its typically best to have the trigger going to the dsp/controller if so equipped. thunder is and you can connect it to the chiller alarm input to gain this function. The legacy MARS series thunders had this exact sensor available at the time of manufdacture.