The most common issue any water jet user will likely encounter is the infamous abrasive clog. It is unfortunate whenever a clog in the abrasive system forms. I would like to share how the abrasive system works, how to resolve a clog in the easiest way, and how to avoid clogs as best as possible.
How Does the System Work?
Essentially, there is a controlled amount of abrasive guided through the Abrasive Drawer output. That metered amount is then pulled into the cutting head through a venturi effect created by high pressure water exiting the head. The diagram below is a great illustration.
- No High Pressure Water = No movement after the output.
- Clog in the Hose = No movement after the output.
- Clog in the output = No movement at all.
How to Resolve Abrasive Clogs?
Essentially, there are three possible clogging locations. I will list them from 1-3, with 1 being the most common and 3 being the least likely.
- Hose Clog - Disconnect the abrasive hose from the cutting head and the catch under the Drawer. Blow compressed air through the hose from the drawer end up. The end inside the tank should flail around wildly when the clog has been pushed through. Compressed air is the best in order to get all moisture and wet sand out.
- Drawer Clog - Empty the Abrasive Drawer of dry abrasive. Find the center drop piece, manually open the pinch valve and lightly blow compressed air through the drop tube. Be careful to manually open the pinch and use light air - the drop tube is rubber and can tear under harsh conditions.
- Nozzle Tip Clog - Unlikely as this is due to too much abrasive or too many small grains of abrasive entering the tip. To resolve this, measure the abrasive flow from the drawer output. Make sure it is within spec. Afterwards, clear the clog in the tip by inserting it upside down in the cutting head and performing a Nozzle Purge.
How to Avoid Clogs?
- Use Barton ALLTEK HPA 80 Mesh.
- Make sure the cut bed is level to the cutting head.
- Utilize plenty of tabs to hold materials to the bed.
- When using thin flexible materials, make sure the middle of the material does not bow upwards at any time. The bubbling water under the material will push upwards.
- When using the black height tool, swivel it side-to-side underneath the cutting head to give yourself spare height between the material and nozzle tip.
- Measure the abrasive flow-rate. Make sure it is within spec (130-150 g/min).
- Make sure the input water gauge stays in the green during the entire cut.
- Verify the high pressure orifice is in good condition.
- Check that the nozzle tip is fully seated into the cutting head.