What To Do When....

0) The garnet tube keeps clogging, or keeps popping off 

If you are using the WJ and the garnet tube keeps clogging, or worse it pops off/water get into the hopper, this kind of behavior *can* be caused by the nozzle being too close to the material. Adjusting it a bit up usually fixes the problem. 

However: 

If it keeps happening and the distance is set correctly, there is the possibility of the machine having a leak in its On/Off Valve. That valve is right above the nozzle and is actuated by the black pneumatic cylinder sitting on top. If this valve has a problem, you can see it drip (video). The dripping can be visible with only the charge pump running, or in less obvious cases (when the leak is not as advanced yet) when the main (high pressure) pump is running, with the dump valve open (=equal to "no cutting, but traversing" during operation). To find out, click on "test", set to "pump only, jet off" and watch if it starts dripping.

This video shows how that looks.

If there's any dripping, stop cutting, the valve needs to be rebuilt.

 Also, make sure to notify me by email: bzender@phas.ubc.ca

1) Use the Waterjet as a tap extractor (P. Eugster)

Tap snapped off while tapping a through-hole?  No problem!  You can use the waterjet to cut the inside of the tap away, leaving untouched threads suitable for further tapping (hopefully this time with less force).  Securely clamp the workpiece in the waterjet, and use the camera to position the WJ nozzle over one of the flutes of the tap.  Piercing in the gap here prevents any blowout that could damage the threads.  Draw a circle in OMAX layout that is a somewhat smaller diameter than the hole, but large enough to cut through all of the arms of the tap.  It may take some trial and error to get it right - you can check by using the camera to see where it's going to move.  Cut on a very low machinability setting - probably "Tool Steel," around 5 or so.  The cut I did took about 2 minutes for a 4-40 tap.  Afterwards the tap was gone and the partially tapped threads had no visible damage.  Obviously this doesn't work if you break off a tap in a blind hole.  Also I hope it's pretty clear that this procedure destroys what's left of the tap so don't expect to "salvage" the tap as well as your workpiece.  Don't try this on an expensive/irreplaceable workpiece as I've only tried it once.

2) Reset the machine after forgetting to turn on the charge pump

If you have hit 'start' but forgot to turn on the charge pump, the machine will start moving the nozzle unit around, but no cutting will be done. Since clicking 'start' also enables the garnet solenoid to be activated, the machine will have a clogged garnet tube that needs to be dealt with. Here's how:

- Stop the run

- Go back to 'home' position

- Take the garnet tube off, both from the nozzle and under the hopper. The tube can simply be pulled out from the slightly undersized holes it is sitting in.

- Clean the tube: Remove all garnet inside by suspending the tube vertically and flick it repeatedly to make the sand come out. If that does not help, use compressed air, but be very careful, use goggles, do not get garnet into your eyes.

- Put the tube back on

- Reset the inverter. The button is on the left side of the machine, near the main switch, and labeled 'reset'.

- Try again! This time, don't forget to turn on the charge pump :))

3) Get it back to work after having a splash-back incident

Sometimes water shoots back through the sand feeder tube and all the way into the hopper. If that happens, the sand flow stops and cutting becomes impossible.

Here's what to do:

• Take off the feeder tube and clean it from all that clogs it, sand and mud.  Be very careful when using the compressed air blow gun! Use goggles to avoid getting sand in your eyes!
• Take the solenoid off the hopper and clean it as well. For that, in Omax Make, click on 'test', and then 'abrasive' to open it, and clean it carefully with the blow gun. Be very careful!
• While doing that, let some of the abrasive run out from the hopper straight down into the tank. Don't catch, don't re-use, it might be wet and cause more problems.
• If you think that all the wet sand is gone from the hopper, and the sand is coming out freely and without clumps,  plug the solenoid back into the hopper.
• Don't put the feeder tube back in quite yet, but try (with the test function) the solenoid one more time when installed to the hopper. When turning it on, the sand should come out freely.
• If that works, stop the 'test' function, put the tube back in place - you're back in business!
• Before running the machine, do set the nozzle distance (z axis) again by checking with the gauge. This has to be done, because the most likely cause for this was the nozzle being to close to the material. 
• If you are cutting warped material, move to nozzle to the highest point of your entire cutting area, to set the z axis. When in doubt, set the distance rather large as opposed to being too close.
• This incident mostly happens when the machine tries to pierce. When cutting continuously, being too close or even touching the material will often not result in a splash back.
• In any case, don't forget: Be on the generous side when setting the nozzle distance. Never forget to check that you are indeed at the 0/0/0 starting position, before you click on the "run" button to cut.  Always be ready to hit the pause button if the machine runs in ways other than you expected.  If you don't stop it when it goes wild, its nozzle can get stuck, rip your workpiece, and even break or do damage to the x/y ball screws.

4) Resetting the machine after triggering a limit switch

• driving the nozzle to the limit of the it's travel will trigger a limit switch which turns on "Babysit mode" in the Omax software
• I managed to turn off babysit mode by twisting the two-position momentary reset/override switch to the reset position (the two parallel lines icon)
• the Omax manual says to turn off babysit mode by twisting this switch to the override position but I found this didn't work
• Be careful! Resetting may erase the XY or Z zeroing .   Make sure you are properly indexed before resuming cutting!

5) Resetting the machine after hitting the Emergency stop button

• The emergency stop button needs to be pulled back out again before you can repower the machine
• Be careful! An emergency stop DOES erase the XY or Z zeroing .   Make sure you are properly indexed before resuming cutting!

6) Piercing (thick) Acrylic without causing damage around the location of the pierce

• put a layer of aluminum sheet metal (1/16" thick) on top of the acrylic (yes, indeed: on top of the material)
• clamp down the aluminum with the acrylic, add extra weights on top as needed
• add 1/8" to the nominal material thickness in the settings to make up for the extra material and thickness that is to be cut

This should enable the user to cut holes and slots, especially in thick acrylic, with no shatters or edge cracks at all. Steel might be usable to perform the same trick, too.

When cutting, you might want to consider using an extra layer of metal (or plywood) below your work piece to prevent damage from back splash, as usual. If so, again increase the

thickness in the machine settings to make sure cutting happens at a slow enough speed. 

If you are having problems still - try using the Pierce setting "Very Brittle Material" but avoid using "Use Low Pressure". Make sure you have long lead in & outs, and avoid using tabs if possible.