Waterjet Group

waterjetphilippines · Member

Dwell times for jet and abrasive

Waterjet Tech 1 · Member

No there is really no reason to dwell for a few seconds between water and abrasive. We typically run a zero dwell for water on and a .5 second for abrasive on. The dwell made need to be increased if you are cutting at 100%. On the off side we run a .5 second for abrasive off and .75 - 1 second for water off.

cmngnscrwd · Member

We use approx. 2 seconds water on before abrasive starts, and 4 seconds after abrasive shuts off.

waterjetphilippines · Member

thanks for the feedback...

Waterjet Tech 1, do you find components life to decrease with zero dwell for jet/abrasive on and .5 abrasive off / .75-1 water off?

I plan to do this because i find the dwell time a waste... i'm currently running 2sec jet on / 1.5sec abrasive on and 1.5sec abrasive off / 2sec jet off.

boise_shull · Newbie

cmn, what are you cutting to use such long dwells? i have basically all the same settings as the tech. and the only reason to really have a longer dwell on anything is to clear the abrasive from the feed line to avoid clogs. besides that you can make things alot faster. especially if your cutting looser tolerances. holes have posed the biggest obstacle to making the dwells TOO short for me. ha ha. just my 2 cents

cmngnscrwd · Member

*sigh*
You'd have to work here to see why. Everything's approximate, except for the dimensions of the finished pieces. Since we're cutting stainless plate, the dwell times don't figure heavily into the actual cut time. Average cut time for a piece is about 10 min. Last nights pieces were a 2,000 minute piece on one machine, several 30 min pieces on another machine, and lots of 8 min. pieces on the third machine. All things considered, we allow lots of room for dwell, to avoid any problems that might crop up. That way, we have time to deal with the rest of the problems that DO crop up. :)

Waterjet Tech 1 · Member

waterjetphilippines,

No we do not find component life to decrease with these settings. The off dwell may seem short for some, but I can not recall a clog since going to these settings about 4 years ago. It may leave a small bit of abrasive in the hose but it is minimal. What I like the best is the pierce is alot cleaner since the jet starts to move right allowing for less spray during the pierce. There will be the occasions were dwells need to increased due orifice size and/or abrasive size.

scott hines · Newbie

I cut a lot of rubber belting. And find that having a zero dwell for water on creates a very quick and efficient pierce. Before when we tried with a longer dwell we where getting a pocket or bubble of water in between the layers of belting and rubber. On the 3/4" belting the bubbles could get large enough to damage the mixing tube.