Need help do build a functional cutter !

It`s late summer now, and I still have not used my 2 laminar nozzles
And that is only because I dont have any cutter that works !!

My first cutter was 2 solenoid electric magnets pushing and pulling a metal shield on the water output.
The metal shield was mounted with a screw and a hole..

Problem is that the water pressure is so hard on the metal, that the solenoid dont manage to push and pull it back!!
And I cant place the nozzle under the ground when I know after 1-2 hours the cutter dont work anymore

So I need help and advice (pictures) how I can build a cutter that will work everyday!!
I have 2pair of solenoids to use on the cutter.
Problem is what blade should I use, and how should it be mounted ??


plz some advice

Yes please, I am struggling with the cutter too, for a while now. The cut is clean buy I can't manage to get the water away from the stream so the Un-cut is also clean. I'm using a linear actuator by the way.

yes to remove the "cutting" water splash away from the output hole is not that easy !
Anyway, I can live with a "bad" cut if it will work 100% every day.

Liteglow,

I spent a lot of time refining the cutters for the nozzles for my pool, for all of the nozzles I've built, they are the only ones that use cutters. I'm on vacation so without pictures this may get confusing but I will do my best to explain. I love keeping things simple, this may sound complex but truly it's not.
- First I fabricated a tower that sits 1 1/8" above the nozzles output, this tower is hyperbolic in-shape " very similar to the cooling tower of a reactor". I built them by shaping a + mold of pine dowel using a oscillating drum sander, drill press and router table, then created a epoxy - mold of the pine dowel in 2pcs a left and right, doing this made it easy for me to fine tune the shape by adding or subtracting material. Then using braided glass and epoxy I make the finished tower out of the - mold. This only took about 5 hrs. After experimentation I found the size and shape that worked best. The towers are about 3 5/8" tall with the smallest I.D. of 11/16" the output of my nozzle is 1/2". This may be hard to explain.,On the top of the tower I mounted a brass tube I made into a ring. Think of a circle now in dead center of this circle draw a line from there straight out at 6 and 3 O'clock on the inside of the ring. With very small holes drilled at the 2 O'clock. That 1/4% cutout between 6 and 3 O'clock was hanging over the inside edge of the top of the tower. On either side of this ring I braised in two little nipples that I attached silicone tubing that run to a fish tank bubblier " little air-compressor " making a curtain of low pressure of air around the top of the tower. This took a couple days. I wanted to make then out of spun stainless but I found that the fiberglass towers with a polished gel-coat finish, was better as the surface was so smooth the water slid right off.
- Next and I hope I'm explaining this well, an your following me. When I started I tried blades of many shapes and sizes which some worked but all had that splash forced back on top of the nozzle. So I tried diverting the water while I cut it! to do this I took a 1" copper pipe and split it down the middle. With a weeks worth of experimentation, what I ended up with was a that 1" copper pipe cut in half looking like a cesta used in the game Jai alai that looks very much like a beak on a bird of pray. There are 3 of these beak shaped curve hooked to a gearbox that rotates in the stream. When the beak cuts the water it also diverts it into a downward stream that isn't that broken up, so any water that is bounced back at the nozzle opening the hyperbolic tower clears away from the stream.

I hope you can make a little since of this to decide if its something you would like to try. I'll be back from vacation in a couple of weeks, when I get back I will be constructing two more nozzles for the fountain I just fabricated at my business. I will post pictures and video of the build and will post some video of a stream running with a knocker I've built to show another member of the forum.

P4H

Thanks again P4H, Always so helpful. Can't wait to see the pictures and videos!

any videos in the cutting section of this forum ?

I really need a working cutter on my Jet now
Would love to have a step-motor cutter, but I dont know how to build one.

Any one here that would like to build and sell a driver for a step-motor?


If not, anyone have pics of cutter that works ?

You could build a driver easily !
*They* make single chips to drive it like the ULN2003 which allows 500mA per channel or higher ones (ULN2065 for 1.5A and on). There are tons of others but it's really that simple. You just attach an external power source to the stepper and the ULN (find the correct sequence) and get going with whatever programmable controller you have.
The rest is just the mechanical part which, judging from your pictures, you could easily do...

I built 4 laminar jets for our Science Museum. I did a lot of experimenting with electro solenoids. I had a few 60 inch oz. electro magnet seloniods with 1" of travel. The problem I found is that the 60 in oz. of force is the last 1/4" of travel. When the piston is extended there is not much power at all which makes the seloniod unreliable, one day it would work the next day it wouldn't. I did find a larger electro selonoid that would work but it took 1 amp which I think is dangerious especially in a public display. I switched to pneumatic ,cylinders much safer. It is 1/2" in diameter and delivers 6lbs. of force at 20 psi the entire length of travel which is 1".

Glenn

My pneumatic cutters have been running since October 1st. 10 hours a day 7 days a week with no problems.

Any chance of a picture?

I'll try to do a few photo's when I get a chance

Jagi wrote:You could build a driver easily !
*They* make single chips to drive it like the ULN2003 which allows 500mA per channel or higher ones (ULN2065 for 1.5A and on). There are tons of others but it's really that simple. You just attach an external power source to the stepper and the ULN (find the correct sequence) and get going with whatever programmable controller you have.
The rest is just the mechanical part which, judging from your pictures, you could easily do...

Thank you for the info..
This is really interesting !!
But I have absolutely NO idea how to get started

Can anyone help out with a (eBay) link of a stepper motor I should buy ?
And where to get started in the progress of a driver?

What I got today is relay to turn ON or OFF the signal..


thank u

Well I'd start with finding a stepper instead or purchasing one. You could calculate the pressure exerted by the jet on the cutter's knife and then acquire the torque required from the motor, but I don't think it's very easy considering the geometry. I'd start with salvaging a stepper off an old printer/CD-DVD-hard drive/scanner and so on. The strongest ones will probably come from a printer and have a resolution of around 1 degree per step (far more then we need).
Once you have a stepper you need to identify it (Bipolar, Unipolar) and find the correct sequence to activate it. Again... Google... ("identifying a stepper" or such).

Parts for a driver:
Controller: Unless you want to delve into electronics - use a programmable controller with at least 4 channels (Arduino or such).
Power source: depending on your salvaged stepper, usually 12-24VDC. I used a converted PC power supply (Google "How to Convert a Computer ATX Power Supply to a Lab Power Supply").
Driver: Almost all steppers salvaged this way will run using the basic ULN2003. It should cost a few dozen cents (depending on qty.). ULN's are simple Darlington arrays which issue high voltage from you power supply when receiving a low voltage signal in the appropriate channel from your controller.

If you end up needing a larger stepper - all you have to change is the stepper (which you would probably have to buy then) and the ULN (very low cost).

Helpful I hope... ?

thank you

i will look into it.

step motor driver ?

http://www.goodluckbuy.com/arduino-dual-stepper-motor-driver-shield.html


motor ?

http://www.goodluckbuy.com/arduino-5v-4-phase-5-wire-stepper-motor-2-pack.html


How do you manage to get the motor to turn only 20-30 degrees ? and not all way around.

The motors are a good start - they seem to be roughly equal to any stepper salvaged from anywhere else.
The driver is a bit of an overkill in my opinion. It's suited for a CNC machine and while it could be used for our purpose - it would cost a lot, especially considering you would still need an Arduino controller (the shield sits on top of it).
I still recommend getting just the controller and a ULN2003 chip. The wiring is very easy, really !
Look at this one (I don't know the site):
http://iteadstudio.com/store/index.php?main_page=product_info&products_id=274

Or this schematic:
http://www.betasix.net/connecting-a-unipolar-stepper-to-arduino/

To answer your questions though: You could very well use the equipment you mentioned, adding an arduino controller (such as the Nano or Mega) to get the job done.
When using Arduino - you literally tell the motor how many steps to take. Your steppers have 64 steps per revolution or 5.625 degrees per step - so you'd need to tell it to take 5-6 steps (the function is actually called "step").

how do I program the controller to take only 5 step ?
Do I need USB... etc from a computer or a CHIP programmer?

If you're using Arduino they have a basic software of their own to program the controllers. You can download it at the Arduino official site. Every controller can be connected to a PC via USB and then programmed. The program is uploaded onto the controller and once it does you could power it up from a different supply if you want to, but could also keep using the USB.

They have examples for basic programs in the software. Steppers have a separate library with examples for turning full circle, turning according to a potentiometer's knob being turned manually and such.
You could simply take the program which tells the stepper to take a number of steps equal to it's steps per revolution value (full circle) - and change it so it takes only 5 steps (type in a "5").

I did some research into step motor and aurdino.... but I did not understand much about it

Think I will go back to the solenoid solution and continue to work on that.

Why is there no "spare" parts from the oase cutters to buy somewhere ?

I also kind of envy these guys (or girls) walking around this forum knowing everything about both machining and electronics...
We might be purchasing a display set of OASE jumping jets "cheap" (as if) for the lab I work at. Perhaps we'll have spare parts...

Can I suggest those interested in jumping jets spares have a look here:www.fountainsdirect.com. But they look a bit expensive.

some one with a CNC machine should start to build a functional cutter!
I did try to build some cutter with solenoid, but the biggest problem is that the moving part stop to work after some time.
Mostly because of the water that wash away oil etc.. on moving parts.

Is home made good enough? I'm building a cnc machine right now...

Jagi wrote:Is home made good enough? I'm building a cnc machine right now...

Sounds good for me

Let me know when you start building some cutters..

Ok, ready for update

Step-Motor cutter did not work out for me (no idea how to work on a step motor) !
So I re designed my old cutter.

here is my design:



it is pretty much "use whatever you got"

Problem with my old cutter was that the force of the water pushed the blade UP, and the pressure was to much for the solenoid to make it move.
So I uses an old brushless motor, removed the magnet housing and used only the shaft and the bearings !!
Then I formed a cutter on the shaft

You can use all the force you want on the cutter blade, but the bearings make it pretty easy to move.
I hope to plant my 2 nozzle into the ground after next week