Waterjet cutter built with a cheap pressure washer-----make money online

today on Applied Science I'm going to

talk about water jet cutters everyone

wants one but they're too big and

expensive so for a long time I've wanted

to try building one out of the low-cost

pressure washer and today the results

are in so let's take a quick look here

we're cutting sixteenth inch thick

aluminum and we're cutting at about two

inches per minute and using about 0.4

pounds per minute of abrasive and the

system is operating around 3,200 psi

here's the same setup have an eighth

inch thick aluminum and we're going

about half 1/2 the cutting speed so

about one inch per minute and everything

else is about the same

here we're cutting 3/8 inch thick

hardwood I think this might be Pella and

the machine also operates in water only

mode and so then we can cut soft

materials like foam and it really tears

through I can't even measure how fast

it's cutting it because it's almost

faster than I can move it you know

accurately with my hands it also cuts

things like breads no problem

so not bad at all actually quite usable

of course a commercial machine is much

faster than this but if you're using us

at home for hobby projects production

speed isn't really much of an issue and

having a water jet cutter lets you cut

materials in shapes that just would

otherwise not be possible so let's get

into the details and talk about how I

built this let's start off with our

pressure source so whereas a commercial

water jet machine might cost $150,000

this pressure washer costs 150 dollars

shipped it's rated at 2,000 psi at 1.7

gallons per minute and it's one of the

most popular electric pressure washers

on Amazon initially I thought I might be

able to connect the pressure washer

right up to the cutting head but as it

turns out there's one modification we

have to make in order to get a usable

system so I disassembled the plastic

case and took out the pump and motor

assembly here's the assembly and it

slides out of the housing pretty easily

it also has this little water guard on

top that just I just pulled off and I

also added an additional cooling fan to

the top so you can see it actually has

its own fan built-in in here but since

we're running the motor quite a bit

harder than it was originally designed

to run I added this extra cooling fan

not super critical though so here's the

main modification originally this

pressure washer system had a feature

that when you let go of the trigger the

pump would stop running and the pressure

in the system would be vented and then

when you squeeze the trigger again the

pump would start up and you'd be back up

to full pressure it's actually a clever

little trick but as you can see there's

no electrics there's no you know button

or electrical signal it's done all

through pressure in the system here's

what the modification looks like now

I've got a spring that's pressing on

this plastic button here so I'm going to

take this apart and then take out the

guts of what's inside this valve housing

so that we can see what it looks like

and I'll explain what it did originally

okay so originally this brass piece was

inside here and then this piece is

pressed down like that and so you can

see there's a hole in the end of the

brass piece and this white plastic

plunger is pressed into that hole and on

the other side of this hole is the high

pressure side of the system so when it's

running normally this thing functions

like a relief valve right because you've

got a spring here and the spring is

pressing on the plastic which is sealing

the hole shut but if the pressure on the

other side of the hole is high enough it

will actually push the plastic away and

then the water escapes past the thing

here so it functions like a relief valve

but there's an interesting twist the

surface area suddenly changes you can

see this plastic part fits in here and

there's even an o-ring that seals on it

so what happens is as soon as the valve

starts to open a little bit the area

that's exposed to the pressure side

suddenly increases because currently

it's just a cone closing off that hole

but when the pressure goes up it pushes

the plunger down and now it's exposing

this much larger surface area so it's

like positive feedback so as soon as you

reach the set pressure this plunger

moves a lot and now it's it has a much

higher area so that pressure really

pushes it far and it does two things one

the white button will stick out at the

end here and there's an electrical

switch that's attached to it like this

and the electrical switch is just held

in by an o-ring it's just pressure fit

in there you can kind of see that yellow

tab of plastic in there so the button

comes out presses presses the electrical

switch cuts power to the motor and

there's a little vent hole in the side

here so that as the plunger is back all

the high pressure is vented out of the

system and then after it vents enough

this thing will close past that hole and

maintain about one or two hundred psi on

the system so then the next time you

squeeze the trigger it goes down to zero

it vents off that one or two hundred psi

and

plunger moves all the way back into its

home position the switch closes and then

starts the motor up again so pretty

clever it's a pressure safety relief an

unloader valve and a motor control valve

all in one moving piece of plastic so

the modification is to convert this into

just a plain old pressure relief valve

so in the original one you can see that

the white plastic plunger fits fairly

snugly in there and even if you remove

the o-ring it still fits snugly enough

where you'll have this positive feedback

effect and as soon as the valve opens it

slams itself way open and you'll get

oscillations in the pump so I turned

this copper copy of the brass piece and

it has a larger internal diameter so now

the plunger just fits loose in there and

the cone of this thing sits down into

that hole that's in the end and if

there's too much pressure it will push

on the plunger and push it out of the

way and relieve the pressure but it

doesn't have this same positive feedback

effect I kept the original spring and as

it turns out the spacing is a little bit

different in mine so I was getting

slightly higher pressure than the

original system pressure just with the

modification just by changing this part

but then I wanted even more pressure and

so I added I had this thing to the

outside that would add more spring

pressure bias to this thing so that we

were pressing even harder on it and I

was eventually shooting for about 3,200

maybe even 3500 psi the motor is a

brushed universal type motor and it

originally had this pressure cutouts

which is just in line with it which I

just shortened out because we don't need

the switch anymore and normally it runs

about 14 or 15 amps at a hundred and

twenty volts sixty Hertz AC but since

we're raising the pressure and the flow

rate is almost about the same it's

actually drawing quite a bit more power

now I put a clamp reader on there and

about 20 or 21 amps at 128 volts so this

is definitely a little beyond what we're

you know a little bit beyond what the

electrical circuit is SPECT for right

it's a 20 amp breaker so you can't

really draw 20 or 21 amps out of it for

very long so in all these test cuts I've

really just been running it for a few

minutes at a time

I added the extra fan of course because

we are pushing this motor quite a bit

harder than it was ever designed for you

can also see this thing is sitting in a

tub of water because it did spring a

leak under high pressure it doesn't leak

when it's running it sort of more normal

pressures but when I pushed it up to you

know 3500 its sprung a leak which has

the interesting effect of being

self-regulating because once it starts

leaking the pressure goes down and then

it doesn't leak as fast anymore so it

actually wasn't as big of a disaster as

it seems also this little thing doesn't

really play a role in what we're doing

it's a soap adding device so if the

pressure in the line is very low it acts

like a venturi in it it actually sucks

soapy water into the solution if you

want to you know soap your car up or

something 3200 psi is actually a good

pressure for this system because the

hose itself is only rated for 2,900

working and you know they have big

safety margins on these things and also

unlike a compressed gas system if you

have a rupture in a in a hydraulic

system you don't really have that

explosive force because the liquid is

not very compressible so keep in mind

that compressed gases are way more

dangerous than compressed liquids

nonetheless it would be nice not to have

this thing you know ruptured and sprayed

water and shrapnel all over my garage

and me okay so here's the business end

of the machine we've got our 3200 PSI

water coming in here I made this adapter

from buying a high pressure or pressure

washer hose coupler and I braised in a

stainless steel pipe into the coupler

these stainless steel pipes are actually

a standard interconnect style I'll put

links to all this stuff in the

description these are actually made for

very high pressure systems all the way

up to 150,000 psi

but this particular variant is rated for

60,000 psi which is of course much

higher than what we're doing right now

but I have some I have some other

experiments coming that will make use of

this it's a rather clever system the way

it works is you just thread the end of a

piece of stainless steel pipe and then

screw on this ferrule and then use a nut

to hold the ferrule into the fitting so

it's literally a metal-on-metal seal

there's no gasket or anything it's just

stainless to stainless conical seal and

it actually works really well they're

all precision parts and everything so

you don't even need that much torque to

seal it so in any case if you were gonna

build something like this at home you

know you don't need any of this fancy

stainless stuff I mean you could go

right from the high pressure hose right

into the cutting head but since I had

all this laying around already and I

wanted to see what the pressure was I

added this nice gauge and a tee in this

really high pressure valve

and then the cutting head is down here

so most most of the exciting stuff is

happening in the cutting head which

we'll look at next when people talk

about water jet cutting what they

usually mean is abrasive water jet

cutting so it's actually little sound

particles that are doing the cutting and

the water is actually incidental if

there was some other way to accelerate

these hard cutting particles up to you

know two times the speed of sound they

would do a great job cutting the

material all by themselves it's just

water is nice because it's not

compressible and you can pump it around

through a hose and so it makes it a

convenient way to just accelerate all

those abrasive particles so the cutting

heads job is to take the stream of dry

abrasive in this case it's 80 grit

garnet basically sand this side of the

cutting head is actually under suction

and so it actually pulls the abrasive in

there so I'm going to take this apart so

we can see how it is built as you can

see there's almost no torque needed to

put these high-pressure style fittings

together this isn't even an official

fitting this is just a stainless steel

bolt that I got from McMaster and made

it work so let's take this over to the

bench so we can get a better look okay

so here's a cutting head and also a

game addict image in the public domain

that shows what's inside here

now this particular cutting head has two

ports for the abrasive that's kind of an

interesting feature one of them is

actually suction just connected to

basically a vacuum pump and the other

one carries the abrasive into the

chamber so it has this feature where you

can get the abrasive flowing through

that space in the cutting head before

you turn the water on even and I guess

for some materials that's a benefit so

we'll take this apart this thing at the

bottom here is actually a tungsten

carbide tube with a very small hole in

it you can see all the way through there

this particular one is about 40,000

diameter and it's three inches long it's

kind of an expensive piece so this is

about $80.00 kind of funny that this is

80 bucks and the hole pressure washer

was 150 so I mean that's kind of how it

goes but keep in mind that tungsten

carbide is really brittle so don't drop

this okay I had a problem when I first

set this up I had a 30,000 and was

having a problem with clogging and I was

poking the wire through here to try to

unjam it and I think I was actually

almost ready to get this thing unjammed

and then I dropped it on the floor and

this is what happened so don't do that

the next interesting bit is the actual

orifice the actual thing that creates

this tiny jet of water and here it is

this one happens to be a ruby and the

ruby has an 18,000 it so you might be

thinking oh wow I mean every B with an

18,000 it's got to be expensive

no actually it's it's literally 12 bucks

I think the sapphires are $15 and the

rubies are 12 or something the rest of

this is just a chunk of stainless steel

as you can see I bought this obviously I

didn't machine this this is a commercial

one from a cue stream by the way I'll

put links to where those places where I

bought all this stuff the only thing is

it has to be quite precise and so the

way that this works all the tapers on

these orifices and this thing and the

mixing nozzle and everything are all

pretty well controlled so when I drop

this

or if it's in here you get it oriented

correctly it seats in there and seals

against the body here and also is it

doesn't jiggle anymore so there's a

taper that gets it nice and concentric

and then same with this this is actually

very precisely fit in here and there's a

ferrule that clamps down on it so that

everything is really concentric and I

don't know if you can see and you see if

I can lined up with the cameras you can

see all the way through there in most

commercial water jet machines the

orifice is typically about 10,000 inch

and the mixing tube diameter is about

30,000 inch and if you change the

orifice size it's good practice to have

the mixing tube diameter be about three

times that however since we're dealing

with a smaller lower powered pump I'm

sort of forced to use a larger orifice

in order to get the maximum power from

the pump so an interesting thing when I

first started this project I was

thinking oh yeah you know since it's a

small power or since it's smaller

pressure washer I could use the really

small orifice and so I started out with

like a fourth ow orifice and then

realized that that actually you know

that logic holds true if pressure is

no-limit right so with the same

horsepower going in you basically want

to have as much horsepower coming

through the jet which means high

pressure and low flow but since pressure

is limited I mean we blow the pump up if

we tried to get much higher than where

we are now

what we have to do is make the orifice

bigger so that we get more flow at a

lower pressure to get that same amount

of horsepower at the jet now the reason

that water jets have to run at such a

high pressure anyway is because the

energy in those particles is V squared

right 1/2 MV squared is the amount of

energy in those moving particles it's

the same reason that being behind a gun

is typically safer than being in front

of it right it's the same momentum the

shooter experience is the same Ament

emits the person who catches the bullet

but the person who catches the bullet is

going to experience much much higher

energy dissipated and it's the same deal

with water jet cutting right the

particles that are coming out of here

are basically like tiny

and you want them going really fast

because you make use of that V squared

term in the energy so anyway you'd be

nice to have super high pressures but

that's difficult because all the pump

seals have to be really nice and the

pump casing has to be thick so we can

sort of make up for it by just having a

higher overall flow and I selected 18

foul because that would allow this pump

to be drawing 20 amps at it's you know

desired flow rate running at 120 volts

and and that's we basically get as much

power as we can with that size orifice

and then they don't really make mixing

tubes that are three times bigger than

the 18 so I went with a 40,000 to so

we're kind of pushing the limits of

what's normal for a commercial machine

but it's still within the realm of of

you know acceptable the last thing to

look at is the abrasive hopper it's

basically just a tub with a hole in the

bottom you know it's funny I went

researching this and looking around all

the commercial abrasive hoppers and

everything I would swear up and down

that they had something more complicated

going on in here most of the commercial

units have like a dial where you can set

how you know the rate at which you want

the abrasive dispensed and a lot of them

have pneumatic controls to shut it on

and off and everything and I thought

there was at least a venturi that was

sort of blowing air through it and

picking up the particles and carrying it

down no none of that is true actually

it's literally just gravity-feed it's a

bucket with a hole in the bottom and a

valve that opens and shuts and then as I

mentioned the air is drawn into the

cutting head because of the venturi

action or even just the momentum of the

water going through the mixing tube kind

of draws a little bit air with it and in

all the commercial water jets as well

the hopper you'll see is always kind of

above the cutting head and the sand just

drips down through the tube now one

thing that happens a lot on commercial

systems and mine is if there's a backup

if you plug up the tube for whatever

reason water will start to go back up

here and into your abrasive hopper which

is very bad so I learned right away that

getting water in your sand is one of

worse things ever because it clumps up

and then it doesn't flow anymore so

protecting your sand from the water is a

big deal and some of them have anti flow

back valves in here even if they're just

the geometry is set up such that if

water comes shooting back up this tube

it doesn't go shooting all the way back

up into you're abrasive it kind of

misses it and goes off the side I had a

lot of fun researching this and putting

it all together since water jet machines

are always so mysterious and expensive

and you can't even buy parts for them I

called one dealer and they said they

only sell to existing customers let me

think about that statement for a second

but anyway the results are pretty

promising and the next steps if I were

to keep going with this would be to add

a CNC control so one thing we can do is

move the whole table underneath the jet

or take the more conventional approach

and move the jet itself if you're going

to cut things out of large sheets it

makes more sense to have that approach

kind of like a CNC router and luckily on

ebay and other sources there's really

low-cost CNC machines maybe they don't

have a really great control or even any

control at all but at least they have

the stepper motors and the drive screws

and everything and I'm sure the

precision would be good enough for a lot

of Hobby projects also I should mention

there is a Kickstarter startup waser

it's sort of like a tabletop water jet

cutter kind of like what I've shown here

today they have it completely enclosed

it's fully setup it includes everything

the control you know the pump and

everything they say it runs off of a

standard household outlet which I assume

is 120 volts at 15 or 20 amps so it's

probably comparable to the cutting

performance of what you saw today but of

course they've time the work of making

it reliable and you know everything is

put together instead of this you know

hose and funnel and stuff hanging around

I haven't tried the waser myself but it

does look pretty cool and I'm kind of on

the fence about thinking about getting

one okay well I hope you found that

interesting and I will see you next timeTop Search Keyword : online earning, , make money online, earn money online, online earning, online earning sites, make money online free, online money income, earn money online free, money online, best way to earn money online, online income site, money earning websites, best online earning sites, easiest way to earn money online, earn money payment bkash, online money income site