Lowrider Waterjet Is It Possible Or Even Worth It

LowRider CNC Advice
1

Been seeing more and more about a Lowrider Waterjet.
Thought I’d shed some light on waterjets in general and give a few things to consider. Love to hear your thoughts and input on the subject.

Costs… Waterjet Specific - Pump and/ or pumps, Intensifier, Filters, Chiller, Garnet, Hopper (tank for storage of garnet), Mixing chamber (area where water and garnet combine) Actuators for water and garnet (to hold pressure during traversing and timing for garnet and water mixtures. Garnet to soon, clog, too late deformation of material surface, too little garnet poor edge/cut quality, too much equals wasted garnet into the tank), Diamond Orifice (Ruby is an option but only at lower pressures), Mixing tube (this is the cutting tip), cutting area tank, supports for the cutting slats (.250 or thicker to support the weight of the materials going to be cut), cutting slats (.125 or thicker to reduce vibration and splash back during cutting and to reduce the time of replacing them).

Then we have all off the cnc stuff, steppers, lead screws. (Yup, probablt not going to be able to use belts, the pressure from the cutting head requires that everything can’t move at all or it decreases tolerances.)
Probably going to have to increase the rigidity of the tubing. If the head lifts from the blow back of the water stream it will change your cutting area and tolerances.

And most of all, the elephant in the room is conquering the kerf. Corner, edge/taper controls. Without being able to tilt the head you will never have a square, concentric part. (I.e. a .250 6061 12" diameter would be 12" on top and 12.025 on bottom) You can slow down the cut speed to cut/erode more material on top, but now your top is undersized and the bottom is oversized. This becomes really prevalent with thicker materials.

Now on to maintenance.

All of your seals can’t leak anywhere or you lose pressure and create heat. Heat creates catastrophic failures. Also any pressure drops changes your cutting tolerances. If there is a issue with the pump, any of those particles materials get passed on down stream and cause problems with everything else in its path)

Let’s move on to the tank… you have all that stuff you have been cutting is in the tank and you have to remove it. Now you have to drain the tank and remove all those materials and garnet. Depending upon the tank size and materials, can be quite labor intensive. Also, if you have been cutting things that are possibly hazardous materials, you will have to have proper authorities dispose of it.

Safety!!!

Most of all is Safety. I can not stress this enough, there is nothing worth your hand or arm or Your Life! No part is ever worth it!

So what happens in the event that you get cut. If you cut the tip of your finger, there is a good chance that you will lose that finger up to the closest knuckle. Cut your palm, good chance that you might lose function to most of that hand.

So when something gets cut with water, it turns your skin into a high speed water balloon. However, your skin only has so much elasticity. So it becomes a high speed water grenade. So you now have a cut and an explosion in the same area.

If you are cutting with garnet and not water only, now you have a whole other battle. You have just injected negative gram bacteria into your blood stream. So in addition to the water grenade you just absorbed, you now are fighting your heart in a battle against spreading bacteria throughout your body.

I’m sure that I’ve missed a quite few things, but look forward to hearing your thoughts on the subject.

#Waterjet
#21Questions
#FatKidsLoveCake
#AnyoneActuallyReadAllOfTheHashtags
#ProbablyNot
#Lowrider

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Note to self: Don’t stick my hand in the cutter. Got it.

I’ve never even heard of a diy waterjet. Ballpark what are the costs of waterjet specific parts?

Regarding sturdy table, kerf, and taper there are those of us running plasma cutters. I’ve even seen one guy running a oxy acetylene torch on his lowrider.

#IReadAllOfTheHashtags!

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Plasma is different than water, in that it fans out the farther away from the surface and it will go in the path of least resistance. So, if you are trying to just trim an edge, it will most likely just deflect of the edge and not remove the desired material.

However, plasma does suffer from some of the same issues when it comes to kerf and cut quality. Every machine has its place. Plasma is a good middle ground cutting medium. Wide variety of materials can be cut and it’s not outrageous to get started.

The highest quality cut would usually be from Waterjet, which gives a very square cut with no dross, and no pierce spatter. Laser is a very close second place, because it also yields a very square cut, but on thicker mild steel or on stainless steel it can leave some dross and generates some pierce spatter. By comparison with these two processes, plasma cutting would have the lowest cut quality. Plasma will always have some edge bevel angle and often causes some dross. It also generates much more pierce spatter than laser, due to the larger kerf width.
Cut part precision is a measure of the actual resulting part size compared to the programmed part size, and also includes consideration of the kerf width, which determines how small of an inside contour can be cut. Heat distortion should also be considered, as it can throw off the finished part size as well as cause the parts to warp. Again, waterjet would be the best precision, usually in the neighborhood of +/- 0.005”, and having a kerf width around 0.035”. Waterjet also causes no heat-distortion. Laser would be very close second place, with typical part dimensions of +/-0.005”, and average kerf width around 0.025”. But laser can cause some heat distortion, especially on thicker plate. Again, plasma comes in last place, having a typical part size tolerance around +/-0.020”, and a typical kerf width of around 0.150”. Plasma also creates some heat distortion, which can be reduced by cutting under-water.

#HopeThisHelpsSome

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How much $ are you looking at for a DIY waterjet?

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It will range greatly upon desired materials, thickness that you want to cut and table size. I can not at this point and time fathom that it an affordable diy project. But your pockets might be deeper than my lent lined ones…

#ShallowPockets

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Someone posted a video of someone who had made a DIY waterjet from a pressure washer. I think they were using sand as a medium, and completely glossed over/skipped any sort of reclamation process.

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And it was cutting plastic and they used it like a bandsaw? If so, I’ve seen it before. The pressure that is generally created by a pressure washer is 1,500 -3,000 psi? Entry level waterjet is 60,000 psi. Just a rough comparison for you…

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“Entry level” can change dramatically when you start making the machines yourself. A lot of people used to say that an entry level CNC was $10k.

From what I remember of the discussion of the waterjet video, just buying enough cutting material was prohibitively expensive.

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Absolutely, it is the best finish and most versatile process, but not the cheapest. Thus, imho it will not be a diy process.

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Never say never. A lot of people said the same thing about 3D printers a decade ago.