Project that Requires Hydraulic Press to Operates at 50 Hz

For speeds that high a mechanical reciprocating system is more likely going to be the better solution.

Far more info is needed though.

It doesn't exist.

Maybe a pair of wheels with a bunch of punches and cavities running a strip process. That's 180,000 parts per hour.

Do the parts weigh a gram, or a kilogram?

Or a crank/piston operating at 3000 rpm.

Tornado,

I was thinking a hydraulic motor turning a cam.

Working to end the use of carbon or fossil fuel for energy, really.

Do you have a free source of oscillating hydraulic pressure?

Good question but checkout 9th post of this forum, nick name has already designed something very close. Nothing is impossible and thanks to this forum, one don't have to re invent the wheel.

You've completely sidestepped the question. Hydraulics are a moderately inefficient way to transmit mechanical power. A crankshaft is more efficient. A cam with a roller follower is more efficient. In general, the more controls introduced into a hydraulic system, the less efficient the system becomes.

But hydraulics and mechanical linkages only transmit motion and force. The energy required to do the work must come from elsewhere: the electricity powering the motor driving the hydraulic pump (which comes from the coal burned at the power plant... which comes from ancient solar power... which came from the big bang... ), for example.

So the question again: Where is the energy to move the fluid (or more efficiently, to spin a cam) coming from? Nickname's design has nothing to do with creating energy.

"Nothing is impossible" but many things are effectively impossible. There is little to no likelihood of overturning the law of conservation of energy, for example.

Hi K_Fry,

Your "Nothing is impossible...." reminded me of a customer I had who designed special purpose machines and he would say if asked by a client if a project was feasible "If we can put men on the moon, we can do anything but have you got NASAs budget".

Best regards,

John

I'm sure that this is possible with some very tiny hydraulic press that obviously quickly compresses something. Since you've not done this before, I would not expect great reliability at first.

On the other hand, an internal combustion engine running at 6000 RPM has the crank shaft spinning at 100 Hz. The hydraulic lifters of a four stoke engine will then be opening and closing the manifold valves at a 50 Hz frequency. So it can be done. I wouldn't plan on using any flexible hoses though.

The hydraulic lifters of a four stoke engine will then be opening and closing the manifold valves at a 50 Hz frequency.

That's inaccurate. Hydraulic lifters are nearly solid while the engine is running.

Hydraulic lifters are nearly solid because the fluid cannot get pumped out of the hole fast enough. This is a fast hydraulic press. I'm fairly certain that this is not at all what the OP has in mind but in principle hydraulics can and do operate this fast.

This may seem pedantic, but I still say your example is inaccurate. A hydraulic press operates through pressurized fluid flowing into and out of a cylinder, causing the rod/piston to extend and retract. A hydraulic valve lifter in a running engine prevents fluid flow. (Well, pressurized fluid -- engine oil -- initially causes the lifter to extend, taking up the lash in the valve train. Once it's pressurized, it stays that way.*)

To look at it another way, hydraulic lifters can be replaced with solid lifters and the engine operates normally. Replace the hydraulic cylinders in a press with solid pieces and it will not function.

* I know, I know, there are some special-purpose lifters that bleed down at low rpm.

The hydraulic fluid, being incompressible, does act like a solid rod. But it moves back and forth, just as a rod would. That's the only way it can make the valves move (alternately open/closed). Solid ≠ stationary.

Your problem has or has not a hydraulic solution depending on the force you want to apply.

If the force is small and the stroke as well it could be possible but not for big forces even if stroke is small.

I designed years ago a hydraulic cylinder with automatic end of stroke commutation and we obtained about 30 Hz for about 10 mm stroke. Diameter was 25/18. It was used as a tool in foundry.

Re: Project that requires hydraulic press to operate at 50 hertz. My lecturer once told me that I should not re-invent the wheel. Thanks to You, 'cause I think I have a solution to what I seek. I would highly appreciate it if you can send me pictures/diagrams of the hydraulic cylinder you are talking about and a description of how it works to enable me know if I could apply it.

A few questions to see if what I did can be used for your project:

- mass to be moved

- force required in process is it a cutting tool or a forming tool ?

- number of hours / day

Why hydraulics ?

If you do not want to give such explanations (since details are required) open then use the private message channel.

As principle the cylinder worked with a mechanical relaxation commuting system and reached less 5 ms full commuting time.

(1) Mass to be moved is not a problem for now as this is a research project. Though, minimal mass of about 10g to 10 kg can be a good start. Success of the project may lead to further research about increasing the load.

(2) This is neither a forming tool nor a cutting tool but a lifting tool. However, what matters is the frequency of operation as the cylinder can be conveniently converted to a lifting one.

(3) Number of hours a day is immaterial for now. It is a research project and I hope it works first. However, assuming the project becomes a success the machine may operate for at most 10 hrs per day.

(4) As to why hydraulic, is there a better way of lifting up and bringing down other than by hydraulic? I'm an electrical and not a mechanical engineer, so enlighten me please.

(5) What I understand by reaching 5 micro seconds full commuting time is that the cylinder from start to finish, takes 5 micro seconds to lift a load. That is okay for me as i could have refrained the question - can we get a hydraulic press that can lift a load in 1/50 seconds, i.e 0.002 seconds or 2 microseconds

(6) I shall find a way to communicate with you on a private channel hence forth.

"(4) As to why hydraulic, is there a better way of lifting up and bringing down other than by hydraulic? I'm an electrical and not a mechanical engineer, so enlighten me please."

Aside from most things that hoist and lower are electric, there is a best way of doing something. To identify the best way one needs to know what the something is.

"hydraulic" is mostly just a way of transmitting power - much as copper is.

Might be, you should be thinking piezo or even electromagnetically stimulated nickle at that Hz.

I agree that electric lifts much things like in the lifts and others, mostly with the help of electric motors. I've not seen applicability of employing electric motor in the project yet and when I do, it will be an option. Thanks.

You have a problem with time units:

1ms= 1 millisecond = 1/1000 of a second

1µs= 1 microsecond =1/1E6 of a second = 1/1000 of a millisecond.

The next steps are the nano=1/000 µ and the pico=1/1000 nano.

If you want to only move a mass it would be of interest to know the velocity profile and the accelerations you expect. If you do not have to apply a force but only to move up and down then look at electrodynamic systems in a closed loop to control the movement as you wish.

What I designed is not optimal for your application.

I was obliged to use hydraulics since over the stroke a "work" had to be done and this was not easy to do with the electrodynamic systems, at that time the available PM were not so strong as today and the parasitic masses became too big. As for that application hydraulics were an optimal solution it appears that today it could be not the best for your application.

Even if it is a research project it could be economical to make a comparative analysis and pin point the direction which can lead to success.

Theory is here to allow a cost reduction in avoiding unproductive directions.

Hi tochi,

This really is a "how long is a piece of string?" question.

Answer as many of the questions asked by the members of the forum as you can and you will get a more definitive answer.

I've seen some very fast (and very big) hydraulic presses in my time, the biggest and fastest was at a can lid manufacturing plant with a multi stage tool producing a finished ring pull can top as one hell of a rate, 24/7 but I doubt it was 50Hz.

The application will be the determining factor as to its feasibility.

Best of luck

John

Thanks very much. Though, 'nickname' a member of the forum said he has designed something close to what I'm looking for, I would still want to get a more definitive direction to any of the hydraulic press you talked about, especially the smaller ones. As for applicability, one can always adapt.

Hydraulic motor with a cam for stroke. Should be able to find one that will have output rpm of 3000 depending on the forces needed to do the work in the press. Some of the force can be aid by a flywheel.

Why a hydraulic motor , the rotation can be obtained with an electric motor and then it is a classical knee or eccenter press.

Because the OP requested a hydraulic means. His reason are not given

GONE CRAZY>?

Well? Nick name a member of the forum has a solution though.

Could you explain your reasons for wanting to go hydraulic. (relieves etc.). If you aré not in need of using hydraulic advantages, I think mechanical would be the best function.

Well, there is a thing called a shake table that NASA uses to test MIL gear. It can move up to an inch, up to 300 Hz and move hundreds of pounds. The one we used in Ottawa was powered by a huge voice coil actuator powered by a 500,000 watt solid state audio amplifier.

To use it, you bolted items to it and shook the crap out of them. I can see the possibility of placing moving work pieces and an anvil with the mold. You would need super quick parts insertion etc. We just tested stuff for the Canadarm project, some years ago.

The vibration of the rocket is of this order of magnitude.

shake table maker

Hydraulic presses are specialist areas, is this a college project or work? If work based then get the specialists involved, if its a college project change the project to a different and safer(!) project.

50hz doesn't seem practical. More info needed, like height / travel of lift , and load.

From the question, I consider standard hydraulic double-acting pistons, where the operating speed is limited by the hydraulic fluid exhaust speed than determined by the operating signal speed.

Further, shaft seals won't last long at that operating speed. If your travel is very small, and the load is very light, there may be some membrane technology applicable.

The answer may lie in mounting 50 pistons operating at 1 second cycles.

Stroke and mass needed.

1 g to move 1 cm will be possible.

1 ton 1 meter is not likely to be possible.

Think about a resonant drive.

RHABE

Context is needed. What mass is being accelerated, and what distance it is moving? If both are small it might be able to work. If they are large probably not. Renault used electro-hydraulic cam-less valves on it's Formula 1 engines when they were V10's I think. The V10's operated at upwards to 20000 rpm, but that is a very small mass moving a very small distance. I get the feeling you are looking for something bigger. More info would be helpful.

Tochi,

Yes a 50Hz hydraulic press is possible. You will have to keep the distance between the control valve and the cylinder providing the press function small as the inertia of the fluid will be significant.

I googled Hydraulic vibration table and received many results. Here is one:

Hydraulic Table specifications:

Force range: 0.2 to 7 g
Frequency range: 1 to 300 Hz
Stroke: 2.5 in. (6.4 cm), peak-to-peak
Table size: 48 x 48 inches (1.23 x 1.23 m)

Maximum capacity: 2,500 lbs (1,134 kg)

http://www.exova.ca/index.php?option=com_content&view=article&id=1585&Itemid=&lang=en

And another: http://www.labequipment.com/vibration_testing.html

And: http://www.astre-tech.com/hydraulic-shakers.html

good luck

You should look at hydraulic breaker circuits and compare them to pneumatic breaker circuits. Only with large breakers do hydraulics function well. The pneumatic type work very fast and the hydraulic type are slow by comparison. There would appear to be little point in the exercise just using a hydraulic motor and cam. A conventional hydraulic solenoid valve will freeze at some 10 hertz.

More information and more to the point why hydraulic?

Oliver Dunthorne

Hydraulic Engineer

http://www.jetedge.com/content.cfm?fuseaction=dsp_applications_101
here is something you might find interesting.