hydraulic vibration

[sam5586]

I have made a hydraulic press. It has six cylinders , one of them us mane ram of 100 ton and other fives are jack up two cylinders, ejector one, injector one, slider one . Except the main cylinder which is of 100 ton the other five which are of 10 to 15 ton show vibration during operation. I am very confused , I am unable to find the reason for vibration. Please help me.

 

[Oldhydroman]

Hi sam5586

Some systems vibrate [until fixed] and others don't need fixing. If you only have experience of systems that didn't need fixing then, unfortunately, you have nothing to draw upon. A few quick answers from an engineering tips forum cannot take the place of the professional fluid power engineer you need on your site.

Often vibration is present because there is something wrong with the design of the hydraulic circuit and/or the particular selection of components. Sometimes it is the way the system is being controlled. No-one will be able to tell you anything of value until they see the circuit diagram. The fact that you didn't think anyone might need to see the diagram sort of points to the extent to which I suspect you are out of your depth.

Regards

DOL

 

[HPost]

1) What are the sizes of the cylinders? Bore diameter?
2) What is the fixing arrangement of the cylinders (Trunnion, flange...etc)?
3) Approximate frequency of vibration?
4) Bearing arrangements?
5) Pipe work arrangements? Are the cylinders that vibrate connected to the same manifold?
6) Is the 100T cylinder bigger (diameter) or does it operate at a higher pressure? What makes it a 100T cylinder???
7) What are the pressure controls and how are they arranged
8) Single of double acting cylinders?
9) Cylinder sealing arrangements? Lip seals, composite, low friction?
10) Fluid? Assume mineral oil, but what viscosity?
10) What type of control valves? Spool, poppet, servo, proportional???

With this information we will be able to identify the excitation source and possibly the root cause. It will be either the pump (high frequency, but damped on the 100t cylinder) or low frequency caused by misalignment of running clearances.

In basic terms, as is often the case, we need more information to be able to help you. As DOL says, the root cause could be one of many things and without sufficient detail, very little help can be offered.

Cheers

HPost
CEng MIMechE

 

[PNachtwey]

Does the vibration only occur while the press is moving down?
Are you using counter balance valves?




Peter Nachtwey
Delta Computer Systems

http://www.deltamotion.com

 

[sam5586]

Vibration only comes when cylinder is operating in upward direction or when the ram is coming out. One more thing I want to add that after manufacturing the machine when I tested it there zero vibration , after 15 days cylinder starts vibrating . I have used a solenoid valve 3C4 and a MSW 01 X 30 . Before installing MSW , I installed a counter balance valve but it didn't worked. Then I replaced counter balance valve with MSW . I have also changed the radial piston pump 2RE -5BE , after changing the pump when I started the machine it operates very good and there is no vibration but after 4 to 5 days same problem occurs . Then I installed MSW 01 . MSW reduced the vibration to some extent but not completely.