[TheForge] Hydraulic Press

[peter fels]

On Mar 19, 2011, at 4:05 PM, Andrew Vida wrote:

> 
> 
> peter fels wrote:
>> I'd add that 2 of the 3 100 ton hydr presses i've seen doing hot work
>> at full capacity, distorted alarmingly under load. Those 2 were home
>> made by competent smiths.
> 
> They may have been competent smiths, but if your definition is 
> "alarmingly" is similar to mine, then they were not competent engineers. 
>  No sin there, but the consequences of ill-designing such machinery can 
> be dire.

At those pressures it may be that i'm easily alarmed, but when i see large members
move 1/2" in a 3' span...I'm alarmed.
> 
> 
>> Which brings me to pose a problem . 
>> Hydraulic presses are by nature slow.
> 
> Put enough oomph behind a given cylinder and they can be every bit as 
> fast at air.
> 
>> Under pressure, the dies suck
>> the heat out of hot work fast. How does one go about either reducing
>> the speed of heat drain or increasing the speed of die travel under
>> load?
> 
> The easiest way is to add more oomph.  Larger power units that move 
> larger volumes of fluid with the same force... or more.  There is really 
> no other way around this.  You can thermally choke the dies so they do 
> not sink heat away into the frame as quickly, but then you end up with 
> glowing dies and that can be a problem too.

That's pretty much what i'd come to...Which leaves me waiting for a 35 odd HP gas motor
to fall  in my lap..figuratively.
> 
> Have you never seen a high speed hydraulic forging hammer?  Those things 
> move with some velocity - looks just like a steam hammer in those terms.

Saw a brief bit of video of one Arf! Arf!
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