"fusible" mechanical eccentric press

[rinato]

good evening to all, I need help, although it is not a molding problem all short:
In the company they were wrong to manoeuvre an eccentric press blema-ghota (made in ddr) and gave the mechanical "fusible" between the worm and the real bat. so the fuse did his job, if nothing else.
Obviously the machine is so vetusta that books and manuals no longer have (if ever had them) and it seems that in germany they no longer produce exchanges of this component from a couple of lusters.
someone who's been there knows how to tell me what material might/should be to hold at least 200tons of car plate (in reality there's not even that, but let's lose).
the measurements I can still deduce from scraps and from the premises, but I can not identify the material (pare a cast iron, as it split, but vallo to know without long and expensive laboratory tests. At least I think they are long and expensive, forget me too, in case). I attach a few photos, for clarity. if I can tomorrow I also put the quoted pdf.

or if you can tell me a national constructor of such objects. the builders of the other presses in firm have been to the system for years with "hydraulic clamp" and there can be no help.
remain confident,
Reborn.

 

[welcome to the machine]

Maybe doc brown can help you.... send it to take the original spare
Sorry if I joke about your problem, but I see very difficult to establish the back breaking load without knowing the material. If it were a simple piece you could try with pieces of increasing size by changing sections, but you should basically break them until you find what resists work to do + a little margin however tolerable by mechanics. It seems like an improbable procedure. If you find a cast iron foundry maybe you can give indications even without "long and expensive laboratory tests " experts, maybe the older ones, sometimes recognize the grain, but it is not easy to rely on uncertain data to realize a protective device of an important machine.

 

[rinato]

here is the design, if it can help:

 

[rinato]

Maybe doc brown can help you.... send it to take the original spare
Sorry if I joke about your problem, but I see very difficult to establish the back breaking load without knowing the material. If it were a simple piece you could try with pieces of increasing size by changing sections, but you should basically break them until you find what resists work to do + a little margin however tolerable by mechanics. It seems like an improbable procedure. If you find a cast iron foundry maybe you can give indications even without "long and expensive laboratory tests " experts, maybe the older ones, sometimes recognize the grain, but it is not easy to rely on uncertain data to realize a protective device of an important machine.

Doc. brown hasn't been found since I asked him some numbers in the lot.

for the rest: hope is the utima to die.

 

[TECNOMODEL]

with a characterization of the material you wield permanently.
A lab does it for you in a few days, usually, and it doesn't even cost madness.

 

[exxon]

find the foundry that makes the crudes in lost ground and ask them to take care of the characterization of the material. have experience and knowledge to carry out work in a profitable way. Since you have a detailed design of the detail, it is certainly the best solution.

p.s. as already recommended by welcome to the machine

 

[stevie]

Spectrometric analysis and hardness test and the game is made.
The problem arises in the fact of merging it, for a single piece risks having a considerable cost.
better then get it from a slice of bar.

 

[rinato]

good morning to all, the external maintainer who still knows how to put hand to this press managed to find the design of the particle.do you know how to interpret the δ sigma shown in the table? Is it traction break, ripple or something?I read δ zb [N/mm2], but should be a very old designation.
I understand what it is, I can reconstruct it in spheroid cast iron (the one I find is a g500) calculating the lathe more suitable for my cast iron.
Thank you for your help,
reborn

 

[andreacap1986]

I can only tell you that traction breaking load in German is called zugfestigkeit bruchlast but I cannot assure you that the sigma pedice zb is the abbreviation.

 

[rinato]

I can only tell you that traction breaking load in German is called zugfestigkeit bruchlast but I cannot assure you that the sigma pedice zb is the abbreviation.

Thanks for the indication, I never thought of an acronym.
The trick is that the g500 I find ready has values of δ [N/mm2] of minimum 420 and are already out of table, while if I look at the lamellar cast irons of the same supplier I find very + low values (<170) . I will have to make a specific casting.
Thank you very much for your help,
Reborn.

 

[meccanicamg]

Surely if you do it for us cast iron ex g25 you will get a more accurate fuse. If you go to tenacious materials, spread the press because the fuse does not shoot.
you have a useful range to use traction break load related to fuse depth. You have to do that.

 

[stevie]

Thanks for the indication, I never thought of an acronym.
The trick is that the g500 I find ready has values of δ [N/mm2] of minimum 420 and are already out of table, while if I look at the lamellar cast irons of the same supplier I find very + low values (<170) . I will have to make a specific casting.
Thank you very much for your help,
Reborn.

if you look at a pearly laminated cast iron the values on the 250 of diameter are on 180-200 so it should be fine.

 

[rinato]

Hello, yes, I did some evaluations and took a couple of gjl250 records, I turned one after having learned that the δ was suitable (but I only deducted the value from hb hardness tests).
at worst the fuse is undersized and will break before, but at least the machine is broken.
thanks to all for contributions,
Reborn.

ps. I saw the hardness values grow from the center to the outside, fortunately the area to the ø that it will have to yield had suitable values (minimum limit, however), but I seem to have understood that for the cast iron is a normal behavior so.