polyurethane springs?

[rinato]

Hello everyone, drawing molds (for sheet metal, cold), I often find myself embarrassed to have to choose whether to use steel or polyurethane springs for the Premiere and similar.

That is, I, instinctively, put in the first choice steel, then maybe with the holder we analyze the first drafting and he leans for the rubber.
apart from cases where nitrogen cylinders are needed, what do you prefer, at equal load, for molds from a few thousand pieces/year?

I have also lost some time and I have "calculated" that the iso10243 yellow springs has the same rigidity of the imgs soft imgs in polyurethane 90°sh, but these last always last me little, or after a few hundred cycles go often because they have lost the preload on the road. while the steel springs work a lot and then they drop all of a sudden (and we would miss ...) .
Will there be any makeup for rubber springs that is not written in the catalogues?

Greetings, reborn.

 

[Simold]

Hello reborn.
I handle injection mold design and I don't know if the same criterion is valid for
sheet metal molds.
here from me in the workshop are mainly used steel springs for medium loads.
when racing is not excessive or when they must
just give a quick point to the plate to get off the other.
for example in the case of oleodynamic extraction, before acting the cylinders we do
a small pre-detachment on the extraction plate with a series of polyurethane springs.
Once they used a cup spring, but I haven't seen them on the molds for a while.
fashion will change.
I don't know about any tricks to improve the duration of springs.

 

[gianluigi]

hi reborn, when I was a designer, we used a lot of springs my calculation was to make the springs work max 70%
so they lasted a lot.
Hello gianluigi

 

[meccanicamg]

the polyurethane spring or however in rubbery materials has the characteristic of having excellent reaction for very small racing and to degrade over time gradually. steel springs work on big races and obviously fall out of gloom over normal life cycles.
for a primer depends if the races are large or small, if the mold drops and compresses the primer and then drops the punch always with the same command does not make much sense to have the tires but better the springs. If you have the two separate or otherwise commanded commands, you can afford 5 mm of primeval race and 50 mm of punzoni racing. Obviously if you compact everything for something very dedicated I would say that you can afford rubber springs, very low rushes of punch and primer.... then save on the springs.

 

[rinato]

hi reborn, when I was a designer, we used a lot of springs my calculation was to make the springs work max 70%
so they lasted a lot.
Hello gianluigi

hi gianluigi: for "70%" do you mean you admit a maximum arrow of 30% of the free length?

 

[rinato]

the polyurethane spring or however in rubbery materials has the characteristic of having excellent reaction for very small racing and to degrade over time gradually. steel springs work on big races and obviously fall out of gloom over normal life cycles.
for a primer depends if the races are large or small, if the mold drops and compresses the primer and then drops the punch always with the same command does not make much sense to have the tires but better the springs. If you have the two separate or otherwise commanded commands, you can afford 5 mm of primeval race and 50 mm of punzoni racing. Obviously if you compact everything for something very dedicated I would say that you can afford rubber springs, very low rushes of punch and primer.... then save on the springs.

Thanks to you too. I will try to keep the applications distinct and understand the yields.
I didn't imagine there could be applications where the prime minister has a separate command from that of the punches. are special moulds, on dedicated presses, or what else?
Greetings, reborn.

 

[meccanicamg]

Thanks to you too. I will try to keep the applications distinct and understand the yields.
I didn't imagine there could be applications where the prime minister has a separate command from that of the punches. are special moulds, on dedicated presses, or what else?
Greetings, reborn.

if in the same mold you have to make a deep fold 10 mm and make punches and for example the thickness is 1 mm you will have that the primer stops immediately perhaps in conjunction with the punching and the fold remains commanded or by mechanism to lever or hydraulically from hydraulic cylinder to whole thread.

however they are for particular applications.

 

[gianluigi]

Hello reborn, I meant 70% of the race, to have even 30% before sending it to parcel.
so springs last for a 30/40% extra even with pulling needles and injection stamoes etc., choose the type of spring
based on the effort they have to make.
If you get the yellow spring catalog there is the graph for intelligent use.
Hello gianluigi