mechanical punching machine size

[Elninio74]

Hello, everyone.
I am brand new to the forum, even if I have already happened several times to end up after various searches on the web.

I joined this forum because I have to make a new mechanical press-puncher.

the company for which I work sells its product for 30 years and now after the new update. . We decided to start with a new project.

not having too much experience in this field of mechanics, I intend to document myself so that it can make the machine properly dimensioned.

It is for this reason that I write, to ask if someone knows or knows where I can find documentation or books that talk about this topic.

I am mainly interested in the size of the inertia flywheel, which is one of the main parts.

for the molding force I have already found something.

we will also have to evaluate whether to choose the option "swan neck" or columns, although at the moment I would be more likely for the second option. . .

I assume that a good documentation speaks of the two cases and that depending on applications and loads, "choose" one rather than the other choice.. .

Thank you all from now on for the help and various suggestions.

Have a good day.

 

[Tequila]

Hello and welcome.

time ago there was a discussion where you can find ideas http://www.cad3d.it/forum1/showthread.php?t=32202As for books, from what I find there is practically nothing apart from an old book in English now introvabile that is quoted on the thread of the link above which is called "mechanical presses" of makelt

 

[Elninio74]

thanks 1000 tequila for the precious link.

cutting the head to the bull, the work necessary for the mold is easily obtained by multiplying the moulding force for the sheet thickness.
w=fs x s with
fs= 4/5 of rm x thickness x 1.2

in this way we obtain the theoretical work of hairstyle in [J]then with this value and how much read on the link you posted me, I can trace back to the inertia of the flywheel.
...
the diagram of the energy is in function of the strokes/mins and not of the races, that according to the semmai races is the power in kn (or tons) providing to the pmi

the formula to use is: e= 1/2*I*(wvol^2)*irregularity*(2-irregularity)
ivol = inertia fly (you should consider all the parts that you mount contribute to increase the inertia of the flywheel, fly+flight+spine+ecc. , but usually it is simplified keeping only the one of the flywheel)irregularities = 0.2 for continuous work and 0.3 per single stroke

angle speed fly wvol= (pigreco*ngirivol) / 30
number of turns fly ngirivol= n blows press * rrid
rrid = reduction ratio...

and also to get the power of the engine, I have everything

...
the formula to be used for calculating engine power is as follows: power=work/time
p(kw)=work (joule)*press blows (turn/minute)/(55x1000xrend)

the work in joule is the nominal work of the press expressed in joules, "n" are the blows of the press to which the nominal work corresponds, 55 is a coefficient that comes from the fact that the engine is considered to return the energy required in 330° after the lower dead point, while it does not yield energy during the 30 ° before the lower dead point, so the time to rotate of 330° to the speed of "n" strikes per minute is t=...

Well, I think I'm on horseback, with all due attention to the case...

Thanks again for the precious help.:finger::finger:

Bye.

 

[Elninio74]

for the documentation I found this, but I don't know if it's exactly what I'd need...because of injection molding presses:frown:
http://www.amazon.it/conoscere-i-pa...=sr_1_2?s=books&ie=utf8&qid=1349070734&sr=1-2

 

[Tequila]

happy to have been helpful.. .

the book in question would be this http://books.google.it/books/about/mechanical_presses.html?id=tpetaqaacaaj&redir_esc=y
http://www.amazon.it/mechanical-presses-h-makelt/dp/0713131764as you also see on amazon is out of print. I passed in my hands a month, a few years ago by a colleague, retired today, who had recovered it in germany by chance in the early 80s (at that time I was 5 years old).

 

[Elninio74]

Unfortunately I'm still here... as I started the first checks, and I find myself with unrealistic values.
I checked and checked, checked the units, but the accounts don't come back. . .
for simplicity I have made the calculations in a "classic" way or without the various correction factors dedicated to this type of application (irregularities etc...)

now we come to my case:

sheet thickness 0.5 [mm]

rm = 500 [N/mm2]Punching perimeter 278 [mm]punching force = 4/5 rm x thickness x 1.2 [N/mm2 x mm x mm]Punching force = 66720 [N]theoretical work of orangery w= fp x s = 66720 [N] x 0,0005 [m] = 33.36 [J]punching shots, or n° rpm fly 5 [colpi/s]Ω=2 x x x n = ω=2 x ψ x 5 = 31.4 [rad/s] e= 1⁄2 and x ω2 -> i=2 x e : ω2 = 2 x 33.36 : 31.4^2 = 0.067 [Kg m2]with i=1/2 x m x r2 and with a hypothetical r of 200 mm I find myself with a mass of the flywheel of 3,35 [Kg]...

Obviously there is something that does not fit...:redface::redface:

 

[Tequila]

Unfortunately I'm still here... as I started the first checks, and I find myself with unrealistic values.
I checked and checked, checked the units, but the accounts don't come back. . .
for simplicity I have made the calculations in a "classic" way or without the various correction factors dedicated to this type of application (irregularities etc...)

I'm going to do my money every now and then, but the irregularities you have to take into account otherwise you're getting high.

I would recommend you before you make accounts of discarding on a sheet of paper what you have more or less in mind (even at large lines) to do.

I have no idea how the punches are classified/made, if they follow those of the presses or if they have tables to themselves, however presupposing to work with that type of thickness and rm, I (underline I but I could be off the road in this case) from the 6.9 ton theoretical calculated to have an idea of the force necessary, I would extend it to a full value, type 8 or 10 ton and I would begin to work to a ritrogro

now we come to my case:

sheet thickness 0.5 [mm]

rm = 500 [N/mm2]Punching perimeter 278 [mm]punching force = 4/5 rm x thickness x 1.2 [N/mm2 x mm x mm]Punching force = 66720 [N]theoretical work of orangery w= fp x s = 66720 [N] x 0,0005 [m] = 33.36 [J]punching shots, or n° rpm fly 5 [colpi/s]Ω=2 x x x n = ω=2 x ψ x 5 = 31.4 [rad/s] e= 1⁄2 and x ω2 -> i=2 x e : ω2 = 2 x 33.36 : 31.4^2 = 0.067 [Kg m2]with i=1/2 x m x r2 and with a hypothetical r of 200 mm I find myself with a mass of the flywheel of 3,35 [Kg]...

Obviously there is something that does not fit...:redface::redface:

the first part is good, from the calculations you find that to draw 0,5 mm of sheet with those characteristics you need 66720 n --> 66.7 kn --> about 6.9 ton and so far I am okay.
for the calculation of inertia I do not find the relationship of reduction of cinematism.
If you consider a flying cinematism (Report 1:1) to make 6.9 ton at 5 strokes at a thickness of 0.5 mm you need a monstrous flying inertia! ! !

now the 5 shots per minute I would like to understand whether they are on a continuous cycle or single stroke.
with i=1/2 x m x r2 and with a hypothetical r of 200 mm I find myself with a mass of the flywheel of 3,35 [Kg]… I don't get this! ! !
you from the initial calculations to pull that sheet you got a force, then with this force and thickness an energy and now from this energy you get the inertia that must have your fly.

 

[Elninio74]

This is tequila.
As for your first statement on the sizing, I am very pleased with you...

I did that first calculus just out of curiosity, to see where we would end up flying over what we have now, just curiosity. :wink:

It is clear that the dissolution and choice of the various parts will require a more detailed analysis!
the current version of the machine is pulled and undersized compared to what we fly to get in the future!

Moreover it has been developed by the current owner of 87 years, self-taught with the passion for mechanics...respect for him, but so far everything has always gone on “to span” without any “scientific” approach. many tests, lots of experience, and the results still gave him reason!

for cinematism, currently we go 1:1, that is why I have evaluated “only” this variant, which does not mean that it will be the final solution...

the frequency of hypothetical punching is 5 strokes per second, but surely in the calculations will be increased to 6-8 for production needs...!!!! so yes, on a continuous cycle.

Finally, for the calculation of the inertia of the flywheel, I should actually resume the courses...

I thought the work needed to pull that kind of sheet metal [J], was comparable to kinetic energy developed by the inertia flywheel [J], since the units of measurement are the same...
but if not, how can I do it?
how are the necessary work linked to that type of operation with the inertia of the flywheel?

 

[Tequila]

This is tequila.
As for your first statement on the sizing, I am very pleased with you...

I did that first calculus just out of curiosity, to see where we would end up flying over what we have now, just curiosity. :wink:

It is clear that the dissolution and choice of the various parts will require a more detailed analysis!
the current version of the machine is pulled and undersized compared to what we fly to get in the future!

Moreover it has been developed by the current owner of 87 years, self-taught with the passion for mechanics...respect for him, but so far everything has always gone on “to span” without any “scientific” approach. many tests, lots of experience, and the results still gave him reason!

very great compared to these people who at their time used only the head, tests on the field and scarabocchi made also on the floor with shrapnel.

for cinematism, currently we go 1:1, that is why I have evaluated “only” this variant, which does not mean that it will be the final solution...

the frequency of hypothetical punching is 5 strokes per second, but surely in the calculations will be increased to 6-8 for production needs...!!!! so yes, on a continuous cycle.

Finally, for the calculation of the inertia of the flywheel, I should actually resume the courses...

I thought the work needed to pull that kind of sheet metal [J], was comparable to kinetic energy developed by the inertia flywheel [J], since the units of measurement are the same...
but if not, how can I do it?
how are the necessary work linked to that type of operation with the inertia of the flywheel?

talk about 5 shots/second but in the formulas used it is about shots per minute, so you should remake the calculation considering 5*60 = 300 strokes /minute

 

[Fulvio Romano]

very great compared to these people who at their time used only the head, tests on the field and scarabocchi made also on the floor with shrapnel.

erm...the head is used when it is not possible to do tests...
the child who plays with the lego, tries to frame the pieces in the form of a cottage did not "rejoined", but "proved". I dare that the results give him reason, the approach starts from there...

who for reasons of time/output/capacity cannot afford to do the tests, replaces them with pencil accounts, possibly even on the floor. Where am I wrong?

 

[Elninio74]

...or you can use it if you are able to control how much you have designed. . .


As regards the calculation of inertia, in accordance with yes, ω is in [rad/s].
in your formula, if we insert n in [copi/min] is however reported in [colpi/s] dividend per 30...
angle speed fly wvol= (pigreco*ngirivol) / 30ω = 2 x π x n = 2 x π x n [colpi/min] 60 = p x n [colpi/min] : 30 and then we return to the starting point compared to what is calculated.

at the limit the strangeness is to use the value in [colpi/min] for the calculation of power, always for a dimensional question.

But in the meantime I had an idea.. .

the purpose of the inertia flywheel is to maintain the smooth and constant movement during the punching, and then try to have a variation of speed of minimum rotation.
Moreover it must be dimensioned as well to allow sufficient "force" to the punch to work correctly.

now, if we use calculated work of 33.36 [J] as energy "loss" or better necessary for punching, this energy could be the result of
< > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > = < < > < > > > > > < > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > 0 > > > > > > > > > > > > > > > > > > > > > > > > > > > > > >
with
i = inertia fly [Kg m^2]ω1= initial rotation frequency [rad/s]ω2= final rotation frequency [rad/s]so to existing fly, can we check how much decreases its rotation frequency due to punching, or am I wrong?
the higher his inertia, the less we will have a decrease in the number of turns of the flywheel...

clearly its sizing must be reasonable, for obvious reasons of loads, moving masses and all that entails having high forces to manage...(and also therefore sizing of the engine...)

I don't know if I'm shooting a big cabbage.
every comment is welcome.

 

[Tequila]

Where am I wrong?

I assume that Mr. 87, at the time when he started (as many other great people), had only good will and ideas.
then with evidence on the field came to build something valid.

in the present day these approaches make you close shack and puppets to the first failure always that you have no well covered shoulders (read so much money!!)
Moreover the mentality and the way to design are completely the opposite to what was done 60 years ago.
Now ( fortunately many) before putting hand on the pieces of "ferro" lie ideas on paper or on pc and make calculations a priori.

 

[Elninio74]

That's right!
began in the middle of World War II with pioneering spirit, and grew thanks to founds and gegnal ideas, and I repeat, without any technical base!
read and documented properly, all alone!
the company is still active, alive and vegetative, with excellent horizons. . .

I also agree with what is said about "modern" times. . .
nowadays we have the great fortune to have the means available to work easily and correctly!

at school the construction professor once told us:
the only difference between a designer and an engineer is that the second can correctly control and dimensional how much designed...:wink:

the experience makes a lot...but usually going to "tons", it tends to oversize parts in which a simple trick suffices for a correct dimensioning. . .

 

[Fulvio Romano]

Yes, I have it with a person in particular, great industrial, who made himself and was able to create an empire from nothing. I dare... After World War II, in the middle of the economic boom where two pieces of iron were sold on the cross because people sold their mother to buy the x that you sold... at the time it was enough to have swallows that enough and a little desire to do.
Today more excellent minds are forced to work at 1200€/month for these padroncini who had the chance to start at the right time... Today day to eat the sharks you must be born sharks, to try to become we end fish soup.

I repeat, I don't have it with your 87-year-old guy, but with a five-year-old younger, who was even kidnapped in 82'...
is simply an uncovered nerve touched by this thread.. .
I'd help you out, but I don't know.

 

[Tequila]

...or you can use it if you are able to control how much you have designed. . .


As regards the calculation of inertia, in accordance with yes, ω is in [rad/s].
in your formula, if we insert n in [copi/min] is however reported in [colpi/s] dividend per 30...
angle speed fly wvol= (pigreco*ngirivol) / 30ω = 2 x π x n = 2 x π x n [colpi/min] 60 = p x n [colpi/min] : 30 and then we return to the starting point compared to what is calculated.

at the limit the strangeness is to use the value in [colpi/min] for the calculation of power, always for a dimensional question.

But in the meantime I had an idea.. .

the purpose of the inertia flywheel is to maintain the smooth and constant movement during the punching, and then try to have a variation of speed of minimum rotation.
Moreover it must be dimensioned as well to allow sufficient "force" to the punch to work correctly.

now, if we use calculated work of 33.36 [J] as energy "loss" or better necessary for punching, this energy could be the result of
< > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > = < < > < > > > > > < > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > 0 > > > > > > > > > > > > > > > > > > > > > > > > > > > > > >
with
i = inertia fly [Kg m^2]ω1= initial rotation frequency [rad/s]ω2= final rotation frequency [rad/s]so to existing fly, can we check how much decreases its rotation frequency due to punching, or am I wrong?
the higher his inertia, the less we will have a decrease in the number of turns of the flywheel...

clearly its sizing must be reasonable, for obvious reasons of loads, moving masses and all that entails having high forces to manage...(and also therefore sizing of the engine...)

I don't know if I'm shooting a big cabbage.
every comment is welcome.

Okay, then if the hits are 5 per second the accounts come back and the inertia of the flywheel drops considerably so you will have a small flywheel that turns fast.
regarding the reasoning you do is correct.
the sizing then follows its logic based on factors that can be different from time to time, type of encumbrance of the machine, existing cinematisms in stock, reduction of the costs of some components and so on.

I am pointing out then to make you a theoretical dimensioning of maximum with precisely the theoretical values that result from the calculations (taking into account frictions and yields since many are known) and then go back replacing some values with the existing ones... example from the accounts is a 400 mm diameter flywheel, in stock I have 420 mm, use the latter.

 

[Tequila]

Yes, I have it with a person in particular, great industrial, who made himself and was able to create an empire from nothing. I dare... After World War II, in the middle of the economic boom where two pieces of iron were sold on the cross because people sold their mother to buy the x that you sold... at the time it was enough to have swallows that enough and a little desire to do.
Today more excellent minds are forced to work at 1200€/month for these padroncini who had the chance to start at the right time... Today day to eat the sharks you must be born sharks, to try to become we end fish soup.

I repeat, I don't have it with your 87-year-old guy, but with a five-year-old younger, who was even kidnapped in 82'...
is simply an uncovered nerve touched by this thread.. .
I'd help you out, but I don't know.

I go too then possibly you can move comments on a new threadsame speech that was made long ago on characters like steve jobs (r.i.p.) or bill gates. they were pioneers at their time, which is not so remote, their luck was to start without having the system braking them and limiting them as it happens today for whatever you want to do, both build space ships, and make the grass moppar along the walls of the country houses.

1) 30 years ago you had enough good will, some good idea and a garage where to start. if it worked and sold you would become rich and powerful to allow you to change 2-3 times a day playboy bunnies.

2) in our day (2012), you must first have the money, the place that is to sanitary norms, with baths, heating, lights, documents in order, that you have opened p.iva, that the vv.ff. to do the eligibility surcharge for the establishment, which you bought (software speaker) licenses of use, etc.
then, for what you want to produce, you have to have the "chiappe" to test of stantuff, i.e. patent to level (minimum) European, not to be found after a few months with the stolen product and receive denunciation of idea theft, check that there is not something similar already done and be careful to the material and color you use, like if you use painted aluminum of white risks that the apple does cause you to be too much risk.

 

[numero1]

I go too then possibly you can move comments on a new threadsame speech that was made long ago on characters like steve jobs (r.i.p.) or bill gates. they were pioneers at their time, which is not so remote, their luck was to start without having the system braking them and limiting them as it happens today for whatever you want to do, both build space ships, and make the grass moppar along the walls of the country houses.

1) 30 years ago you had enough good will, some good idea and a garage where to start. if it worked and sold you would become rich and powerful to allow you to change 2-3 times a day playboy bunnies.

for nothing... people like this made good fortune because they were pioneers precisely, no matter whether or not there was the system that brake them, what was important was that there was no market.
they invented it...... for those products at least.
if you point to a market that doesn't exist and this has luck, you have centered.

Agreed on point 2 instead... the apple is exaggerating.
Hi.

 

[Tequila]

I do not agree with the simple fact that I saw people with good ideas that they had to give up for problems first of all monetary, then logistic. The only ones I have seen are those who have had the "lucky" to sell their ideas to more powerful people by finding in the worst case money and a document that obliges you not to disclose anything you have sold and in the best money more a contract of work.

 

[meccanicamg]

I throw it there: if instead of making a flying press with hydraulic clutch brake I made a hydraulic press with push cylinder?
if you support yourself as planners of hydraulic power stations can give you a compensated solution with or without storage tanks and you can also make 4 or 5 strokes per second if you optimize the vacuum lift/descent stroke while feeding the sheet or ribbon to be cut off.

the system is reduced dramatically to a mechanical level and you can vary the performance by changing the operating pressure of the hydraulic control unit and varying the load/download pressures of the accumulation lungs.

If you do not want to download all the oil of a cylinder chamber, you can connect it to the cylinders so that you have the automatic return.

the choice of swan neck or columns should be made according to the fact of the sheet size or ribbon to be fed. also in swan neck increase efforts but you can draw a lot at the bottom of the sheet. with columns you have geometric limitations but you can draw much higher thicknesses or altoresustainable materials.