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injection molding-sformo

  • Thread starter Thread starter LucaLuca
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LucaLuca

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Good morning to all .. this is the first message on this site. .
I have no practical problems but only theoretical problems being a student, so with no practical knowledge of my problem:
in which areas of a plastic component is present the sform and why it is used. .
equal to conditions what involves the doubling of the minimum thickness of a component. . .
equal to conditions what involves the doubling of the number of figures (improper) in the mold. .
and double the maximum tightening force of the machine (and therefore its size). .

Thank you in advance
♪
 
Bye-bye
I try to help you understand
- the sform is used to extract the piece from the mold, so the parallel walls to the molding axis must be "formed" for example if I had to print a glass with the circular wall perfectly straight there would be problems extracting the piece from the mold because the straight wall strips on the steel of the mold creating an friction instead if they prone that wall (taking a cone : imagine a vase) the piece is removed much more easily from the mold
- the minimum thickness must be determined according to the characteristics of the piece and the type of plastic used (more or less fluid during the molding)
- with regard to the number of prints to be placed on the mould depends on the production needs and economic convenience: in general if the number of prints decreases the cost of each piece but increases the cost for the realization of the mould therefore it is a matter of finding the necessary compromise
- I think the machine is chosen in relation to the size of the mold and the number of prints of the same
 
nice questions, it is not easy to answer synthetically.
in addition to what has already been said, I would add that:
- in general we try to draw the pieces with the constant thickness, areas with greater thickness involve a greater withdrawal and therefore can result in a deformation of the piece, of course it affects very the type of material to print, but in principle it is so.
- as regards the number of footprints, it is decided on the basis of the demanding production and the economic evaluations of the case.
- the closing force of the machine is determined by the size of the mold, the number of prints, the amount of material to be injected etc., of course it would be non-economic (not to mention the practical aspect) print 4 plastic glasses with a 400 tons.
 
Good morning to all... .
to what is said you could add that:

the shape can also be influenced by the type of surface finish. i.e. if the piece is photo-engraved, to mean it has that "great" aspect that makes so cool :36_1_1: the minimum shape must be 3-4 degrees.

the thickness can also be modified for aesthetic needs: that is to avoid that phenomenon, said Risucchio that sometimes makes it crazy:36_1_16:

if you can use a quick calculation to determine the type of press is p= printer surface * 500 kg/cm^2;
therefore if you double the number of prints you double the press, i.e. you pass from a 400 ton to a 800 ton.
 
Mould Inventor said:
if you can use a quick calculation to determine the type of press is p= printer surface * 500 kg/cm^2;
therefore if you double the number of prints you double the press, i.e. you pass from a 400 ton to a 800 ton.
Click to expand...
where by printer surface means the front area of prints on the mold opening plane.
 
Mould Inventor said:
if you can use a quick calculation to determine the type of press is p= printer surface * 500 kg/cm^2;
therefore if you double the number of prints you double the press, i.e. you pass from a 400 ton to a 800 ton.
Click to expand...
Sorry, what is the equivalent of ....* 500 kg/cm^2
Thank you:
 
Hi.
this is a value that is for the type of printed material
obviously changes from abs to methacrylate to acetalic
and so forth
(I'm sorry but I have at home and not here the table I had drawn)
multiplied by the front printed surface and by the fingerprint number.
Hi.
peace and good:
_
 
Guys... I have to put in order what you have told me because on some points my mind becomes a little 'nebula'. .
If I can hear you for further explanation?
Thank you again. .
♪
 
tecnico_plast said:
where by printer surface means the front area of prints on the mold opening plane.
Click to expand...
excellent punctuation.

with 500 kg/cm^2 you are safe, but very much, with almost all the most common materials, or better those most used by me :36_1_13:

also because sometimes I happen to have changed the material completed the mold :4404:
 
Mould Inventor said:
Good morning to all... .
to what is said you could add that:

the shape can also be influenced by the type of surface finish. i.e. if the piece is photo-engraved, to mean it has that "great" aspect that makes so cool :36_1_1: the minimum shape must be 3-4 degrees.

.
Click to expand...
hi mould... .
I don't know if it's fair to say that the deform can be indicated in 0° degrees.
perhaps it would be appropriate to talk about mm for each "side of the mold

in practice if I say 3rd on a 10mm "h" I give a 0.5mm sform
indicate 3rd on h 50mm the thing and very different

However generic by international convention
where there are no indications from prog. sforms are always to increase the nominal quot
is the task of the prog of the final product to draw the printed
in order to predict any deforms and to determine the relative section of the piece
Let's open a discussion that won't end
how many progs of the final products do you know that prog already with sforms and sez??? ? ?
how many moldists are forced to review correcting
with hours and hours of various discussions with the prog of
what comes from the various offices??? ? ? ?
and na endless battle:
Thank you very much
 
Hi.
Annex to the table of pressures I used in the "tamps". .
I hope you can help
attentive to the sform ... first the roughness finishing surface
and then I preferred degrees ( centesimals and not sexes)
If you have any other questions...please. .

Hi.
Linus57:smile:
 

Attachments

SHIREN said:
how many progs of the final products do you know that prog already with sforms and sez??? ? ?
Click to expand...
for my experience, I can tell you that we design the pieces and their molds, so no problems.
once we had to deal with a guy who wanted the molds for some pieces, and they were all in-printable, in the sense that they were redesigned, not modified:biggrin:

According to me it is impossible to design a piece if you do not know the technique of production, molding in this case, or rather, it is possible but with the risk of punching with the moldists :smile:
 
I think that, in a resumption, everything has been said clearly. Given the experience of molding I allow myself to put some consideration on the forces in play; the pressure normally considered for the calculation of the tonnage of the press does not exceed 300kg/cm2 (to be applied to the surface of the piece/i), this pressure is already inclusive of safety coefficients.
 
perhaps it is trivial but in the calculation do not forget the surface of the materozza in case this is present.

Hello.
 
from what I understand everything is based on theoretical and practical knowledge.. I could say that I could hire you as full-time professors. .
I'll ask you one last thing. .
I have two materials such as hdpe and pp...I have to choose the most appropriate injection machine so that the formed piece can be detached from the mold and fall for gravitational fall in a collector (think of the max identifiable size)
average thickness 1.2 mm
maximum thickness 1.5
area of net projection on the mold plane=50 cm^2
rectangular plant with larger size 10 cm
height 7 cm
of the materials I have densita' diffusevita ti,t molds, t extraction; injection pressure
and table with various fserrage,volume of a charge,existing time cost,dry cycle duration ,max molding and nominal power

ps look that all this has been explained very little, think to me as if I had never seen a press...
 
SHIREN said:
hi mould... .
I don't know if it's fair to say that the deform can be indicated in 0° degrees.
perhaps it would be appropriate to talk about mm for each "side of the mold

in practice if I say 3rd on a 10mm "h" I give a 0.5mm sform
indicate 3rd on h 50mm the thing and very different
Click to expand...
I am sorry to contradict you but for photonynx pieces the regulations specific precisely the degrees, so that in the extraction phase there are no aesthetic defects.
By reasoning how you would run the risk of making "macelli" if you need to know how much to move the quota if you get a piece devoid of reform just take the calculator.
 
luca luca for your last question sincerely I did not understand what you want to know.
 
Mould Inventor said:
I am sorry to contradict you but for photonynx pieces the regulations specific precisely the degrees, so that in the extraction phase there are no aesthetic defects.
By reasoning how you would run the risk of making "macelli" if you need to know how much to move the quota if you get a piece devoid of reform just take the calculator.
Click to expand...

:confused::rolleyes:
 

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