mold vents

[MoldMaker]

Good evening to all,

mainly I plan molds for rigid, flexible polyurethanes etc. every day the request of the various customers is to have the most beautiful piece possible and who makes molds of this kind knows that unfortunately with the polyurethane you have to fight with the bubbles that come to form to finished piece, I asked you that systems of used vents? in the last designed mold I happen to have to predict more than 100 vents on a mold of 600x400mm approximately... I didn't know where to put them in.

 

[ale47p]

Yeah. I'm on my phone now. I have the time to write something from the pc

 

[PaoloColombani]

is the problem of low-pressure molding with rather fluid mixtures, as happens for bicomponents. more than filling the mold of vents, it could be useful to work with the vacuum.

 

[ale47p]

@moldmakerdo you have a machine to test the molds before delivery?
Are they for casting or for injection?
Are there mold pieces that move after injection or are injected in closed mold?
the vents you've done start from the figure and bring the air out being dug on the adaptation surfaces?
can you create a "bava" to be trimmed after molding or not possible?

If you tell me what type of mold we're talking about, I might have generic advice, I don't write them because maybe they're not suitable for that kind of technology. . .

in any case depends much on how good the customer is to print
commitment, experience and technology really make the difference to the final result

is the problem of low-pressure molding with rather fluid mixtures, as happens for bicomponents. more than filling the mold of vents, it could be useful to work with the vacuum.

I know casting with protective film
Do you know any other guys for pu?

 

[PaoloColombani]

I know casting with protective film
Do you know any other guys for pu?

Hi.
there would be the possibility to put "in hold" the downstream mold of the vacuum channels with the closure. I guess we're talking about low-pressure closed molds. I don't know if for protective film you mean the classic vacuum bag or if you mean an adhesive film to be applied on the closing edges of the mold. In any case, it seems to me that it requires application times for each print.

 

[ale47p]

Of course, I was talking about low pressure
Let's hear @moldmaker

 

[MoldMaker]

@moldmakerdo you have a machine to test the molds before delivery?
Are they for casting or for injection?
Are there mold pieces that move after injection or are injected in closed mold?
the vents you've done start from the figure and bring the air out being dug on the adaptation surfaces?
can you create a "bava" to be trimmed after molding or not possible?

If you tell me what type of mold we're talking about, I might have generic advice, I don't write them because maybe they're not suitable for that kind of technology. . .

in any case depends much on how good the customer is to print
commitment, experience and technology really make the difference to the final result



I know casting with protective film
Do you know any other guys for pu?

Sorry the latitude:roflmao:, unfortunately we do not have the machine to test the molds also because we make molds for various types of pu from the rigid, re, flexible, expanded, semi rigid and who more has it, and having a machine able to manage all the materials is not simple, especially counting that we also make molds for laboratories that we study various types of materials.
we happen to make both low-pressure injection molds and by casting, but also we say it varies a lot according to the piece, material etc.. the vents some we prepare them in figure and others on the mold line according to the needs of the customer, for the bava also goes a lot according to the customer. any advice or suggestion is well accepted, even because maybe from an idea/chat can always arise an intuition to develop something new,

 

[ale47p]

too generic, generic advice (especially stamping, since a good customer will print much better than a less good customer at equal mold):
hot molds the right (better some degree less than some degree more)
good, fresh materials (no 2-day old stuff... )
remake the pol/iso reports every half day
hot materials the right
no condensation on the injector ---> chiller
do not exaggerate with the detachment, less possible and better
if possible, do not make edge finishes
if possible, do not leave areas with less than 3mm of material passage regarding the foam. the more dense the material, the more this value can descend, but I would say never less than 1mm
if possible, a beautiful 1.5mm gag and gogo vents