electric heaters for moulds

[Jari]

electric heaters for moulds:

I have little experience in this matter,
However, I must apply them in a mould (in matrices).
I look for any kind of information
(e.g. formulas to be used that may be useful to me -
specific software or that you could lend to the question)
In short, any information, because I have 4 prints to print
and I must bring the mold to about 140°.
uniformly, of course.
From the point of view of power stations and so on I should be fine.
I would like to understand how to choose the right resistance and try (simulating ?)
its correct positioning, how to place them.
Thank you in advance.

 

[SHIREN]

electric heaters for moulds:

I have little experience in this matter,
However, I must apply them in a mould (in matrices).
I look for any kind of information
(e.g. formulas to be used that may be useful to me -
specific software or that you could lend to the question)
In short, any information, because I have 4 prints to print
and I must bring the mold to about 140°.
uniformly, of course.
From the point of view of power stations and so on I should be fine.
I would like to understand how to choose the right resistance and try (simulating ?)
its correct positioning, how to place them.
Thank you in advance.

Hello jari
I'm sorry that no one currently has the necessary specific experiences to respond to you
or at least we are in a forum for moulders
Maybe you need someone to make molding
in fact for resistors as well as for the injectors-torpeds-hot rooms
asks the manufacturer
Thank you very much

 

[Jari]

Bye!
in fact I solved by asking the manufacturer of the resistant (to the trader), but it is based mainly on the experience.
are still looking for a more "scientific" method, or a software that allows you to quickly try different solutions.
reducing the question to the minimum, I would like to know how to dimension the power of the resistive cartridge (depending on temperature and distance from the figure).
something I found but I wanted to read other ideas, methods etc... in other words.
thanks anyway for the suggestion, also the molding in fact I was of help.

 

[IPdesign]

Well as you see almost everyone, I understand, we rely in part on our expertise and in part on that of resistors manufacturers and as you see there are many variables in play.
some variables may be:
temperature of injected material to be printed
theoretical thermal range of the mould
presence or not of temperature reading probes
possible differentiation in areas
heating times

and I could continue.

this is why we usually rely on the experience of the builders.

 

[gianluigi]

being a former thermoplastic mold designer, I changed work for lack of tools and moulders in milan and interland.

I agree with you the parameters for a good result of the printed piece.
the main problem is to adjust the control unit well, the temperature varies in each position, it is necessary to consider well the cooling that varies from the matrix
to the male.
the filling times of the piece.
cooling time.
thanks to all for the experiences that are treated.

 

[Jari]

always about electric heaters. . .
I would like to know if it is actually useful, in the case of cylindrical heaters, to drill
and alesare the offices.
the manufacturer recommends this because the heaters after several cycles do not maintain the same size (ø) or they "flame" of a few cents.
if the hole has a low wrinkle (trapano) after you definitely have problems disconnecting the resistance.
In short, I would like to understand whether it can actually be useful to alease the hole, because otherwise (if you frame all the same) then I have to take measures now.
I would like to read the opinion of those who have molds for several years with heaters that can remove and put when you want with ease.

 

[Mocca]

Bye.
I put some notion of thermo-hardening moulds that I designed many years ago.
to dimensional the "heating machines" to be inserted in the mold I used the following formula:

kw=(kg * cs *dt)/(864 * tm)

kg--- weight of the mass to be heated in kilos
cs---> material specific heat (for steel should be about 0.1 kcal/kg)
dt---> temperature difference between the one to be reached and the initial one
864---> transformation ratio between kcal and kw
tm--->time in hours to reach temperature

at the end of the calculation increase by 15% to compensate for losses.

(Click if there is any engineer who can confirm or deny this formula)

It's clear that you get a kw value that you're going to split up for the cartridges you choose. I used 600 to 1000 watt cartridges.
the distribution of cartridges in the mold, as the other users already recommended, was dictated by the experience. consider, however, that if you need to insert 10 cartridges, you will put them in a homogeneous and equidistant manner, avoiding concentration in one or more zones.

As for the seat, it was argued to make sure that the cartridge, once inserted, did not have air areas that burned the cartridge itself.

Today I imagine there are sophisticated software capable of analyzing the necessary power according to the temperature to be achieved, as today it is absolutely not able to do without the mold-flow and mold-temp .

I hope I have been of help waiting for some expert of moulds for radiators.
We said hello.

 

[Jari]

thanks for the answer that can be useful to many people, but now I am oriented on another theme (not that of beginning discussion).

I would like to know from who has molds or sees molds with cylindrical electric heaters, if it is actually necessary for the disassembly of the above heaters carry out the seat with low roughness or alesare (or drilling with cannon tip).
in my direct experience (using drill holes) I do not run into overheating problems but in dismantling problems.
the builder of the resistors tells me to alesare the holes, and therefore this must be done (ok).
But I am not sure that this guarantees me an effective disassembly in the future after a long series of heating cycles.
So I do not know if I have to take measures on the mold now (but this has a cost) or entrust myself to the words of those who sell them and distribute them.

 

[ccentazzo]

Good morning, I read this discussion and would be interested in solutions, having passed a few years since the beginning of this thread, is there someone who in the meantime experienced and found some new solution/method/formula?
Thank you.

 

[TECNOMODEL]

I also see the thread for the first time, I found interesting the formula indicated by mocca although I have some perplexity.
It takes a time to reach the temperature, I think it is an unimportant parameter.
It would affect only the time that the mold uses to go into temperature at the start of the plant, time that is almost certainly less than the one required to heat the injection cylinder.
In my opinion it would be more important to consider how much heat is "exported" during the process, so as to dimensional the resistors so that they are not always under charge and lengthen their life.
speech, I think, quite complicated because usually the system is composed also of a conditioning unit that has the task to maintain stable temperature.
the whole is connected to a series of thermocouples that regulate the ignition of the resistors and the opening/closing of the cooling circuit.
if we talk about "spinte" productions then it is worth to calculate everything in detail, even few watts saved per day multiplied by years of production make the difference.

 

[yudansha]

Hello.
I attach a link to "roctool" if someone had never heard of it.
I would like to ask the Commissioner whether he is a member of the Commission.https://www.youtube.com/watch?v=jcarcbtjbsg