Choose a runner system for injection molding

[cht211]

Dear members,
I just needed a help from your side if its possible. I am currently working on a project based upon Injection molding. The project is mainly based upon the " Determining the correct injection molding process" (i.e. Hot runner system or cold runner injection molding system).

I would be really very thankful if someone can answer the questions below

1. What are the factors that influence choosing a hot runner injection molding system over cold runner injection system or vice versa?

2. How does a manufacturer decides whether to go ahead with hot runner or a cold runner system dealing with different grades of polymers?

3. For example, if a consumer wants to produce million parts (high quality) per year using material such as polystyrene or liquid crystalline polymers. Which injection molding system would a manufacturer recommend (hot or cold runner system)?

4. Is there a kind of algorithm or mathematical model that a company follows which determines choosing the correct system (hot runner or cold runner system) to obtain the final product depending upon the conditions/requirements? What are those conditions are really make a consumer to switch from cold runner system to hot runner system?

5. Are there some grades of polymers that cannot be processed using hot runner system but can be processed using a cold runner system or vice versa??

I am aware of the advantages and the disadvantages of both the systems (hot runner and cold runner systems).

I would be really thankful if you could help me with this project or help me to get in touch with the right person that could help me to answer these questions.

If you want we can discuss this in detail over the phone as per your convenience

Sorry for the inconvenience occurred by me

Hope you have a great day

Thanking you

Regards
Chandresh Thakur

[ExcelWord]

Hello,
that is too many questions :) Looks like you are either a student or a sales guy.
You must talk to a hot runner manufacturer and also to those who quote the molds. A mold maker or so. Don't get me wrong, but this is a very complicated topic.
Saludos!

[brentb]

LCP can be a real challenge with HR
Tolerances can dictate if hr can be used
All comes down to money.
You save runner scrap (or need to handle sprue/runner)
You can save on cycle time


KOM

brent

[Jendalf]

1. What are the factors that influence choosing a hot runner injection molding system over cold runner injection system or vice versa?
Factors:
Complexity of the tool (length, dimensions of the runner)
Quality (of the part)
Expected project costs
Funds awailable
Size of the product (If you have to use gates (hydraulic/pneumatic) its nearly impossible to use cold runner in larger applications)
Material (plays less important role if the product is small (100g max))
Size of the IM machine


Everything what you will compare you have to compare on the whole project length.


2. How does a manufacturer decides whether to go ahead with hot runner or a cold runner system dealing with different grades of polymers?
If he is almost sure that cold runner is sufficient to produce quality parts with considering the points from Nr.1, he takes cold runer. Otherwise he takes always hot runners. (from my experience in automotive its 7%/93% - cold/hot)



3. For example, if a consumer wants to produce million parts (high quality) per year using material such as polystyrene or liquid crystalline polymers. Which injection molding system would a manufacturer recommend (hot or cold runner system)?
depends on other factors (point 1)
for example if you have part 100g weight max. It nearly doesn´t care from what material you will inject the part. Cold runner will be ok even if the part has visible A surface. Offc in some materials you could have problems with sprue ejecting (central sprue if too long).


4. Is there a kind of algorithm or mathematical model that a company follows which determines choosing the correct system (hot runner or cold runner system) to obtain the final product depending upon the conditions/requirements? What are those conditions are really make a consumer to switch from cold runner system to hot runner system?
It usually follows simple rule. How does the part look like and how will the runner system look like. Than you will consider other factors as a economical (sprue waste/profit), quality, machine limits, etc.


5. Are there some grades of polymers that cannot be processed using hot runner system but can be processed using a cold runner system or vice versa??
I don´t have experience with such a materials or applications. Common materials are all eligable to perform good parts in both systems.


My answer is too shallow I know but it depends on purpose of this informations. Breafly its enough. For your chief probably not and as a study for your teacher its notally F (or 5 if your from EU) :)