Generally, plastic injection molds can be devided into 2 types based on the type of runner used: Hot Runner and Cold Runner. The price of the mold used Hot Runner is different from Cold Runner one, and the reason to use which one also depend on the part being made, the production’s volume and the requirements of parts’ finish. Then, you are not sure you should use Hot Runner or Cold Runner for your mold, you could ask your injection molder to make sure. When that supplier is experienced in plastic molding, they will be able to give you the best advice which can help you get the best cost as well as the best quality mold, and the best benefits of the runner with your mold required. Both Hot Runner and Cold Runner have their own advantages and disadvantages, then knowing the differences between these runner will help you make better decision for type of mold that will work for your projects.
Nowadays, inspite of 3D printing technology, most of plastic parts are still made with a mold, especially injection mold technology is used a lot. With this technology, plastic resin will be melted in the barrel of injection molding machine then is injected into the mold. The liquid plastic will move through runners, then a gate that separates each runner from the mold cavity. When the plastic come to the mold cavity, the final part will be made. Therefore, hot runner or cold runner will effect the part being made, so what is the difference between these two runners?
The hot runner became popular since the 80’s and 90’s, even though the first hot runner system was used in the 60’s. In the 80’s and 90’s, the technical advances made hot runner become more reliable and more desirable when the price of plastics material increased. With a hot runner mold, the runner will be heated in order to maintain the plastic in a liquid state with in the tool except when it passed through the gate in to the cavity, which means that instead of being ejected with the part, the runner will be kept inside the mold to fill the cavity to make the next part.
The amount of the pastic used will be reduced a lot with a hot runner system when making the parts won’t almost waste the material. Even though, generally, using hot runner system is complicated and will make the mold more expensive to manufacture, run and maintain, for the production with high volume, especially with small parts, the decrease in costs per part will be more effective with hot runner system.
How about cold runner system? Of course, there are some differences! The passageway carrying the resin is machined into the mold plate, then the mold itself and the passageway will have the same temperature. The 2 plate system is the simplest style. The runners and the parts will be attached and separated from the mold with an injection system. Therefore, after molding the part, both the runner and the part will be ejected. Then, you have to remember to separate the parts from the runners. This is different from a 3 plate mold, the runner will be contained on a separate plate, then the parts will be ejected alone.
"In the cold runner system, the runners that are ejected from the mold can represent a significant amount of the total plastic resin used. If the parts being molded are large, the runner is usually a small percentage of the resin being used, but for smaller parts, the runner can be a larger percentage of the resin used. Many times the runner can be reground reducing plastic waste, but the process can increase cycle time. Cold runner molds are less expensive to make, but the added material waste and increased cycle time can offset the savings in tooling costs."
Here is to compare the advantages
and disadvantages of Hot Runner and Cold Runner:
----------------------
Bluestar Technology Group Co., Ltd
Plastic Injection Mold Maker & Automotive Plastic Part Manufacturer.
Website: http://bluestar-mould.com Email: Marketing@bluestar-mould.com
Tel: (+86) 755 2689 0382 Fax: (+86) 755 2685 9566
Factory Add: No.1&3, Tongfuyu A-2 Industry Area, Buyong Shajing Town, Baoan District, Shenzhen, China 518104
HQ Add: CD, 2F Technology Main Building, 1067 Industrial 7th Road, Shekou, Nanshan District, Shenzhen, China 518067.
No comments:
Post a Comment