Only an Educated Buyer Can Reap the Rewards
Choosing the right electrically-actuated hot runner system is important, so is asking the right questions upfront to better understand what you are buying. It’s easy to be sold on all the fantastic benefits you could see, while looking passed the downsides of the system you are choosing.
Patented electronically-actuated valve gate systems precisely control each valve pin’s position, acceleration, velocity and stroke allowing molders the unique ability to control the flow rate out of each nozzle gate at any time during the fill process. This technology is ideally suited for injection molding applications that require precision, responsiveness and repeatability, such as multi-shot/multi-material, sequential/cascading molding or for parts that require premium cosmetic surfaces. It is ideal for use in all electric and cleanroom environments.
The operating principle is as follows:
- A linear electric actuator with electronically-controlled open/close and motion/position profile.
- Variable opening stroke length, intermediate closing position and opening/closing speed of each valve pin.
- High precision, individual pin position, repeatable to within 0.01 mm increments
Now, it’s time to do a little digging before you purchase an electronically-actuated valve gate hot runner system. The first common pitfall of some electric systems is the cut-out required to house the electric motors and the device, which links the motors to the valve pins. How much steel must be removed from the back-plate to house motor assemblies? Some electric systems on the market today require an excessive amount of steel to be removed. This not only adds machining costs but can weaken the tool potentially creating other problems. Furthermore, in some cases there are surfaces the motor assemblies mount to with critical tolerances. Machining to these tolerances adds even more costs and then failure to hit those tolerances can cause premature wear, which results in failures during production.
How complex is the mechanism that takes the movement from the electric motor and converts it to be capable of moving the pin? Simpler is better when it comes to these types of devices. Even if the electric motors are thermally isolated from the hot runner system, they generate their own heat when running and moving a load. Motors allowed to overheat can fail over time requiring expensive repairs that may be needed when production is critical. Does the system have a way to prevent the motor from overheating?
Because there are fewer choices of hot runner suppliers when it comes to electric systems, be sure that the supplier is one you want to work with. Are they known for supporting their products? Will they be there when you need them most?
Ask these questions and understand what you are getting. Yes, it’s important to consider the pros of each electric system, but it is equally important to take the time to understand the cons. By doing this, you will make the most informed choice possible.
By asking the aforementioned questions you can ensure that you get the system that is right for your mold. Whether you are a moldmaker, a molder, or the end-user of the molded parts, electric actuation maybe be the answer you have been looking for.
Moldmakers need to be aware of how different gating technology can affect their customers when designing a hot runner system into a mold.
While both hot runner and cold runner systems have their benefits, for design flexibility as well as reduced cycle times and costs, hot runner systems will probably be the better choice.
Selection criteria and common coating attributes for PVD, CVD and other common coatings.