Page 36 - Plastics News July 2018

FeAtures

to stall or hesitate. The constant, non-fluctuating pressure A specialized controller is needed for the injection molding
continuously advances the flow front at every point, even machine, enabling the process to be controlled by plastic
where it encounters ribs, bosses, or other features. pressure, rather than by velocity and holding pressure.
A pressure sensor is added to the machine nozzle to
The process relies on the cooling of the melt in the mold provide real-time measurement of the plastic pressure
to create resistance to flow, which in turn allows pressure entering the material delivery system. The controller uses
to stabilize and remain constant in the interior of the flow plastic pressure as its primary control signal throughout
path and at the flow front. Because the mold is filling very the filling of the mold. Sensors are added to the mold,
slowly, the polymer is continually cooling and densifying providing indication of pressure in the mold and flow-front
while the mold is being filled. The part actually “packs progression.
as it fills.”
Feedback from the mold sensors is essential to provide
Figure 3 shows short optimal pressure in the mold and to make real-time
shots from an iMFLUX adjustments to injection pressure resulting from material,
process and a typical mold or process variations. A user interface is provided
conventional process. to allow entry of process parameters and to monitor
As you can see, the the process. Figure
iMFLUX short shots 5 shows the elements
are co mpletely of the proprietary
packed no matter where the flow front is stopped, while control system.
the conventional parts are not packed and continue to
densify behind the flow front. The iMFLUX process
can be integrated
The iMFLUX process fills slower, but results in a faster with most machine
molding cycle. There are several contributing factors:
types, including
1. Lower filling rates result in less shear heating, which hydraulic, all-electric and hybrid injection machines.
then requires less cooling time. There are many OEM kits for new presses available

2. The mold is filled so slowly that the mold is “packed for this technology from several major machine
as it fills,” thus the material is continuously in contact manufacturers, which provide fast and simple integration.
with the mold walls, providing efficient cooling. However, iMFLUX can be integrated with existing machines
as well. The process works efficiently with molds designed
3. When the mold is completely full, the part is already specifically for iMFLUX and with retrofitted mold and press
packed, which essentially eliminates the packing combinations.
phase and reduces the cooling portion of the cycle.
The combined effect results in a faster cycle time, This system is in production in multiple industries,
as shown in Fig. 4. including automotive, medical, packaging and consumer
goods. Running the process with a closed-loop, low,
constant pressure control means that most polymers run
better with iMFLUX than in the high-shear environment
of a conventional process.

Benefits of the imflux process

The benefits the iMFLUX process result from four key
differences versus conventional molding:
How to implement this new process
1. Low, constant-pressure filling;
iMFLUX Inc., established in 2013, offers this patented
technology, which is available under license. The 2. Packing as the mold is filled;
technology has been vetted at full production scale across 3. Filling with no flow hesitation;
hundreds of comercial applications. It is exclusively 4. How it uses cavity-pressure feedback from the mold.
supplied by iMFLUX Inc., based in Hamilton, Ohio.

Plastics News July 2018 36