Scientific Molding
Scientific Molding Benefits
1. Zero Defects
Consistent part
quality based on cavity pressure.
2. Locked Process
Based on hard
data, not black magic.
3. Part
Discrimination
It is a way of knowing the part is
good or bad as molded. Allows us to
accept or reject parts as molded, true
process control.
4. Scheduling
Flexibility
Allows us to produce parts of consistent quality, no matter where they are run. Process parameters are
derived from the plastic variables,
not machine variables.
Scientific Molding Objective
Performance of the plastic melt in the mold. Not the set points on the machine.
Scientific Molding Parameters
A machine-independent process that provides four (4) basic
parameters to optimize the molding process.
1. Plastic
Temperature
We measure heat
or plastic temperature.
2. Velocity of
Injection (Viscosity or flow rate)
Viscosity varies by fill speed. The faster you push the plastic material the less viscous it becomes and
the easier it
flows. The less viscous the plastic, the more consistent the molding process
and the part.
3. Plastic Pressure
We use (CIM) to
monitor cavity pressure with a transducer
We use (CIM) to
monitor press hydraulic pressure
We use (CIM) to
monitor back and hold pressure
4. Cooling
We monitor
cooling by measuring the coolant temperature in and out of the tool.
This enables us
to have a lock process to run the same cycle shift after shift.
Scientific
Molding Process
1. We correlate good parts with the
process measurements and then lock in the process. We use data derived from pressure transducers
inside the cavities to activate part segregation.
2. We perform a rheology study (study
of flow and deformation of matter) with a series of short shots. Data from these shots is used to derive a
rheology curve, which is used to establish optimum velocity for the first-stage
injection. This velocity assures we mold
at the best possible viscosity for this mold.
3. Optimizing the mold, we read cavity
pressure performance. We optimize
injection pressure, injection velocity, transfer position, fill time, pack, and
hold pressure and then conduct a gate seal study to determine pack time.
4. Once the process is stabilized and
acceptable parts are produced, basis data is recorded for the mold, specific to
the mold, not the machine.
This becomes the “Locked
Process” for this mold and correlates to the parts submitted to the
customer for approval.