Essentially, you cannot generate reliable machine independent process documentation based on process outputs if the mold cavity fills completely during 1st stage injection. Problem: I see many companies trying to utilize machine-independent process documentation while still filling the cavity completely during 1st stage injection. Since the mold cavity is both filled and packed during first stage injection it […]
Category Archives
Plastics Technology
Glass-Filled Nylon with Regrind
Since the regrind has variable sized pieces, additional drying time may be necessary to ensure the thicker chunks are fully dried. The regrind process results in irregular-sized pieces which have different cross sections. Question: Most of our parts use an industrial grade resin ( recycled PA with GF) and often with 20% of regrind resin. […]
Hydraulic vs. Position Transfer
When filling the mold completely during 1st stage fill, many processes respond well to pressure transfer when compared to position transfer. In either case, you will see even better results with a 1st stage short shot (90-95%) using position transfer. Question: I recently moved to another company and all the setups are using Injection Pressure as […]
Improving Process Efficiency – Packing Time
A 2nd Stage Packing study is a critical aspect to optimizing any molding process. You should perform a gate seal test for each of your molds to ensure you are not using wasting energy with excessive packing time. Gate Seal Time: To determine the time required for the gate to seal requires a gate seal […]
Molding Issues with Red PMMA
Design issues are very difficult to process around. Your defects indicate a potential venting problem which should be addressed first by reducing clamp tonnage and/or adding more vents. Question: I am processing both clear and red transparent PMMA of the same grade. For the red part, the thickest area is 4mm compared the average wall thickness 2.5 mm. […]