I received this question from a frequent blog contributor, and believe it makes a good discussion on decoupled processes… Milan On some of our machines, we can adjust the hold velocity. How should this feature be used when molding a decoupled II process. My Response Before I respond, I want to relate the general attributes of […]
Category Archives
Plastics Technology
Fill Time, Viscosity & Molding Economics
A friend emailed me this great question the other day regarding the relationship between fill speed and pressure… JM The pressure required to fill a particular mold went up from 950 psi at 1 in/s to 1050 psi at 3 in/s. I understand the higher pressure needed to hit the higher speeds, but shouldn’t this be […]
PET Screw Design For Injection Molding
I received this blog topic request yesterday… Samer Concerning injection molding, is there a specialized screw used for PET? My Response Yes, the goal in PET processing is to (1) maximize output, (2) control shear heat, and (3) minimize melt tempertaure… yet ensure the polymer is fully melted and as homogeneous as possible. (1) The need to maximize output is […]
Buffered Pressure Limit Settings
This question came in last month. Although I could not get any specifics about the machine such as age or model, I believe the question still makes a good discussion… E-Mailer Today I tried to adjust limit of injection pressure on Demag machine. I adjust maximum of machine 210 bar actual injection pressure was 160 […]
Boss Cracking on a Polysulfone Part
A recent question was received via e-mail… RZ We are encountering cracking at the bosses on a polysulfone part. We press fit inserts on the bosses but we don’t see cracking during insertion. It is not until a day or two later that we see the cracking. Any thoughts? My Response The occurrence of cracking and crazing in […]