What is the processing temperature of HDPE?
Extrusion Processing Guide: PE-HD – High-density polyethylene
| Processing Guide: | PE-HD – High-density polyethylene |
|---|---|
| Cylinder Temperatures: | 180-205°C 356-401°F |
| Melt Temperature: | 180-205°C 356-401°F |
| Pre-Drying: | No, 3 hours at 105-110°C (221-230°F) for regrind |
| Calibration: |
What is the effect of temperature during plastic processing?
Higher melt temperatures increase energy consumption, degrade the polymer, and extend the cooling time needed to create a dimensionally stable part. To compensate for this extended cycle time, processors will rely on reduced mold temperatures to gain back lost productivity.
How does temperature affect polymers?
Higher temperatures lead to lower young modulus of the material. Weak points of every polymeric material are the secondary bonds between molecules of your polymer. With increasing temperatures, the molecules have more kinetic energy, thus the weak secondary bonds have less and less effect.
Why is Moulding temperature important when processing thermoplastic polymers?
Setting this time properly will ensure that the injection machine will yield desirable results. If the residence time is insufficient, the plastic will not reach the desired temperature and may harden prematurely upon entering the mold cavity, leaving sinking spots where plastic did not completely fill the mold cavity.
How is HDPE processed?
The Process of Making HDPE HDPE is made under controlled conditions by applying intense heat to petroleum. This process, also known as “cracking,” helps create ethylene gas. During its production, the gas molecules will attach to form polymers, which then produce polyethylene.
What temperature does HDPE mold?
Best results are obtained when HDPE is molded at temperatures ranging from 400 F up to 430 F. Too high of a temperature can cause problems with excessive flashing and burning and with shrink phenomena such as sink marks, warpage, shrinkage, and void formation.
What is melting temperature of polymer?
Melting Points of Polymers
| Polymer Name | Tm1 (°C) |
|---|---|
| Poly(etheretherketone), PEEK | 357 |
| Poly(ethylene adipate) | 63 |
| Poly(ethylene oxide), PEG | 66 |
| Poly(ethylene terephthalate), PET | 264 |
What happens to polymers at high temperatures?
Simply put, even in the absence of air, polymers will begin to degrade if heated high enough. At high temperatures, the components of the long chain backbone of the polymer can break (chain scission) and react with one another (cross-link) to change the properties of the polymer.
Why is heat deflection temperature useful?
The heat distortion temperature (HDT) – also known as the deflection temperature under load (DTUL) or heat deflection temperature – is an important property of polymers. It gives an indication at what temperature materials start to “soften” when exposed to a fixed load at elevated temperatures.
Why is important to control the degree of cooling in a thermoplastic injection molding operation?
The Importance of Temperature Control in Injection Molding Effective temperature control prevents quality issues such as shrinkage, warping and stresses from developing in the material. A critical technical objective is to find a balance among: The temperature of the cooling fluid.