I have read some industry discussion groups lately and have noticed some confusion on the difference between Thermosets and Thermoplastics, so I will use this post to help clarify these points… Thermosets Thermosets are polymerized during processing while thermoplastics are polymerized before being processed. During processing, the polymer chains in thermosets fuse together, or cross-link. […]
Category Archives
Plastics Technology
Drop Packing Pressure and Time…?
This question came in from a molder overseas… HM During process optimization, which is best, keep both the packing pressure and packing time to zero OR only holding pressure? My Response This is based on your machine. On most machines, you can turn the pressure down to zero and the pressure will turn off. Before […]
Retaining Defects…
I was recently visiting a molder who was having a specific problem… Supervisor We are having trouble with our employees properly identifying and naming part defects… any suggestions as to how we can improve this? note: After a couple questions, it was determined that they do not retain defective parts as they are all discarded, reworked, or reground. My Response It […]
The Affect of Moisture on Injection Pressure…
The other week, I received a multiple part question regarding many aspects of materials, this is one part… Nathan Although the 1st stage injection time is the same, the virgin PC/ABS (<0.06% moisture) has a 1RMPa higher peak injection pressure than virgin PC/ABS (0.08% moisture). Is this change in pressure common? My Response Moisture in the polymer causes hydrolysis to occur. As […]
Determining Intensification Ratio Using Specifications…
I was asked this question during an on-site visit earlier this week… Technician I know this machine is rated with a maximum injection pressure of 38,000psi, but I am not sure how to convert this to an intensification ratio. note: The intensification ratio is a factor which is used to convert the hydraulic pressure being applied to the […]