The prospects of modern thermoanalytical methods for characterisation
of flow, curing and final mechanical behaviour of
moulding compounds were demonstrated. Using urea resin
moulding compounds from different manufacturers the possibilities
of the various techniques could be shown. With comparatively
low effort, fundamental information can be gained
before production process had been started. On this basis it is
possible to make appropriate material selection at an early
point in the process chain. On the basis of thermoanalytical
data an incoming goods inspection can be established. Also it
is easy to control the compliance with the conditions of delivery.
In some cases it could also be helpful to have stored analysis
data especially when problems appear in manufacturing
process or unexpected part damages occur
With the ultrasound measuring system it is possible to transfer
the findings from the analytical methods directly to the processes
in the mould. The application of ultrasound provides
Dynamic Mechanical Analysis in the mould. Beside quality
assurance ultrasound can also be used for process optimisation,
especially for reduction of cycle time. In an advanced form
ultrasound information can be used as a basis for improved
machine control based on material state. The ultrasound measuring
system developed by ISK Iserlohn and BAM can be
obtained from the ISK.
Commercially available melamine/phenolic (MP) moulding compounds used for manufacturing electro installation parts were investigated by laboratory thermal analysis methods: Dynamic Mechanical Analysis (DMA), Differential Scanning Calorimetry (DSC) and Dielectric Analysis (DEA). The results were compared with on-line measurements in a compression mould using incorporated dielectric and ultrasound sensors. Softening and cross-linking behaviour were analyzed. For on-line process monitoring, only the ultrasound method worked well. The dielectric method was distorted by water formed as a by-product from the poly-condensation reaction.
Thermosetting moulding compounds are synthetic materials which can be easily formed in the molten state and achieve high temperature stability due to a cross-linking process which takes place during manufacture. To ensure thermal and mechanical properties, post-curing of moulded phenolic resin components is necessary for high quality applications. In the industrial practice, post-curing time-temperature-programs are heuristically acquired. In this paper, dynamical mechanical thermal analysis is employed to determine optimal post-curing conditions for injection moulded parts from phenolic resin.