INNOVATION | THERMOPLASTIC COMPOSITES
deviations within an adjustable narrow tolerance band. This results in a uniform heating rate for all control zones and all control zones reach the temperature setpoint at the same time. What is of particular importance is that the process control strategy does not require a lead control zone. The values measured by all the pyrometers are perma- nently considered and a highly dynamic heating process is implemented in all control zones; the process is adapted to the specific behaviour of the matrix material during heating, melting and further heating of the material in the melt phase. When the surface temperature approaches the
temperature setpoint, further granular adjustment during process control must prevent the surface temperature from overshooting. High temperature consistency in the soaking phase – the heat required to melt the core area – ensures that the target temperature in the core area is reached at a precisely predictable time. Heating up of the thermoplastic composite can therefore be termi- nated after a defined, and shortest possible duration; this in turn contributes towards protect- ing the material. Especially in the soaking phase, it is crucial to keep temperature deviations low to avoid local overheating and degradation of the material. For this purpose, the control parameters must be adjusted in the best possible way. For example, if the material, the blank size or the thickness of the material is changed, the control parameters for the soaking phase also need to be readjusted. A separate measuring cycle can be utilised to automatically optimise the control parameters. Doing so delivers information on the existing control behaviour and based on these, the control parameters are recalculated and adjusted. KraussMaffei reports that there is rising demand for technologies that allow efficient use of materials and other resources for cost-effective manufacturing of thermoplastic composites. Complete production cells are in demand, includ-
Left: The FiberForm process developed by KraussMaffei combines the thermoforming of organosheets and injection moulding into one process
ing injection moulding, tape laying and consolida- tion, automation and oven technology. “After the Covid-19 crisis, we are now registering increasing demand, particularly from the automotive industry, for FiberForm applications,” says Michael Fuchs, Global Application Owner, Surface & Lightweight. “The FiberForm process developed by KraussMaf- fei combines the thermoforming of organosheets and injection moulding into one process. This process results in fibre-reinforced plastic compo- nents that are particularly lightweight yet feature a high level of strength.” One major trend for thermoplastic composites in injection moulded applications is sustainable production to meet the needs of the circular economy. “For the production of thermoplastic composites, this means less raw materials usage and energy consumption as possible in order to produce
long-lasting, sustainable products with a low CO2 footprint,” adds Fuchs. “Another technical trend is load-path orientated carbon fibre reinforcements in the component. In addition, there is increased use of UD-tapes instead of large organosheets.” The company adds that the FiberForm process
offers a number of advantages. Substituting steel and aluminium with fibre-composite construction provides a high degree of weight reduction and complex structures can be produced with no need for re-work. The use of continuous fibre-reinforce- ment within the composite sheets achieves high strength levels. The process is suitable for large series production with cycle times corresponding to typical injection moulding processes. The process allows reproducible transfer of the composite sheets into the injection mould through highly precise gripping. It is a one-step process due to the integrated re-shaping process in the mould, which is fully automated as a compact production cell. Short composite sheet transfer times are achieved by positioning the infrared heating station near the mould. Integration of additional functional parts is possible during the injection moulding process. Current challenges include long heating times
that need to be improved, as well as different wall thicknesses of organosheets due to load-path- oriented tapes that require new heating concepts. To meet these needs KraussMaffei has recently developed an intelligent control for the FiberForm oven. In addition, the company has integrated complete control of the FiberForm cell in the KraussMaffei MC6 control panel. This makes operation and control easier. Other developments have included a decrease in temperature difference between the top and bottom of the oven from 15℃
18 INJECTION WORLD | January/February 2022
www.injectionworld.com
IMAGE: KRAUSSMAFFEI
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72
