Plastics and their composite materials not only enable a weight reduction of approximately 40% for components and a reduction in procurement costs of around 40%, but they also allow for the fulfillment of personalized user requirements-and the catering to evolving market demands-through appropriate material selection and molding processes. In recent years, their application in commercial vehicles has become increasingly widespread; specifically within interior components, the proportion of plastic usage has been steadily rising. Currently, with the exception of load-bearing structural elements, the interior components of medium-to-heavy-duty commercial trucks have largely transitioned to plastic construction.
The instrument panel is a critical component within a truck's interior, serving as a convergence point for safety, functionality, comfort, and aesthetics. The design of each specific section is primarily driven by its inherent functional requirements, as detailed below:
1. The instrument panel must possess a requisite level of rigidity to ensure that its attached components function correctly under conditions of high speed and vibration. Furthermore, it requires superior energy-absorption capabilities to mitigate the impact of external forces on front-seat occupants in the event of an accident. For the main structural skeleton of the instrument panel, designers may opt for either a metal frame or mineral-reinforced PP material; conversely, for the central control panel and the trim surrounding the instrument cluster-given their intricate and complex structural designs-harder materials such as PC/ABS are frequently selected.
2. The instrument panel must exhibit robust thermal resistance to ensure its continued functionality under operational conditions. Specifically, materials located at the front edge of the panel require a thermal resistance rating exceeding 120°C; areas exposed to direct sunlight require a rating exceeding 110°C; and areas not exposed to direct sunlight require a rating exceeding 90°C. The surface skin of the main instrument panel body demands particularly high thermal resistance, for which materials such as PVC/ABS or modified PP are typically chosen.
3. The instrument panel must also possess a certain degree of aesthetic appeal. While the use of the slush molding process for the main body can significantly enhance surface quality, the associated costs are relatively high; consequently, this technique is currently employed primarily for passenger vehicle instrument panels, whereas medium-to-heavy-duty trucks typically utilize vacuum forming or injection molding processes. All fascia panels-including the trim surrounding the left and right air vents as well as the central decorative strip-can be enhanced with surface treatments such as simulated wood grain textures or hydro-dipping. For these applications, polar materials-such as ABS or PC-are preferred, as they are highly amenable to painting (while non-polar PP materials can be painted following surface activation, the process is typically more complex, and achieving consistent paint quality can be challenging).
4. The surface gloss of the dashboard must be controlled to prevent glare. Material options include PP or PVC/ABS; the former typically exhibits a gloss level of <5, while the latter-offering superior results-maintains a level of <3. Additionally, surface gloss can be reduced by applying surface paint to plastic components or by utilizing mold texturing techniques such as sandblasting.
5. Based on requirements for a soft tactile feel, dashboard bodies can be broadly categorized into two types: rigid and soft. The latter is generally perceived as being of a higher grade than the former. Rigid dashboard bodies feature a simple structure, consisting of a single uniform material; they typically do not require a separate surface skin and can be directly formed via injection molding. Soft dashboard bodies, conversely, comprise three distinct layers-a surface skin, a cushioning layer, and a structural frame-and utilize a combination of materials. Common material combinations include PVC/ABS for the skin, PU foam for the cushioning, and a metal frame (or mineral-reinforced PP/ABS/PC) for the structure. These components are typically formed using processes such as positive-mold thermoforming, negative-mold thermoforming, slush molding, or PU spray coating. For commercial vehicle dashboards-where cost-effectiveness and specific customer expectations are key considerations-lower-to-mid-range models typically employ rigid, modified PP materials formed via injection molding. In contrast, high-end models predominantly utilize a composite structure consisting of a PVC skin (thermoformed), a PU foam cushioning layer (cast-molded), and a steel frame (stamped) or mineral-reinforced PP frame (injection-molded).