The result in four numbers
The full picture
The client - a European electric bus OEM - approached us with a housing design for a low-voltage system control module. The existing ABS version was heavy and did not meet the HL2 fire resistance requirements.
Objectives: weight reduction of at least 15%, compliance with EN 45545-2 R22 / HL2, retention of the existing mounting points on the bus frame, readiness for production of up to 60k pcs per year.
We proposed an FR grade of PC+ABS with glass fibre in selected structural ribs. We analysed the housing geometry using FEA for mounting stiffness and optimised the rib layout in Moldex3D, including a warpage analysis after the cooling cycle.
The mould was built by a reference EU partner. PPAP level 3 validation; vibration and climatic validation confirmed in the client's laboratory.
The component entered series production in Q3 2024. Final weight 22% lower than the baseline version - above the client's target. Component BOM 14% lower thanks to simplified assembly (two metal inserts eliminated and replaced with post-moulding inserts).
Production cycle: 38 s - within the window required by the client's logistics plan. The project is being extended with two further housing size variants for derivative vehicle models.
What was key
- An early material decision. Choosing PC+ABS with GF only in selected ribs (local overmoulding) - weight reduction without loss of stiffness.
- Warpage simulation. A full thermal model in Moldex3D allowed us to design the mould with directional shrinkage compensation - the housing needs no calibration after ejection.
- Early vibration validation. A 3D-printed + CNC-machined prototype was delivered to the client in week 6 - this made it possible to validate the mounting before the mould was built.
“Switching from ABS to PC+ABS GF sounds simple. Doing it without changing the mounting points - not so much. MS-PROGRESS closed the topic in two iterations.” - Senior Engineer · OEM client
