The Challenge
A two-wheeler accessories manufacturer based in Ahmedabad was developing five new fairing variants for an upcoming model year update to their commuter motorcycle range. Each variant required a prototype mould for pre-production validation — testing part release, surface finish quality, and fit to the motorcycle chassis before committing to production steel moulds.
CNC aluminium prototype moulds were quoted at ₹45,000–70,000 per fairing half (two halves per variant × five variants = 10 moulds total). Budget: ₹6–7 lakh. Lead time: 3–4 weeks. The team contacted Layer X in Ahmedabad to explore SLS additive manufacturing as a tooling alternative.
Technical Requirements
- Mould type: Open-face lay-up moulds for hand-lay fibreglass/GRP fairing panels (not injection moulding)
- Temperature: Moulds see 60–80°C during resin cure — no elevated temperature required
- Surface: Mould face must be smooth enough for gel coat application (Ra < 2.0 µm after surface finishing)
- Structural: Moulds must resist hand-lay compaction force without deflection > 0.3 mm
- Volume: 50–100 pull cycles per mould before discard — prototyping only, not production
- Quantity: 10 mould halves (5 variants × 2 halves each)
Material Selection: PA12-CF for Tooling
Layer X recommended PA12-CF (carbon-fibre reinforced PA12) SLS for the mould bodies. The carbon fibre reinforcement raises the heat deflection temperature from PA12's standard 175°C to over 185°C and significantly increases bending stiffness (Young's modulus 5,200 MPa vs 1,700 MPa for standard PA12). This makes PA12-CF suitable for lay-up tooling applications where dimensional stability under compaction force is critical.
The mould face skin was printed with a 0.3 mm high-density outer shell (6 solid perimeters in the slicer) to provide a dense, non-porous surface that accepts mould release agent and gel coat without paint primer. Interior volume was printed at 25% gyroid infill to reduce weight and material cost.
Geometry and Build
The customer supplied Class A surface CAD data for all five fairing variants (Class A IGES surfaces from their design studio). Layer X's team converted these surfaces to SLS mould tool geometry, adding:
- 3° draft angle on all mould walls for part release
- Peripheral flange (40 mm wide) for clamping to a backing frame
- Registration pins (6 mm diameter, SLS in-situ) for two-half alignment
- Parting line definition matched to the customer's existing production parting line strategy
All 10 mould halves were printed across 3 SLS builds over 4 days. Largest single mould piece: 380×220×65 mm. Total material consumption: 4.2 kg PA12-CF powder.
Post-Processing for Mould Surface
SLS PA12-CF as-printed surface is Ra 8–12 µm — too rough for direct gel coat application. Post-processing for each mould face:
- Bead blast (glass bead, 60 psi) — removes loose surface powder, uniform surface texture Ra 6–8 µm
- Spray apply 2-part epoxy primer (Awlgrip 545 equivalent) — fills surface porosity
- Sand 400 grit wet — Ra 2.0–3.0 µm
- Sand 800 grit wet — Ra 0.8–1.2 µm
- Wax release coat (Meguiar's Mirror Glaze or similar) × 3 coats
Finished mould face: Ra 0.9–1.1 µm. Adequate for prototype gel coat GRP panels with light post-pull sanding.
Results
| Metric | CNC aluminium moulds | SLS PA12-CF moulds (Layer X) |
|---|---|---|
| Total tooling cost (10 halves) | ₹6.2–7.0 lakh | ₹2.4 lakh |
| Cost saving | — | 65% reduction |
| Lead time (10 halves) | 3–4 weeks | 8 working days |
| Pull count achieved | Unlimited | 80–100 (sufficient for prototype) |
| Dimensional stability | Excellent | Good (0.2 mm deflection under compaction) |
| Part quality (GRP panels) | Production-equivalent | Prototype-grade (light sanding required) |
The OEM pulled 60 prototype panels across the five variants within the 8-day window and completed chassis fit verification for all variants in the same month the CAD data was finalised — a product development timeline that would have been impossible with the CNC tooling lead time.
Three variants passed fit validation and proceeded to production steel mould investment. Two variants required geometric changes to the fairing profile — changes that would have cost ₹30,000–60,000 per mould modification in aluminium, but were implemented as simple CAD updates and re-prints at Layer X for ₹8,000 per remade half.
Key Learnings
SLS PA12-CF is a production-viable tooling material for GRP lay-up moulds up to ~100 pull cycles. For Indian automotive prototype tooling — where design iteration is frequent, volume is low, and speed to physical validation is critical — additive mould tooling delivers compelling economics and time advantages over CNC aluminium at the prototype stage.
Contact Layer X for custom SLS and DMLS tooling for Indian automotive and product design customers in Ahmedabad and across Gujarat.