A hot riveting welder is assembly equipment that heats plastic studs with a heated riveting head until soft, then forms them into rivet heads — mechanically joining plastic parts to each other or to metal inserts. It is widely used in automotive plastic part assembly.
1. How hot riveting works
Plastic parts are molded with cylindrical studs, and the mating part has matching holes. During assembly the studs pass through the holes; a heated head presses down, the stud tips soften and are formed into mushroom heads, which lock the parts together after cooling. No screws or adhesives needed.
2. Typical automotive applications
Interior parts: brackets and trim on door panels, dashboards and consoles — hot riveting is dust-free and vibration-free, so plated and painted surfaces stay undamaged.
Lamps and exterior: internal lamp-housing brackets and bumper brackets — rivet points are strong with a clean appearance.
Functional parts: sensor brackets and harness clips — riveted joints resist vibration, suiting the long-term shaking of vehicle service.
3. Advantages over screws and ultrasonic spot welding
Vs. screws: no screw cost or tightening steps, no loosening risk — ideal for automated lines.
Vs. ultrasonic spot welding: hot riveting needs no energy-director design, tolerates a wider range of material combinations, and reliably joins hard-to-weld glass-fiber-reinforced materials; with no high-frequency vibration, pre-assembled electronic components are unaffected.
4. Process essentials
Temperature: the head must soften studs fully without degrading them — too cool gives incompletely formed heads, too hot yellows the material and weakens the joint.
Force and time: force sets the forming result, time sets heat penetration depth; tune them together, accepting heads that are full-formed and crack-free.
Head geometry: customized to stud diameter — a mushroom head around 1.5 times the stud diameter generally gives good joint strength.
Cooling under pressure: hold pressure for a cooling period before retracting; lifting too soon lets the head spring back and deform.
5. Hot riveting machine selection advice
Choose stations by rivet-point count and takt requirements: single-head machines for one or few points, multi-head or rotary-table machines for many points; prefer temperature control with zoned regulation and good uniformity; for strict rivet-depth consistency, consider servo models controlling both force and displacement. Always trial on your actual parts before selecting, confirming full-formed, crack-free rivet heads. For multi-head machines, also check temperature consistency across heads to avoid uneven rivet quality on the same part.
If your automotive plastic assembly is considering hot riveting, contact us for hot riveting welder selection. Jingjin offers riveting trials to confirm process feasibility on your parts.