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Soldering is probably the most versatile joining method for coil terminations, and it certainly has a long and proven history, but the use of solder is coming under increasing regulatory pressure because of its lead content. Lead-free solders are available, but are more expensive, and not as reliable. Two of the most popular alternatives to soldering are arc welding and laser welding. These both eliminate the environmental and health hazards associated with soldering, and have the added advantages of low cycle time, localized heating, and reduced part contamination. Laser welding equipment is very expensive, though. It is difficult to set up and maintain, and has a higher cost of operation than arc welding. For these reasons and others outlined below, Nittoku is offering the NAC Series micro-arc welding system as its preferred alternative to soldering.
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| Soldering | Arc Welding | Laser Welding | |
| Environmental Concerns | Lead is an environmental hazard | None | None |
| Health Concerns | Lead vapor, flux fumes | Negligible | Negligible |
| Contamination | Solder balls, flux splashing | Negligible | Negligible |
| Cycle Time | ~1.0 s | ~0.1 s | ~0.1 s |
| Efficiency | Multiple points per cycle | 1 point per cycle | 1 point per cycle |
| Heat Diffusion | Large - heat can damage surrounding plastic | Minimal | Minimal |
| Machine Price | Inexpensive | Inexpensive | Expensive |
| Material Costs | Inexpensive - flux, solder | Inexpensive - electrode, argon gas | Moderate - lamp, spark coil |
| Maintenance | Flux density control, solder level control, solder replacement | Electrode regrinding | Spark coil regrinding, lamp replacement |
| Ease of Handling Equipment | Moderate - very hot surfaces, liquid solder bath | Easy - one gas line | Difficult - alignment critical, cooling water lines |
| Coil Design | Terminal must be unobstructed for dipping | Terminal must be grounded | Terminal position accuracy is critical |
| Terminal Material | Any | Copper, phosphor bronze, not brass | Copper, phosphor bronze, not brass |
| Coil Size Limits | Small parts difficult | Large parts difficult | Large parts difficult |