Cutting consumable costs on SMT lines
Consumables such as solder paste, SMT adhesive, stencil wiping paper and cleaning solvents make up a significant share of SMT line operating costs. Optimizing how these consumables are used can reduce costs substantially while maintaining, or even improving, soldering quality.
Below are the improvements the AMS engineering team commonly recommends when auditing customer production lines.
Solder paste: reducing waste on the stencil
Most wasted solder paste is lost because it exceeds its stencil life or is discarded at the end of a shift. Some solutions:
- Add paste in small, frequent amounts, keeping the paste roll at 15–20 mm in diameter.
- Use jar sizes that match production volume, and avoid opening large jars for small orders.
- Choose paste with a long stencil life of 8 hours or more.
- Use recovered paste for prototype boards or repairs in accordance with internal rules.
Stencil wiping paper and solvent
Underside stencil wiping frequency is often set higher than actually needed. By monitoring print quality with SPI, the wiping interval can be extended from every board to every three to five boards without increasing defects. Combining dry and wet wiping modes appropriately also reduces solvent consumption.
| Item | Typical practice | After optimization | Estimated savings |
|---|---|---|---|
| Solder paste waste | 15–25% | 5–10% | 10–15% of paste |
| Stencil wiping interval | Every 1 board | Every 3–5 boards | 50–70% of wiping paper |
| Wiping solvent | Wet wipe every cycle | Alternating dry and wet | 30–50% of solvent |
| SMT adhesive | Oversized dots, large needle | Standardized dot size | 15–20% of adhesive |
Standardizing and consolidating consumable part numbers
Many plants use three to four types of solder paste for similar product lines. Consolidating to one or two qualified part numbers increases order volume, reduces expired inventory and simplifies training. The same applies to SMT adhesives and cleaning solvents.
Measuring to sustain results
Establish a consumable usage index per thousand boards and track it monthly. When the index rises abnormally, you can trace the cause, such as a worn stencil, changed printer parameters or off-spec consumables.
Importantly, every change must be accompanied by quality checks: monitor print defect rates, AOI and X-ray results for several weeks after an adjustment before officially applying it across the entire line.
AMS is ready to audit your line and propose consumable optimization measures free of charge. Contact AMS Vietnam to schedule a meeting with our engineers.
