Standard Work · SOP
Velvet Liner Installation Quality
Standard operating procedure for consistent, high-quality application of velvet liners in custom packaging and presentation cases. This SOP ensures repeatable appearance, adhesion, and finish.
Estimated Time
30 min
Difficulty
Intermediate
Regulation
ISO 9001:2015
Version
1.0
Purpose
To establish a repeatable, defect-free method for installing velvet liners onto rigid surfaces. This procedure minimizes bubbles, wrinkles, misalignment, and edge lifting, reducing rework by >90% and meeting customer-grade finish standards.
Scope
This SOP applies to all technicians in the custom case finishing department. It covers the preparation, cutting, adhesive application, placement, trimming, and final inspection of polyester and cotton-blend velvet liners (1.5 mm thickness) on flat or gently curved surfaces of wood, MDF, or non‑porous substrates.
Safety Precautions
- Wear nitrile gloves to prevent oils from transferring onto velvet or adhesive. Wear a NIOSH-approved N95 mask when using spray adhesive to avoid inhalation of volatile organic compounds (VOCs).
- Use only in a well‑ventilated area with an ISO Class 8 cleanroom extraction system or dedicated spray booth. Maintain LEL monitors below 10% of lower explosive limit.
- Always cut away from the body. Use a new no. 11 blade per shift. Retract blade immediately after cutting.
- Keep heat gun at least 100 mm from surface. Do not apply heat to adhesive faster than 2 seconds per 25 mm. Allow 30 s cool-down between passes.
Required Tools & Materials
- Velvet liner material (polyester or cotton blend, 1.5 mm thick, 137 cm width)
- High-tack, low-VOC spray adhesive (3M Super 77 or equivalent)
- Self-healing cutting mat (A2 minimum)
- Utility knife with fresh no. 11 blades (replace every 4 cuts)
- Steel measuring tape (metric, 3 m)
- Stainless steel straightedge, 600 mm length
- Rubber roller (4 inch width, firm durometer 70A)
- Adjustable heat gun (300–400 °C, with two-speed fan)
- Lint‑free microfiber cloths (x3)
- White marking pencil (water-soluble)
Procedure: Step-by-Step
1
Measure & cut blank – Place the velvet face‑down on the cutting mat. Measure the target surface and add 2 mm overhang on each edge. Mark with white pencil. Cut using a single pass of the utility knife against the straightedge. Do not saw.
2
Apply adhesive – Mask off any adjacent surfaces. Hold spray can 20 cm from substrate, apply a continuous, even coat. Cover entire area with a 50% overlap pattern. Wait 30–60 s until adhesive becomes tacky (finger‑touch test does not transfer). Do not oversaturate.
3
Position & roll – Align the velvet starting from the far edge. Lower slowly at a 30° angle while applying light tension. Use the rubber roller from centre outward in 15 cm wide passes. Apply firm, even pressure (approx. 5 kg). Ensure no air pockets.
4
Trim the excess – Using the straightedge flush with the workpiece edge, cut the overhang at a 45° angle with a fresh blade. Make a single continuous cut per side. For inside corners, make a small relief cut first (45° to edge).
5
Heat‑set edges – For any edge that lifts more than 0.5 mm, apply heat gun at 300 °C, 10 cm distance for 1–2 seconds. Immediately press with a clean cloth until cool. Do not overheat (velvet will scorch > 150 °C surface temp).
6
Final inspection – Examine under 60° raking light. Reject if: bubbles > 2 mm diameter, wrinkles > 1 mm height, misalignment > 1 mm offset, or edge lift > 0.5 mm unseated. Rework any defect; do not patch single areas.