Custom Sheet Metal Case for POS Terminal Stations
A leading global retail equipment supplier initiated a 2024 deployment of 1,200 POS terminal stations across 80+ European grocery chains (e.g., hypermarkets and neighborhood stores). The client’s requirements were tailored to high-traffic, food-service retail environments, with worktop stability (no-slip for items like mineral water) as a non-negotiable core demand:
- No-Slip Worktop: A 500ml standard mineral water bottle (common in checkout areas) must remain stationary when placed on the worktop—even during cashier movements (e.g., scanning items, typing) or minor accidental bumps. This required the worktop to maintain a levelness tolerance of ≤0.5mm per meter (any greater unevenness would cause sliding).
- Food-Safe Hygiene: The worktop must meet EU EN 1672-2 food contact standards—no gaps ≥0.03mm (to avoid trapping crumbs/sauce), and surfaces must resist 10,000+ daily wipe cycles (with food-safe disinfectants) without corrosion.
- Brand Alignment: The support frame’s matte white finish must match the client’s Pantone 11-0601 TPX (off-white) with ΔE ≤1 color accuracy—critical for uniform in-store branding across 80+ locations.
- Device Compatibility: The worktop must integrate 210mm×150mm card readers, 120mm×60mm receipt printers, and 180mm×120mm touchscreens with ±0.05mm cutout tolerance (no device wobble or rework).
- Load Capacity: The station must support 50kg (e.g., stacked grocery bags) without structural deformation or loss of worktop levelness.
After evaluating 7 suppliers, the client selected Sanjun Hardware (est. 2010, specializing in precision sheet metal) for its track record in levelness control and scalable, high-tolerance fabrication.
Sanjun’s production was centered on meeting the client’s granular requirements, especially worktop levelness:
- Worktop: 1.5mm antimicrobial 304 stainless steel (JIS G 4305) – FDA-compliant, 100-grit brushed finish (low friction for slip resistance) + 5μm passivation film (corrosion resistance).
- Support Frame: 1.2mm SPCC cold-rolled steel – 350MPa tensile strength (supports 50kg load) + 60μm matte white powder coating (Pantone-matched).
- Cable Tray: 1.0mm 6061 aluminum alloy – lightweight (30% lighter than steel) to avoid assembly-induced levelness shifts.
- The worktop was cut from a single 1200mm×800mm stainless steel sheet (no 拼接 seams) using a 4000W fiber laser (±0.05mm tolerance) – eliminating levelness inconsistencies from joined panels.
- Frame mounting points were cut to ±0.03mm tolerance to ensure alignment with the worktop’s base.
- Worktop: Post-cutting, the sheet was processed with a precision leveler (±0.02mm/m flatness) to remove rolling-induced stress – verified via CMM before bending.
- Frame: Bent via AMADA 8-axis CNC brake (±0.1° angle tolerance) – the frame’s top mounting surface was calibrated to 0.05mm flatness (CMM-scanned) to support the level worktop.
- The worktop was mounted to the frame with M6 precision bolts (torqued to 8N·m) to distribute pressure evenly.
- Each station was tested with a digital spirit level: worktop levelness was confirmed to ≤0.5mm/m, followed by a bottle stability test (500ml water bottle placed on the worktop; no sliding when the station was gently tapped).
Maintaining ≤0.5mm/m levelness across 1,200 stations (standard suppliers average 1.2mm/m) was critical for the no-slip requirement.
Solution:
- Implemented automated leveler + CMM inspection for 100% of worktops.
- Used custom 3D-printed frame jigs to ensure mounting point alignment – reducing levelness variation to ≤0.3mm/m on average.
Welded seams often create 0.1mm+ gaps (trapping debris) or surface warping (disrupting levelness).
Solution:
- Laser-welded worktop joints (≤1mm seam width) + robotic grinding to 0.03mm gap – meeting EN 1672-2 and preserving flatness.
Coating thickness variations (≥2μm) can warp surfaces and distort levelness.
Solution:
- Robotic powder coating (60μm ±2μm thickness) + controlled oven cooling (1.5°C/min) – no post-coating warping, with ΔE ≤1 color accuracy.
- Compliance: 100% of stations met the client’s levelness (≤0.5mm/m), hygiene (≤0.03mm gaps), and device fit (±0.05mm) requirements.
- Field Performance: 6 months of use showed 0 bottle sliding incidents, 0 worktop corrosion, and 0 brand color mismatches.
- Client Renewal: The supplier ordered 1,800 additional units in 2025, noting Sanjun’s ability to “deliver granular, scalable precision for our retail needs.”
