Custom-made Thin Beam Micro Load Cells for Jewelry Scale

• Custom-made Thin Beam Micro Load Cells for Jewelry Scale

• Capacity:500g,1kg,2kg 

• Comprehensive precision: 0.02%FS 

• Material :Alloy Aluminum

• Output Signal: 1mV/V

• Input/Output Resistance:1000Ohm

• Wire Length:10-80cm

• Application: Medical industry, precision jewelry scale,etc.

Ultra-High Precision & Resolution: Jewelry weighing requires detection of minute weight changes (milligrams to micrograms). Thin beams maximize strain under tiny loads, generating a stronger signal for higher resolution.

Ultra-Low Capacity: Capacities are typically very low (e.g., 10g, 20g, 50g, 100g, 200g, 500g). Standard cells may lack sufficient sensitivity.

Compact Size & Low Profile: Jewelry scales need discreet, elegant designs. Thin beams minimize sensor height and footprint.

Material Sensitivity: Precious metals (gold, platinum, diamonds) have high value per gram. Accuracy is paramount.

Environmental Stability: Lab/bench environments require minimal drift from temperature changes or air currents.

Key Design & Manufacturing Considerations for Custom Micro Load Cells:

Beam Geometry:

Extremely Thin Flexures: Flexure thickness might be fractions of a millimeter (e.g., 0.2mm - 0.5mm). Precision machining (milling, wire EDM) is critical.

Optimized Length/Width: Maximizes strain while maintaining structural integrity under max load.

Symmetry: Crucial for minimizing off-center load errors (though tolerance will still be lower than larger cells).

Material Selection:

High-Strength Aluminum Alloys (e.g., 7075-T6): Most common. Excellent stiffness-to-weight ratio, high elasticity, good machinability, high sensitivity.

Stainless Steel (e.g., 17-4PH, 304/316): Used for superior corrosion resistance, hardness, lower creep, or higher temperature stability. Slightly lower sensitivity than Al for same capacity.

Special Alloys (e.g., Titanium, Beryllium Copper): For niche requirements (e.g., non-magnetic, specific thermal expansion).

Strain Gauges & Bonding:

Micro or Ultra-Micro Gauges: Very small grid patterns designed for high strain sensitivity on tiny areas.

Precision Bonding: Requires specialized processes (surface prep, adhesive selection, curing) under controlled conditions to ensure perfect adhesion, minimal thickness, and stability. Automated bonding is often used.

Full Wheatstone Bridge: 4 active gauges on the flexures for maximum sensitivity, temperature compensation, and linearity. Dummy gauges for compensation might be included.

Overload Protection (ESSENTIAL):

Integrated Mechanical Stops: Must prevent any plastic deformation of the ultra-thin flexures. Stops are designed to engage just beyond rated capacity with minimal deflection. This is non-negotiable for reliability.

Sealing & Environmental Protection:

Minimalist Housing: Often a thin, laser-welded stainless steel cover or a conformal coating to protect gauges/wiring from dust and moisture without adding significant mass or stiffness. High IP ratings (e.g., IP54) might be achievable.

Temperature Compensation: Advanced compensation circuits within the gauge network or external instrumentation are vital.

Mounting & Load Introduction:

Precision Ground Surfaces: Ensure flatness for consistent mounting.

Dedicated Load Button: A tiny, precisely located contact point ensures force is applied correctly to the active area. Material choice (e.g., ceramic, hardened steel) matters.

Typical Specifications for Jewelry-Scale Micro Load Cells:

Capacity: 5g, 10g, 20g, 50g, 100g, 200g, 500g

Resolution: < 0.001g (1mg) to 0.0001g (0.1mg)

Nonlinearity: < 0.02% FS (Full Scale)

Hysteresis: < 0.02% FS

Creep (30 min): < 0.02% FS

Output Sensitivity: 1.0 - 3.0 mV/V (higher is better for resolution)

Zero Balance: ±1% FS

Operating Temperature Range: 10°C to 40°C (compensated)

Thickness (Beam Height): 1.5mm - 5mm (highly dependent on capacity)

Material: 7075-T6 Alum, 17-4PH SS, 304/316 SS

Excitation Voltage: 5V or 10V DC (lower voltage reduces self-heating effects)

Cable: Ultra-thin, shielded, low-noise cable.

Why Custom vs. Off-The-Shelf (OTS)?

Optimized Performance: Tailored sensitivity, linearity, creep, and stability specifically for the exact capacity and physical constraints of the scale design.

Form Factor: Designed to fit the specific mechanical envelope of the scale housing and weighing pan mechanism.

Cost at Volume: While NRE (Non-Recurring Engineering) costs exist, unit cost for high-volume production can be competitive or better than adapting OTS cells.

Supply Chain Control: Guaranteed availability and consistent quality for production.