What are the detection methods for the dimensional accuracy of copper strip processing?

The detection methods of dimensional accuracy of copper strip processing mainly include thickness detection, width detection, length detection, flatness (roughness) detection, etc. Appropriate tools and means should be selected according to different accuracy requirements. The following are specific detection methods and application scenarios:

I. Thickness detection

Thickness is the most critical dimension index of copper strip, and the detection methods are divided into contact measurement and non-contact measurement:

1. Contact measurement

Micrometer (screw micrometer)

Principle: The copper strip is clamped between the micrometer screw and the anvil, and the scale value is read.

Accuracy: ±0.001mm, suitable for laboratory or sampling inspection.

Key operation points:

When measuring, make sure that the surface of copper strip is clean, and there is no oil stain or foreign matter.

Uniformly select multiple points in the longitudinal direction (length direction) and transverse direction (width direction) of the copper strip (such as 3 points at the head, 3 points at the middle and 3 points at the left, 3 points at the middle and 3 points at the right) to avoid local deviation.

Thickness gauge (feeler gauge)

Principle: It consists of several standard steel sheets with different thicknesses, and it is inserted between the copper strip and the datum plane to detect the gap.

Accuracy: ±0.01mm, suitable for quick and rough detection on site.

2. Non-contact measurement

laser thickness gauge

Principle: The upper and lower surfaces of copper strip are irradiated by laser beam, and the thickness is calculated by measuring the time difference of reflected light (without contact).

Accuracy: ±0.002-0.01mm, which can be used for real-time online detection and dynamic monitoring of rolling production line.

Advantages: fast speed, no damage to the surface, suitable for thickness fluctuation monitoring in continuous production process.

X-ray thickness gauge

Principle: The thickness is calculated by the attenuation degree of X-ray passing through copper strip, which is suitable for synchronous measurement of substrate thickness and coating thickness of coated copper strip (such as tinned copper strip).

Accuracy: ±0.001mm, commonly used for high-precision electronic-grade copper tape (such as lithium battery tab tape).

Eddy current thickness gauge

Principle: Based on the principle of electromagnetic induction, the thickness of conductive materials is detected, which is suitable for non-magnetic metals (such as pure copper and brass).

Accuracy: 0.5%, suitable for batch rapid detection, but sensitive to surface roughness.

Second, the width detection

Detecting whether the transverse width of copper strip meets the tolerance requirements can be divided into manual measurement and online detection:

1. Manual measurement

Steel ruler/vernier caliper

Principle: directly measure the distance between two sides of copper strip.

Accuracy: steel ruler ±0.5mm, vernier caliper ±0.02mm, suitable for sampling inspection or testing after cutting to length.

Precautions: the measurement should be perpendicular to the edge of copper strip to avoid tilt error; For coiled copper strip, it is necessary to measure it after unfolding or select multiple sections on the reel for measurement.

Width template

Principle: Use the limit size template (general gauge/stop gauge) to quickly judge whether the width is qualified, which is suitable for mass production site.

2. Online detection

Laser scanning width gauge

Principle: The laser beam scans the edge of copper strip horizontally, calculates the distance between the two edges, and displays the width value and deviation in real time.

Accuracy: ±0.05-0.1mm, which can detect the width fluctuation caused by edge wave, and is used in rolling or slitting production lines.

Visual inspection system

Principle: The copper strip image is taken by an industrial camera, the width is measured by image processing algorithm, and the edge defects (such as burrs and cracks) can be detected.

Accuracy: ±0.02mm, high integration, suitable for high-precision copper strip (such as strip for precision electronic components).

Third, length detection

Mainly for copper strips cut to length (such as rectangular sheets and stamping parts), the detection methods include:

Steel tape measure/laser rangefinder

Steel tape measure: Manual measurement with accuracy of 1 mm, suitable for short dimension (e.g. ≤2m) detection.

Laser rangefinder: Non-contact measurement with an accuracy of ±0.5mm, suitable for long-sized (e.g. ≥5m) copper strips, especially in automatic production lines triggered by photoelectric sensors.

Encoder counting method

Principle: Install a rotary encoder on the cutting or shearing equipment, and calculate the traveling length of copper strip by the number of turns of the roller, and the error can be controlled within 0.5%.

Application scenario: Fixed-length shearing control on continuous production line, such as battery pole cutting.

Four, flatness (roughness) detection

Flatness reflects the shape quality of copper strip, and the detection methods include:

Plug gauge+platform method

Principle: Put the copper strip on the standard flat plate, measure the maximum gap between the strip and the flat plate with a feeler gauge, and calculate the roughness (gap value/measured length).

Accuracy: ±0.5mm/m/m, suitable for laboratory or random inspection, and the measuring length is usually 1m.

Tenometer method

Principle: Constant tension is applied to both ends of copper strip, and flatness is calculated by measuring the sag in the middle, which is suitable for online detection after rolling.

Laser flatness detector

Principle: The surface of copper strip is scanned by several groups of laser sensors, and the three-dimensional contour is constructed, and the parameters such as waviness and sickle bending are calculated.

Accuracy: ±0.1mm/m/m, can display the shape curve in real time, and is used for high-precision copper strip (such as aerospace strip).

Five, other size detection

Edge verticality

For the copper strip used for stamping or precision machining, it is necessary to detect the verticality between the edge and the datum plane, and it is usually measured with a square ruler and a feeler gauge, with an error of ≤ 0.1.

Coil diameter and coil weight

The diameter and total weight of the coiled copper strip need to be tested to ensure that the packaging and transportation meet the requirements. The diameter of the coiled copper strip is usually measured with a tape measure and weighed with an electronic scale (the accuracy is ±0.1kg).

Six, the detection standard and frequency

executive standard

Domestic: GB/T 2059-2017 "Copper and Copper Alloy Strip" stipulates the size deviation range;

International: ISO 4370, ASTM B152 and other standards have similar requirements for accuracy.

Detection frequency

First article inspection: Before production or after process adjustment in each shift, inspect the full dimensions (thickness, width, length and flatness).

Process inspection: 1-3 volumes are sampled every hour, focusing on detecting thickness and width fluctuations.

Full inspection after completion: 100% test the length and edge quality of the cut-to-length products, and sample the rolled products in batches (e.g. 5 rolls per batch).

summary

The dimensional accuracy detection of copper strip needs to select appropriate tools in combination with production process, accuracy requirements and efficiency requirements;

Laboratory and sampling inspection: traditional tools such as micrometer, vernier caliper and platform feeler are preferred to ensure high accuracy.

On-line monitoring of production line: automatic equipment such as laser thickness gauge and visual inspection system are adopted to realize real-time feedback and process adjustment.

Special requirements: such as coating thickness and complex shape defects, it needs to be equipped with professional equipment such as X-ray thickness gauge and laser flatness detector.

Through multi-level inspection, the dimensional accuracy of copper strip can be effectively controlled to meet the stringent requirements of high-end fields such as electronics and aerospace.