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Professional Zinc Alloy Surface Finishing Solutions

Other Polishing

Vibration, Centrifugal, Magnetic & Electrolytic Polishing — A Complete Comparison

Four mechanical finishing methods compared head-to-head: process parameters, surface results, cost, and which parts each method suits best.

Four Polishing Methods at a Glance

Each method has a sweet spot — the right choice depends on part geometry, target roughness and volume

Vibration Polishing

35–45 Hz, Ra ≤ 0.4 μm

Centrifugal Polishing

High speed, small parts

White desktop magnetic polishing machine with blue control panel and translucent processing bucket.Conceptual illustration based on reference photographs; not test evidence.

Magnetic Polishing

Complex internal cavities

Electropolishing

Brightness + passivation

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How Each Method Works

Four technologies, each with its own process window

1Vibration Polishing

Workpieces + ceramic/polyethylene media + compound in an oscillating bowl at 35–45 Hz. Ideal for deburring precision machined parts (Ra ≤ 0.4 μm). Batch process, gentle on edges.

Key Parameters
Frequency: 35–45 Hz
Media: Ceramic / PE cones
Target Ra: ≤ 0.4 μm
Cycle: 30–90 min
Close-up of triangular and conical ceramic polishing mediaConceptual illustration based on reference photographs; not test evidence.

2Centrifugal Polishing

High-speed rotating barrel — parts + media pressed against the wall by centrifugal force. Fastest method for small sturdy parts (zipper pulls, small buckles, buttons). 5–15 min cycles.

Key Parameters
Speed: 100–300 RPM
Media: Steel balls / ceramic
Cycle: 5–15 min
Best for: Small parts under 20 g

3Magnetic Polishing

Stainless steel needles (0.5–2.0 mm diameter) suspended in a rotating magnetic field. The needles penetrate slots, threaded holes and internal cavities that other methods can't reach.

Key Parameters
Needle size: 0.5–2.0 mm
Magnetic field: Rotating AC
Best for: Complex internal cavities
Cycle: 15–60 min

4Electropolishing (Electrolytic)

Anodic dissolution in a phosphoric-sulfuric acid bath. Removes 0.01–0.05 mm of surface metal, micro-smoothing to Ra ≤ 0.2 μm. Also passivates stainless steel — best for food/medical grade parts.

Key Parameters
Target Ra: ≤ 0.2 μm
Current density: 5–15 A/dm²
Temp: 55–75 °C
Time: 3–10 min
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Comparison Table — Pick the Right Method

For every part geometry we recommend the best fit — and we can combine methods

MethodBest ForRoughnessCycle TimeCostEdge Damage Risk
VibrationPrecision parts, deburringRa ≤ 0.4 μm30–90 minLowLow
CentrifugalSmall, sturdy partsRa ≤ 0.3 μm5–15 minVery lowMedium
MagneticComplex cavities, threadsRa ≤ 0.3 μm15–60 minMediumVery low
ElectropolishStainless steel finishRa ≤ 0.2 μm3–10 minHighNone

📌 Polishing Method Quick Reference

Vibration frequency35–45 Hz
Centrifugal speed100–300 RPM
Magnetic needle0.5–2.0 mm
Electropolish current5–15 A/dm²
Best roughness rangeRa 0.2–0.4 μm
Combined methods possibleYes — 2-stage
💡 Multi-stage polishing is commonMany parts go through 2 methods: vibration (bulk deburr) then electropolish (final finish). We call this hybrid polishing and recommend it for stainless steel hardware where both cost and quality matter.

FAQ

Which method is best for deburring zinc alloy zipper sliders?
Vibration polishing with fine ceramic media. It removes parting line burrs without damaging the thin walls. Centrifugal is too aggressive for thin-walled zinc alloy.
Can magnetic polishing clean internal threads?
Yes — magnetic needles penetrate M2 threads and even cross-drilled holes. This is the only mechanical method that reaches internal cavities without disassembly.
Does electropolishing change part dimensions?
Yes — material removal is 0.01–0.05 mm per surface. For tight-tolerance parts, we do a trial first and adjust the machining allowance accordingly.
Which method gives the best Ra value?
Electropolishing delivers Ra ≤ 0.2 μm — a true micro-smooth surface. But it only works on conductive metals, primarily stainless steel.
Can you combine methods on one part?
Frequently. e.g. vibration deburr → electropolish finish for stainless steel hardware. Or magnetic polish internal threads → vibration polish external surface. The combined per-part cost is still lower than hand polishing.

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