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Development of drum-type manufacturing method for electroplated diamond wire tools

MetadataDetails
Publication Date2016-01-01
JournalTransactions of the JSME (in Japanese)
AuthorsYu Zhang, Yasuhiro Tani, Okiharu Kirino, Yuji Kawahata
InstitutionsTD Bank, Ritsumeikan University
Citations1
AnalysisFull AI Review Included

Expert Technical Documentation and Analysis: Drum-Type MPCVD Diamond Wire Development

Section titled “Expert Technical Documentation and Analysis: Drum-Type MPCVD Diamond Wire Development”

This documentation analyzes the successful development of a novel drum-type manufacturing system for high-efficiency electroplated diamond wire (EDW) tools. This innovation addresses the key industry challenges of low production efficiency and high cost in EDW manufacturing.

  • Manufacturing Innovation: A compact, multi-wire, drum-type electroplating unit was developed, enabling simultaneous, high-speed production of multiple diamond wire tools.
  • Performance Achievement: The agitated plating solution (using rotating fins) significantly thinned the diffusion layer, achieving high limiting current densities (up to 200 A/dm2) and increasing the nickel deposition rate.
  • Material Uniformity: Strategic placement of internal obstacles within the plating bath induced localized turbulence (vortex flow) around the wire, ensuring highly uniform deposition and strong adherence of the 10-15 ”m diamond abrasive grains.
  • Process Efficiency: The drum system utilized a sulfamate nickel bath at 60 °C, enabling high-rate composite electroplating with superior control over abrasive density (up to 160 A/dm2).
  • Application Validation: Trial EDW tools (core $\phi$0.12mm) manufactured at 5 m/min successfully sliced large polycrystalline silicon ingots, demonstrating cutting performance and abrasive retention equivalent to commercial products.
  • 6CCVD Value Proposition: The strict material demands of high-speed wire sawing (wear resistance, precision componentry) are perfectly matched by 6CCVD’s ultra-high purity Single Crystal Diamond (SCD) and large-area Polycrystalline Diamond (PCD) plates, essential for long-life reactor components and metrology references.

The following table summarizes the key experimental and performance parameters extracted from the research on the drum-type electroplating system and subsequent slicing tests.

ParameterValueUnitContext
Core Wire Diameter0.25 (Initial Test), 0.12 (Final Wire)mmPiano Wire
Plating Bath TypeSulfamate NickelN/AHigh current density requirement
Plating Temperature60°COptimal process stability
Core Rotor Speed (Tested)100, 200, 300, 400rpmUsed to induce turbulence
Abrasive Type55 wt% Ni-coated DiamondN/AFor composite plating
Abrasive Grain Size10-15”mUsed for slicing brittle materials
Limiting Current Density (Max)200A/dm2Achieved at 200 rpm rotor speed
Optimal Composite Plating Current Density160A/dm2Max density tested for strong abrasive adherence
Deposition Rate (Composite)Approx. 45”m/minAt 200 A/dm2, independent of rotor speed
Plated Layer Thickness80 (Average)”mMeasured layer thickness on $\phi$0.12mm wire
Slicing Speed (Manufacturing)600m/minCommercial equivalent speed
Diamond Wire Manufacturing Speed5m/minAchieved continuous manufacturing rate
Wafer Surface Roughness (Ra)0.45 ± 0.05”mAchieved with high-density diamond wire (30/mm)

The drum-type electroplating method was designed for high-throughput, high-current density (HCD) deposition, focusing on intense agitation and controlled flow to overcome limitations inherent in traditional plating baths.

  1. Core Pretreatment: Piano wire cores (cathode) underwent degreasing with organic solvents, followed by cleaning with 10 vol% hydrochloric acid to remove surface grease and soft brass coating, ensuring optimal nickel adhesion.
  2. Strike Plating: Wood’s or Watt’s bath nickel strike plating was performed to enhance adhesion between the exposed piano wire and the subsequent thick nickel layer.
  3. HCD Plating Unit Design: A drum-type reactor featured a core rotor with multiple fins rotating up to 400 rpm inside a cylindrical plating vessel. The anodes (Nickel pellets in Titanium baskets) and wires (cathodes) were positioned in the flow channel.
  4. Flow Control and Agitation: Rotor rotation generated intense turbulence, which effectively thinned the diffusion layer near the cathode, allowing high Ni2+ ion supply necessary for high current density plating (Kawasaki’s HCD principle).
  5. Uniform Abrasive Distribution: Two small columnar obstacles were strategically placed upstream of the wire (cathode) to intentionally disrupt the laminar flow, generating controlled vortex/turbulent flow that ensured uniform distribution and deposition of the suspended diamond abrasives (10-15 ”m) around the entire wire circumference.
  6. Continuous Process Integration: The continuous manufacturing system incorporated multiple stages: Source Wire Reel, Degrease, Pickling Bath, Strike Plating Unit, Composite Plating Unit, After Plating Units (3 stages for embedding), Rust Inhibitor coating, and Winding Wire Reel.

6CCVD is positioned as the primary material partner for advanced slicing and abrasive tool development. While this research focuses on wire manufacturing, the success of slicing hard materials (Silicon, Sapphire) depends entirely on precision alignment and materials that resist extreme wear, thermal stress, and chemical erosion—areas where 6CCVD’s MPCVD diamond excels.

Replicating or extending high-speed slicing research requires diamond materials for key wear-resistant components and precise metrology.

6CCVD Product LineMaterial Requirement MatchSpecific Recommendation
Optical Grade SCDHigh precision, ultra-low roughness, and extreme hardness required for metrology and high-contact wear parts (e.g., Wire guides/Dies).SCD Plates (Ra < 1 nm polished). Thicknesses up to 500 ”m for ultra-thin wear inserts.
Mechanical Grade PCDDurability, erosion resistance, and large area coverage required for core rotor fins, secondary anodes, or large-area clamping jigs used in the continuous process.Large Area PCD Wafers (up to 125 mm diameter) with polishing Ra < 5 nm for minimized friction losses.
Boron-Doped Diamond (BDD)Required for electrochemical applications or highly precise current control components.BDD Thin Films or Plates. Can be engineered as highly conductive, inert electrodes to test alternative plating bath chemistries.

The paper demonstrates the necessity of high-precision componentry and advanced material interactions in the electroplating environment. 6CCVD provides bespoke solutions to support this highly technical field:

  • Custom Dimensions and Substrates: The research required precise control over the current distribution, which involves complex electrode geometries. 6CCVD offers custom shapes and dimensions for both SCD and PCD components (e.g., custom wire guide bushings or obstacle geometries) up to 125 mm.
  • Advanced Metalization Services: The study relies heavily on Nickel plating and using Ti/Ni anodes. 6CCVD offers extensive in-house metalization capabilities (Au, Pt, Pd, Ti, W, Cu). We can apply precision thin films to diamond components to test galvanic corrosion, electrical shielding, or localized electrochemical reactions within the complex drum environment.
  • Ultra-Precision Polishing: To minimize friction and ensure long life for the high-speed wire transport components (pulleys, guides, feed mechanism) which contact the wire core and the finished EDW tool, 6CCVD provides SCD with exceptional surface finish (Ra < 1 nm).
  • Engineering Support: 6CCVD’s in-house PhD team specializes in diamond material physics and applications. We offer consultation on material selection for high-wear environments, thermal management (crucial given the resistive heating discussed in Section 3 of the paper), and optimizing diamond componentry for continuous High-Speed Diamond Wire Slicing projects.

Call to Action: For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly.

View Original Abstract

Diamond wire saws are widely used in slicing various kinds of hard and brittle materials, such as silicon, sapphire, etc. Electroplated diamond wire tools are used for high-efficiency slicing process, because of high abrasion resistance. However, low production efficiency of diamond wire tools causes high cost in the production process, because the electroplating rate is low. To solve the problems, a drum-type manufacturing method for electroplated diamond wire tools was developed in this study. Multiple diamond wire tools could be manufactured simultaneously at high speed in one machine. The mechanism of drum type electroplating unit was introduced, firstly. Then the electroplating characteristics, such as maximum current density, Ni deposition rate and uniformity of electroplated wires, were evaluated. Composite electroplating experiments using diamond abrasive were carried out and the effect of electroplating factors on the amount of electrodeposited diamond grains was discussed, too. It was found that turbulence flow of electroplating solution could improve amount of deposited diamond grains. Long diamond wire tools were manufactured and used to slice Si ingot, it was confirmed that the developed wire tools have high slicing performance equal to the commercially available diamond wire tool.