TECHNOLOGY AREA(S): Materials
OBJECTIVE: Develop 3D printable materials that will survive the chemicals and temperatures of a plating facility and be nonporous in aqueous solutions. One version has to be a hard/rigid material and a second version has to be a soft / flexible material.
DESCRIPTION: Many aerospace components require plating in certain locations on the part. Non plated areas are required to be masked. Current masking processes uses a one-time use plastic maskant material, various tapes and lacquer. The application of maskants has been described as “hand assembled work of art” rather than technical process. Substantial rework is associated with the masking process. After plating the current masking is removed by hand and disposed of as hazardous waste. AF maintenance activities need a cost effective, rapidly manufacturable, multi-use masking system for plating aerospace components. Cost savings would come from reduced energy used to keep the plastic maskant material liquid, reduced rework resulting from the improper/poor application of the maskant, reduction of hazardous waste and reduced time required to: re-assemble the fixtures, re-electroplate components, remove the maskant. Additive manufacturing (3D printing) maybe a logical path for manufacturing masking fixtures. Currently no 3D printable materials have been identified that are nonporous, electrically nonconductive (volume resistivity 1 x 1010 Ohm-cm minimum), and resistant to the chemicals and temperatures encountered in electroplating processes used in AF maintenance activities. The electroplating shops need both solid and flexible 3D printable materials to use as maskants for anodize and plating: chrome, nickel, and cadmium. The masking fixtures shall be reusable for at least 20 full electroplating runs (note that parts being plated can remain in the plating solution up to 48 hrs). The masking material shall not swell due to exposure to the plating solutions or be detrimentally affected in any way. The masking material shall not absorb electroplating solutions.Additional requirements for the Hard Material: Thermal expansion coefficient must be less than 0.006” per inch length for a temperature change from 70 °F to 200 °FNonporous in the plating solution (maximum percent weight change after 6 hours exposure to the plating solution shall be 0.1%).Printable with 0.010” or better resolution. Mask must be printable using current additive manufacturing equipment (3D printers)Impact resistance at least 50% of the impact resistance of CPVC at room temperatureBondable (compatible) with the soft materialResistant to the following chemical baths and temperatures:Chromium plating solution (per MIL-STD-1501) at 130 °FHeavily alkaline solutions (rust strip 20% NaOH) up to 150 °F30% sulfuric acid at room temperatureNickel plating solution (per MIL-STD-868 solution #2) at 130 °F 20% H2SO4/5% HF at 70 °FCadmium plating solution (per MIL-STD-870) at room temperatureAdditional requirements for the Soft Material: Nonporous in the plating solution (maximum percent weight change after 6 hours exposure to the plating solution shall be 0.2%)Form an aqueous tight seal with the plating substrate(s)Bondable (compatible) with the hard material (if used as a gasket material)Printable with 0.020” or better resolution Mask must be printable using additive manufacturing equipment currently available on the open market Durometer or Hardness Range: 40 - 100 Shore A (ASTM D2240)Tensile Strength: 300 - 2000 psi (ASTM D412) Elongation at break: 70% minimum (ASTM D412)Resistant to the following chemical baths:Chromium plating solution (per MIL-STD-1501) at 130 °FHeavily alkaline solutions at 150°F (rust strip 20% NaOH)30% sulfuric acid at room temperatureNickel plating solution (per MIL-STD-868 solution #2) at 130 °F 20% H2SO4/5% HF at room temperatureCadmium plating solution (per MIL-STD-870) at room temperature
PHASE I: R&D solution that meets the above requirements and conduct preliminary business case analysis (BCA) to determine implementation costs, including a return-on-investment (ROI) calculation that compares anticipated savings to expected costs. Proof-of-concept prototype(s) shall be developed to demonstrate conformance to the requirements.
PHASE II: Initiate and complete the test plan developed in Phase I. Proof-of-concept prototype(s) shall be refined to installation-ready article and shall undergo testing to verify and validate all requirements. This process may require multiple iterations before a final design is selected. Refine BCA/ROI based on the final design.
PHASE III: If developed technologies are cost effective, passes verification / validation and qualification testing, then it shall proceed to transitioning and implementation of the technologies.
REFERENCES: 1. MIL-STD-870 “Cadmium Plating, Low Embrittlement, Electrodeposition”; 2. MIL-STD-868 (solution #2) “Nickel Plating, Low Embrittlement, Electro-Deposition”; 3. MIL-STD-1501 “Chromium Plating, Low Embrittlement, Electrodeposition”; 4. SAE AMS2403 “Plating, Nickel General Purpose”KEYWORDS: Mask, Electroplating, Plating, 3D Printing, Additive Manufacturing
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