Metal Finishing Guide Book


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period indicates good initial anodize coating formation during the ramp cycle. Please compare the voltage and current values with APCD and without APCD on the data logger graphs (see Figures 3 & 4). Voltage Without APCD With APCD 15V 25–50 Amps 300 Amps (min) 20V 150 Amps 400 Amps 30V 340 Amps 540 Amps (min) (APCD disconnected after 30 Volts) PROBLEM-SOLVING SITUATIONS/TROUBLESHOOTING DEFECTS The following represent defects, properties and control factors which were involved in problem-solving situations. Procedural requirements along with concentrated organic additive/modifiers also represent improvements and solutions to problem-solving and troubleshooting situations as follows: 1. Smut, Powder and Burning Reduced by Pulse – Step – Ramp plus concentrated additives/ modifiers 2. Burning: Prevented by the Complete Spectrum Approach Endothermic properties of concentrated additives/modifiers Pulse – Step – Ramp and ADO ADO during Constant Current Density Ranging CCDR 3. Pits/Blisters (7000 Series) Tendency to Pit Reduced by PSR Activation @ 3–5 Volts 4. Corrosion Resistance Increased by RSR and Amperage Decay (ADO) (Due to better pore structure for sealing) 5. Slow Anodize Formation Rate (Speed) Faster Anodize using PSR and CCDR Controlled using amp hours during pulsed current 6. Anodize Tank Temperature Range Wider Range to 100º F+ using concentrated Chemistry and PSR (Concentrated additives & modifiers increase heat absorption in pore structure) 7. Poor quality (dull) color Anodize Increased Dye Penetration using PSR +Dwell 8. Pore Structure Development/Bonding Properties PSR/Dwell times are keys to proper formation and development PSR for Superior Adhesive Bonding Properties @ 5-10 Volt 9. Final Microfinish Improved due to PSR – Temperature Increased concentration of additives and modifiers 10. Power Savings (Lower KWH) Low Voltage / Higher Current / PSR, ADO, Dwell THE BALANCING ACT The following balancing act5 found in another anodize workshop/paper can be very beneficial in troubleshooting situations. Please note how the many chemical and electrical control parameters affect the anodize formation process. There are many different chemical products which can be used as electrolytes, but we will only consider sulfuric acid since it is the most common. However, the control parameters we will consider would be applicable to any electrolyte. 229

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