Metal Finishing Guide Book


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anodizing. The amperage must be allowed to drop off as it pulses within a range. To better define the procedure process, we will use the term Constant Current Density Ranging (CCDR). For example – If we are anodizing at 40 ASF, we may set the (ADO) at 10%. If the amperage is calculated at 1000 (representing 40 ASF) and set plus 5% (1050) and allowed to delay Figure 2. ATS Training Graph—2000 Series Aerospace. (drop off) 10% to 950 amps before manual or automatic reset to 1050 Amps, then we are anodizing at an average of 1000 Amps (40 ASF). Also, with the addition of pulse, we may open the CCDR by 25% while still anodizing at an average Current Density of 40 ASF, with increased energy savings. This CCD Ranging, (CCDR) or average CCD ranging (AVCDRG) is extremely important for the production of all type II – III – 23 and 123 anodic coatings. CCDR run in the voltage mode is a key secret sometimes overlooked by many anodizers. Process Time vs. Ampere Hours: There are at least three ways to process anodize. These include Time, Final Voltage and Ampere Hours. Most loads are run strictly by time. However, Ampere hours is actually the best way to run the process, especially when pulse is used and may vary during the process run. When Pulse Ramp and Constant Current Density Ranging are used along with time, the addition of ampere hours will give very accurate final thickness results: (± 0.0001mil), allowing for the extremely tight tolerances of today's critical 1. Voltage Ramp to Control Current Activation pulse can be added indicated in RED 2. Initial Current (25% or 10ASF) – 5 Min. Activation pulse can be added indicated in RED 3 – 4. Manual Control – Dwell Steps ADO (Amp Drop off) occurs during dwell periods 5. Pulse – Step – Ramp – Dwell Automatic control if available 6 – 7. CCDR – Constant Current Density Ranging Automatic control if available Plus 5 – 10% ADO (Amp Drop off – Decay) 8 – Slow Pulse Reset during CCDR Run Cycle Amp Hour Meter should be used with Pulse Table 1. Training Graph notes (See Figure 2). 227

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