Coho Dip Processing | REL Inc.

Coho Dip Processing

Coho Control

What is Coho Control?

Coho Control is a real-time training and tracking control software. Coho Control is specifically designed for FPI, and surface treatments like cleaning, plating, and etching. Integral machine learning and process learning to increase efficiencies in traditional training intensive aforementioned processing is the backbone of Coho Control.

Definition of Automation?

‘Things are not getting less automated’ is a quote from a friend, Jay Isaacson. Gone are the days of the little calendars that used to be in shirt pockets. Important daily functions such as storing personnel information/notes, starting cars, turning on lights, sending cards, paying bills, etc. get stored into handheld automation devices. The devices learn shopping and buying trends, and compile a real time history of where the user has been for historical recall if necessary to remember or discover what happened and when. There is an increasing rate of dependence on data and automatic control of every-day things in our lives. This automatic data storage, control, and historical recall on handheld devices is what is called Human Automation.

Automation has been an industrial trend for decades. Industrial automation began with relays that took signals from a switch and turned something ‘on’ or ‘off’. ‘Relay-Logic’ is binary (on-off control) and is the foundation of Programmable Logic Controllers (PLC). This has grown over the past decades. There are now 1000’s of switches and devices that take inputs and/or give outputs that can be used for process control. This type of machine automation is called Mechanical/Electrical Automation and its function is to create processes that run automatically.  Mechanical/Electrical automation has been traditionally used on processes that follow set recipes. It works extremely well to add consistency to processing that must adhere to set Timing, Pressure, and Temperature specifications. ‘Set it and Forget it’ is the mantra of Mechanical/Electrical automated devices.

Human Automation and Mechanical/Electrical Automation is REQUIRED in processing aerospace components. Real time database decision points from humans pertaining to Penetrant coverage, Rinse adequacy, and Dryness in FPI processing is paramount to ASTM E1417 specification adherence. Etch Rate affecting part thickness, Coating thicknesses, and part cleanliness are decision points during surface processes like plating and etching. Therefore, Human automation and Mechanical/Electrical automation must be integrated to have industrial success. This integration is the foundation of Coho Control. Coho control encompasses control over mechanical/electrical systems along with the data storage with historical recall with access by Handheld devices.

Coho Control allows for machine control along with real time access of process data via handheld devices. The machine control can be Human Automation, processing of complex parts that REQUIRES human interaction at every step, this control is the essence of Coho Capture. The machine control can be via PLC for Mechanical/Electrical control. This is called Coho System control.

Coho Capture Example for FPI

This software application can fully replace all the manual paperwork associated with the FPI process per ASTM 1417. All pre-penetrant process checks can be logged, gage calibration intervals by gage number, and process timings will be recorded.  This application will also have the ability to scan CoC and other documents such as NIST traceability paperwork into the platform.

Security level login capabilities are included.

  1. OL – operator level
  2. L3 – Level 3 (process owner)
  3. Maintenance Level
  4. OEM level

Process Paperwork

Need ability to load ‘scanned papers’ or high-res pictures to save in the database as a file of stuff that would normally be hanging around to be printed upon demand whenever from wherever remotely.

  1. Written procedures
    1. Drawings/prints
    2. Sample defects
  2. Certificate of Conformances/Certifications
    1. Blacklights
    2. Spray Guns – Water
    3. Dryer certification
    4. NIST/Gage R&R for -Temperature gages, Pressure gages, and Timers

Process quality check mode

Checks that are databased and initially set up on a schedule will be accessed as soon as an operator logs in. (Timings listed are from ASTM directly. Some facilities take variances. Example: At some customers air gages are calibrated every 12 months not 6 as stated by ASTM). The software will alert the UI that these need to be done before any processing can occur. (i.e. if a process quality check expires the system cannot perform until complete.) Therefore, the operator, Level 3, and/or maintenance should have a look ahead screen to make sure they are out in front of this to not pause the process. If an operator (OL)/Level 3 (L3)/maintenance personnel (MP) performs a process quality check before it’s due then the check is reset from the date performed. Level 3’s have the ability to change the timing interval after setup. This will be LOGGED!! The specific operator checks off what they did before the system runs. Every check has a security level associated with the sign off. For example: an operator should never sign off on a dryer calibration. And the dryer calibration guy shouldn’t ever sign off on the penetrant brightness test.

Below is a list of checks and at set intervals, with the corresponding level of security assigned.  It is safe to assume that higher levels of security can allow additional access for lower level security clearance along with the ability to review all the process check Data.

  • Daily – All at OL
    • Penetrant Contamination
    • Dry Developer Condition
    • Aqueous Developer Contamination
    • Penetrant System Performance
    • UV-A Lamp Intensity
    • Special UV-A Lamp
    • Examination Area Cleanliness
    • Water Wash Pressure Check
    • Water Wash Temperature Check
    • Drying oven Temperature
    • Air Pressure Gauge Check
  • Weekly – All at OL
    • Water content Method A Penetrants – Water-Based
    • Hydrophilic Emulsifier Water Concentration
    • Aqueous Developer Concentration
    • UV-A Lamp Integrity
    • Visible Light Intensity
  • Monthly – All at OL
    • Water content Method A Penetrants – Non-water based
    • Lipophilic Emulsifier Water Content
  • Quarterly
    • Penetrant Brightness – L3 Level
    • Examination Area Ambient Light Intensity – OL
    • Drying Oven Calibration – L3 Level
  • Semi-Annually – All at L3 Level
    • Light Meter Calibration
    • Water Pressure Gage Calibration
    • Water Temperature Gage Calibration
    • Air Pressure Gauge Calibration
  • Detailed by Process specification – Variable timing needed.
    • Water-Washable Penetrant Removability – OL
    • Emulsifier Removability – OL
    • Comparative Penetrant Sensitivity – L3 Level
    • Battery Powered UV-A Lamps – OL
      • Before and After use
        • This may be defined in the procedures to incorporate before and after guidelines, such as per part, per lot, per shift, etc.

Recipe Creation mode

The responsible Level 3 needs to go to each station and enter min/max times then name it to a recipe. Constraints need to be set to establish run recipes. Example: For some facilities this means penetrant dwell can occur in the penetrant tank. Some facilities need the parts to be transferred to the dwell be considered as dwelled. This will be clarified in the recipe setup with the use of constraints.

Operation Mode

There is a timer status screen that shows all parts in line and what the current times are on the parts. The timing is communicated by the system stack light and the interface with the timing sequence is accomplished with the barcode scanner. To start a basket or part in penetrant it is scanned in. The basket/part scans out when the next process is scanned in. The only exception is one must scan out of the line after developer dwell.

  1. Stack light sequence (Configurable) – Top Green (Solid Green – process Running); Middle Amber (Flashing Amber – Needs operator Input + three blind mice soundtrack plays) – Bottom Red (Flashing Red – Wrong sequence need to interact with computer to fix)

Preventive maintenance/lubrication mode

Need a maintenance user defined page with inspection intervals for specific motors, cylinders, gearboxes. Need to be checked off for system to run.



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