Painting & Coating Industry (PCI) logo Powder coating summit logo
  • Sign In
  • Create Account
  • Sign Out
  • My Account
  • NEWS
  • PRODUCTS
  • MATERIALS
  • TECHNOLOGIES
  • FINISHING
  • RESOURCES
  • EVENTS
  • DIRECTORIES
  • EMAGAZINE
  • CONTACT
cart
facebook twitter linkedin youtube
  • NEWS
  • Latest News
  • Market Trends & Reports
  • Price Alerts
  • Subscribe to eNewsletters
  • Global Top 10/ PCI 25
  • Weekly Featured Article
  • COATLE Word Game
  • PRODUCTS
  • Product News
  • Must See Products and Services
  • MATERIALS
  • Additives
  • Resins/Polymers
  • Pigments
  • Equipment
  • Distributors
  • TECHNOLOGIES
  • Adhesives
  • Architectural Coatings
  • Industrial Coatings
  • Nanotechnology
  • Powder Coatings
  • Solventborne
  • Special Purpose Coatings
  • Sustainability
  • UV Coatings
  • Waterborne
  • Waterborne
  • FINISHING
  • Finishing News
  • Finishing Technologies
  • Finishing Equipment
  • RESOURCES
  • Columns
  • Blogs
  • Coatings Supplier Handbook
  • Podcasts and Videos
  • PCI Store
  • eBooks
  • Sponsor Insights
  • White Papers
  • COATLE Word Game
  • Columns
  • Ask Joe Powder
  • Did you know?
  • Distribution Dive
  • Focus on Canada
  • Formulating With Mike
  • Innovation Insights
  • Moody's Coatings Conundrums
  • Powder Coating Perspectives
  • Target the Market
  • TiO2 Insider
  • Blogs
  • Editor's Viewpoint
  • Industry Insights
  • Podcasts and Videos
  • COAT-IT! Podcast
  • Videos/PCI TV
  • EVENTS
  • Coatings Trends & Technologies Summit
  • Paint and Coatings Academy
  • Webinars
  • Calendar of Events
  • Lifetime Achievement Award
  • DIRECTORIES
  • Buyer's Guide
  • Equipment Directory
  • Materials Directory
  • EMAGAZINE
  • Current Issue
  • eMagazine Archive
  • China Issue Archive
  • Editorial Advisory Board
  • CONTACT
  • Contact Us
  • Advertise
  • Subscribe to eMagazine
  • Subscribe to eNewsletters
Painting & Coating Industry (PCI) logo Powder coating summit logo
search
cart
facebook twitter linkedin youtube
  • Sign In
  • Create Account
  • Sign Out
  • My Account
Painting & Coating Industry (PCI) logo Powder coating summit logo
  • NEWS
    • Latest News
    • Market Trends & Reports
    • Price Alerts
    • Subscribe to eNewsletters
    • Global Top 10/ PCI 25
    • Weekly Featured Article
    • COATLE Word Game
  • PRODUCTS
    • Product News
    • Must See Products and Services
  • MATERIALS
    • Additives
    • Resins/Polymers
    • Pigments
    • Equipment
    • Distributors
  • TECHNOLOGIES
    • Adhesives
    • Architectural Coatings
    • Industrial Coatings
    • Nanotechnology
    • Powder Coatings
    • Solventborne
    • Special Purpose Coatings
    • Sustainability
    • UV Coatings
    • Waterborne
    • FINISHING
      • Finishing News
      • Finishing Technologies
      • Finishing Equipment
    • RESOURCES
      • Columns
        • Ask Joe Powder
        • Did you know?
        • Distribution Dive
        • Focus on Canada
        • Formulating With Mike
        • Innovation Insights
        • Moody's Coatings Conundrums
        • Powder Coating Perspectives
        • Target the Market
        • TiO2 Insider
      • Blogs
        • Editor's Viewpoint
        • Industry Insights
      • Coatings Supplier Handbook
      • Podcasts and Videos
        • COAT-IT! Podcast
        • Videos/PCI TV
      • PCI Store
      • eBooks
      • Sponsor Insights
      • White Papers
      • COATLE Word Game
    • EVENTS
      • Coatings Trends & Technologies Summit
      • Paint and Coatings Academy
      • Webinars
      • Calendar of Events
      • Lifetime Achievement Award
    • DIRECTORIES
      • Buyer's Guide
      • Equipment Directory
      • Materials Directory
    • EMAGAZINE
      • Current Issue
      • eMagazine Archive
      • China Issue Archive
      • Editorial Advisory Board
    • CONTACT
      • Contact Us
      • Advertise
      • Subscribe to eMagazine
      • Subscribe to eNewsletters
    FT Archives

    Managing Your Bath with Meter Controls

    By Craig Henry
    August 1, 2007
    All electroplaters, anodizers and electrocoaters have baths that need to be maintained. One of the most frequent needs in the maintenance procedure is to replenish one or more materials that are depleted as items move through the process. This goal often is accomplished manually based on an operator’s “best guess.” However, a more efficient method is to use meters that regularly and accurately measure parameters such as ampere hours, time, conductivity, pH and other process conditions to determine the precise additions needed at the correct times.



    All electroplaters, anodizers and electrocoaters have baths that need to be maintained. One of the most frequent needs in the maintenance procedure is to replenish one or more materials that are depleted as items move through the process. This goal often is accomplished manually based on an operator’s “best guess.” However, a more efficient method is to use meters that regularly and accurately measure parameters such as ampere hours, time, conductivity, pH and other process conditions to determine the precise additions needed at the correct times.

    Manual Methods

    It is a common practice in the industry to add brighteners, plating solution, acid, caustic, pigment, resin and other materials manually based on existing conditions, educated guesses, or test-and-add methods. Such additions can vary from measured amounts at prescribed times to a 5 gallon bucketful whenever someone thinks of it. Some of the obvious disadvantages include:
    • Forgetting to add the materials
    • Adding the wrong amounts
    • Adding the wrong materials
    • Peaks and valleys in bath chemistry because of inconsistent additions
    • Adding too much material, resulting in scrap, rework and wasted material
    • Adding too little material, resulting in scrap, rework and loss of business
    • Inability to certify the process
    • Difficulty in tracking process costs
    • Process control limits exceeding the specification limits


    Figure 1. Variation in bath concentration with additions every eight hours.

    Reducing Variation

    The depletion of bath chemicals occurs as a function of time, temperature and the number of items moving through the bath.

    As shown in Figure 1, if additions are made every eight hours, the concentration of the bath varies significantly during the day. This illustration is based on the premise that the amounts added are correct. If the additions are made less frequently, then the effect is even more pronounced.

    Figure 2. Variation in bath concentration with additions every hour.

    Compare the previous variation to Figure 2, where additions are made once per hour. It is obvious that much less variation occurs within the bath. The variation can be further reduced by making additions more frequently.

    By measuring the correct parameter (time, ampere-hours, conductivity, pH) that correlates to the rate of depletion and replenishing the bath at the corresponding rate, you can minimize process variation. Reducing variation can optimize both costs and quality because expensive chemicals are not wasted, scrap and rework is reduced, and process predictability is enhanced.

    Ampere-Hour Basis for Additions

    Whether you are an electroplater, an anodizer or an e-coater, using amp hours to add materials is based on a direct correlation between the depletion rate and the amount of product going through the bath. An amp-hour measurement combines both.

    Amp-hour meters measure the time and current used and accommodate variances in load size, as well as the time spent in the bath. They constantly sample the amount of current being used by the rectifier and generate an amp-hour measurement. The controller then sends a signal to the pumping system to add the required amount of material to the bath to replace the amount consumed. The length of time to pump and the frequency of additions can be adjusted to provide the precise amount needed. After these adjustments, an operator should find that the bath will not require testing as often because the chemistry will remain more consistent throughout the day, week and month.

    The meter typically has several inputs and outputs, including power (110 or 220 VAC), millivolts from the rectifier ampmeter or shunt, pump outputs from relays in the meter, alarm outputs from the meter, and level inputs from the additive container.

    Basic meters will show cumulative amp-hour totals. Optional features can make the meter a more valuable tool and can also make the operation less labor intensive and more reliable. For example, resettable amp-hour totals for load, shift, daily or weekly tracking can allow you to track and trend productivity and compare different operators, shifts, bath chemistries or other factors. (Such devices must also have non-resettable amp-hour totals to meet environmental compliance laws and regulations.)

    The ability to handle multiple pump operation allows two or more components to be added to a bath at different rates based on the same rectifier and bath outputs, while multiple rectifier summing allows the amp-hour totals from one bath that has multiple rectifiers to be summed so that the additions can be based on the aggregate total. Meters that have the capacity to sum pump cycles and pump run time can allow you to track the amount of material added to the bath. This data can be used to determine performance trends, and to generate precise cost data as a function of amp-hours, run time or product. Permanent memory retention without the use of batteries is essential to maintain the integrity of the data.

    Material level alarms provide a warning before the reservoir is empty so that bath chemistries remain in tolerance, while fused pump outputs protect the meter in the event that a pump motor fails. Meters with PC Network capability allow you to access all of the data in the meter from a personal computer or PLC, download the data directly and integrate it into spreadsheets and reports. It should also allow you to change meter settings if necessary to prevent tampering with the meter itself. Other meters allow handheld computer infrared data access, which is a different method of downloading data directly from the meter or changing parameters with the use of a handheld computer.

    Meters with integral pumps and controllers contain all of the components necessary to “plug and play.” They come with one or two pumps and simplify the maintenance and installation of a system.

    Not all meters have these features. However, meters with a variety of options can save you a considerable amount of time, money and effort compared to a less versatile product.

    Time Basis for Additions

    Some processes, such as cleaning or electro-less processes, will deplete materials proportionate to the length of time that an item spends in the bath. In this situation, an operator would benefit from a time-based controller. These units can replenish either with fixed additions every time a rack enters the bath, or as a function of the total number of minutes that accumulate while parts are in the bath. These units are usually activated by a limit switch that is tripped when a rack is placed in the bath.

    Most of the same features and benefits described for amp-hour based additions pertain to time-based additions.

    Conductivity or pH Basis for Additions

    This approach affects not only the direct processes involved in plating, anodizing or coating, but also ancillary processes such as off-line generation or waste treatment, since many of these have portions of the process that are controlled by or sensitive to either pH or conductivity. In these applications, the process in question can either be monitored with alarm outputs for out-of-tolerance conditions or controlled with pump outputs.

    In the latter case, the meter will constantly track the process parameter selected. When either a high or low level is reached, the meter will activate a pump to add the necessary material to bring the process back within tolerance. More sophisticated meters will track the rate of change and add material at a variable rate to achieve process limits.

    As before, the benefits of automated control and the meter features will be similar. Additional considerations include temperature compensation to maintain measurement accuracy and the ability of the meter to accommodate the range that needs to be measured.

    Additional Meter Options

    Besides the basic meter types, other meters can be used to monitor and control specific conditions that exist in a process. Some examples include ripple meters, flow meters and current density meters.

    Ripple Meters – These units measure the rectifier output and express their readings as a percentage that the AC voltage is of the DC voltage. This measurement is significant for a number of reasons:
    • Process susceptibility – If you are operating a process that is vulnerable to high ripple, such as e-coat, bright chrome or nickel, rectifier components can fail or degrade while the rectifier is still capable of providing output. Consequently, your process might produce unsatisfactory parts without warning and without an immediately visible cause.
    • Rectifier failure – Your rectifier may experience partial failure or component degradation that will ultimate lead to complete rectifier failure. The ability to sense problems before a catastrophic failure occurs can reduce repair costs, unscheduled downtime and loss of production.
    • Power consumption – A rectifier operating with a defective component creates high ripple, which also means that the rectifier is operating inefficiently. As a result, your power bills are higher to produce the same amount of work.
    Additional features to consider for this specific product include auto-ranging so that all voltages can be measured, as well as alarm outputs at adjustable settings.

    Flow Meters – These units can both monitor and control the flow of material within the process. They can balance levels in baths, make additions based on the amount of material passing the measurement point, and provide summary data and alarm outputs to ensure process control.

    Current Density Meters – The ability to measure current density is an invaluable tool to determine whether you are optimizing ion transfer within your bath. By measuring the current density over the entire surface of part racks, you can assess:
    • Anode placement
    • Anode-to-cathode ratios (Do you have the right number of anodes?)
    • Bath efficiency
    • Deposition rates


    Meter Selection

    Determining which brand and model of meter fits your needs should be based on several factors, including the meter’s ease of use, reliability, visibility of the display, 110 or 220 VAC output, resistance to harsh environments, size and convenience of mounting, and value, as well as options such as:
    • The ability to operate multiple pumps
    • The ability to summarize multiple rectifiers
    • The ability to prime pumps from the meter
    • The ability to operate both electric an pneumatic pumps
    • The ability to communicate on a data network with your PC
    • The ability to download data to a hand-held computer
    Of course, one of the most critical factors in product selection is in choosing a vendor that understands your process and has a track record of supplying reliable products. By using the right meter controls, you can reduce process variability and increase your profits.


    For more information, visit www.jptechinc.com.


    Editor's note: A variation of this article originally appeared in Southern Metal Finishing and on FinishingTalk.com.

    Share This Story

    Looking for a reprint of this article?
    From high-res PDFs to custom plaques, order your copy today!

    Craig Henry is vice president of JP Tech, East Troy, WI, a manufacturer of meter controls for metal finishing. He can be reached at 262.642.7672 or craigh@jptechinc.com

    Recommended Content

    JOIN TODAY
    to unlock your recommendations.

    Already have an account? Sign In

    • PCI-0724-Global10-Feature-1440.png

      2024 Global Top 10: Top Paint and Coatings Companies

      Who ranks on top? PCI’s annual ranking of the top 10...
      Paint and Coating Market Reports
      By: Courtney Bassett
    • PCI-0724-PCI25-Feature-1440.png

      2024 PCI 25: Top Paint and Coatings Companies

      PCI's annual ranking of the top 25 North American paint...
      Paint and Coating Market Reports
      By: Courtney Bassett
    • pci1022-Kinaltek-Lead-1170.jpg

      A Novel Pigment Production Technology

      Following an extensive R&D program that demonstrated...
      Paint and Coating Pigments
      By: Jawad Haidar and Nitin Soni
    You must login or register in order to post a comment.

    Report Abusive Comment

    Subscribe For Free!
    • eMagazine
    • eNewsletter
    • Online Registration
    • Subscription Customer Service

    More Videos

    Sponsored Content

    Sponsored Content is a special paid section where industry companies provide high quality, objective, non-commercial content around topics of interest to the PCI audience. All Sponsored Content is supplied by the advertising company and any opinions expressed in this article are those of the author and not necessarily reflect the views of PCI or its parent company, BNP Media. Interested in participating in our Sponsored Content section? Contact your local rep!

    close
    • paint sprayer in a workshop
      Sponsored byallnex

      Enabling Performance and Compliance: allnex Introduces a New Line of VOC Exempt Solvent-Borne Resins

    • various shades of orange pigments and colorants
      Sponsored byVibrantz Technologies

      Solid Colorant Technology Paves the Way for a Sustainable, High-Performance Future in Coatings

    Popular Stories

    Default Aerospace Image

    PPG Plans Major Aerospace Facility

    A collage of products using non-PFAS

    A Surge in Non-PFAS Releases

    Names-467607423.jpg

    Two PPG Scientists Earn Rare Honor



    PCI Buyers Guide

    Submit a Request for Proposal (RFP) to suppliers of your choice with details on what you need with a click of a button

    Start your RFP

    Browse our Buyers Guide for manufacturers and distributors of all types of coatings products and much more!

    Find Suppliers

    Events

    January 1, 2030

    Webinar Sponsorship Information

    For webinar sponsorship information, visit www.bnpevents.com/webinars or email webinars@bnpmedia.com.

    View All Submit An Event

    Poll

    Longest-running laboratory experiment

    What is the longest-running laboratory experiment?
    View Results Poll Archive

    Products

    Automotive Paints and Coatings, 2nd Edition

    Automotive Paints and Coatings, 2nd Edition

    Now in its second edition and still the only book of its kind, this is an authoritative treatment of all stages of the coating process.

    See More Products
    pci  webinar april 2025

    PCI CASE EBOOK
    ×

    Keep the info flowing with our eNewsletters!

    Get the latest industry updates tailored your way.

    JOIN TODAY!
    • RESOURCES
      • Advertise
      • Contact Us
      • Directories
      • Store
      • Want More
    • SIGN UP TODAY
      • Create Account
      • eMagazine
      • eNewsletters
      • Customer Service
      • Manage Preferences
    • SERVICES
      • Marketing Services
      • Reprints
      • Market Research
      • List Rental
      • Survey & Sample
    • STAY CONNECTED
      • LinkedIn
      • Facebook
      • Youtube
      • X (Twitter)
    • PRIVACY
      • PRIVACY POLICY
      • TERMS & CONDITIONS
      • DO NOT SELL MY PERSONAL INFORMATION
      • PRIVACY REQUEST
      • ACCESSIBILITY

    Copyright ©2025. All Rights Reserved BNP Media.

    Design, CMS, Hosting & Web Development :: ePublishing

    Painting & Coating Industry (PCI) logo Powder coating summit logo
    search
    cart
    facebook twitter linkedin youtube
    • Sign In
    • Create Account
    • Sign Out
    • My Account
    Painting & Coating Industry (PCI) logo Powder coating summit logo
    • NEWS
      • Latest News
      • Market Trends & Reports
      • Price Alerts
      • Subscribe to eNewsletters
      • Global Top 10/ PCI 25
      • Weekly Featured Article
      • COATLE Word Game
    • PRODUCTS
      • Product News
      • Must See Products and Services
    • MATERIALS
      • Additives
      • Resins/Polymers
      • Pigments
      • Equipment
      • Distributors
    • TECHNOLOGIES
      • Adhesives
      • Architectural Coatings
      • Industrial Coatings
      • Nanotechnology
      • Powder Coatings
      • Solventborne
      • Special Purpose Coatings
      • Sustainability
      • UV Coatings
      • Waterborne
      • FINISHING
        • Finishing News
        • Finishing Technologies
        • Finishing Equipment
      • RESOURCES
        • Columns
          • Ask Joe Powder
          • Did you know?
          • Distribution Dive
          • Focus on Canada
          • Formulating With Mike
          • Innovation Insights
          • Moody's Coatings Conundrums
          • Powder Coating Perspectives
          • Target the Market
          • TiO2 Insider
        • Blogs
          • Editor's Viewpoint
          • Industry Insights
        • Coatings Supplier Handbook
        • Podcasts and Videos
          • COAT-IT! Podcast
          • Videos/PCI TV
        • PCI Store
        • eBooks
        • Sponsor Insights
        • White Papers
        • COATLE Word Game
      • EVENTS
        • Coatings Trends & Technologies Summit
        • Paint and Coatings Academy
        • Webinars
        • Calendar of Events
        • Lifetime Achievement Award
      • DIRECTORIES
        • Buyer's Guide
        • Equipment Directory
        • Materials Directory
      • EMAGAZINE
        • Current Issue
        • eMagazine Archive
        • China Issue Archive
        • Editorial Advisory Board
      • CONTACT
        • Contact Us
        • Advertise
        • Subscribe to eMagazine
        • Subscribe to eNewsletters