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Plating Plant key variables?

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  • #39961

    Russ
    Member

    I am doing a project in a Chrome Plating plant and am having trouble identifying the key inputs. Data is limited, info on rejects and failure mode, daily solution pH and Surface tension for Nickel tanks and bi weekly data on additions. Has anyone else had any experience in plating projects which may point me to most likely areas to focus on to find critical criteria? I’ve scoured the web to no avail..
    Thanks Russ

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    #122860

    Abul Faisal
    Participant

    Greetings,
    Russ are you mentioning about Electroplating ? If yes Current and voltage and the concentration of the dipping solution also can be your CTQ’s.
    Regards,
    Faisal

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    #122861

    Andy P
    Participant

    Consider time the product spends in each solution and the surface quality of the product being plated itself, eg.cleanliness, surface finish etc.
    Also contact between the product and the plating fixture.

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    #122862

    Russ
    Member

    What a timely reply, Thanks!!!!!
    Yes it is electroplating, I’ll see if I can get any data on those variables. I have tried to implement TPM to ensure contacts are kept clean so voltage and current variation is reduced. The current and voltage are displayed real time but not recorded so I’ll need to put something in place to capture that data.
    Concentration of the “dipping” solution is only checked every two weeks (if you mean the Chrome), would you expect this to vary much? Our platers say they are designed to work over a wide range so monitoring is not a priority….?
    Thanks Russ

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    #122864

    Schmidt
    Participant

    If you do plating you probably use jigs with more than one part on it.Measure the rejects and try to stratify the data to jig, position of the part on the jig.Monitor the charge that has been applied to the jig, parameters like temperature, pH .. that can change quickly.
    Concentration of your dipping solution should be quite stable, but you should be able to tell this from historical data.. just plot them, do not try to plot a SPC chart, as concentration in electroplating bathes are not stable processes.
    What you will probably find out is, that rejects are mostly related to jigs, and position on the jigs, as each part on a jig is in a singular special condition. Charge on the edges is quite different from charge in the middle of the jig e.g. , you will need than an expirienced electroplater who can tell you what to do to get a more uniform deposition.
    Good luck with your project
    Marcus

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    #122868

    Russ
    Member

    Many thanks -Yeah, I had an idea this was the case, however there is great resistance to collecting this data since it means the platers becoming much more disciplined in their methodology during the load/unload and inspection, having to record jigs and position. You haven’t come across any kind of automated system (such as a bar coding method) that might help fool proof this or at least make it less reliant on operator have you?
    ATB  Russ

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    #122871

    Robert Butler
    Participant

      A possible solution to the data collection issue is to sit down with everyone and explain the need for some high quality process data.  If you set up the data collection scheme before hand and give it a definite start and stop date and also make it a point to keep the platers in the loop with respect to analysis and findings you may be able to gain their cooperation and assistance. The targets of a real start and stop time (and keeping to the promised times) lets everyone know the effort is not going to be just-one-more-d!!!!d-thing-I-hafta-do and that there is a real focus to the data gathering effort.
      Of course, I have had situations where even this didn’t work.  In those cases I turned myself into the gopher and spent several weeks living on the production floor gathering the data myself.  It’s tedious and time consuming but the data did get gathered, the analysis was run, and at the end of the day, the problem was solved.

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    #122873

    Schmidt
    Participant

    I think Robert is right, without the assistance of the people working direct in the plating area it will be quite difficult to collect the data. But in my experience. if you talk to the peolple, explain them what you do and why, and that it is only for a defined period of time you want them to do this, most people are willing to help you.
    I don’t know a good system to automize this process, it also depends on your parts. I suppose you do decorative chrome-plating, if there is a space which is not visible on the end-product you could attach some marks or numbers. This also is dependend on the help of the workers there, but makes it easier to collect the data after.
    Marcus
     

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    #122911

    Russ
    Member

    Yes, I think that’s really what needs to happen. I had identified the jig issue and have been considering methods of monitoring with the engineer, unfortunately there seems contentment with the current reject rate. This is the challenge of the job and, when successfully overcome, is part the reward I get from doing it.
    If anyone has managed to develop any innovative methods of capturing such data I’d love to hear about them. Each jig carries a number of components depending on their size (from 3 to 50), these are loaded onto a bar carrying between 3 and 5 jigs which is transported from tank to tank. There are no standard configurations for these, they depend on operator experience and an assessment of surface area on each bar. This variation doesn’t appear to affect the risk of rejects, since I suspect we operate well within the bounds of the plant in that respect.
    We do run an assessment of the jigs for our most important job once a month but I would like to roll this out to all jigs and introduce a system enabling monitoring of their performance on an ongoing basis.

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    #122930

    Robert Butler
    Participant

    According to your posts
    Each jig carries a number of components depending on their size (from 3 to 50), these are loaded onto a bar carrying between 3 and 5 jigs which is transported from tank to tank. There are no standard configurations for these, they depend on operator experience and an assessment of surface area on each bar. This variation doesn’t appear to affect the risk of rejects, since I suspect we operate well within the bounds of the plant in that respect.
    We do run an assessment of the jigs for our most important job once a month but I would like to roll this out to all jigs and introduce a system enabling monitoring of their performance on an ongoing basis.
    Concentration of the “dipping” solution is only checked every two weeks (if you mean the Chrome), would you expect this to vary much? Our platers say they are designed to work over a wide range so monitoring is not a priority….?
    Data is limited, info on rejects and failure mode, daily solution pH and Surface tension for Nickel tanks and bi weekly data on additions.
     
      Before you try to set up a data collection scheme and implement it I think you should reflect on what you have already posted and back up a bit.
     
    1.       Jigs  Capacity varies, component position varies jig number entering a tank varies and yet you state “This variation doesn’t appear to affect the risk of rejects, since I suspect we operate well within the bounds of the plant in that respect.”  So what is the reject rate by part by time by shift by bath change by location within current bounds…and what are the bounds and does anyone pay any attention to them?
    2.       Your statement “variation doesn’t appear to affect the risk of rejects, since I suspect we operate well within the bounds of the plant in that respect”   How do you know this?  According to your first missive “Data is limited”. Just because you are operating “well within the bounds of the plant” doesn’t mean anything unless operating within the bounds of the plant is acceptable in which case you are being asked to address a problem of no importance to anyone.
    3.      Concentration of solution is only checked every two weeks….platers say they are designed to work over a wide range  – I’m glad they think so, however, this needs to be confirmed.
    So far the possible list of variables (in no particular order) is: jig, jig capacity, number of jigs on a bar, distribution of parts on a jig, distribution of parts on a jig at a given time of the production day, week, cycle, concentration of elements in the dipping solution over time, variation of the dipping solution over time (pH, surface tension, etc.), variation of the dipping solution as a function of kinds and numbers of parts on jigs, operator-to-operator variation with respect to all of the above.
      Your posts give the impression that you have not sat down with the people who matter and taken the time to fishbone the process and do all of the other things essential to the Define phase.  This impression is enhanced by the turns of phrase you have used in your posts.  It sounds like you are trying to move straight to Measure.  If this is the case then please don’t.  You will waste a lot of time and effort trying to set up measurements of things that don’t matter.  If you have done the Define phase then it might be worth posting your prioritized list to this forum.  Since we do have others on this site who have experience in plating they may be able to offer some very helpful suggestions once they have a clearer picture of what you and your team believe to be the critical process variables.

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    #122933

    Russ
    Member

    file://R:PublicSix Sigma1-RGRIFFIN Project2 – Plating3 – PMap C&E FMEAP&P Cause and Effect.vsd
    Not sure this link will work since it’s on a network drive.
    However this is the Cause and effect diagram. You are right though, I am trying to move to measure though not as blindly as it sounds I hope. I have spoken to those that matter and so investigating certain variables has been ruled out on their say so, however it would appear that critical ones (Voltage and current) are not monitored. I intend to start here along with the jig aspect.
    My comment about “operating within the plant parameters” was regarding the loading of the jigs/flight bars. We only seem to get a problem when jig integrity is compromised. It is this I want to be able to monitor so we don’t have to produce rejects to identify faulty jigs. It is this aspect that is seen as more trouble than it’s worth currently.
    Nickel Blow and Roughness are the main issues. Roughness is apparently due to contamination but only becomes apparent once contamination has occurred.
    Nickel Blow is due to contact integrity and can be jig related. It is this that I want to implement to ensure we identify the faulty jigs before making defective parts.
    All other variables I have data on – Variations in Solution pH, Surface Tension, solution concenetration are not presenting as linked to the reject rate, from Minitab interactions plots
    However, other than identifying each jig and manually recording the position from which jig and which position on the jig rejects are from, I can’t think of a way of monitoring it. It is this that is the blocker, operators reject it as too much work and Team Leader as not worth forcing in for the saving. I don’t agree and will be doing some costing soon to see if I’m right. However if I could come up with a simple monitoring method it would be easier to sell. We have barcoding at the inspection station which was recently introduced so I am looking for ways to utilise this.
    Bit rushed I’m afraid so apologies if this doesn’t read to well. 

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    #122964

    Schmidt
    Participant

    I think the main problem you will have is that you are making different parts on different jigs. What you need to install is a good preventive maintenance of the jigs, and also standards for how jigs are loaded. Make sure that there are always the same amount of the same part per jig, the amount of jigs per carrier. Make sure that jigs are rejected or reworked if a certain amount of hooks is missing. If jigs are maintained well , there shouldn’t be a great difference between them.
    The critical parameters you have to look at is current / part and the charge applied to the part. Voltage should not be a critical parameter.In the chrome plating you also should have an eye on the current applied at the start of the process, if it is to low you will get nickel blows. 
    Roughness in crome plating is mostly due to high current density on a edge, nickel blow is due to low current density in the chrome plating. Both can be caused by contact problems or by setting the wrong parameters or by the geometrical shape of your jigs, anodes, shields in the electrolyte …, here you will never find an optimum set up for all parts you manufacture, you will have to decide which one you will like to optimise.
    By the way, your measurement system for roughness and nickel blows will probably visual inspection, have you done an gage R&R on this?
    Once again good luck
    Marcus

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    #123187

    Ganapathi
    Participant

    Dear Russ,
    In addition to the valuable answers you hv already received from other readers,  my views are as below:
    1. Before looking for ‘inputs’ for improvements, it is worth IDENTIFYING and DEFINING the real problem in your works. Others might hv improved in their works but they might have faced different problem. Your problem could be a bad surface, bad spots, bad colouration, large reject rate, fluctuation in rejects (inconsistency or unstable condition), non uniformity in coating thickness etc etc etc. So, you need specific solution to your specific problem. Different ‘Y’s are caused by different ‘X’s.
    2. Once you identify and define the problem in real terms – like cost of poor quality expressed in $ ), then your workers (platers) may readily come forward to cooperate collecting data, analysig them and finding soultions – the correct “X”s for your “Y”s
    Wish you best of luck
    MG
     

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    #123200

    Mal
    Participant

    Russ,
    Have you done a complete process map? At each step you should be able to identify the inputs … with a little tribal knowledge you should be able to narrow down the critical inputs.
     

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    #123217

    Martin haste
    Participant

    Voltage may not play a big part in chrome plating but it gives you a good indication of jig to job contact the higher the voltage the lower the contact at the same curent setings

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    #123251

    Ralph
    Participant

    Russ
    I am unable to access your cause & effects diagram on line, could you send me a copy, as I am currently conducting a black belt project on a plating plant with very similar problems, we have gathered 3-4 months of data, into our 6 sigma database, the critical data collected to date P/H, Temperature, voltage, current 1&2 bar (different rack configurations) x Amp hours, conductivity, metal contamination, chemical make up levels and paretto chart recording of all yield, scrap and rework performances
    We are currently refining and automating the data collection/test method regime, prior to starting the project, as we have initially found some large variation between tank results dependent on substrate material and coating finish applied.
    I would appreciate your feedback
    Ralph

     

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