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Aluminum extursion

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This topic contains 15 replies, has 7 voices, and was last updated by  Guest 10 years, 7 months ago.

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  • #52066

    Guest
    Participant

    I work for a small extrusion company and I’m having trouble drilling down to a project. This will be my first project so it needs to be as simple as possible. I was just looking for some ideas. I would like to reduce the process scrap that ends up in the packing dept, but there is a lot of different shapes we extrude. I thought it would be hard to follow all the different shapes. I was curious what kind of time frame I should use for data collection…. Month, year, week. Any ideas are helpful   Thanks.

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    #182537

    GB
    Participant

    Hey there.
    I’ve done several proj’s in this realm.   For sanities sake, i’d do a high-level yield analysis and then rank them in order of highest scrap to lowest (either in %, or dollar value).   I’d limit the scope to a single p/n, or product shape.  
    In one case, I had a part that began life as a 500 + Lbs. forged slug with partial extrusion on one side and laser welding on the other and ended up under 1/2 weight through multiple machining ops/centers.
    50% scrap stinks, so it was a natural choice.   I broke up the project along machine center boundaries, with each phase taking roughly 30 days.
    We ended up working with our Customer and end user on DFMA/DFSS and a new near-netcast/forge/extrude protocol.
    Moral of the story, choose a high-impact part and limit the scope accordingly.
    We

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    #182551

    Guest
    Participant

    Thanks for the advice
     
    I’ve collected data and have determined what the high scrapping shapes are. I’ve kept track of what defects occur the most. So what you’re saying is, just stick with one shape or the top few, and try to improve them throughout the different processes (painting, anodizing fabricating)?  This might be something I can handle.
     

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    #182564

    GB
    Participant

    You go it.  Pilot against one particualr part/shape.   You may be able to leverage gains across other shapes, esp with shared processes.

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    #182568

    Vallee
    Participant

    Just curious.. are you defining defects as what produces scrap even if it is a planned part of the process? Or defects as what is wrong with the product that allowed the product to be scrapped? You may be missing an opportunity if you don’t ask this.HF Chris Vallee

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    #182570

    Taylor
    Participant

    Hey Chris, Off the subject, but wanted to let you know I spoke with the boss and looks like this year is out on the training and software we talked about. Not sure I understand his motive, but like everyone else, cash is tight………………

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    #182571

    Vallee
    Participant

    We have seen clients take two approaches; many are training more people now so not to lose out at the end of the year, while others are waiting till the end of the year. I sent you an e-mail on the side. HF Chris Vallee

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    #182588

    Guest
    Participant

    The scrap that I’ve identified is not planned scrap. Its defects like paint runs, dents, roughness. Its defects that happen as the extrusion carries to different departments. For instance, the press department might miss denting. Then it gets painted, thus adding that much more value to the part before getting scrapped. Am I still on the right page? Should I be going after planned scrap?

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    #182591

    shri11
    Member

    Hi, Planned scrap is almost always predictable and hard to change. butt ends, stretching table scrap, etc are hard to reduce.  It can be done, but as a starting project it is hard to tackle.
    If you are able to analyze where most of your scrap comes from, Anodized product, or painted product or mill finish product, that gives you a start.
    Then do a pareto analysis, 3- level, for source of scrap, then drill down by type of defect, and the shape itself, (heavy wall, thin wall)
    This is how I had done some of my projects when I worked in the Extrusion Industry, S
    Shri

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    #182593

    Vallee
    Participant

    There is nothing to say that these may or may not be exclusive.  As you walk through the process keep both in mind to see what is going on; then you will know if planned scrap can also be impacted or if it has an impact on the process.
    Getting material closer to size if economical may also reduce rework and scrap caused by trimming too much off. I watched a business case for purchasing a leather cutting machine for aircraft chairs because once the batch was too small to be used for a complete aircraft it could not be used again.  Each leather had a different shade.
    Just keep your eyes open. Think about it.. where does extrusion scrap go when cut?  Does it get mixed up with virgin material and not have it’s mil ID on it?

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    #182597

    shri11
    Member

    Chris, typically, extrusions are sized by diameter, and the scrap is always reused, melted back especially with “soft” aluminum alloys. Shri

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    #182607

    Adam L Bowden
    Participant

    Here is some information on Alum Extrusion that might be useful
    …To identify yield opportunities you have to think process – what is
    causing the yield issues (root cause).Firstly you have to get data on optimal yield vs actual yield.
    Optimal yield is the % yield that you will get taking into
    consideration :
    – Starter billets / End billet waste
    – Lap marks
    – stretcher jaw marks
    – some multi-hole extrusion length differencesOnce you have the optimal yield numbers Vs Actual then this
    difference is the target of your yield project.
    Next you need to collect data …
    You need to break it into defect and defective – defects can be re-
    worked costing money and if it cannot be re-worked it is defective
    or scrap.
    Typical reasons for defects / defectives are:
    Blisters
    Blow Holes
    Tearing
    Straightness
    Score line / handling damage
    Lap
    Too long / shortAfter collecting this data you can focus on the root cause and drive
    process changes such as …
    – handling damage – change the walk beam table covering or
    roller conveyor transferSome of the more analytical root cause issues will be resolved by
    optimizing…
    – Billet surface quality, inclusions, cut off straightness, air bleed
    pathways
    – Heat of billets (saturation) billet rotation (hard / soft end)
    – Press speed
    – Die design, bearing qualityMost of the issues can be resolved without getting into analysis
    paralysis – and most of the issues are already known by the
    operators.Drop me a line if I can assist you further.Best regards,Adam adamlbowden@yahoo.comPS – do you know any one that wants to but a 4,200 t Press “cheap”

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    #182608

    Vallee
    Participant

    Shri11,
    I understand where you are focusing; however, companies I have dealt using raw material do not melt all their scrap; instead there is a poor process that does not control for it and it gets put in virgin raw material.  The wrong grade gets selected and the issue is not found out until too late.
    The point is for him to keep his eyes open for possible improvement areas. He must observe what is going on to understand the numbers he tracks to decide on where and how to start.
    HF Chris Vallee
     
     

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    #182616

    Adam L Bowden
    Participant

    Good morning Chris,
    We should chat over our experiences – Your Aluminum and My
    Aluminum and Magnesium extrusion experiences.You have my number – give me a call next week to chat / catch up.Best regards,Adam

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    #182624

    Paul Gibbons
    Participant

    Suggest once you have found an area of focus use OEE as a measure in the DMAIC process….
    Measure OEE for six weeks capturing data on failure modes in relation to availability, performance and quality. Then focus your improvements around removing/reducing/controlling these failure modes. Perhaps a Kaizen event on the piece of plant identified?
    Good luck.
    Paul  

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    #182628

    Guest
    Participant

    I guess I’ll use the last six months, and try to improve the top 3 running dies that also have high scrap by the time they reach the packing department. Thanks for everyones help, like i said i’m very new to this. I’ll keep checkin back 

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