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  • Surface finish for Injection Mould tooling.

    Discussion in 'Surface finishes' started by Lee_G, Jan 28, 2019.

    1. Lee_G

      Lee_G New Member

      Jan 2019
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      I have a received a drawing for an Injection moulded part that requires a surface finish of 'E8' to all A-side surfaces.

      Personally I am only familiar with the SPI fininishes i.e. A-1, A-2, etc through to D-3, Would someone be able to tell me what E8 is equivalent to or direct me to where I could find relevant information on such grades?

      Thanks in advance,

    3. Bill Toulas

      Bill Toulas Well-Known Member EngineeringClicks Expert

      Sep 2017
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      Ok, here’s what I’ve found: E8 corresponds to 6A, so it should have a surface roughness (Ra) of 2.914 μm. I have even found EDM settings to achieve this result, so if you need them, let me know.

      E8 as a term is used for tension testing, so maybe they have given you the wrong information because of a mistake? That is always a possibility as a mistyped word or even letter is enough to cause us engineers confusion. First, ask again, clarify. If you are not asking the client because you don’t want to give the impression that you’re clueless, do not follow this practice. :)
    4. GoodCat

      GoodCat Well-Known Member EngineeringClicks Expert

      Nov 2018
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      I did not quite understand the question, correct me if I am wrong. On some plastic parts, the size is indicated with the letter E8. What's the question? What is the tolerance for this size or what is the maximum surface roughness or what is the recommended roughness for this surface?

      E8 is the size tolerance with guaranteed gap.

      What is your Internet light?

      What is the maximum allowable surface roughness for this tolerance?

      What is the recommended surface roughness for this tolerance?
    5. john mariner

      john mariner New Member

      Dec 2019
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      As you said you have " received a drawing for an Injection moulded part that requires a surface finish of 'E8' to all A-side surfaces."
      I would say that for such grades you gotta ask someone personally newr you who is more experienced
      RX Marine was established in 1996 in Mumbai, India; as chemical manufacturing company catering exclusively to the needs of the marine industry. In a short span of 12 years the company has established itself as one of the leading wholesale suppliers of a wide range of chemicals for - Marine industry internationally - and other local industires and plants. Our client list bears testimony to this. The RXSOL policy has its foundations on two pillars of strength - a continuous investment in research and development to deliver premium quality products and a commitment to service.


      Last edited: Jan 2, 2020

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