Exposure Process Stage

Jul 2021 Author: Geoff Warleigh
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Exposure Process Stage

Introduction

This document will explain the basic steps necessary to expose and prepare resist effectively and efficiently so as to not waste time or material through lack of preparation.

It is important to follow the steps to ensure consistent and efficient production.

Exposure

  • The exposure process basically allows you to transfer your artwork to SR3000 photopolymer film, using ultra violet light using nuarc 26-1ks or Letralite unit  -- when washed out it will become a sandblast-able mask.
  • The emulsion side of the resist is placed over the black print of the artwork, UV light is passed through the artwork onto the film.

Check artwork

  • Check artwork is black.
  • Check spelling & grammar.
  • Check artwork against original customer supplied details.
  • Check artwork against the piece to ensure artwork is correct size, with overhang to avoid taping up.
  • Check orientation (front or back etch).
  • Check for problem areas that could occur during washout; very fine lines or centres of letters too small to wash out.

Prepare Resist

  • Check if 3mil or 5mil resist is required for the project:
    • Basic etch use 3mil resist.
    • Deep etch and/or paint fill use 5mil resist.
    • Use 3mil for very fine detail paint fill.
  • Cut resist to suit artwork with minimal wastage.
  • Store offcuts in a safe area (e.g.: black bag). Keep resist out of light as much as possible.
  • Ensure the glass is clean when using the Nuarc 26-1ks, or the cylinder is clean if using the Letralite unit for exposure.
  • Try to keep artwork/resist in order that will reduce error and duplication when in production.
  • It is very important when exposing the film that there is tight coupling between the artwork and the film, this will avoid producing a blurred image when washing out.
  • It is very important to expose the film for the correct time (20 seconds).
  • Exposing for less time will not wash the film out properly.
  • Over exposing will make it difficult to wash the film and film may get damaged due to over washing.
  • Always ensure when working with the Resist that it is not exposed to natural sunlight as this will damage the film, always keep protected in a safe place.

In Summary

  • Check Artwork is BLACK
  • Check Artwork is correct size.
  • Check if 3mil or 5mil for Paint fill.
  • Ensure surface glass/cylinder is clean.
  • Ensure tight coupling between film and artwork to avoid blurred image.
  • Expose for correct amount of time -- 20 seconds.
  • Always keep resist protected from unnecessary UV light to avoid damage.