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Encoder discs - Encoder disk - Encoder disc

/include/files//Groepen//images/products/encode.gif   The general function of an Encoder disc (with or without an aperture mask) and a linear Codestrip is motion control. Because the Encoder disk, mask and Codestrip play a key part in these applications, Stork Veco B.V. has two excellent technologies at its disposal to give it all the quality features that are required by your application in order to function optimally.
Stork Veco is well known for its electroformed high resolution encoder disk which can easily compeat with the glass encoder disc. Because of the exact position of the center hole and the high intensity slotcount the performance is very good. Comparing the price of the Electroformed encoder disc with the glass encoder disc, the Electroformed encoder disc is more value for its money.

On this page you will find more information about:
 •  Electroformed Encoder discs    
 •  Photo-etched Encoder discs 
 •  Linear codestrips
 •  Reticles, Aperture Masks 
 •  Advantages Stork Veco´s Encoder discs
 •  Technical Specifications Encoder discs
 •  Technical Specifications Examples

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Electroformed Encoder discs

Electroforming is the best choice for Encoder manufacturers, who need a consistent pitch all around the slot area of the disc, mask or Codestrip. To respond to this need, excellent Photo-tooling and Electroforming know-how results in a very well controlled process. Doing this, Stork Veco guarantees reproducibility of the slot angle within every disc as well as disc-to-disc consistency. Compare us with Photo etched or laser cut parts and you´ll come to the same conclusion.

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New developments for higher pulse counts
The need for higher pulse counts for encoder discs has resulted in the development of two different manufacturing technologies in electroforming:

  • The Double-layer technique creates a second layer on the disc, but not on the slots. This means a thicker and stronger Encoder disc, so the disc can contain more slots by a thicker disc (up to 100 µm.). 
  • The Thick Photoresist layer technique allows the nickel to grow (up to 75 µm.) between the thick Photo resist film walls.

    For more information please look at our Technical Specifications. Here you can also see the difference between Electroforming and Photo-etching.

  • Photo-etched Encoder Discs

    Photo etching is often used when a specific metal material is needed in a certain environment required by the customer´s application. Many different materials can be etched in various thickness and sizes. Photo etching is often more suitable for Encoder components above 100 microns thickness. Flat and burrfree parts can be produced in a variety of magnetic and amagnetic alloys or metals necessary because of specific environmental conditions.

    Linear Codestrips

    To control linear motion a rugged metal codestrip can be applied. Among all options metal Codestrips have the large advantage over photoplast or film to be:

     •  More stable 
     •  Can cope with high environmental temperatures over 100°C
     •  Low tooling costs, especially compared to glass scales, is certainly an advantage.

    Linear Codestrip can be electroformed up to 1310 mm having 7 slots/mm.
    If the strip is etched, dimensions can be achieved up to 900 mm length having 5.5 slots/mm. 

    Reticles, Apertures Masks

    Metal aperture masks can be used in co-operation with all kind of Encoder discs and Codestrips, metal as well as glass, film or photoplast. Aperture masks are made according to customer requirements.

    Advantages Stork Veco´s Encoder disks, Apertures Masks and Linear Codestrips

    Veco´s metal Encoder components can offer all this and more......

    General advantages of metal Encoder discs, Aperture masks and linear Codestrips compared to glass, film or photoplast:

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     •  high durability, making it well suited for environmental vibrations and shocks
     •  lower moment of inertia, because of the lighter thin metal components
     •  endure high temperature (±130 °C) and humidity
     •  high stability, caused by the use of hard metal material
     •  final product free of burrs, giving a nice, shiny flat product
     •  economical tooling and parts, resulting in competitive prices
     •  good concentricity in application warranted by design, easy mounting
     •  achieving sharp edges along the slots resulting in a well-defined pulse count (CPR). Compared to Laser cut or Photo etched the edges of the slots are much smoother. 
     •  very flat surface and very tight tolerances on slot width, pitch and centerhole.
     •  the electroformed metal Encoder components are lighter than for instance glass or plastic, resulting in reductions in torque motor size and electronic control circuit complexity.

     

    Technical specifications Encoder discs

    For deciding what process your encoder-disc should be made with, please look at the tolerances and the maximum thickness of the disc. 

                       Electroforming Photo etching
    Thickness

    Slot/bar width = thickness

    t = 0.025 mm - 0.100 mm

    Depending on material and thickness

    Tolerances:

    - absolute

    - relative

     

    0.010 mm

    0.002 mm

     

    0.020 mm

    0.015 mm

    Minimum bar width Formula: 2t + 0.020 mm Depending on material and thickness
    Maximum no. of slots

     

    Formula: (pi*Di)/(4t + 0.40 mm)

    Di = inner diameter

    t = thickness

    Depending on material and thickness

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    Technical specifications examples

    Disc design examples:

    No. of slots Thickness Inner diameter Outer diameter Electroformed Etched
    500

    0.05 mm

    0.075 mm

    8 mm

    12 mm

    27 mm

    50 mm

    Yes

    yes

    Yes

    No

    720 0.05 mm 12 mm 50 mm Yes Yes
    1024 0.05 mm 8 mm 42 mm Yes

    No

    Products made with thick-film technology

    Veco84 Hart-Nickel

    General tolerance ± 10 micron

    Product-thickness

    Minimum

    Minimum

    Pitch or

    Minimum

     

    Single layer

    barwidth

    slitwidth

    Period

    Holediameter

    Tooling

    23 micron

    35 micron

    30 micron

    65 micron

    60 micron

    Glasstooling

    35 micron

    45 micron

    40 micron

    85 micron

    75 micron

    Film or Glasstooling

    47 micron

    55 micron

    50 micron

    105 micron

    85 micron

    Film

    We hope that you have intrest in our products and we can imagine that you need more information. Please feel free to contact us.