Encoder discs - Encoder disk - Encoder disc

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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.