MARKING & DECODING 2D SYMBOLOGIES

Track, Trace & Control Solutions

MARKING & DECODING 2D

SYMBOLOGIES

About Your Instructors

Matt Van Bogart

Global Channel Manager

Joined Microscan in 1999

Held management positions in

Marketing, Product Management

and Sales

Juan Worle

Technical Training Coordinator

With Microscan since 1996

Held positions in Service, Applications,

Sales and Marketing

Today’s Objectives

By the end of today’s Webinar, you will know

Proper marking techniques for your application &

maximizing readability

Different marking methods available

How a 2D symbol is decoded

Today’s Topics

Selecting a Symbology

Marking Methods

Decoding a 2D Symbol

Maximizing Readability

Decodability

MARKING METHODS

Selecting a Symbology

Select a Symbology

Many things to consider:

–Space, surface shape & quality

–Amount of data

–Cost of equipment (printer type, scanner vs. imager, consumables)

–Cosmetic, product appearance

–Type of equipment down the supply chain

Some applications may only require a laser scanner

–Good contrast, non-reflective material, flat surface

Data Matrix is more common for DPM

–Easy to make with many marking methods

–Easy to decode on different substrates

–Error correction recovers from misprints

and damage

Some DPM marks can be

decoded with a laser scanner

Marking Methods

Print

Inkjet, laser, thermal printers onto labels and paper

Most commonly used

This can be done with standard office printers

Marks are fragile and temporary

-Warehousing

-Packaging

-Pharmaceutical

Advantage:

-Supplies are readily available

-Simple and fast to make

-High quality/contrast

Disadvantage:

-Fragile

-Consumables

Marking Methods

Electrochemical (chem etch)

Electrical current passes through a stencil into the conductive metal part

Material is not weakened or distorted

Good for thin or fragile material

Can produce toxic fumes

- Military

- Aerospace

- Medical device

Advantage:

- Permanent

- High quality mark

- No debris from process

Disadvantage:

- Potentially toxic material bi-product

- Low-volume use

- Complex process

Direct Ink Jet

An ink is applied by spray nozzles, typically resulting in round dots

Food grade inks

Quality and contrast varies

Print on difficult shapes

Marking Methods

- Post-packaging

- Warehousing

- Automotive

- Bio-science

- Pharmaceuticals

- Packaging

- Clinical R&D

- Electronics

Advantage:

- High contrast if done right

- Low entry cost

-No damage to part surface

-High speed printing

Disadvantage:

-Temporary in most cases

-Easy to make a poor print

-Contrast varies

-Consumables (ink)

Marking Methods

Laser Etch: Anneal, Ablation

Laser is used to cut away a thin layer of surface material.

Ablation exposes another material for higher contrast.

Anneal heats a Materials surface to alter its composition.

-Aerospace

-Military

-Automotive

-Electronics

-Surgical tools

-Medical Implants

Advantage:

-Clean, high resolution

-Can be high contrast

-Permanent (if not using labels)

-No consumables (if not using labels)

-Does not alter part surface (anneal)

Disadvantage:

-Possible consumables (if using labels)

-Affects surface integrity

-Process creates debris

Dot Peen

A multi-axis pointed stylus hits a part like a hammer, which displaces

material, leaving a dimple in its place

Typically used on metals

Recommended for automotive and aerospace

where the marks must last the life of the part

Marking Methods

-Automotive

- Aerospace

- Military

Advantage:

- Permanent

-No consumables

Disadvantage:

- Alters surface

- Low contrast mark

- More difficult to read

- Inconsistent depth will create smaller elements

- Background noise

DECODING 2D SYMBOLS

Capture an Image

A light source is used to illuminate the part

A sensor captures the reflected light and converts to a digital image

Software is used to decode the image

Decoding a 2D Symbol

Decoding consists of two parts:

Locate

Decoder must locate the symbol within the image using unique traits to

each symbology

A higher resolution sensor will take longer to locate

It will take longer to locate a symbol in a noisy field of view

Decode

Decoding algorithms are unique to the products you are using

When a decoder is configured to look for several symbologies, decode time

will be longer

A minimum number of Pixels Per Element (PPE) will ensure consistent

decodes

Decoding a 2D Symbol

Pixels Per Element (PPE)

•The number of pixels that cover an element in either the X or Y dimension.

•The number of Pixels Per Element is determined by:

• Symbol size (size of the elements)

• Camera resolution (sensor size)

•Field of view (optics)

2 Pixels per

Element

One Element

Microscan’s read range tables have this calculated for you.

Maximizing Readability

Consider the following when designing a code:

Contrast: maximize the difference between white and black elements

–Easier to read

–No special lighting or algorithms

Quiet Zone: increase the Quiet Zone to improve decode speeds

Element size: the larger the better for DPM

–Overcome surface texture (DPM)

–More versatile with reading equipment

Quality: good codes decode more reliable

–Damaged codes use error correction

–Improperly marked codes reduce contrast

Mark position: choose a smooth flat location

–Avoid curved or bumpy surfaces if possible

–Position where it is accessible by a reader

A nicely printed Dot Peen

can be easy to read

Decodability

Common problems with Direct Part Marks

Dot center offset

–The elements do not have a consistent placement

Cell fill

–The percentage that an element fills its ideal size

–Slight underfill is typically more readable than overfill

Contrast

–Low contrast can be a problem on DPMs

–Adjust the imager and lighting angles to optimize

Dot center offset

Contrast

Cell fill

The best solution:

Decodability

Common problems with Direct Part Marks

Modulation

–Uneven printing or illumination can make it difficult to

read a code

–Adjust the imager and lighting angles to optimize

Quiet Zone (Margin) violations

–A poor Quiet Zone may make it hard to locate a code

Verification prevents these errors

Modulation

Poor quiet zone

Verifiers

Microscan’s LDP and DPM Verifiers provide complete reports to current

Data Matrix verification standards for printed and Direct Part Marks.

ISO/IEC 16022 • ISO/IEC 15415 • AS9132 • AIM DPM Guidelines • MIL-STD-130

Decodability

Example images on Direct Part Marks

Before After Before After

Effect of surface structure: rotate 90°

Effect of curved surface: use external line light

Effect of concave surface: use dome light

Effect of shiny surface: use diffuser

Effect of reading angle: change reading angle

Effect of low contrast: change reading angle

Marking & Decoding 2D Symbologies

Conclusion

Marking Methods

–Printed

–Chem Etch

–Direct Ink Jet

Decoding a 2D symbology

–Locate, and then decode

–Minimum resolution (PPE)

Maximizing Readability and Decodability

–Making a better image will improve reliability

–Laser Anneal, Ablation, Etch

–Dot Peen

Next session….

Applications and technology:

Data Matrix applications in vertical markets

Reading technology for applications

Thank you!

For More information

Website: www.microscan.com

–Online courses

–Spec sheets

–Technology brochures

–Support self-help and support request form

Webinar feedback: www.microscan.com/feedback

Instructors:

Juan Worle, Technical Training Coordinator

Email: jworle@microscan.com

Matt Van Bogart, Global Channel Manager

Email: mvanbogart@microscan.com

MARKING & DECODING 2D SYMBOLOGIES

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