Fundamentals of Direct Part Marking

When people think of direct part marking the first thing the often comes to mind is steel marking dies

In essence, Direct Part Marking (DPM) is applying identification that lasts from cradle to grave and will sustain very rugged environments. Many US government agencies are making unique device identification (UDI) and direct part marking (DPM), mandatory. The private sector, from automotive manufacturers to medical offices have been using DPM more and more as they have embraced the Deming Principles of TQM. 

​Direct Part Marking is used most frequently when marks are needed on a variety metals, plastics and wood. Common equipment solutions range from traditional hand stamping processes to cutting edge technology of fiber laser marking. Direct part marking is often a less costly alternative to purchasing RFID tags.

When to Choose Direct Part Marking

• The part is too small for a barcode label
• The item will be exposed to environmental conditions that traditional labeling may not withstand
• When it could be more cost effective to DPM over barcode labels
• If identification or data must be tracked throughout the life of the item
• If the item could be marked during the manufacturing process
• The ability to track items in high-temperatures and other harsh environments
• Providing more accurate and reliable part identification
• Preventing errors in just-in-sequence production
• Eliminating manual data collection approaches for inspections, inventories, and maintenance reports
• Ensuring the lifetime traceability of each part
• Enabling track-and-trace initiatives that provide chain-of-custody tracking and protect against product diversion
• Reducing or eliminating counterfeit parts by providing end-to-end traceability using a method that is difficult to duplicate, and doesn’t rely on package marking
• Enabling more comprehensive inventory management

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Direct Part Marking Options

Laser marking

• Traditional options range from steel hand stamps and holder/type arrangements to various numbering and impact presses, including roll marking machines
•  Advanced technologies such as dot peen, scribe and laser marking machines enable marking processes to be done automatically communicating with other manufacturing technologies and allow the addition of machine readable codes for component traceability.

2D Codes: Most Popular for Direct Part Marking

In most cases, direct part marking applications use two-dimensional (2D) barcodes such as Datamatrix or QR Code, which carry much more data than linear (1D) barcodes. By using 2D barcodes, manufacturers can also identify very small items and parts​​.

Dot Peen vs Vibra Peen vs Scribe and a 2D QR code

2D codes can pack a large amount of data as opposed to linear codes because they can carry data in two directions on the code vs. just one.  To give you an idea of the relative size, a 1D barcode can store around 25 characters up to about 80 characters depending on whether it’s Code 128 or Code 39, but a 2D code can store up to 2,000 characters.  

In the automotive sector, there is an established standard (AIAG B11) for direct part marking, and a number of large auto OEMs like Ford require suppliers of certain components to use DPM for part traceability.

​Manufacturers like to use the 2D code not only for the storage capacity, but for their relative size as well (square vs. rectangular).  The flexibility of a 2D code allows for the variation in the amount of information stored in the barcode as well as the size of the item being marked.  The most popular uses of the mark are for applications that require:

1. Traceability
2. Verification & Error Proofing
3. Part Identification

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