Direct part marking (DPM)is a process to permanently mark parts with product information including serial numbers, part numbers, batch numbers, date codes and bar codes instead of printing the code on a paper panel which is then stuck to the surface. It acts as a permanent identifier for the product allowing manufacturers to trace the product through its complete lifecycle. The basic requirements of direct part marking is durability and legibility. The mark should be able to last the complete life cycle of the product throughout the supply chain even if exposed to adverse environmental conditions.
Each product has its own set of requirements when it comes to direct part marking and as such different factors need to be considered while selecting a marker machine –
- Material type – the nature of the material to be marked highly influences the choice of marking technology. Some marking technologies are fit for only certain type of materials and their use on other materials might lead to a mishap. As is in the case of chemical etching which can be done only for conductive materials. Inkjet marks may also not adhere to certain type of plastics.
- Part function– the function of the part to be marked is also important in determining the etching machine to be used. In case a permanent mark is required laser, chemical and dot peen marking can be done. Only dot peen and laser etching device can produce engraved markings. Due to the delicateness of the material sometimes only no contact marking systems can be used like laser marking systems and inkjet marking systems.
- Part geometry– if the area to be marked is recessed or the mark is to be made in different planes then only those part marking machines can be used which allow three dimensional movement of the marker.
- Surface finish– the condition of the surface of the material also affects the marking process. Even if a mark is made it might be difficult for the scanner to pick out any details from the mark leading to errors. As such laser can be used to rough or smooth the surface as required.
- Mark dimensions/Part size– part size influences the choice of marking technology as the area over which a mark can be varies for each technology. Each industrial marking machine model comes with its own limit for mark dimensions which needs to be considered.
- Mark content– not every marking technology is suitable for all types of marks. Dot peen and inkjet and not suitable for making intricate and detailed markings such as logos as their mark quality is quite low.
- Integration-sometimes it is critical how well the direct part marking machine can be integrated with the current setup. Laser markers are the most versatile and can handle barcodes, custom text strings and remote programming. In case of space concern, a small marking model needs to be used. If marking is to be done on the fly, inkjet and laser marking systems are the only options as chemical etching and dot peen marking systems are offline processes.
- Mark quality– laser and chemical etching are able to etch clear marks with high resolution offering more legibility. Dot peen and inkjet marking systems offer low mark quality generally.
- Environmental profile– the type of consumables that are used for the marking process can also affect the choice of marking technology to be used. Inkjet and chemical etching both use chemicals while on the other hand laser marking has no consumables in most scenarios.