Marking Processes for Casting and Forgings

January 2008

Traceability of castings is critical in many industries now to enable them to be tracked throughout the production process from casting to machining, through to inspection, final assembly and testing.  The castings may need to be marked with human readable data such as a serial or part number, a machine readable 2 dimensional data matrix (DMx) code or a coloured dot mark for simple identification of a pass or fail when testing.  Logos and graphics can also be easily marked.  Marks can be made on flat, curved and undulating surfaces.

There are a variety of marking methods that can be adopted for marking castings in either machined or un-machined states. Two of the most popular processes for marking castings and forgings are electrochemical oxide (high contrast black mark) or etch (etch below surface) marking and dot peen (dot marking/ indent marking).

Dot peen is an ideal marking process for variable data such as serial numbering batch marking or simple part numbering. Logos and DMx codes can also be marked. Hand held, bench top or integrated systems could be used for one off or small volume applications as well as full production line marking. Dot peen is also an ideal partner for a vision inspection system where the camera and software can verify a good part, then signal the dot peen marking to mark a part number, serial number etc as proof of test or inspection. DMx codes can be marked and used to track the casting through the production process or used for traceability thought the life of the component.

In some applications cutting tools are marked using the electrochemical marking process to mark the tool with a DMx code and this is then linked to the casting to track what tool has been used to machine each specific casting.  In the event of an error in the machining of the casting, the faulty or damaged tool can be traced quickly thus eliminating errors in complete batches of components.

Ink Dot Marking Applications

Some marking applications only require a simple ‘pass’ or ‘fail’ to be indicated on the casting.   For this application, an ink dot system is ideal.   When the casting or forging is tested a simple coloured dot is spayed onto the casting, for example green for ‘pass’ or red for ‘fail’.  It can also be used for basic component identification, for example to identify what engine type and engine block would be used for; a pink dot may be used to indicate diesel and a yellow dot to for petrol.

UMS manufacture, supply and fully support a range of systems for marking castings and forgings.  Contact info@ums.co.uk to discuss your marking application in more detail or call us on 020 8898 4884.  Website:   www.ums.co.uk