Permanent Product/Part Identification
- One tool shop estimated it saved one minute per part on their CNC machining center by marking outside the machine.
- Another shop estimated it saved $125,000 in labor cost per year using a hand holder instead of hand stamps.
- A well-known racecar shop was able to trace parts back to cars that performed well, with respect to those that did not.
- A parts manufacturer increased sales because people were able to identify his company as the manufacturer.
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These are just some of the many reasons why manufacturers should take a closer look at how parts are permanently identified.
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For this discussion, we will rule out stickers and ink as options because they typically represent an added cost to the part and, for the most part, are not permanent.
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For hundreds of years, the old hammer and hand stamp has been used to mark or identify most products…golf clubs and automobile V.I.N. numbers first come to mind. And in some cases, this process still remains the best available marking solution. However, many new marking innovations and technologies, with specific purpose and application, have been introduced and are proving to be better solutions, as well as providing significant cost savings. Traceability is still the best method of analyzing and tracking parts in a manufacturing or production process.
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Marking is extremely important because:
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Many job shops and manufacturers frequently mention how customers recall “horror stories” about tracking a part or getting blamed for someone else’s bad parts. The solution is to simply mark the part with the customer’s order number, production line or fixture I.D. serial number, company logo or at least the date code on a specific part which quickly identifies it.
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Permanently Marking the Part
So how can information be permanently marked into parts? The basic tips for selecting the proper tool, machine or process is simple.
- How many parts will you mark in a given time? Usually this is rated by day, hour or week.
For example, as a cost savings exercise the next time a part is marked, calculate the time it takes to do it. Then time how long it takes to do more than one part, and then the time it takes to repair a miss-marked part. With most old style hand stamps, it can take up to five minutes to mark a part.
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Where to start…What to mark is always the “64 Thousand Dollar question.”
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These types of marks can include:
- Job numbers
- Date codes
- Logo or company initials
- Weight or part size
- Part numbers
- New Matrix 2D UID codes (now replacing bar codes)
- Serial Numbers
- Lot numbers
- Part size or description
- Web-site
- Phone numbers
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*Materials(sheet metal) .040-in or thinner (Force x .60-in)
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…and when hand stamping, a hammer blow force chart helps to provide a basic starting point for manual pressing in of marks. Never attempt to hand or impact stamp parts with a hardness above 40Rc .
Estimated Maximum Force per Hammer Blow (in tons)
Size of Hammer |
Average Machinist |
Experienced Machinist |
Exceptional Machinist |
3/4 lbs |
1.5 |
2.0 |
2.5 |
1 lbs |
2.2 |
3.0 |
3.7 |
1 1/2 lbs |
3.0 |
4.0 |
5.0 |
2 lbs |
4.5 |
6.0 |
7.5 |
2 1/2 lbs |
6.4 |
8.5 |
10.6 |
3 lbs |
11.2 |
15.0 |
18.7 |
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Note: Remember…keep marking pressures to a minimum. More characters equal more required area, which means more required power, and ultimately a more costly process. Using lower stress dot style marked characters reduces the required marking force by 55%.
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The Typical Hand Stamp Set
Characteristics and limitations include:
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The Logo Hand Stamp
Characteristics and limitations include:
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The Hand Stamp Holder System
Characteristics and limitations include:
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Conventional Impact Marking
Characteristics and limitations include:
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Squeeze Press Marking
Characteristics and limitations include:
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Roll Marking
Characteristics and limitations include:
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The Programmable Dot Peen System
Characteristics and limitations include:
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The Diamond Scribe System
Characteristics and limitations include:
- Laser marking does have a heat treat effect on some parts. For that reason, it is not allowed on most high tolerance or aerospace parts
- Laser Markers are fast and accurate
- Laser marks are typically shallow and scratch off of shiney or very smooth surfaces
- Laser marking fixturing is easy to design and build, but guarding can be a challenge (must be rated for class 4 radiation)
- Laser markers typically require service contracts
- Cost: Laser marking systems range from $40,000 to $120,000
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The Laser Marking System
Characteristics and limitations include:
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Summary
Part traceability and part identification requires processing in the same manner as one would process a part for manufacturing. Production quantities and the labor involved are the important factors to consider when selecting the marking process that will produce the right kind of mark in the most cost-effective manner. Evaluating and choosing the right marking equipment and the supplier to provide the best marking solutions should involve broad engineering and product familiarity with the complete range of marking processes.














