Background

Mini-Circuits’ product line includes well over 10,000 parts of varying shapes and sizes, including many devices developed over the 50+ years of our company history. Device marking and identification is key to many aspects of customer use from quality assurance to assembly processes. Marking methods may change over time based on new technology or environmental compliance, but such changes will never have a material impact on device appearance. The required information must always be present, including:

• Product / part number identification (where space permits)
• Orientation index or port indication

Additionally, the marking must be permanent and withstand the customer assembly process. This application note enumerates the different device marking methods used on Mini-Circuits products

Common Marking Methods

Ink Marking

Ink marking has been used for decades with several methods of application including silk screen, ink jet, pad print and others. Marking permanence is achieved by curing the ink at medium temperature. Ink provides good contrast for visual recognition but it can be subject to smudging or dot matrix spreading if not controlled. Ink preparation and cleanup, however, pose an environmental risk and require hazardous waste disposal. Mini-Circuits is consciously reducing our ink marking in keeping with our ISO14001 commitment.

Figure 1: Ink marking on plastic unit covers.

Laser Marking

Laser marking is an efficient alternative to ink and has been used at Mini-Circuits for several decades. This method achieves excellent contrast, permanence and legibility when used on plastic covers. Laser marking is most effective when incorporated into automated test handlers (e.g. Mini-Circuits’ ADE mixer line). Additionally, lasers are commonly used to mark MMIC devices with limited space.

Figure 2: Laser marking on plastic unit covers.

Mechanical Engraving

Metal covers for pin (plug-in) and other surface-mount units are etched with a mechanical stylus to engrave the product information. Although this technique does not provide comparable contrast to that of ink marking, the characters are clearly visible and have superior marking permanence. The mechanical engraving process is semi-automated, with a few units mounted on a fixture at a time.

Figure 3: Mechanical engraving on metal unit package.

Laser Engraving

Similar to laser marking above, laser engraving uses a high-power laser to engrave metal covers, providing an indelible surface etch of high legibility and compact size. Laser engraving may also provide color contrast, depending on the material being marked.

Figure 4: Laser engraving on metal unit package.

Mylar Labelling

Mylar labels are the default option for Mini-Circuits’ connectorized product line. This method has completely eliminated the environmental concerns that have historically come with ink marking. Mylar printing is a well-established process in many industries and has several benefits, including various label sizes to match different component case styles, crisp, legible markings (including bar-coded information), programmable content and ease of application.

Figure 5: Mylar label on coaxial unit housing.

Ultra-Violet LED Printing

Large devices like Mini-Circuits’ Test Equipment product line have historically used silk-screen ink marking. This is either done in-house or at the supplier for the relevant subcomponent. In addition to environmental concerns, this was an unforgiving process making it difficult or impossible to correct errors. We have since implemented a programmable UV LED plate mark-and-cure method that simplifies the process and produces professional-grade marking.

Figure 6: UV LED plate markings on the front panel of equipment chassis.

Markings and Product Change Notification

Mini-Circuits is constantly looking for product marking solutions to optimize quality, process efficiency and environmental compliance for the various device types in our portfolio. Clearly, marking processes have evolved over the 50+ years we’ve been in business, and we make changes to take advantage of the technology available. These changes are always in the best interest of both Mini-Circuits and the customer as they generally improve the quality of the marking, reduce production cost and eliminate requirements for disposal of hazardous materials. Our position is that any change in product marking method should not impact the appearance of the product, much less its fit or function, and therefore will generally not result in a product change notification (PCN).