Columbia Marking Tools – Home of the Square ◙ Dot®

Published by Marc Steele on

Columbia Marking Tools, Inc. has a U.S. Patent and Trademark on their programmable CNC scribe marking machine technology.  The patent relates to scribes marking a (2D) machine readable code onto hard materials. Two-dimensional (2D) barcodes look like squares or rectangles that contain many small, individual dots. A single 2D barcode can hold a significant amount of information and may remain legible even when printed at a small size or etched onto a product. The trademark for the marking technology is Square ◙ Dot®.

Clear and Distinct Cells from CMT’s patented Square-Dot marking process

The basic design of the programmable CNC (2D) barcode marking system utilizes an x-y-z axes slide arrangement that is driven through precise linear ball screws. Standard machines are all electric but air-operated units are also available for extra deep marks. The scribe head, mounted on a plate that is linked to the slides, uses a diamond stylus to quietly scribe text or graphics into hard or soft surfaces producing fully-formed lines, curves, and in this case, (2D) barcodes. The control of the head movement is provided by a programmable controller that interfaces with standard Windows® systems using special software which allows the user to create the (2D) barcodes.

Comparison of standard dot-peen 2D code and CMT’s Patented Squre-Dot

The key element of the patent is the ability of the Square ◙ Dot® scribe marking system to, in essence, displace material in a manner leaving a specifically recessed area formed of grooves and surrounded by ridges of displaced material that to the eye, or a camera, look like round dot-like indentations. These grooves and ridges form a very reflective multifaceted data cell with extremely high contrast between the grooves and the unscribed surface to enable a vision system to clearly and accurately distinguish where the grooves are, even in the presence of extraneous interfering marks or deposits. 

Close up of mark on cast iron surface

By interfacing the highly-accurate movement of the scribe head and x-y axes with CNC control, Square ◙ Dot® 2D matrix codes can be marked at very high speed with Grade “A” readability, the highest standard rating, equivalent to 1,200 reads per second with no variations.

If you have further questions or would like a quotation, please give us a call at 586-949-8400. Or e-mail  

Marc Steele

Marc has been in the marking business for over 15 years. He provides technical assistance through emails and online chat.