Additive aids laser marking

08 Jul 2004

Marking plastics with low power carbon dioxide lasers is made easier thanks to a new range of additives.

Sherwood Technology of the UK has developed an additive which when added to plastics allows them to be marked by a low-power carbon dioxide laser. According to Sherwood, its DataLaser Masterbatch technology is compatible with most common plastics and the resulting mark is highly durable.

"The additive allows you to use a low-power CO₂ laser rather than a higher powered YAG laser to mark plastics," Andrew Jackson of Sherwood told Optics.org.

Sherwood's compound is added to the plastic when it is being moulded. Jackson says the additive is invisible and does not unduly affect the color of the plastic.

When between 2 to 3 W of 10.6 micron light from a CO₂ laser is shone on the plastic, the additive changes color leaving a permanent mark. Provided the additive is incorporated in the plastic, the mark can be made at any point in the distribution chain or at any time in the future.

According to Jackson, only a small amount of additive if required. "If its human-readable text, then you need as little as 0.5% to 1% of the total plastic material," he said. "If you need to put larger graphic such as bar codes or logos, you'll need more than that." The additive could prove useful in the pharmaceutical, food and beverage industries where a date, text, or logo has to be applied to the product.

Sherwood is now developing a range of compounds that leave colored marks in the plastic.

Jackson says the company's long term plan is to license the technology. "Although we are a relatively small company, we are selling and developing applications with end-users," he said. "But we are ultimately looking to setup licensing agreements with a third party or parties."

Author
Jacqueline Hewett is technology editor on Optics.org and Opto & Laser Europe magazine.