Coding variable information like lot and date directly onto high-density polyethylene (HDPE) bottles has always been difficult. Ink jet will do it but is messy and there may be solvent bleed-through issues. It can also be removed. Lasers work great on a variety of materials but not on HDPE.
At Pack Expo Las Vegas, DPSS Lasers (Booth N-512) is showing some white bottles with what looked like high-quality inkjet printing. When they told me it was laser, my first thought was that there was an additive in the plastic.
The DPSS uses an ultraviolet scribing to code text and two-dimensional (2D) codes directly on the bottle. Printing is a very dark, almost black, grey. Since it is a laser, the code can be focused down optically to as small as 50 microns. This is great for hidden product surety codes. Speeds can go to 600 bottles per minute with three to four lines of text.
I've been a laser fan for many years but applications with plastics have been limited. This ultraviolet (UV) laser gives manufacturers a whole new way to code.
Known as the Changeover Wizard, John R. Henry is the owner of Changeover.com, a consulting firm that helps companies find and fix the causes of inefficiencies in their packaging operations. He has written the book, literally, on packaging machinery (www.packmachbook.com) and is the face and personality behind packaging detective KC Boxbottom, the main character in Adventures in Packaging, a popular blog on packagingdigest.com.