Laser Welding Reflections

April 01, 2020 Laser Welding

Humans have been fascinated by reflections for millennia. Narcissus was bewitched by his reflection in a pool of water and mirrors have magic powers in fairy tales. Speaking of mirrors, they are simply smooth surfaces with shiny, dark backgrounds that reflect very well. In addition to glass mirrors, polished and sometimes coated metal also reflects light very well.

Using mirrors in laser plastic welding is an innovative way to direct the light waves to weld ribs that might be otherwise impossible to reach without either moving the part or the laser source.

Cylindrical parts can be efficiently welded using a single laser source from a conventional 2D scanner. Rather than directing the beam at the exterior of the round weld rib and rotating the part, the mirror can be designed to reflect the laser beam into the stationary cylindrical part. The efficiency of the reflective surface is high enough that there is minimal need for an increase in wattage. A good practice for designing cylindrical parts for laser welding is an interference fit at the weld rib. 0.1% - 0.2% of interference in the part diameter is a good design rule of thumb.


Another use of mirrors to optimize the quasi-simultaneous laser welding process is for undercuts or obstructed sections of the weld rib. Using specialized software, we can engineer the path the laser beam takes to penetrate the weld rib from the 2D scanner source. This same software helps design the mirrors that reflect the laser beam to areas of the geometry that otherwise couldn't be penetrated by the laser directly.

Extol loves to help customers sort out options when choosing the right plastic manufacturing process. We’re ready to chat, email, and talk live on the phone while we all sit isolated and have lots of time to ‘reflect’. Think you have an application that could benefit from the precision and particulate-free technology of laser welding? Get in touch with us and learn more about Extol’s configurable laser welding solutions today.

Drew Jelgerhuis

Drew Jelgerhuis

Drew is a mechanical engineer who has evolved into a plastics geek over 20+ years of injection molding and plastics-joining experience. He looks forward to summer days and stand-up paddleboarding on Lake Michigan.