Welding Clear-to-Clear Polymers with QPC Brightlock, 1908nm Laser

Transcription

1 Page:1 of 5 Welding Clear-to-Clear Polymers with QPC Brightlock, 1908nm Laser Proprietary Information The information contained in this document is proprietary to the QPC Lasers Division of Laser Operations LLC and should not be disclosed, copied, reproduced or distributed without the written permission of Laser Operations LLC. Prepared, reviewed, or Function Signature Date approved by PRA Kendra Gallup Director of Sales 06/01/2012 RA Dr. Jeff Ungar Chief Technology Officer 06/01/2012

2 Page:2 of 5 1. Interpretation of Results Laboratory trials took place on May 22 through June 1 using a QPC Lasers BrightLock Ultra- 500 diode laser operating at 1908 nm wavelength. Trials took place at Lumyn Technologies LLC, an external applications lab. Critical process parameters such as laser settings, beam delivery parameters, including galvo scanner and software parameters, are noted in this report. 2. Introduction Laser plastic welding has advantages over other traditional techniques such as adhesives, hot plate welding, ultrasonic welding, and friction welding. In medical device manufacturing, lasers offer advantages for non-contact, contamination free, precision manufacturing. Laser welding creates strong joints only where the laser beam is focused, leaving the surrounding areas outside the weld seam untouched. Micron precision is possible even for complex geometries using galvo scanner systems that are available for laser welding. Multiple processes such as part singulation (laser cutting), serialization (laser marking), and joining (laser welding) can be achieved using a single laser source. Transparent polymers are of high interest for applications in medical device manufacturing. Transparent polymers combined with good seam quality and particle-free processes have a huge potential in medical device manufacturing. In this branch, the usage of special additives is not recommended because of the tedious approval procedures. Therefore, solutions are needed that definitively work without any additives, specifically those that will work with the material combinations that are already approved and used. For transparent plastics, the welding principle is completely different. Without additives such plastics normally do not absorb light from the visible range, even up to 1550 nm. However, it is possible to use the intrinsic absorption of polymers starting at a wavelength of approximately 1800 nm. The intrinsic absorption is caused by the vibrations of the polymer chains under the influence of the light >1800 nm. As the process happens in the bulk material and not at the surface, this is well-suited for foil welding or tube welding, resulting in a through-welding process.

3 Page:3 of 5 3. Experimental A QPC Lasers BrightLock Ultra-500 diode laser was used to demonstrate laser welding capability for clear-to-clear polymers at the Lumyn Technologies LLC laboratory in Mountain View, CA. A series of 25 mm x 75 mm x 3 mm samples were prepared from: Poly Methyl Methacrylate (PMMA) Acrylic Polycarbonate (Makrolon ) Polypropylene The beam was focused using a multi-element lens set-up with an effective working distance of 85 mm which produced a 3 mm measured spot size on the sample. The clear plastic samples were clamped together and the laser beam was focused at the interface between the two plates. A transmission welded joint was formed using a multiple pass technique at various laser power and laser focus settings. Laser power was changed incrementally over a range of 6 40 Watts. 4. Results Polypropylene (PP) to PP samples demonstrated the strongest shear strength among all of the welded polymers.

4 Page:4 of 5 An overall view of two PMMA plates welded together is shown in Figure 1. An optically clear seam is produced. A cross section of the weld joint between two polypropylene sheets is shown in Figure 2.

5 Page:5 of 5 A medical grade multi-lumen tube welded to a single lumen tube (polyethylene) is shown in Figure Conclusions Plastics commonly used in medical device manufacturing have been shown to be weldable using a QPC BrightLock Ultra-500 diode laser operating at 1908 nm wavelength. Optical grade transparent seams were produced for all polymers. This additive free, highly controllable laser welding technique is applicable for many other joint configurations such as spot, edge, and T joints.