Abstract The joining of materials is essential to many industrial applications used today. However, it still lacks a reliable and true single step method to join different types of materials including polymers. Laser welding was primarily employed for metals until some decades ago, but with the rise of high power solid state lasers, applications have emerged in the polymer field. With the recent addition of fiber lasers, true clear to clear welding, joining two of the same transparent polymer layers, has become feasible at a different wavelength range, which benefits the sealing of microfluidic devices. A number of research efforts were made at performing welds of thermoplastics at this wavelength range, however without attempts at offering elaborate explanation of the observations. In our work, a laser welding system using a Thulium fiber laser at 1940 nm was used to join a variety of thermoplasts, without the use of additives or prior processing. By optically and chemically characterizing the materials, a basis was established that links intrinsic material properties to observed welding performance, as determined by mechanical shear tests on the welded materials. We found that four of the ten considered thermoplastic polymers lend themselves to sufficiently strong bonding to allow the creation of leak-proof microfluidic devices by use of laser welding at this wavelength.

中文翻译：

---

用于连接热塑性聚合物的透明至透明激光焊接：基于物理化学特性的比较研究

摘要 材料的连接对于当今使用的许多工业应用至关重要。然而，它仍然缺乏一种可靠和真正的单步方法来连接不同类型的材料，包括聚合物。直到几十年前，激光焊接主要用于金属，但随着高功率固态激光器的兴起，聚合物领域出现了应用。随着最近增加的光纤激光器，真正的透明焊接，连接两个相同的透明聚合物层，在不同的波长范围内变得可行，这有利于微流体设备的密封。在此波长范围内对热塑性塑料进行焊接进行了许多研究，但没有尝试对观察结果进行详细解释。在我们的工作中，使用 1940 nm 铥光纤激光器的激光焊接系统用于连接各种热塑性塑料，无需使用添加剂或预先加工。通过对材料进行光学和化学表征，建立了一个将内在材料特性与观察到的焊接性能联系起来的基础，如对焊接材料的机械剪切试验所确定的。我们发现 10 种热塑性聚合物中有 4 种具有足够强的粘合力，可以通过使用该波长的激光焊接来制造防漏微流体装置。由焊接材料的机械剪切试验确定。我们发现 10 种热塑性聚合物中的 4 种具有足够强的粘合力，可以通过使用该波长的激光焊接来制造防漏微流体装置。由焊接材料的机械剪切试验确定。我们发现 10 种热塑性聚合物中有 4 种具有足够强的粘合力，可以通过使用该波长的激光焊接来制造防漏微流体装置。