none

Hot new technology: laser plastic welding

31-08-2010
by 
in 
Hot new technology: laser plastic welding

 

Laser plastic welding, often referred to as “through-transmission welding,” is a process of bonding plastic using focused laser radiation. 
 
The process much different to traditional metal welding.
 
The concept involves passing a focused laser beam through an upper, laser transmissive part to the interface of the two parts to be joined. 
 
The laser light is turned into heat energy as it is absorbed by the lower joining partner. 
 
The heat created at the interface creates a molten weld seam and the two plastics are fused.
 
The process relies on four main factors: 
 
  • A laser transmissive layer
  • A laser absorbing layer
  • Plastics material compatibility and 
  • Good contact between the parts.
 
Natural thermoplastics transmit infrared laser radiation. Most often sources of either 980nm or 808nm are used as they transit the more energy at these wavelengths.
 
The lower layer is responsible for turning the light energy into heat. As the majority of thermoplastics are naturally transmissive to IR radiation additives must be used to give absorbing qualities to the part. 
 
Most often carbon black is used, but many additives will promote absorption including various pigments and fills. 
 
It should be noted that the upper layer can be colored and even opaque using special no-absorbing colorants.
 
Material compatibility is determined by a few factors including surface energy and polymer chain length, but the most important consideration is to find plastics with similar or overlapping melting temperatures.
 
Once the light energy is converted to thermal energy at the surface of the lower part, some of that energy must make its way into the upper layer in order for melting to occur in both parts. 
 
Good contact between the parts ensures that energy can be transferred via conduction. 
 
To ensure good contact clamping force is applied to the part. This typically accomplished with clamp tooling and nests, but can also be realized through interference fits.
 
Embedded Logic Solutions Pty Ltd/L
Ph: 02 9687 1880

Related news & editorials

  1. 14.12.2018
    14.12.2018
    by      In
    HRS Heat Exchangers has developed a range of pasteuriser/steriliser units for the food packaging industry.
    All HRS Thermblock systems allow for full adjustment of the heating-holding-cooling cycle of the product, so that it can be tailored to a specific product and method of working. They can also... Read More
  2. 13.12.2018
    13.12.2018
    by      In
    Optibelt reckons its low-stretch and maintenance-free Red Power 3 v-belt drives offer a range of advantages in heavy-duty applications. Crucially, the belts are designed so that once correctly tensioned the first time, they don’t require retensioning - a valuable saver of time and money.
    A major... Read More
  3. 13.12.2018
    13.12.2018
    by      In
    Exair’s has developed a fine-mesh nonwoven drum cover for use on 60 and 205 litre drums. The breathable material allows the air from an Exair Line Vac air-operated conveyor to circulate when moving material in or out of a drum. The drum cover prevents contamination of the material and keeps it... Read More
  4. 12.12.2018
    12.12.2018
    by      In
    With almost 40 years of experience in applications of incremental shaft encoders, Plant Control & Automation has developed a number of instruments for both testing and simulating these complex devices.
    Now the company has put all this expertise into one instrument: the EncoderLab is both an... Read More