In additive manufacturing, temperature is one of the factors on which the quality of the final product depends. Thermal imaging cameras record temperature developments and deviations in real time and enable rapid intervention in the ongoing process. 

Monitored Process Control and Quality Assurance 

Additive manufacturing involves material  

applied layer by layer to create three-dimensional objects. Thereby chemical and physical hardening and melting processes take place, in which temperature plays a decisive role. Infrared cameras support the systematic monitoring of the entire manufacturing and machining process. 

Numerous of these manufacturing processes are based on laser technologies such as laser melting, sintering or build-up welding. Other processes, such as binder jetting, are completed by a sintering pass to fully cure the material. Temperature also plays a decisive role in thermal spraying for achieving the best possible surface hardness and optimum non-stick properties. In order to localise and detail thermal conspicuities in these processes, InfraTec infrared cameras support the determination and subsequent adherence to thermal process parameters by in-line monitoring. Infrared cameras can be integrated directly into the process control system to enable a non-contact and non-invasive temperature measurement. 

Here, the detection of the temperature distribution of the powder bed surface and the measurement of melting temperatures are relevant in most cases. Both can be realised for temperature ranges higher than 2,000 °C and while the laser is working (in-situ measurement). 

Close monitoring of machines, processing plants, materials and temperatures during the production and processing of additive parts is of fundamental importance both in industry and in research. The mapping of heat flows in components is necessary for a complete understanding of the process and allows precise control of the temperature development in the parts and materials to be processed as well as exact thermal control of the process. An early detection of errors in production is therefore possible, rejects are actively avoided, and returns are minimised. 

Furthermore, process and cycle times can be significantly optimised and correlations between process parameters and (melting) temperatures can be derived. 

Requirements for Infrared Cameras in Laser Based Additive Manufacturing 

Due to the characteristics of lasers in additive manufacturing, the infrared cameras used must meet specific requirements. This applies, for example, with regard to the temporal resolution. 

Working with a laser is typically characterised by short laser action times, where heat input takes place within fractions of a second. This requires measurements with high image frequencies in full and partial images. Particularly in micro material processing with pulsed laser light, the demands on thermography systems are very high. Suitable for this application is, for example, the ImageIR® 8300 hs, as it can image high-speed processes with an image format of (640 × 512) IR pixels and the high image frequency of 1,004 Hz. 

The thermal and geometric resolution of infrared cameras is equally important. Depending on the process and material, lasers can be used to create very large or very small temperature differences, which must be monitored continuously and very precisely. Here InfraTec offers different camera functions, such as HighSense mode, HDR function, HighSpeed mode and geometric resolutions in the HD range. 

Integrated Trigger / Process Interface and Interfaces – Digitally Controlling of a Infrared Camera and External Devices 

The internal trigger interface guarantees highly precise, repeatable triggering. Each of the two configurable digital inputs and outputs are used to control the camera or to generate digital control signals for external devices. In this way, for example, the operation of a printed circuit board and the interval of a measurement can be synchronised. 

The selection of different camera interfaces allows the processing of analogue data, such as the voltage directly through the camera and thus the insertion of this information into the thermal image data. Relevant variables can be included in the evaluations with the software, which makes it easier to draw conclusions about the causes of temperature changes. 

Reliable Localisation and Detailed Mapping of Thermal Anomalies 

By in-line monitoring of thermal process parameters, infrared cameras from InfraTec support the optimisation of additive manufacturing processes. 

  • Non-contact and non-reactive temperature measurement 
  • Mapping of heat flows in components to gain a complete understanding of the process 
  • Precise control of heating and cooling of the materials to be processed 
  • Monitoring of defined energy inputs and reduction of thermal load 
  • Precise thermal and even spatial control of the process due to high-speed data acquisition, high geometric resolution and delay-free triggering 
  • Complete recording, documentation and evaluation of temperature distributions to determine the optimum energy input by the laser 

InfraTec Infrared cameras are available in the UK and Ireland exclusively through Quantum Design UK and Ireland. For more information, please contact our Technical Sales Manager, Dr. Luke Nicholls by email at luke@qd-uki.co.uk or call us on (01372) 378822.