Experiments on the laser treatment of radiators
A significant segment of Pokkels’ work consists of research and experiments on the application of laser equipment. Since the end of 2021, we have been performing a series of tests on the laser treatment of heating elements of electric convectors at the request of a thermal technology plant. We invite you to get acquainted with the work process and the interim results of our work.
Customer
Factory of heating equipment, one of the largest manufacturers of heating equipment in Europe, produces heaters, infrared heaters, electric convectors. Production of heating elements for electric household convectors is a separate major direction of the company’s work.
Research task
The plant approached Pokkels to conduct experiments with laser treatment of aluminum heating elements. In addition, the company wanted to develop an automated system that could process the profile with the same speed and efficiency as a sandblasting process.
The heating element is an extruded aluminum profile with four segments. It is processed by different methods in order to obtain the maximum heat output for the same size. To do this, it is necessary to increase the area of the heating element. This process consists of two steps.
First, the metal is «stretched», usually by sandblasting. Thanks to such an impact, the morphology of the segment surface changes, as a result of which the effective area increases by 1.2 times. The next stage is stamping, which is used to knock out the ribs on the surface of the radiator, which leads to an increase in area by 1.5 times.
Methods of increasing the profile area
| Processing type | Result | |
| 1 | Surface texturing by sandblast or laser | 1,2x |
| 2 | Stamping | 1,5x |
Final appearance of the radiator
Work stages
The development of an automated system takes a long time because it requires selecting the optimal laser source power and processing modes. First and foremost, the Pokkels’ task was to experimentally select the optimal parameters based on the customer’s requirements and needs.
Preparing
Conducting any experiments begins with the preparation of bench equipment. For the research we needed:
- laser modules
- laser control systems
- mechanical systems for profile movement
- laser module movement system
- a system to control power and mode of operation.
Signing up
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First experiments
The customer handed over 10 samples of aluminum profiles. Each sample was numbered, as the profiles were further processed by laser in different modes. Due to the ability of laser radiation to create complex morphology on the surface of the metal, a fully matt surface was created. The profiles were processed at different speeds using different automated laser units.
Profiles after laser processing. The size and the shape of the pattern affects the heat output of the radiator
Testing by the customer
After the first series of experiments, the processed profiles were handed over to the customer for research. The company conducted its own tests to determine the heat transfer of the samples. For this purpose, the profiles were additionally processed and heated.
As a result, it was found that some methods of laser treatment lead to satisfactory indicators at the edges of the TEN, but insufficient heat transfer in the center. Another treatment mode showed good results in terms of heat transfer exactly in the center.
Customer’s test report. Table of surface temperature measurements of the heating elements at 230V (temperature should not exceed 420°C)
| Heating elements 2000Вт | ||
| Т1 (left side) | Т2 (center) | Т3 (right side) |
| 294 | 440 | 253 |
Intermediate results and future work
Tests conducted by the customer showed that in order to obtain uniform heat transfer over the entire radiator surface it is necessary to develop a combined mode of laser processing. In the case of an automated system, this means that the mode will automatically change in the course of processing.
One of the options for solving the problem is different processing speed. Since the laser unit will be integrated into the conveyor, it can in some situations overtake the conveyor belt and spend less time processing one area and slow down in another place to ensure more intense interaction of laser radiation with the profile surface.
Aluminum profile machined with an automatic laser system
Another challenge Pokkels has is to achieve optimal laser power in terms of cost and processing effect. It is important to us that the customer does not overpay for higher plant power when it is not necessary.
Heating element inside the convector
At present, the tests are still in progress. Based on the results of the study, a prototype of the automatic system will be developed and final calculations on the cost of equipment for the customer will be made.
