Manufacturer of components for fire protection systems
- As a result of preceding production processes, the object subjected to blasting can often be contaminated with oils, greases or lubricants, which are then carried over into the blasting process.
A German manufacturer of building services engineering components must, amongst other things, coat welded water pipes with powder and still forge them afterwards. In addition the anticorrosive coating must be designed so that the adhesion and toothing between the coating substance and the metallic substrate allows the forging process with process reliability and without delamination. I.e. the surface of the substrate requires appropriate roughness and purity.
So far, the weathered outdoor storage profiles were able to be sufficiently prepared for the required coating solely by blasting in a continuous throughput system.
In a different way to what was previously the case, through significantly shorter throughput times in production, the semi-finished products are today introduced directly into the coating process after delivery from the rolling mill. Pre-cleaning or remedying the weather effects from outdoor storage are no longer possible. Therefore oils and greases are carried over from the rolling process into the peening process for surface preparation.
So far, the consequences have first been oil contamination of the blasting medium, and then the carryover of oil and grease and "uniform" distribution on the peened surfaces. In addition, an extremely negative chain reaction starts in the blasting process itself.
The filter media of the dry filter clog continuously in a short time and thereby reduce the flow velocity in the air separator of the blasting system. As a result, the air separator could not separate the resulting blasting dust and the undersized particles of the blasting media properly anymore. The operating mixture of the blasting media became noticeably finer and finer.
In spite of constantly high power consumption of the blasting wheels, the material removal rate of the blasting machine therefore decreased by up to 70%. The required purity and the roughness depth (Rz of approx. 40 microns) on the peened surfaces could not be achieved anymore.
- damage caused by too much fines
Therefore, the prerequisite for subsequent powder coating was no longer present, so that the compounding of the substrate with the coating was no longer sufficient to survive the forging process. Detachments of the coating kept occurring, which then had to be remachined with great effort. In addition, we had to find out that there was excessive wear to our blasting system through the operating mixture being too fine and contaminated; in particular the blades of the blasting wheels were affected badly.
“Through a reference from our blasting media suppliers, Krampe Harex, we became aware of the new method of the company PantaTec for dealing with this problem” the Production Manager reveals. “With this method, an additive in powder form is simply added to the blasting media which separates oils and greases from the blasting media and from the workpieces and binds them”.
Through normal dust extraction and the air separator, the additive is then removed from the blasting system together with the adhering oil and grease.
First we carried out wetting tests with ordinary tap water on peened surfaces and also the penetration test on the blasting media to examine and to assess the contamination of the metal surfaces. Afterwards we vaccinated the blasting media of the running blasting system with the additive. Because of very strong contamination, we needed approx. 10 litres of the additive ULTIMATE for our 3 tons of operating mixture.
Already after approx. 30 minutes we were able to discern a clear improvement of the wettability of the peened surfaces. The penetration time of the water into the blasting media decreased from approx. 8 minutes to even less than 2 minutes and with a further tendency to decrease. In the subsequent normal operating mode we give approx. 2 litres of additive per hour into the system to ensure the blasting performance and cleanliness from grease required by us.