- Poly Fluoro Ltd
- Updated on :
Polymer Scraper Blades - An effective, non-damaging solution to automation systems
The advent of mechanisation, automation, and the use of robotics in manufacturing shows no signs of slowing down. One of the critical requirements of such systems is continuity. Any automated system only works when each segment of the process functions smoothly and without any interruption. Considering the speed at which some of these systems move the smallest glitch can often push the entire manufacturing line to shut down.
Polymer scraper blades are primarily used to remove obstructions, clear surfaces, and remove sticky materials – such as glue or residual polymers from running systems. Their purpose ensures that debris and other materials are taken out of the process so that they may not cause jamming or scratch surfaces.
There are many advantages of polymer scraper blades in such applications. While metal blades were used earlier on, there is a lot of potential damage that can be caused by these. Polymers, in contrast are hard enough to be effective scrapers, but not so hard that they will damage other elements. Further, with polymers, a designer can choose the level of hardness needed, depending on the other materials the scraper will interact with. There are numerous polymers that can be thus employed.
PTFE has multiple advantages as a scraper blade. The low coefficient of friction means that it can smoothly run over a system – such as a conveyor belt or glass surface – without putting any load on the other material. PTFE is also soft – so even delicate systems can benefit from PTFE scraper blades. However, the same softness places a limit on how sharp the blade edge can be made with PTFE. Although fillings of glass, carbon, and even stainless steel (see picture) can improve the stiffness of PTFE, its use is mainly beneficial where aggressive scraping is not needed.
Like PTFE, UHMWPE has a low coefficient of friction. It is also lightweight and exhibits superior wear resistance. UHMWPE is also soft, so again, its use is limited in non-aggressive applications. Unlike PTFE, UHMWPE does not perform well in high temperatures. However, it is very cost effective, highly machinable, and does exceedingly well against rough materials, that would necessarily place a lot of wear load on the scraper blades.
Both PA6 and PA6.6 perform well as scraper blades. The addition of Molybdenum di Sulphide further improves wear resistance while the inherent hardness of the material exceeds that of PTFE and UHMWPE. Nylons are light weight, but are also prone to moisture absorption, making them better suited to dry environments.
One of the most versatile polymers, POM (Polyacetal, acetal, or Delrin) is an exceptional choice for scraper blades. Unlike PTFE, UHMWPE, or Nylons, POM is a harder and can be machined to a far finer and shaper blade edge, making it excellent for fine and even aggressive scraping. The addition of PTFE fillers to POM can help reduce the coefficient of friction further. Unlike PTFE, however, POM cannot work in temperatures above 150°C.
PEEK combines all the best characteristics of the other polymers. It is very hard, making it possible to machine to a very sharp edge. The toughness of PEEK means that it can be used in very harsh environments – mechanically, chemically, and at temperatures in excess of 250°C. The blade will not dull easily and the addition of PTFE can help to make the material more smooth. However, such a swell of properties does come at a price. PEEK is at least 6-8 times more expensive than PTFE and about 20 time more expensive than POM. Hence, it’s use is limited in applications where nothing else can be used.
At Poly Fluoro, we have the capability to design, blend, mould, and machine the scraper blade that best suits the client’s application. The use of special blends can be incorporated, if the end-use calls for it, while the dimensions of the blade itself can be fine-tuned before bulk production commences.