Thermoplastic vulcanizates (TPV) from Santoprene or other companies allow you to make a huge range of different items. But before you start the extrusion process, there are a few tips you should know. Take a look at the following ideas.
Choose the Right Size and Shape of Extruder
When you're choosing which extruder to use, think closely about the size. If you're making something with a small cross sectional profile, you need an extruder with a small barrel, while large cross sections call for a larger barrel. Also, take into account the length-to-diameter ratio.
Consider Pre-Drying Your Material
Often, you need to pre-dry the Santoprene TPV before you start the extrusion process. This gets excess moisture which could lead to bubbles in the final product. But if you want to avoid pre-drying, you can use a vented extruder with a two-stage screw. That provides extra airflow during manufacturing, thus eliminating the need for pre-drying.
However, if you want constant dimensions and consistency at high production speeds, you should take the time to pre-dry. Then, you should use a metal gear pump instead of vented twin screw extruders.
Use Mesh Screens
Ideally, you should use a few different mesh screens when making your TPV extrusion. The first mesh screen should be near the breaker plate, and it should support your fine screws. Then, the other mesh should protect your extrusion die. The die is basically the "cookie cutter" of this process — it helps you get the shape you need, and the mesh protects it for future use. If you position one of the screens so that the melted TPV has to run through it, that also helps to keep the final product smoother.
Balance the Die Plate During this process, the TPV flows through the die to create the desired shape, but if it flows out of the die in an unbalanced manner, that can lead to irregularities. To prevent that, you need to keep the die balanced. That means balancing it at the beginning, checking to see how the pressure levels of your metal flow affect its balance during the process, and adjusting as needed during manufacturing.
Take Care of Metal Dies You can handle Santoprene TPV extrusion with plastic dies, but in some cases, you may want to opt for metal. When using metal dies, keep them a bit rough. That allows the mould to come over more easily. Additionally, in between use, clean them with brass tools and apply an anti-corrosion spray to preserve them.
This process is complicated, and to ensure you get the best results, you may want to hire an industrial and manufacturing professional who specialises in TPV extrusions.Share