When cutting materials with a vinyl cutter there is a force balance between the resistive force of the blade during cutting, other resistive forces on the material travel and the roller driving force of the material supported by its rigidity. More rigid, softer materials can be run at higher speeds with higher cutting forces and sharper blade angles. More flexible materials need to be run at lower speeds and lower forces and more shallow blade angles. (In the extreme, consider window tint as the most flexible material.) In the limit, trying to cut a material too fast or with too much downforce or with too aggressive a blade angle can result in bunching. When this occurs, your blade will no longer be able to cut at the rate that the material is being fed at and the material will bunch up between the blade and the pinch rollers. Different environmental and material factors can impact the conditions at which bunching can occur. Cutting at colder temperatures for instance may increase the likelihood that your material may bunch up because the material may be more difficult to cut when it is colder. Variance in the production processes of materials may cause a material to be less rigid/more flexible and hence may cause the material to bunch up. Variance in production processes may cause your material to be tougher and hence more difficult to cut causing bunching. As there are several factors at play to determine optimum cut parameters it is difficult to provide a specific speed, force and blade angle that will work for any given material for all conditions. As such, if your material starts to bunch up please follow these steps to alleviate this condition.
1. Reduce the speed. This will allow your blade the time it needs to do the cutting work needed for the condition of your material.
2. Reduce the force. This will result in less work being done by the blade over the same amount of time / travel.
3. Reduce the blade angle. Changing the blade angle from 60° to 45° or even to 30° allows the blade more cut surface over the given depth and hence will reduce the cutting stresses involved.
4. Change the blade. Duller blades will allow materials to bunch up more easily.
5. Clean the cutting strip and cutter deckplates. Make sure there is no sticky tape residue or other debris on the cutting surfaces and the surfaces the material travels on. This residue will add resistance to material flow and can cause the material to bunch.