Spectracut II should cut at 100-130 grams of downforce on the Roland GX-24. If it is not cutting properly, you will need to conduct test cuts, examine them and adjust accordingly.
How to do a test cut on the GX-24 (other cutters might be similar)
Now that you have set the blade we need to do a test cut to make sure that the depth of the blade is correct.
Hit the Test button on your cutter. The carriage should perform various movements and the blade will now make its cut.
After movement is stopped, use the down arrow key to scroll your material out until you see what you have cut.
Take your weeder tool and peel up the first layer of the box that was cut.
After peeling up this layer, simply take the weeder tool and lift up the center circle as well. After lifting the circle you must examine the clear mylar backing to make sure you have an accurate cut.
An accurate cut will be demonstrated by the fact that everything peeled up easily to this point and no blade/score marks are present on the mylar backing where your circle was peeled from.
Upon weeding, if everything peels up and the circle is not left on the backing then your blade is not deep enough. Go back and adjust your downforce. Make sure your downforce is adjusted to cut SLIGHTLY deeper.
Upon weeding, if you notice blade/score marks you will need to decrease your force.
Upon weeding, if the mylar backing is completely cut through in any areas go back and decrease your force significantly.
If none of the symptoms above are present: your blade is set properly.
If any of the above symptoms are present: continue to repeat the force setting process and test cut process until you get accurate results.