Tracking is the ability of a vinyl cutter to be able to return to the correct point after cutting out a loop. It is easy for a vinyl cutter to track over short distances and small loops of a few inches or so however, if your loops become substantially large such as 10′ or so you may need to adjust some things so your loops close and your vinyl cutter maintains its tracking.
Here are some parameters you will need to adjust when your loops exceed 10 feet or so:
1) In general, servo cutters track slightly better than stepper cutters. This is due to both the higher resolution of the motor encoding for a servo motor as well as less vibration (smoother operation) being present in a servo system.
2) Dirt and dust that get deposited on both the rubber wheels on the top rollers and on the grit rollers on the bottom will reduce the friction between the wheels and the vinyl. The cutter depends on a high friction factor between the roller wheels and the vinyl to maintain a good track. Usually, what happens is that when a long cut is made, the vinyl hits the floor. When it hits the floor it picks up substantial debris (lint, dust, etc) due to static charge. This debris deposits itself on the rollers and makes them slippery. We recommend for long cutting that you get a basket to catch the vinyl so it doesn’t hit the floor. In addition, prior to any long cutting, we recommend cleaning the top and bottom rollers. The top rollers can be cleaned with a cotton cloth with some ammonia based cleaner (such as glass cleaner). The bottom rollers can be cleaned with a dry tooth brush. Be careful not to deposit cloth fibers on the bottom roller.
3) In order to increase the friction force between the vinyl and the rollers we recommend increasing the force on the top rollers. This can be done with the adjustment nuts on the back of the rollers.
4) Another factor that decreases the tracking ability of a cutter is the speed which it is run at. When cutting at high speed, the rollers will depart more kinetic energy into the vinyl. When the cutter has to stop the vinyl from a high speed condition, some of that kinetic energy may result in slippage between the vinyl and the rollers. To reduce the vinyl inertia and reduce slippage between the roller wheels and the vinyl it is advisable to reduce the cutting speed. In general, cutting at slower speed will result in better tracking. Use a speed of about 100 mm/s for Saga cutters.
5) Roll out your vinyl in advance and use a sharp blade. By doing this, you can reduce the force against the roller bar and thus reduce any slippage that would occur due to these forces. By rolling out your vinyl you will also insure that your vinyl is adequately lined up to the cutter over the distance you expect to be cutting. We recommend rolling out the length of vinyl that will be used in your run and making sure that the vinyl is tracking straight with the cutter over that distance. Line up the vinyl with the cutter within 1 mark on the ruler over the distance of the cut. The vinyl can wobble left / right within a mark but it cannot walk more than 1 mark in either direction. This can be frustrating to get the vinyl running that straight but it is necessary for good tracking. It takes a little practice and a little time.
6) If you are running vinyl that is smaller than your cutter size (for instance, 24″ wide vinyl being run in a 48″ cutter), center the vinyl with respect to the rollers which are closest to the center of the cutter. There is a natural bow in the cutter due to the roller spring forces and the blade forces. Not centering the vinyl on the cutter will cause the vinyl to creep due to this bow. It is more important to select the rollers that are evenly spaced for the vinyl width over vinyl centering. For 24” width vinyl on a 48” cutter this means using rollers 1, 3 and 4 for a Saga cutter. This is better than running the material down the center of the cutter.
7) Use the sharpest blade. This is likely a 60° blade. This will allow for the least resistance of the blade through the vinyl. Use a newer blade. Newer blades are sharper.
8) Use the lowest possible force that cuts through the vinyl with the sharpest blade. For the servos, this is a setting around 50 or so for a 45° blade, possibly lower force for a 60° blade.
9) Make sure that the vinyl is free to loosely fall in front and behind the cutter. If there is any extraneous left / right forces or if a corner of the vinyl snags on something or if it kinks it will throw the tracking off. The vinyl must be free to move as it needs to. A basket is highly recommended for the best vinyl handling.
10) The above recommendations will apply not only to ProCut / Saga vinyl cutters but most vinyl cutters that don’t employ a perforation tracking system. With perforated vinyl, the cutter does not depend on friction between the vinyl and the rollers for tracking but rather has the vinyl perforations and mechanical pins to mechanically restrict vinyl tracking to the rollers. Because of this, in general, perforated vinyl systems track better than roller friction based systems.