1. Introduction
Friction measuring device CPF / CTC
Measuring Software Graf Friction Lab 2.9
The friction of a sewing thread or embroidery yarn has a decisive
influence on the machinability and productivity.
The more uniform the friction of the yarn, also from one batch to another,
the more constant the yarn can be processed. A regular low friction avoids
hooking and picking of the yarn in the thread guiding devices.
The speciality of the graf fricton measuring device CPF / CTC is the measuring of sewing
thread and embroidery yarn. Our philosophy in this item is to imitate the tension
device systems of a sewing machine, but to have reproducible conditions, of course,
under same climatic conditions. Because of this we use a standard sewing thread tension
device (see picture 1) for our CPF friction device. Our CPF-CTC friction device is equipped
with a yarn roller tension break (see picture 2).
As a sewing machine makes no constant pull speed, we can measure at different speeds.
We can measure, for example, friction at 5m/min and the characteristics of pulling the yarn
from a standing position with 5cm/min. It is called “stick-slip”.
A yarn with a bad stick-slip really stops in the tension device and then, when tension is
high enough it slips through. Then friction diagram looks like a saw-tooth.
picture 1: Tension device
Instruction Manual FRICTION MEASURING SYSTEM CPT/CTC / Version 2.0 –06.2020 3
picture 2: Yarn roller tension break
