All of this information is courtesy of Schmetz.
1 Definition of Needle Life
During the sewing process different forces and influences are attacking the sewing machine needle. There might be
- Abrasive forces
- Penetration force
- Influence of operator
- Influence of sewing thread
- Influence of sewing machine
Every one of these forces and influences are the enemies of needle life. They might destroy the point, abrase the needle surface or even break the needle. Some of these influences and forces and their effects are directly visible, e.g. if you get holes in your fabric something has happened to the needle point or if the thread breaks there might be damage to the eye of the sewing machine needle.
As a general definition of the end of needle life we can say
2 Parameters influencing Needle Life
In the previous paragraph we already named a few influencing factors on needle life. If we look closer we will find the following parameters
- sewing good
- machine setting
- machine speed
- thread quality
- thread size
- needle size
- needle point
besides other parameters being specific to every plant like climate, work environment and others. All these parameters are of influence to the needle life and are very individual to every sewing factory. The life of a sewing machine needle has come to an end when the needle looses its proper function.
If we just take the operator as one of the most influencing factors on needle performance we can see that the skills and work experience is a significant parameter. But also here the human factor comes in because not everyday the operator works the same depending on the physical and mental condition. If you put two operators side by side sewing the same workpiece under the same outer conditions like same machine, same speed etc. it can happen that the results are very different, especially when we look into the needle consumption.
From all these influencing parameters it becomes very clear now that they cannot be predetermined because they are individual to the specific sewing factory. Almost every factory has different conditions and setups even if they make the same product.
Broken needle points because the needle has touched some machine parts. The fabric never would cause this type of fault.
Abrasion on eye sidewall because the needle was deflected during sewing and was touching the sides of the needle hole in the throat plate
Total abrasion of eye sidewall. The eye is open. This happened with a very abrasive sewing good containing a flame-retardant chemical.
4 How to find your individual needle life
As the manufacturer of the sewing machine needle we are not able to give a prediction of needle life for the individual plant because it is impossible to know all your individual factors. But a lot of sewing factories have the data available or are able to find the data for every sewing line or even for every sewing machine. It just is a matter of about a month collecting data for every needle change, log the data and categorize by reason for the needle change.
This will give a good basis for quality improvement because if you have these data you will be able to implement a needle change policy in your factory as already a lot of the high quality manufacturers do. You will have the possibility now to change the needle before it starts to abrase or before the needle point gets damaged.