Sewing machines for bags: maintenance and settings.
Sewing machines for bags and nets are simple to use and do not require special maintenance.
In this article we will describe the main replacement parts, consumable materials and adjustments that you can normally perform.
Although we will provide information generally valid for all kind of sewing machines, we remind you that details vary depending on brands and types. However, all sewing machines are provided with user manual with all detailed information. 
Needle and crochet hook operating principle.
Pressing the sewing machines button, the needle makes an up/down motion. This movement is coordinated with the crochet hook that, catching the thread, allows the chain stitching. Therefore it is crucial to use a specific needle for the sewing machines you are using. Moreover, the needle must not be damaged or bent.
Sewing thread for FPMP sewing machines
For these reasons, we suggest to buy in advance some reserve needles avoiding sewing machines to stop production due to accidental damage (i.e. unsuitable materials, accidental fall, etc.). The crochet hook is instead a consumable part that should be replaced after an high amount of seams.
Consumables materials: sewing thread.
Sewing machines for bags can be used with several types of thread.
The FPGK series normally mount conical coils with a length of 1000 linear meters.
FPMP models are equipped with cylindrical coils with a length of 1500 linear meters.
Each spool can sew about 300/350 meters of material.
The most used rolls are 100% white polyester and perform well also in wet or outdoor environments.
Equipping the FPGK sewing machines with a specific adapter (optional) it is possible to use also the cylindrical roll thread.
Sewing thread features.
The thread could have this features:
Polyester standard thread: high-strength polyester thread, NM title (metric number): 20/3, mean resistance: 5500gr, stretching: 16%, 1000 meters reels.
POLYAMIDE fiber: Polyamide fiber thread
RED/BLUE COLORED: Red or blue colored thread
BLACK POLYESTER: 850 mt 100% polyester black thread
Adjusting the thread tension.
The wire tension is the main factor to achieve a good seam on any kind of material. In case of low tension, the chain stitching will be loose and the seal poor, vice versa, if the tension is too high the seam will be too tight with low elasticity and high probability of breaking. Our recommendation is to reduce tension when you sew compact or thick materials, conversely it is better to increase tension in case of thin materials. This kind of adjustment is made with the regulation nut located on the tension disk: screwing it you will increase tension while unscrewing it you will lower the tension. To test the thread tension you have to slide the thread holding it with two fingers. If the thread flows smoothly the tension is correct, otherwise if the thread do not slides or slides too quickly the tension should 
be adjusted accordingly. A second check can be done using a test sample, just place it under presser, start the sewing and check the resulting seam.
Sewing machines for bags require minor maintenance, in general the cleaning and lubrication is strongly dependent on the workplace and usage intensity. In case of wet environment or floury products we suggest to clean and lubricate the sewing machines daily. Cleaning can be done with compressed air in particular for the cutter, the notched plate located under the presser, the hook and the engine block. Lubrication should be done on all moving parts with a specific oil. In particular we suggest to lubricate the cutter, the needle bar and the presser gears.
We recommend having the stapler checked at least once a year, during a period of non-use.
In this way, worn parts can be replaced, preventing them from breaking just when the stapler is being used.
Potential issues and solution
| ISSUE | SOLUTION |
|
The sewing machines does not start |
Check the power cable, carbon brushes and electrical connection. |
|
The stitching point is irregular or not done |
Check the thread tension (tension disk). Check if the thread is correctly insured. Check the position of the needle and the hook (contact the service center). Check if the needle size is suitable with thickness and type of material. |
|
The thread breaks during sewing |
Check the thread tension (probably too tight). Check if the thread is correctly insured. Check if the needle size is suitable with thickness and type of material. |
|
The needle breaks |
Check the needle wear. Check the position of the needle and the hook (contact the service center). |
|
Holes formed during sewing |
Check the needle size and that is not dull. |
|
The dragging is irregular |
Check the pressure of the presser. Check if the needle size is suitable with thickness and type of material. |
Please note: All prices and models are sample and are for guidance. They may change at any time without notice.
We invite you to contact us for further information and personalized advice by writing an email to info@sos-imballaggio.com OR by calling 01732123.
