Automatic overlockers

Automatic overlockers and stitching machines are devices for overcasting the edges of fabric and making a seam along the seam. They differ from a standard sewing machine in the type of thread feed; not two, but three or more spools are used in the work.

This makes it possible to overcast stretchy fabrics like jersey. Overlock and cover stitches are used for areas that have an increased load such as pockets, fly, inner thigh, shoulders.

The difference between the devices is in functional tasks.

The principle of operation of automatic overlockers

Principle of operation

Sewing machines for textile processing are divided into three types:

  • Overlock;
  • Sewing machine;
  • Coverlock.

An overlocker is a sewing device that cuts and trims edges. Suitable for elastic and non-elastic fabrics. In modern industry – the only tool for working with knitwear.

The machine simultaneously cuts off excess millimeters of fabric, making the hem even, and overcasts its edge with stitches. It is possible to work 3, 4 and 5 threads in one seam. The device carries out from 3 different types of a line.

With the help of an overlock, you cannot make flat multi-line seams, which are also called cover stitches. For this, a separate device was created.

The sewing machine is a kind of device for stitching elastic fabrics butt-to-butt. It is used for sewing complex products and areas that have a large load during wear.

The device cannot overcast matter, its functional tasks include the connection of two parts of the future product. The basis of a strong seam is a connection of 3, 4 or 5 lines.

A coverlock is a device that combines the functions of an overlocker and a sewing machine. This is possible due to the fact that the devices are based on a single principle of operation, based on the “looper” part.

The looper replaces the bobbin (bottom feed part in a standard twin spool sewing machine) by picking up the thread from the bobbin. This allows you to create loops of the desired length and diameter in a certain direction, connecting the joints of the fabric or processing the edges.

This type of machine has two loopers: for several lines.

When choosing an automatic device with 3 or more threads, pay attention to the purpose of the purchase. An overlocker is suitable for overcasting the hem, a sewing machine is suitable for sewing individual parts. If you need to combine functions, purchase a carpet.

Design features

Design features

Overlock is a body with a control unit and a narrow working panel equipped with a needle and blade. Automatic thread feed is a useful feature, its absence reduces the cost of the device, but slows down sewing.

The cover stitching machine cannot process the edge of the product, the blade is not included in its design. If you need a universal device for working with elastic fabrics, then pay attention to the combination of two types – a carpet lock.

All three devices work automatically, it is enough to set the operating mode, set the type of seam and the number of active coils. The fabric feed system regulates the processing speed. Coils are pre-filled.

Pay attention to models with digital control, which allows you to fully automate the process. Manual adjustment of devices requires professional skills and knowledge of the mechanism. Debugging devices is possible only in the service center.

The weight of the devices is from 5 to 12 kg, depending on the number of functions. The size of the working panel and coils. Apparatus for professional tailoring weigh from 8 kg.

The cover stitcher is equipped with a flat, wide working surface, with a diameter of 10 inches or more. Professional equipment is marked along the perimeter to work with different types of seams, technical and decorative. The carpet is equipped with the same panel.

Manufacturers do not standardize the dimensions and weight of the devices, paying attention to the minimum height of the working unit with the upper needles and nozzles (feet) for sewing.

The design includes a mechanism for automatically regulating the fabric and feeding the cord, there are models with manual control, in which it is more difficult to create an even stitch. Automation allows you to stitch and process the fabric with a minimum error in the sides.

The devices support additional functions by connecting accessories. The weight of the nozzles is not included in the total (5-12 kg).

Functions of automatic overlockers


The difference between the devices is in functional tasks. The work is based on a single principle, but devices are designed for different purposes. Let’s consider in detail:

Overlock is designed for:

  • turning the edges of the product with threads;
  • trimming the hem with a blade;
  • processing of internal seams;
  • work with knitted and other elastic fabrics.

Overlock creates stitches that stretch in both directions, which allows you to process knitwear. An indispensable device for sewing T-shirts, jumpers, underwear.

The sewing machine is designed for:

  • grinding of individual parts of the product;
  • creating a flat overlock seam (processing the neckline on T-shirts);
  • strengthening areas of the product with increased load (pockets, fly);
  • curly seams of a decorative nature.

A functional feature of any of the devices is the number of threads in operation. Overlock and sewing machines are recognized as devices with 3 or more cords in operation.

There is also a separate type for processing edges and joining parts into two threads – flatlock (2 or 3 coils that create a “pseudo volumetric seam”).

A line of 3 cords: the average price category of devices. Creates a basic stitch suitable for sewing standard knitwear.

The first stitch is created by the needle, the second by the looper, they are fastened together by loops of the third thread. The line is designed to hold the edge of matter that crumbles.

4-thread stitch: Created using the second upper needle. Allows you to simultaneously process the edge of matter and sew parts together. Functionally switches to 3-line work.

The overlocker cannot sew two parts in a flat surface, this task is feasible for a carpetlocker and a sewing machine. 5 cord stitch: made with three upper needles and two lower loopers. The function is present in all three types of devices.

A stitch of 5 threads is intended for sewing products from coarse fabrics, industrial production of covers (for car seats, interior trim) and workwear.

The chain stitch, which is done by machines with 3, 4 and 5 threads, looks like a pigtail. Does not unravel when one cord breaks. The stitching is designed to stretch with the fabric and maintain the shape of the seam and edge.

Standard machines perform 5-20 types of sewing operations. Give preference to automatic devices with the maximum number of functions if their price range is above average.

Pay attention to the function of automatic threading of the lower loopers. The procedure itself takes from 5 to 10 minutes for each new cord change.

Types of automatic overlockers

Species Comparison

The overlocker is designed for overcasting and finishing the edge of the fabric, the sewing machine is for flat joining of parts, and the carpetlocker combines both functions. Among themselves, they differ in the number of tasks performed, working coils and process automation.

Pay attention to the following features when choosing:

  • automation of thread feeding, regulation of tension and supply of matter;
  • foot lift height – from 5 to 14 mm;
  • waste tray: built-in waste collection container;
  • stitch width and length;
  • task execution speed;
  • foot step;
  • built-in blade for cutting threads and excess fabric;
  • blade shutdown function;
  • stitching seam (front side with stitches, wrong side – with overcasting);
  • clamping the fabric to the working panel;
  • rolled seam – overcasting thin fabrics like chiffon (edge ​​twisting technique);
  • built-in tray for accessories and work supplies;
  • removable sleeve block for processing narrow areas;

When choosing, pay attention to the cooperation of all the listed functions in one automatic device. A useful feature is the color marking of the loopers and spools in order to independently distinguish the color of the future line.

An important indicator is the power of the motor and the electricity consumed. There is an indicator from 75 to 250 watts. When choosing a multi-line model, give preference to a power of 100-220 watts.

Cheap devices with five coils can malfunction if the motor power is less than 100 watts. If it is a professional multi-tasking equipment, get models with a power higher than 220 watts.

Overlockers are suitable for working with soft elastic materials, the edges of which crumble and are designed to stretch.

Give preference to models with a built-in knife, its shutdown mode, automatic stitch control and trays for collecting debris and storing working tools.

Covering equipment is suitable for creating a folded edge, where there will be a straight stitch on the right side, and overcasting on the wrong side. Give preference to models with manual and automatic seam indentation.

The surface must be wide to work with large products.

The coverlock combines both types, but if the equipment is below the average price range, then instead of a universal device, you can get a device that is completely unsuitable for sewing products.

Operating rules

Operating rules

Operating rules depend on the type of equipment and are written in detailed instructions. Please note that a brochure is included with the description of operations, sutures and device settings.

It replaces the tutorial and is required to learn how to work with a particular manufacturer’s model.

Basic rules of operation:

  1. Make sure the power cord is intact.
  2. When threading the needle and looper, make sure that the machine is de-energized.
  3. Change operations only with the presser foot raised;
  4. A whole backlight is required to work. Without it, the machine may not start.
  5. Use operations and functionality as intended. It is not recommended to experiment with thick types of material if the equipment is designed for thin fabrics.
  6. Use the blade only when you need to trim the edge. Disable the function while creating a cover stitch butt to butt.

The main rule is to follow the instructions in the instructions and not exceed the operating parameters of the equipment.

Precautionary measures

Precautionary measures

Before starting work, read the instructions. Learn the rules for threading the needle and looper. Be careful when working with the blade, do not put your fingers and body parts under the work area.

Before starting work, make sure that the cable and plug are not damaged. The work area should be carefully illuminated by an additional light source in addition to the built-in light bulb.

Do not wash equipment with water. Do not install devices in close proximity to water sources, put on a wet surface. Before starting work, wipe your hands with a dry cloth or towel.

During operation, wear shoes with rubber soles, it is not recommended to press the pedal with bare feet. Monitor the general condition of the device, lubricate with oil in time.

Do not lubricate the immediate work area, loopers and needles. Follow the directions in the instructions.

Faults and solution

Faults and solution

A typical breakdown of sewing equipment is a spinning belt that has flown off, a broken needle, and a burned out light bulb.

The first type occurs after improper use, if the sewing mode is not selected in accordance with the type of matter.

The second type of failure is also the result of a settings failure. Give preference to automatic modes in the first terms of operation. Learn how to select accessories, needles and presser feet for certain fabrics and stitches.

The machine may not start. If the backlight bulb is burned out or unscrewed. Check its condition before use. All types of problems are corrected in the manufacturer’s service center.

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