Discovering the Basics of Draw Frames: What They Are and How They Work

The process of yarn manufacturing involves multiple stages. Following the blowroom stage and the carding stage, draw frames are used to make the sliver obtained from the carding phase more uniform. Generally, rollers are used to treat the sliver and perform a wide range of tasks - right from blending and levelling, to sliver doubling, drafting and others. Put in another way, the primary function of draw frames is the parellalisation of carded sliver, while ensuring that there are no damages - and the original sliver parameters are not compromised in any way. To ensure maximum drawframing efficiency, using custom breaker drawframe cans is necessary.

Given the importance of draw framing in spinning, it is vital to have in-depth knowledge about this stage, and how it helps in continuous yarn quality optimisation. In what follows, we will focus on this.

What Exactly Are Drawframes in Spinning?

To meet the precise requirements of buyers, mills need to be particularly careful about maintaining high yarn quality standards. This is where the draw frames play a crucial role. Right from ensuring high yarn strength and evenness, to removing hairiness, neps & more - drawframing is essential to remove common sliver irregularities, and make the carded sliver free (or, as much as possible) from external impurities. In fact, the quality of sliver obtained from this stage is directly proportional to the final yarn quality.

Types of Drawframe Machinery and Their Roles

Broadly speaking, drawframing machinery can be classified under two heads: the breaker draw frames and the finisher draw frames. While the former is used to prepare parellalised sliver (from the sliver obtained in the carding stage), finisher draw frames use this ‘drawn sliver’ and process it further - to ensure even more uniformity and parellalisation. Both types of draw frames need to work in tandem, to make sure that the sliver processing is not hampered in any way. 

Key Functions Of Draw Frames

Doubling and drafting are the two key actions performed by draw frames. The doubling process involves feeding at least two carded sliver in the machine, and ensuring that the linear density of the combined sliver remains the same. In most cases, 6 to 8 slivers are used together at this stage. The drafting task, on the other hand, brings down the sliver weight per unit length, and optimises the overall arrangement of fibres (by making them parallel with the length of the sliver). 

At this point, it is also important to consider the wastes generated by draw frames. Apart from sliver cuts & neps, filter wastes are also produced. The onus lies on mill operators to efficiently manage and dispose of such waste.

How To Monitor Draw Frame Performance?

From making the slivers even through doubling, to maintaining high fineness levels and removing dust & impurities, drawframing is vital for maintaining high yarn quality parameters. Specialised HDPE spinning cans, manufactured by top suppliers, need to be used, for glitch-free draw frame performance.

In order to understand whether the draw frames are functioning in the desired manner, two factors are generally taken under consideration. These are:

1. the Coefficient of Variation (CV%) of yarn.

2. overall sliver evenness.

Why is Drawframing So Important in the Yarn Manufacturing Process?

The drawframing stage in a spinning mill has to be handled very carefully. This is important, given the importance of the draw frame operators. Apart from optimising fibre uniformity and maintaining the parallel nature of the sliver, efficient drawframing helps in removing the hooks / curls in the fibres, eliminating micro-particles & dust elements, and blending the hanks in the proper manner. The final objective is always on ensuring that the output is of homogenous quality.

Key Parameters of Contemporary Draw Frame Machinery

Draw frames have evolved a great deal since the early days. In modern-day spinning mills, drawframing machinery has an auto-doffing system, high-performance drafting systems, and an auto-leveller for controlling the sliver regularity automatically. The drafting mechanism is handled with a pneumatic system and a pressure bar. Advanced draw framing setups also have length measurement systems and indicators for prompt fault detection.

The rate of production of a properly functioning drawframing machinery can be upwards of 950 metres per minute.

Note: Creeling zone, guide roller, coiling area, drafting zone and can doffing area are some of the main sections of draw frame machines.

Probable Problems in Draw Frames

If the draw frames are not properly maintained and/or the right spinning cans are not used, that is likely to cause a myriad of problems. For instance, sliver irregularities can crop up, there can be sliver breakage, coiling glitches, and missing-end problems. Inconsistent yarn thickness is also commonly encountered, when the draw frames are damaged or defective. 

A wide range of factors can contribute to efficiency losses in draw frames. These include roller lapping, lack of scheduled maintenance, doffing problems, and other related issues.

Draw Frames in Spinning Mills : The Way Forward

The textile spinning industry is constantly transforming - with automation and smart operations having an impact on practically all phases. The drawframing stage is no exception to this. The latest draw frames typically have a tension measuring mechanism, quality monitoring system for checking the output (through camera), auto-levelling systems, and other such cutting-edge fixtures. The drafting rollers are generally fitted with ‘pneumatic pressure heads’, to ensure proper fibre control. The break draft setting is also managed meticulously. Going forward, more advancements in drawframing will make this process even smarter.

Often referred to as the 'sliver remaking' phase, draw framing also helps in eliminating sliver impurities / imperfections, and ensuring proper coiling in cans. Top spinning can manufacturers, like Jumac Manufacturing, have specialised breaker draw framing cans in their portfolio, in order to ensure that yarn quality is maintained at all times. Key aspects of the final yarn - like its fineness, strength and elongation - depend on the quality & efficiency of draw frames. The demand for flawless yarns is increasing exponentially, and spinning cans in general, and draw framing in particular, play a vital role in helping mills deliver output of the desired quality.