During button attachment in informal jackets and trousers, a considerable space is left between the button and the fabric. This is done to ensure that while inserting the button inside the buttonhole, enough space is left to accommodate the thickness of the fabric. The ‘stem’ created by the strands of thread is wrapped to provide strength and stability to the ‘stem’ of the button sewn to the fabric and is called button wrapping. If this operation is done manually, it could lead to inconsistencies in quality from one garment to another. This article by Taneya Bose, MF Tech student and Dr. Prabir Jana, NIFT, Delhi aims to explain the different levels of technology available for button wrapping.
The study has been carried out by considering three developments of performing the operation. The study traces the way the operation is being performed, and the advantages and the cost analysis associated with all the levels.
Basic level of technology
The basic level of technology relies on pure manual workmanship. In this, the operator is expected to wrap the button by using needle and thread only. The operator can perform the wrapping cycle depending upon the quality requirements. The major issue associated with this level is that there are chances that the consistency in quality is not maintained. Also, the productivity is low. It has been observed that by using the manual method, the scope of unwinding of thread increases.
Intermediate level of technology
With the aim of improving on the productivity, the process of wrapping has been automated to a certain extent. The machine wraps and secures any type of already sewn button at high speed and with constant precision. The problem of unwinding of thread observed in the basic level of technology has been resolved at this stage as the wrapping operation is carried out not just by mere winding, but entangling the thread so that there are minimum chances of unwinding. The economic use of yarn and the computer-controlled process makes the machine a perfect choice for this operation. This process is performed using a button wrapping/knotting machine. Immense increase in productivity, sealing the thread with heat, thread cutting mechanism, option of setting the wrapping frequency, shank height are some of the features which are associated with intermediate level of technology.
A button shank wrapping machine comprises of the following to make the task easier:
• A support adapted to receive and support a button shank at a support station. • Winding element equipped with elongated rotatable element to wind thread around the button shank. • Tensioning devise to apply tension to the thread as it is wound. • Means to supply thread to the winding device. • Means to form a bond on the shank adjacent to the support station. • Shank bonding either by heat fusing or by applying a bonding agent to the shank. In order to ensure heat fusing, a fusing iron is arranged to be moveable into momentary engagement with the shank after whipping. • Two catching elements to provide automatic control and consistency in production. The dual catching arrangements ensure that the machine when fully supplied with thread is always ready again for the next button wrapping operation.
Few brands of button wrapping machine at intermediate level of technology
CAPE SEWING MK 11
This is a fully automatic machine with 360 degrees bonding suitable for high volume orders. The process of wrapping, sealing and finishing the button shank takes only 1 second. The machine is computer-controlled, with button support for long buttons and it is easy to switch from one shank style to another. The capacity of the machine is 1,100 buttons per hour with provision of 7 to 99 wraps.
ASCOLITE BSS-MK 8
This semi-automatic machine is suited for small- to medium-size volumes. The machine has a built-in seal control system, LCD display, heating fork positioned upwards and optical and sonic indicators. With capacity of 600 buttons/hour, the machine has wrap option from 10 to 99 per button.
LOIVA INTECH PVT. LTD. ST-10: With maximum 3,000 SPM, this machine is very flexible and has option of selecting the button type/shank type. The wrapping frequency, button height, thread cut on/off and sequence of operations can be programmed. The machine also boasts of a pneumatic thread cutting system.
Advanced level of technology
The next level of advancement in button attachment came in the form of clubbing of the button sewing machine with the button wrapping machine. This technology replaces the use of CAMs and ROMs (read-only-memories) which are being used in the conventional machines with motors and flash cards. This is because a large quantity of ROM is required for changing a button sewing-on pattern according to the kinds of buttons, cloths, or threads. In the case where a new sewing pattern has been created, the ROM would have to be replaced with a new one. It requires maintaining large inventory of ROM covering all kinds of sewing patterns. Whenever the predetermined stitch number has to be changed owing to a change in the sewing pattern, the sewing machine must be disassembled to exchange cams and other parts. This involves unnecessary expenses, time and labour.
An added advantage being the thread tensions for button sewing and neck wrapping can be separately set on the operation panel. Some highly useful features like automatic thread cutting, button loader, adjustable neck height and negligible lubrication have been incorporated in the machine. The productivity is almost the same as compared with the dedicated button wrapping machine.
Few brands of button sewing+wrapping machine at advanced level of technology are Juki AMB-289, MMS BAT 20C and 20L, AMF REECE EBS MARK II and AMF REECE BT-2700.
The advanced level machines offer several other features and advantages. The AMB-289 finishes four-holed buttons with a hand-stitched appearance (V-shape stitching) by fixing the tucking position at a preset location. This results in the sewing of a neat seam on the wrong side of the garment and neck-wrap knots at a single location. Cycle sewing data can be set/edited with the sewing item graphically displayed on the operation panel (the number of buttons, button sewing locations, and sewing order of buttons). AMB 289 is equipped with separate stepping motors for needle throw, feed system and auto lifter. The AMB-289 is provided as standard with an LED-type handy light and marking light. The sewing area is now brighter and more viewable than it would be under the incandescent light of a conventional machine. LED light also offer the advantage of a longer service life. The machine is optionally provided with a marking light for sewing flat buttons directly to cloth.
During the sewing/wrapping cycle the operator places the button in the loader to enable fast and precise button transfer to the jaws without any wasted handling time. MMS BAT 20 can be equipped with either a lockstitch or chainstitch head, and automatic heat sealing included in the cycle. Operators can choose any three easily selectable options – button attach, button wrap or attach and wrap. Stitch pattern and shank height can be adjusted precisely and instantly.
The AMB-289 does not require the use of exclusive thread intended for button sewing. General-purpose cotton threads and spun threads are both applicable, depending on the type of material. A full range of thread counts from #60 to #30 can be applied. This ensures use for diverse processes. The thread-trimming position is set to reduce the remaining length of thread on the material to a minimum. The machine incorporates a thread-fray prevention function that ensures the tying of strong and reliable knots at the last stitch.
AMF REECE EBS MARK II has an option of multi-threading system, a pneumatic system for bringing the thread from multi-threading system to the needle eye. Both AMF and Juki offer thread tensions for button sewing and neck wrapping can be separately set on the operation panel. Both the models provide a button feeder that lets the operator place the next buttons to be sewn during overlapping-style work. AMF REECE EBS MARK II also has an especially designed ergonomic table equipped with an additional lower-level desk for easy placement of the sewn garment. The lower-level desk and the sewing table itself can be adjusted for operator comfort.
ROI calculation for the basic and the advanced technological levels
The ROI is calculated on the manual button attaching and shanking vs. automatic button attachment and shanking.
As evident from the data, by using the automatic button attachment cum wrapping machine, apart from remarkable improvements in productivity and quality, the cost of the machine can be recovered within as the cost of machine is nil in case of basic level, the ROI may be quick. However the quality consistency issues and ergonomic vulnerability of worker are negatives for basic level.
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ROI calculation of manual attaching and shanking versus automatic button attachment and shanking |
|
|
Basic Level of Technology |
Advanced Level of Technology |
|
SAM for single button sew + wrap (min) |
0.92 |
0.19 |
|
Number of buttons per day (shift of 8 hours) |
523.64 |
2482.76 |
|
Working days/month |
26.00 |
26.00 |
|
No. of months/year |
12.00 |
12.00 |
|
Production per annum |
163374.55 |
774620.69 |
|
CM price per button |
2.40 |
2.40 |
|
Cost output/annum |
392098.91 |
1859089.66 |
|
Production Target (pcs/day) |
2482.76 |
2482.76 |
|
No of machine/ men required |
4.74 |
1 |
|
Cost of one machine (Rs.) |
5.00 (cost of hand needle) |
1855000.00 |
|
Cost of total machine (Rs.),T |
23.71 |
1855000.00 |
|
Annual Depreciation (%) |
0.15 |
0.15 |
|
Depreciated value of m/c after one year (Z) |
20.61 |
1613043.48 |
|
Salary of one operator per month |
5800.00 |
5800.00 |
|
Total operators salary per year (Y) |
330000.00 |
69600.00 |
|
CM price from total m/c (X) |
1859089.66 |
1859089.66 |
|
Cash Inflow (I) |
1529089.66 |
1789489.66 |
|
ROI for the first year,(X-Y)/Z |
7417474.91% |
110.94% |
|
Payback Period (T/I) |
0.00 |
1.04 |
ROI calculation of manual attaching and shanking versus automatic button attachment and shanking
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