Trends in Apparel Manufacturing Technology
Trends in Apparel Manufacturing Technology: A Plateau or IT take-over? Prabir Jana, B.Tech, GMT, CText ATI Introduction Traditionally developed countries invent new technology through R&D and then commercialise it in their own country for benefit of industry. While the technology is being exploited commercially by the industry, research institutions in collaboration with industry simultaneously keep developing newer generation of technology. It is an ongoing process. When the newer generation of technology is ready for commercial use the old technology is being transferred to the developing third world countries as ‘collaborative projects’ and ‘technology transfers’. Firstly the availability of readyto-use technology from advanced countries make most of the developing countries complacent & reluctant to invest in indigenous R&D and secondly this is why the developed countries are always ahead in technology level compared to developing countries. We have to understand the two industries well. While the apparel manufacturing industry migrated to southern hemisphere the apparel machinery manufacturing industry did not. Traditionally it is Germany, Italy and USA who were the leaders in apparel machinery technology development before Japan and Taiwan joined the bandwagon in late 70’s. If we look at worldwide market for apparel technology, we can see that the ‘big five’ together controlled 80% to 75% share of worldwide market during last decade. Worldwide market for clothing and industrial textile processing technology Country % share in 1995 % share in 2001 Japan 36.1 30.2 Germany 19.0 18.0 Taiwan 18.5 19.1 USA 7.8 7.7 Italy 6.6 3.4 Others 20.0 25.6 If we take a closer look at the technology exhibitions during in last decade we can see a definitive change. Innovation, the driver behind new technology development till 80’s, gave way to solution, the new driver behind technology development. The declining apparel manufacturing industry resulting huge job loss in the older economies restricted the fund availability for R&D to develop new technology for apparel manufacturing, while the newer economies are not geared up for necessary R&D. While at one hand innovative fundamental development did not take place, but numerous microchip applications have transformed the machinery to a smarter breed. It is the flexibility (and not especiality any more) and user friendliness that have directed the necessary
development. It is expected that apparel machinery technology will further proliferate to Asian and East European countries with user-participative machine development programme in the coming future with China playing a major role. The technology for apparel manufacturing may be divided into three categories; pre-sewing, sewing/joining and post sewing. Let’s take a close look at the technology evolution. Evolution in Pre-sewing technology Fabric inspection was traditionally a manual process as defining defects in fabric was very much subjective and proven to be one of the most difficult of all textile processes to automate. It was primarily a slant table with translucent/opaque surface with edge sensor and meterage counter, but scanning of defects was still human eye. Current automated fabric inspection systems are based on adaptive, neural networks, they can learn. Now automated fabric inspection machines are equipped with CCD (Charged Couple Device) camera, scan the fabric using advanced Fractal scanning (Dorothy et al) techniques and uses Fuzzy Wavelet Analysis (Dorothy et al). The users are able to simply scan a short length of good quality fabric to show the inspection system what to expect. This coupled with specialized computer processors that have the computing power of several hundred Pentium chips makes these systems viable. These machines are designed to find, catalog and analyse defects for a wide variety of fabrics.
Fabric spreading technology almost remained same as it was in the beginning of 60’s except computerized tension control, CCD camera based plaid matching etc. It can be best summarized as, “….what operator used to push during 60’s, he/she merely rides it today”. The expensive CNC cutting technology that we use today is not much different from CAMSCO invented during late 60’s except the mechanical controls that are being replaced by microchips. The seamless integration of data and interconnectivity between equipments taken front seat. Other advanced cutting technology like water-jet cutting (Durkopp had a prototype developed during 1997), plasma and laser cutting either remained at prototype stage of development or used mainly for non-apparel (technical, automotive etc.) applications. The only notable commercially feasible development worth mentioning in automated cutting technology is single or low ply cutter with fixed (drag cut) or rotating blade (chop cut).
Durkopp HydroCutter for leather cutting
Accumark V-Stitcher for virtual fit
The technology development that has given facelift to the pre-sewing category is nothing but CAD (computer aided design). It all started with 2D CAD where pattern were drafted in computer using PDS software, graded and then pattern layout (marker making) is made for optimized fabric utilization. There were numerous research initiatives (Shanley et el) to automate the marker making process and AMGT (automatic Marker Generation Test bed), Nest++ are some of the results that commercially adopted. Then came 3D CAD to virtually test fit garments as well as simulate fabric fall using actual fabric objective measurement (FOM) value like FAST, Kawabata etc. This will reduce product development time, cost of multiple iterations of sample garment production, and provide a graphical collaboration tool for all involved in the product development process. Optitex Runway and V-Stitcher from Browzwear are some of the commercial offerings in this area. Using dynamic simulation to virtual catwalk is a reality now and the pioneering work from Stephen Grey from Nottingham Trent University and Nadia Tahlmann from Switzerland are worth mention. Digital Textile printing, the only cross industry technology penetration, had already created its’ niche and promising a drastic time reduction in prototype development as well as test marketing of a new clothing line. Evolution in sewing technology Sewing, once considered the only means of joining components is giving away market share to unconventional technologies like heat sealing and ultrasonic welding. Ultrasonic welding has a special niche since it welds, unlike those depending on heat, can be “adjusted” according to application. Since welded joints can be airtight, watertight and dust tight, they are highly sought after for biomedical application, air conditioning and environmental engineering. Let’s take a look at the evolution pattern of sewing technology from yesteryears till date. There was a time when increasing sewing machine speed was perceived as directly related to higher production and so a challenge for machine manufacturer. From a moderate speed of 2000 SPM (stitches per minute) we have seen the 10000 SPM overlock sewing machines. Once the human limitation become very clear that whatever
developments speed up the stitch formation, still there will be two human hands aligning & adjusting the fabric being sewn together, the focus shifted to reduce non-sewing elements, i.e. loading and unloading functions, aligning and adjusting etc. Though Basic sewing kinematics remained same over the years, there are minor differences between Japanese and German technology. Japanese preferred gear drive and pump lubrication whereas Germans banked on toothed belt drive and sealed forced lubrication. However with current convergent in technology direct drive and dry head technology may be accepted as worldwide standard. The main shaft driven synchronized motion between needles, take up lever, feed dog and hook/looper is world wide standard. The only radically different technology that developed in recent years was from Tice Engineering by de-linking of sewing machine head & bed function. The Tice technology has freed the mechanical linkage to the bobbin, opening the doors for unprecedented versatility in sewing. Tice introduced industry’s first double needle belt loop tacker and multiple head buttonhole sewer. Currently Brother uses this technology in several of its’ model.
Tice technology concept Picture courtesy: Brother The use of lockstitch in automated workstations and cycle machines were limited due to continuity problem i.e. frequent and inevitable bobbin changing requirement. Automatic bobbin changer by JUKI, Philip Moll and Kinoshita can be catagorised as revolutionary development in sewing machine history. Since JUKI first exhibited at 1995 Bobbin Show International, this development (in a little modified way) quickly commercialized and now becoming a regular feature for many cycle sewing automats.
Automatic Bobbin Changer Picture courtesy: Tajima
Multistitch by Macpi
Multistitch by Macpi was revolutionary in the sense that for the first time joining of two plies (by overlocking) & topstitching (double needle chain stitch) was achieved in single operation. This development could not popularise further due to the fact that use was limited (only inseam operation in Jeans, leg closing in knitwear) and does not offer any notable aesthetic or functional benefit over conventional lap seam method. The need for versatility and flexibility is breaking long-standing taboo in sewing technology. Now sewing machines are available with drop feed and needle feed interchangeable in same head and even parallel chainstitch/overlock and lockstitch at same head, the features never dreamt off! “Automatic Levi’s Type Waistband Attach” from Vi Be Mac 3022LV is another example how brand power influence (dictate?) technology development. A notable trend in the area of sewing motor was a move toward more versatile and compact motors. Each sewing head has different functions and timings. We have one basic motor plugged into a piggy-back board to achieve the various functions of the different machines out there. These motors are not conventional configurations that are mounted under the table. They’re smaller and can be mounted behind the sewing head or in a direct drive fashion. The development of near-end-contour manufacturing i.e. three dimensional manufacturing in connection with robot technology and single arm stitching systems, is already well advanced and definitive step towards 3D Sewing Technology If we analyse application of microchip in machinery technology the list is endless. Though there was no fundamental development but microchips helped to control & diagnose the sewing machine functions better than manually possible. Electronics is applied everywhere. The following list is only a testimony to that. • • •
Programming stitch profiles (cross tack, cresent tack etc.) in Pattern Tacking machine Control the speed of the machine Program the number of stitches in different sewing bursts
• • • • • • • • • • •
Control the feed dog movements. Diagnose the machine malfunction area. Voice activated start-stop of machine Step motor for driving puller Computerised Thread tension monitoring (Active tension Control from Juki and Yamato) Thread break/exhaust indicator for Needle, Bobbin and looper On Line seam quality inspection (Clapp et el) Speed Responsive Presser Foot pressure Elastic/tape metering device Fabric Ply sensor Computer controlled needle throw in zigzag machine
Sunstar Zigzag can directly take input command from computer The impact of microchip application in sewing technology is best realised in button sewing machine. While in archaic mechanical cam-follower technology changing from “C” stitch to “X” stitch would require manual CAM replacement i.e. minimum 1 hour machine downtime, while in new generation no part replacement; it is just pressing a button. Post Sewing Technology Finishing is always preferred (because it is continuous process, thus more productive) over Ironing and pressing, which is a batch processing technology. Technology developments remained stable over the years expect electronic digital controls repalced analog mechanical controls resulting better accuracy of parameters like temperature, pressure etc. With the development of (fashion trend) soft handle texture-based fabric the hard pressing gave away to non-contact finishing. Application of laser light helped increasing alignment accuracy and also simultaneous measurement checking of garment. At one hand there is continuous decline of formal clothing and proliferation of casual clothing, which necessitated development of laundry technology. We have now fully computer controlled and networked laundry equipment where dye recipe, liquor
ratio, and wash cycle everything is programmable. Latest fad of sandblasting effect in denim is achieved easily by laser with excellent consistency and reproducibility. Conclusion With mechanical engineering development at cross roads the question is whether Information Technology (IT) is going to make a clean sweep? If we introspect the recent developments, described above, the picture is very clear, microchip based controls and thus IT is gradually but inevitably taking control over all technology development. Sewing machine, once considered a dumb mechanical device, is now intelligent enough to be responsive, self-adjusting, communicative and even net-savvy. Transferring software programmes (pattern tacking, button holing, embroidery etc.) from one sewing machine to another or upgrading the software version in different sewing machine through web is already taking place (Daras from Durkopp Adler). Networking sewing machines for real time data collection on actual production and error status (Efka Ethernet, JUKI-Net etc.) is poised to be the next “big thing” in sewing technology. The time is not far when a sewing machine in a remote factory off shore can be switched on or off by typing command from a computer located at central control office or a mechanic will diagnose and even repair a machine from a remote location. Be it a plateau for mechanical technology or not it is the Information Technology which will rule the future! Bibliography and References: Dorothy, L. J., Vachtsevanos, G., Jasper W., 1994, “Real Time Fabric Defect Detection and Control in Weaving Processes”. Project No. G94-2. National Textile Centre, USA Shanley, L.A., Anderson, L.J., Milenkovic, V.J., Kaliman, I., 1994, “Part Layout and Optimisation of Part Shape for Marker Layout in Apparel manufacturing”. Project No. A94-13, National Textile Centre, USA Clapp, T.G., Titus, K.J., Olson, L.H., Dorrity, J.L., 1994, “The On Line Inspection of Sewn Seams”. Project No. S94-4, National Textile Centre, USA Jana Prabir, 2000, Technology Trends in Apparel Manufacturing: An IT take-over? Millennium Document, NIFT, New Delhi
Press Information packs: Bobbin Show 1995 & 1998, IMB 1997, 2000 & 2003 JIAM 1999 Machine catalogues from technology vendors
About the Author: Mr. Prabir Jana completed his graduation in Textile Technology from Calcutta University and finished his Post Graduate diploma in Garment Manufacturing Technology from NIFT, New Delhi in 1991. After having worked in industry for 3 years he had joined NIFT as Assistant Professor. Currently he is pursuing part time PhD from NTU, UK in Supply Chain Management. A firm believer in R&D and avid follower of technology and IT, Mr. Jana is closely associated with many organisations for indigenous R&D and improvisation. His special interest areas are critical chain management, IT application in clothing manufacturing, methods improvement using industrial engineering, Fabric Objective Measurement and it’s application in sewing dynamics, ergonomics in clothing manufacturing, and team working.