Ask for customized sewing automats
Automation and robotics in apparel manufacturing are hot topics of discussion nowadays! They were the favourite topics of machine manufacturers and researchers during ’90s, and now they are making a second coming with a greater vigour and every possibility to succeed. The transition started with mechanization to automation and now robotics. Automation and robotics are often used parallel to each other with only a fine line of difference. Whereas automation can only follow one set of operations, which cannot be changed once programmed, robots on the other hand are made to perform several jobs at once, and the sequence of operations can be switched around to make the processes more efficient.
It seems that there is growth in these areas since mass manufacturers in Asia are exploring newer product segments (both apparel as well as non-apparel) and bespoke manufacturers ( for whom scale of manufacturing was never an advantage) are also facing severe shortage of skilled labour. The normal payback period based on US wage rate is generally between 12-18 months.
Custom automats generally have higher percentage of success or adoption as the equipment and solutions are custom- designed for specific needs keeping all the working parameters in mind. Off-the-shelf automats sometimes face resistance from shopfloor due to the rigidity of their operations. In this new series, Dr. Prabir Jana, Professor, NIFT and Frank Henderson, President of Henderson Sewing Machine, USA bring to you an experience of customized automats for sewing.
Automation in essence reduces the flexibility ( generality) of any operation and increases standardization. The possible automations for operations in commodity garments are already done, commercialized, copied and now affordable to many. However, the ever- changing style and development of innovative raw material poses challenge to off-the-shelf automats. Therefore, standard automats offered by many sewing machine manufacturing companies are often not appropriate for a particular operation. Thus, the need for customized automats arises. There are many vendors in US, EU and Japan who have the capability, technical know- how and expertise to create automation using the sewing heads of established sewing brands.
Here we will discuss about the three cases of customized automats being developed
While these autonomous work cells do not require any human intervention (i.e. all three processes – loading, sewing and unloading, are automated), these can be re-programmed to sew different profiles or different sides and thus can be called application of robotics.
for sewing non-apparel products. Although the cases are for non-apparel and executed in USA, similar intervention is very much a reality in Asia.
Profile sewing of furniture fabric with Dacron
Furniture industry requires fabric, Dacron and foam for upholstery where Dacron, a kind of polyester batting ( cladding sheet) is added to any foam surface so that the foam does not get exposed directly to the fabric. Sewing such a fabric with Dacron is a very simple profile sewing operation involving large fabric component. The shape of the profile varies from straight line to curves, and the measurement of one side of profile can exceed one metre. As the sewing operation does not require much manual skill and requires handling of large mass of fabric (vulnerable to repetitive strain injury to the operator), the operation was deemed fit for automation.
This autonomous work cell was developed with a gantry style robot that loads and sews Dacron and a furniture fabric panel together with a single needle lockstitch unison feed machine. The Dacron and fabric component are loaded into a set position on the work surface in front of the robot and sewing head. The gantry style single beam robot positions the carrier plate on top of the Dacron and fabric component holding both cut components in alignment. The robot plate moves the cut components into the sewing head. As the sewing process begins, the robot is synchronized with the sewing head and moves the product around the total circumference of the outer edge of the fabric components until both components are joined together. The machine pauses momentarily to trim the thread and moves the finished sewn components into a set position where a stacking arm will remove the finished panel and stack into a dropframe receptacle underneath the machine’s work surface. And the process continues repetitively. The loading time is 10 seconds, while the sewing time for sixsided profile is 43 seconds and stacking time is 20 seconds.
Gantry robot load and sew ironing board covers
Profile sewing of ironing board covers is done using overlock machine in manual mode. The first option considered to sew ironing board cover was serger type off-the-shelf automat. Even in such an option, the manual loading of component was required. As the fabric- layer in this case is dimensionally stable, it was decided to automate the loading process using gantry robot. This work cell takes precut ironing board covers and loads and sews the fabric cover with a 1- needle, 3-thread overlock machine. The ironing board fabric component is loaded from a stack into a set position on the work surface in front of the gantry robot and overlock sewing head. The gantry style single beam robot positions the carrier plate on top of the fabric cover components and moves the cut components into the sewing head and around the circumference shape of the ironing board cover. The robot is synchronized with the overlock sewing head and moves the outer edge of the fabric components around the plate thus sewing the ironing board fabric completely around. The robot pauses briefly to trim the overlock thread, then moves the finished sewn fabric component to the rear of the machine and through a removal slot to the rear of the work surface and behind the sewing machine head dropping the panel into a receptacle underneath the machine’s work surface. The process continues repetitively after each finished component. While loading and unloading take 3 seconds each, the sewing takes 11 seconds to complete all sides of sewing and trimming together.
Standard automats offered by many sewing machine manufacturing companies are often not appropriate for a particular operation. Thus, the need for customized automats arises.
Frank Henderson, President, Henderson Sewing Machine
Dr. Prabir Jana, Professor, NIFT Delhi
Profile sewing of furniture fabric with Dacron
Gantry robot sewing ironing board covers