Greater flexibility in pattern designing, grading and marking, reduction in waste %, increase in quality of cutting room and reduction in sample making time are some of the benefits of application of CAD/CAM system in garment manufacturing, asserts V Parthasarathi.
Textiles and computers are genetically related. It is so because computers are believed to be from punch card system used in jacquard weaving machine. In the environment, where computer is a normal need for every industry, textile industry is no exception. Textile companies that continue to excel in today's competitive business climate understand the importance of computers.
After more than a decade of computer revolution, some textile corporates in India have understood the dire need of the IT EVOLUTION. Most of the Indian industries have not come under the influence of this evolution. The ability to withstand the revolution in science for several decades has enabled computers to be used very much as an effective tool in information technology and communication fields.
In international and domestic boom in the last few years, the fashion designing industry is riding the crest of wave of success. Fashion designers are mushrooming, their earnings are rising, and promotions are coming at a very faster rate. The direct employment in the fashion sector is running into millions. Textiles are India's single largest foreign exchange earner contributing to about one third of total export. In addition India's share in the world market with regard to leather are significant. It is certain that job and business opportunities in the fashion trade are likely to grow at higher rates.
CAD & CAM are a part of computer technology. Increased competitiveness and demand for shorter lead times has lead to the slow, but definite proliferation of CAD/CAM systems in India, even in the textile and apparel industry. Traditional working methods are being phased out in favour of futuristic and globally prevalent methods of working. The evolution in technology has been influenced by the proposition to reduce cost and lead time, to increase interactivity between what is real and virtual and to enhance one's creative abilities. This article is a part of the author's research work -- a comparison of CAD/CAM & Manual systems in garment manufacturing -- reveals the advantage of CAD/CAM system over manual approach in the garment industry.
Experimental procedure and results
In order to assess the improvement in productivity and quality, CAD/CAM manufacturing is compared to Manual manufacturing processes. Various work processes followed in CAD/CAM (Unit C) and MANUAL (Unit M) are discussed and the results are provided below.
The following are the key areas where the author makes his observation:
Time required in pattern designing, grading, pattern alteration.
Waste percentage in cutting room.
Quality of cutting.
Time taken for sample making.
Lead time for production.
A common sort, which was processed in both units was considered for the observation, and so it was decided to compare men's shirt (size L) (casual wear, long sleeve) with the following dimension:
Results of the experiment
Time required in pattern designing, grading, pattern alteration:
Both in unit C and unit M the time required for preparing a sort of the above said dimension was observed. Particular time required for each operation was observed, by using the stopwatch and six sets of reading were taken. The average time taken is mentioned above.
Time taken for the following activities in CAD/CAM System:
Time taken for the following activities in manual system:
Comparison between the unit C & unit M:
Waste percentage in cutting operation
In order to determine waste percentage in both manual and CAD/CAM system, following observations were made. The fabric consumption for 500 shirts was determined by taking the dimension of centre size, ie, L the area of front, back and sleeve part of shirt is taken for 'L' size shirt. The fabric required is 2.15 metres without tolerance. With tolerance, the fabric required is 2.4 metres.
Total no of shirts observed = 500
Fabric required for 500 shirts = 500 X 2.42
= 1209.06 mts
= 1210 mts
No of shirts made out from 1210 metres with (90% fabric realisation) in CAD/CAM system:
= (1210 X 90) 1100
= 1089 mts.
No of shirts = 450
No of shirts made out from 1210 metres with (80% fabric realisation) in MANUAL system:
= (1210 X 80) /100
= 968 mts
No of shirts - 403
This exhibits a fabric saving of 10% by CAD/CAM system over MANUAL system as shown by the following Table:
Quality of cutting:
In order to determine the quality of cutting, 10 rolls from 100 rolls of cloth were received both in cutting and sewing department. It was observed every day. Amount of rejected garment was collected taking into consideration the following quality particulars:
All components cut on the correct grain lines and in accordance with the pile direction of the fabric.
Dimensionally accurate garment that do not exceed specified tolerance.
All materials spread at correct tension to prevent under- or over-sized component and/or garment.
Consistent and accurate marking.
Quality of cutting in Unit C
Quality of cutting in UNIT M
Time taken for sample making
Sample making is a continuous process in clothing industry during the development of a new product. The following steps are involved in the process:
1. New material, design and processes have to be identified.
2. The production of garment patterns has to be altered and perfected to rectify faults during making up of the sample.
3. At the sample stage, the quantities of fabric and trimming are established and quick costing is made.
4. The finished garment sample has to undergo scrutiny to evaluate whether they fit in the viability of producing the garment.
In order to determine sample-making time, the author followed the process of sample making in both units. The following was the time taken:
Productivity of Unit C & Unit M was obtained by taking into account per day production and monthly production capacity when similar sorts of garment were produced. The number of finished garment obtained each day as observed were as follows:
Per day productivity (Unit C) = 15,856 pieces
Per day productivity (Unit M) = 4,013 pieces
Lead time for production:
A typical product development cycle of a garment industry consists of the following steps:
One has to compare lead-time of garment, taking into consideration the above-mentioned procedure in both Unit C and Unit M. The observed time required for each stage of procedure, details of the time taken in the two units are as follows:
Lead time for Unit C = 39 Days
Lead time for Unit M = 55 Days
Results and discussion
Time reduction in CAD for pattern designing, grading and marking:
As mentioned in the experimental procedure, the CAD/CAM system takes 36.81 minutes, whereas MANUAL system takes 350 minutes. By this, one can say that the MANUAL system takes nearly 10 times of the time taken by the CAD/CAM system. MANUAL system takes comparatively much more time because of: New Pattern Creation, Measurement of Marking, Pattern Grading, Marker Planning, Sketching, etc. These activities are done only by an individual and so the time taken depends on the skill of the person.
TUKA DESIGN Software in Unit C uses powerful CAD tools to draft pattern, which gives them unlimited saving in time compared to the manual method used in the Unit M. A previously constructed pattern in the system can be used as the base pattern for a new style.
Waste percentage in cutting room:
With the use of CAD/CAM system through experimental procedure it can be observed that about 10% of material is saved, as compared to the manual method. This is achieved due to the following reason:
1. Do not cut until a trial layout shows the best location for all pieces within minimum length of cloth.
2. Place all pattern pieces close together, so as to reduce the waste % of the cloth.
3. Spreading waste is considerably reduced due to correct length spreading, remnants are also reduced by TUKA SPREAD machine. Since the CAD/CAM system has mathematical algorithms in-built in CAD System, this ensures the most economical use of material.
Quality of cutting:
As mentioned in the experimental procedure, the CAD/CAM system has 0.38% of the waste reduction whereas MANUAL System has l.03%. This shows that quality is very good in CAD/CAM because, the spreading of fabric is done by the TUKA spreading machine, where the 'Photo Electric Guides' are used to maintain uniform tension in the fabric, so that creases in the fabric is avoided during spreading, whereas in the MANUAL system it is unavoidable. Tuka Tech Cutter has an automatic sharpening device for knife, and raw-edge of the fabric do not fray out; As in manual cutting, which happens due to imperfect sharpening of knife.
Time taken for sample making:
In Unit C using TUKA CAD Software and ENCAD: CROMA 24, Plotter it is easy to make sample. Sample making time was observed to be around 5 days for Unit C and about 10 days for Unit M. The CAD software helps designer of pattern to alter it easily in quick time. This is mainly due to collection planning CAD Software, which helps in:
Developing the variation from core design.
Trying the same cloth on a number of different designs.
Modifying some of the ideas to make the garment more acceptable to a wider range of customer.
With this flexible CAD System and plotte,r Unit C is able to reduce 50% of sample making time compared to Unit M.
As mentioned in the experimental procedure, the CAD/CAM System has a production of 15,856 pieces/day whereas the MANUAL system has 4,013 pieces/day.
As the CAD/CAM process requires transfer of information or data for marker planning via floppy, the process is simplified and the production is increased.
In CAD/CAM system, the capacity of the cutting room has to deal with a mixture of different types of cloth. Whereas in MANUAL system it is highly impossible to work with mixture of different types of cloth.
With such a flexible cutting room facilities available, Unit C must have higher production rates compared with Unit M member together with very high cutting speed.
Lead time for production:
Lead-time of garment production is the number of days required to finish a garment from sample stage to finished garment. Lead-time of Unit C is about 39 days and of Unit M is around 55 days. Due to faster sample production, highly saved time and higher productivity combined with flexibility, CAD system Unit C is more acceptable.
Unit C is using CAD/CAM system for garment manufacturing. There is a significant improvement in productivity, and quality, leading to time reduction. The following are the some of the benefits of CAD/CAM that the author observed from the Unit C.
Reduction in pattern designing, grading, and pattern alteration time by around 90%. The time required for Unit C is 36.81 minutes and for line M is about 350 minutes.
Greater flexibility in pattern designing, grading and marking
Reduction in waste% of up to 10%.
Increasing quality of cutting room by around 50%.
Reduction in sample making time by 60%.
Unit C ---- 5 days
Unit M ---- 10 days
Increasing monthly productivity by 75%.
Productivity/day (Unit C) -15,856
Productivity/day (Unit M) - 4,013
Reduction in lead-time up to 45 days.
Unit C ----- 39 days
Unit M ---- 55 days
5. Gerry C: Introduction to Clothing Manufacture, Blackwell Science (London) 1991.
6. Pooja Gupta: Evolution of Design Solutions in the Textile and Apparel Industry, Clothesline, Vol 14.
Note: For detailed version of this article please refer the print version of The Indian Textile Journal February 2010 issue.
Department of Fashion Technology
PSG College of Technology, Coimbatore 641 004.