Pattern Engineering in Product Development Process

(As Seen In www.stitchworld.net – December, 2004)
Imagine this, you go to a tailor with fabric and YOUR proposed design, he / she measures you and make a garment for you, you try it on and the fit is terrible, no problems, the tailor agrees to do the alterations, pin and chalk the changes and you feel assured that finally you will get your garment the way you wanted. You go back after few days and try on the altered garment and all the changes you asked for were not there so you get another pinning, changes and fitting session. This goes on for three to four fittings and finally you walk off with a semi-satisfied look with a compromised fitting / looking garment.

Now let me ask a question, WILL YOU GO BACK TO THE SAME TAILOR? If the answer is no, now think, why should your customer come back to you when you really do not understand and value the time it takes for you (as a company) to get the final design approved. There is only a lose-lose situation, you lost either the customer or the time and money in developing, shipping again and again and your customer is now either preparing to drop the program or have to change plans in shipping that will effect total cost.

There are two things that essentially make this a lose-lose situation; Poor speed or time efficiency and poor accuracy or process efficiency. And these are primarily the two determinants of efficiency or success of the Product Developmental Process.

Before we address these issues, let us examine few basic requirements

  • Product development and approval time should be 15 days or less
  • Style/ fit iterations to a maximum of TWO iterations.

Tools at our disposal:

  • Technical knowledge and good technique will help at all levels.
  • Technology use will help in shortening the cycle time.
  • Systems and standardization is important towards the same end
 
Ram K. Sareen is currently Chief Executive Officer and Founder of Tukatech Inc., a CAD-CAM and unit productions systems company with world headquarters in Los Angeles and offices in New York, Vancouver, Toronto, Seoul, London, New Delhi, Bangalore and Milano. Earlier, he was Consultant and Regional Manager for Canada , Mexico and Western US for Gerber Technology (formerly known as GGT). He also held several manufacturing and consulting positions including President, R. Sareen & Associate, Executive Vice President, London Fog, Vice President, Torfeaco Industries, Vice President/General Manager, Work Wear Corporation. Ram had an all-pervading education in various streams like mechanical, industrial, production engineering, business and finance, materials management, inventory control, MRP and purchase management. Ram is a Board Member and Advisor with Los Angeles Trade Technical College, Fashion Institute of Design and Merchandising, Cal Poly Pamona, Santa Monica Fashion Institute, American Production and Inventory Control Society, and Coalition of Apparel Industries In California.
Ground Reality check: What we HAVE and may not recognise:
  • 85% of the Apparel Industry works without any CAD systems
  • Developing countries consider this to be a luxury and their investment in CAD systems is at a bare minimum. 15% of users are mostly in developed countries.
  • Almost ALL CAD users use these systems for Grading and Marker Making ONLY. Most of the patterns are done by hand.
  • Patterns are digitised only AFTER the order is received. Which means, typically the 1st pattern, sampling and development process is a manual, iterative and error-prone process.
  • Also, almost all pattern makers put in the minimum amount of effort on the FIRST SAMPLE which is demanded for costing/bidding purposes.
  • Each pattern maker can and will interpret the Spec Pack differently, thus creating a pattern-sample that MUST BE REVISED. So, with the way the existing process is devised, multiple iterations MUST and will happen.
  • It takes almost three to four samples before approvals, thus creating frustrations, higher cost of development and additional TIME that none of us have.
  • Most of the pattern makers in exporting countries do not have the skills and knowledge to make ENGINEERED PATTERNS.
  • Amount and quality of information into the developmental may be inadequate and non-standardised, thereby causing further confusion in the process.
  • It is extremely difficult to give all instructions for first patterns/samples by designers; they are not trained to COMMUNICATE effectively to remote locations. Most of the designers are trained to work with in-house, trained pattern makers who work with them under one roof for many years, sharing information such as fit, size, and the designer's language.


Drill Holes for matching

Pattern Engineering and Standardization

A pattern is a map!

Can you imagine a bad map that will require you to ask for clarifications on every turn? You may never get to your destination or if you finally do get there, it may be too late.

And like landmarks for turns and stops on maps, an engineered pattern should have the correct notches, drill holes for placements of pockets, and engineered seams with proper corners etc that reflect instructions graders, marker makers, spreaders, cutters and sewers are supposed to follow.

It is extremely important to STANDARDISE the process and the instructions that go along with it. It's also important to train all the readers and users of this 'map' to read the same information in the map that was put in there by the maker. And standardisation along with organisation-wide training adds tremendously to the reduction of errors and increase in efficiency.

A step towards adopting 'best practices'

Implementation of computerisation requires an unshakable commitment all the way from the top. That's because this process essentially involves "change", which is not easy - especially when it comes to breaking comfort zones of bad habits and inefficiency. But one must realise, sooner or later you will have to, there really is no way out!!!

Some essentials those are easy to overlook:

  • You need to make sure the operators are absolutely trained, no matter what it costs, the benefits of accuracy and efficiency are too numerous to compromise.
  • Make a good library of blocks.
  • Keep the history of each style with number of attempts and changes.
  • Those with minimum changes should be kept to RE-USE, may be that can be developed as a block.
  • Make sure there is ZERO tolerance in patterns for fitting at Pattern Making level, tolerances are for cutting and sewing only (no excuse to really use tolerances).
  • All adjustments of shrinkage should be done after the sample fittings are complete (prior to any washing or treatments). All patterns must be 100% accurate without any shrinkage allowances. The original stored pattern should be adjusted for fabrics without losing the original patterns.
  • The adjustments for shrinkages, etc., should be done to NET PATTERNS without any seam allowances, the seams do not grow. The CAD system must have ability to change part of the pattern instead of uniform adjustment.
  • All Grading must be applied to sew points instead of cut lines.
  • Engineering the seams with proper corners will bring in better fabric utilisation and reduce sewing time while giving better, consistence quality.



Automatic Shrinkage addition


Superior V notches


Notches at the bottom hem area


Grading: A science

Importance of notches

For the lay person, notches are small markings on the perimeter of the pattern that are intended to convey sewing and folding instructions to the operator. These need to cut in or cut out, as the case may be, to form an incision into the perimeter in the seam allowance area.

  • Notches must be used for all straight seams longer than 16 inches, and on seams like arm holes, collars, waistbands, longer than 3 inches.
  • Each hem should be identified by a set of notches, where to fold and how to fold. For example, if we are doing a hem on a pant with half inch fold and then a one and a half inch hem, there should be two notches showing both operations.
  • The type of notches will also determine many things, e.g. two notches on the back armhole corresponding to two notches at the back side of sleeve's cap will always help in aligning back and front of sleeve at exact place.
  • There are many kinds of notches - for example the slit notch, T, V, U-box, castle notches are the most commonly offered. But the most commonly used notch is the slit notch. Although the most commonly used one, it is absolutely the WRONG notch form as it defeats the purpose of engineering the pattern. There are too many disadvantages to the slit notch. In manual cutting, cutters can cut them too deep, away from exact location and the sewers have to use three to five extra motions of flicking the edge in identifying the notch.
  • It is our strong recommendation to only use V-NOTCH. It is easy to cut and can be identified visibly, saving a lot of sewing time. The research shows as much as 12% increase but a minimum is 4% productivity is attainable just by having V-Notches.
  • V-Notch can be inside or outside, in case of any KNITS, only outside notches should be used whereas other fabrics can have inside V Notches.
  • The size of notch is also a very important factor. There are two considerations, the size of notch and the ratio of width and depth of V-Notch. 100% nylon Lycra for swimwear can use as small as 1/32 "depth where as a loosely knitted sweater can be as deep as half inch.
  • When we consider the ratio of depth and width, we must make sure the width is twice the amount as depth, for example, a 1/8th inch deep notch must be 1/4th inch wide. It is very important for a numerical Control Cutter to cut the V-Notch with having to stop and lift and plunge at the notch. A 135° angle between the axes will allow the cutter to cut without stopping.

The essential components of technology are an easy to use, intelligent and progressive CAD system, and that of technique are standardi-sation, systems and skill training. With a good mix of technology and technique, the twin targets of increasing speed and accuracy of process can be achieved.

An Art or A Science?

Pattern making may be an art, but marker making and grading are very logical and scientific - and if I may say, mechanical! CAD systems can be very easily trained these aspects of the process, whereby

  • increasing efficiency and productivity
  • relieving the pattern maker to concentrate on better and more accurate patterns first time round
  • removing the repetitiveness of this task.

Although science it may be, but believe me, it isn't rocket science.