A vitally important part of your tech pack are the technical drawings. Here's what you must know to get them right.
We've talked a bit about technical packages ("tech packs") and you should know that they are step 1 in the production process. If you are developing your product with AC Ashworth & Co., we can draft your patterns along with the tech packs, even if you don't have them quite ready yet. The tech pack is compiled of many parts, and it is basically a blueprint of your design, including everything your factory needs to know to put your garment together.
In this segment, we will talk about one component of the tech pack, and that is the technical sketch. When you designed your garment, you may have made a fashion sketch, or collected a picture for inspiration. It's important to know how the technical drawing differs from your fashion sketch.
A technical sketch is a flat drawing that shows the details needed to make your garment. Let me emphasize flat. The first thing that will distinguish your technical drawing from your fashion sketch is that there should be no depth, or volumetric detail.
While a fashion illustration can be used to make a technical drawing, the tech drawing must look as it would stretched out flat on a table, not how it would look on the body.
Here's an example of a flat tech drawing :
While other sketches within your tech pack may include colorways, the technical drawing should not.
There should always be a front & back view. The drawing should be 100% accurate to the design, and include all details- trim, zippers, buttons, seams and stitches.
There should be no shadows or extra lines.
These drawings will be used for the pattern specification sheet, a document that includes the measurements for each dimension.
I hope that this quick article on technical sketches has been helpful. If you have any questions or comments, let us know in the section below.
Here's something you might be asked by your pattern maker, factory, or consultant... "What stitches do you want used in your design?"
This is an important question because it effects many aspects of your design, from strength, durability, and usefulness to look and cost. If you don't have a clue about stitches, you're in the right place. And even if you do, read through to the end for some great links to some excellent tools that will help you develop your tech packs even more efficiently!
Due to the comprehensive work of ISO (International Organization for Standardization), the worldÔÇÖs largest developer of voluntary International Standards, we can use a classification of stitches that is universally understood and communicated-- using the ISO 4915 Stitch Matrix. WAIT! Don't leave.....it gets better, honest. Founded in 1947, ISO has published 23,613 International Standards covering almost all aspects of technology and business, and the standard referenced above can be really handy for you in making your tech packs. In fact, it's essential. If you got bored just now, and noticed that the acronym ISO is switched a little...(why isn't it IOS? After all, they were around waaay before Apple!), your observation is correct. The truth is, What? No, wait... seriously, don't leave, I will get to talking about what the stitches are, I really will. The International Organization for Standardization is headquartered in Geneva, Switzerland, and exists by a different name in every language. Rather than having several acronyms in different languages, they chose ISO as its abbreviated name. The word ISO is derived from a Greek word isos meaning equal. Aaaand, back to the topic.
So let's say you are designing an article of clothing, and you have it all sketched out, you know how it should look, and even the fabric you want. Different fabrics call for different types of stitches based on what you expect from it in terms of stretching, stability, and the type of fabric you're using. It is normal for a single garment to be comprised of many stitch types.
Stitches are broken into six main classes :
Let's take a quick look at the most common stitches within these classes, that you will likely need to know (and choose from) as you develop your product.
103 is a chain stitch that is commonly used in a blind hem. There are no visible stitches on the face side, and a chain pattern is visible on the underside. It's formed by a thread carried by a single, curved needle. AC Ashworth & Company uses the blind hemmer on our fine dresses and menswear. When designating this stitch, your production team will need to know SPI (stitches per inch) and whether or not you want a skipped stitch in between.
301 is the most common of all construction stitches. It's a straight stitch formed by a single needle and bobbin; used for seaming and top stitching. It is a strong stitch that will not stretch. You'll be asked for the SPI.
304 is a lockstitch, but in a zig-zag formation. It is used on areas that must be strong, but also stretch; such as intimate apparel and athletic wear. A special lock stitch machine is also used to create rectangular button holes. You will need to specify the width ("throw"), and the length (density), which is measured in SPI. The top and underside look similar, but are not identical.
401 is a single chainstitch. This stitch is used in combination with an overedge (see 516) to form a safety stitch in wovens, to seam and overedge in one step. Because of its excellent elasticity, it is often used in fabrics that must stretch. Used alone, it is a perfect choice for a knit or spandex seam, when the raw edges must be pressed open ( and therefore should not be serged together) such as V necks and backs. It is not quite as secure as a lockstitch, and is somewhat bulky in comparison. When choosing this stitch, specify SPI.
406 & 407 are double and triple needle bottom cover stitches. These stitches are great for hemming and coverstitching knits, and making belt loops. Most home (portable) cover stitch machines have these features. You will need to specify the needle spacing and SPI.
408 is a coverstitch with double chain stitches on the underside, comparatively the opposite of seam 406. You've probably seen this stitch connecting your pocket to the facing in jeans or chino pants. This 5-thread stitch also makes durable, flexible decorative seams in sportswear. The machines that make this stitch have a fixed width and SPI; if you are using this stitch to seam sportswear, your pattern must be cut accordingly.
503 is a simple overedge stitch, using 2 threads--one needle, and one looper. Most commonly referred to as "serging" this stitch is unsuitable for any seam or stress-bearing function. It is a good choice for finishing raw edges in unlined garments. Specify the width bite and SPI.
504 is a three-thread overedge stitch. More durable than 503, it is used to finish heavier and more fray-prone fabrics such as linen and wool. It can be used in seaming lightweight knits if little seam stress is expected. This stitch will add a bit more bulk, so is not the first choice for sheers and lightweight edge finishing. As with 504, specify width bite and SPI.
505 has the same look and configuration as 504. The difference lies in the tension: the lower looper thread is tighter, and the needle thread is looser in this stitch. Uses are the same as 504. Specify width bite and SPI.
512 & 514 are both 2-needle, 4 thread configurations. Stitch 512 presents as a mock safety stitch, providing a flexible seam and overedge finish for medium weight knits and light to medium wovens. Stitch 514 has an extended loop, which places the needle threads inside the stitching. Specify SPI.
516 is a 5-thread safety stitch perfect for seaming and finishing midweight to heavy knits and wovens. It is formed by combining a chain stitch and an overedge stitch. Plan seam allowances for the width of this stitch; and be sure the design does not require the seams to be pressed open. This stitch will make impressions on thinner fabrics, and is more expensive to process due to thread consumption. When properly applied, 516 remains as an industry standard for strong, flexible seams and durability. Specify needle spacing bite, and SPI.
Moving on to the 600 class, we have the 2, 3, and 4 needle cover stitches. These stitches add a decorative touch to binding, lap seams, and coverseams in sportswear, underwear and fleece. Specify needle spacing for 602 & 605, and SPI for all.
I hope this has been helpful in planning your designs! As always, if you have questions or need help in planning your line, contact us today!
Lastly, here's a place to download a quick-reference list of all the common stitch class types. http://www.amefird.com/wp-content/uploads/2009/10/Stitch-Type-Matrix.pdf
I found it helpful to print the matrix, laminate, and hang on a hook near my work area.
Another great reference tool I use often is a book called "101 Seams" by ABC Seams. While the numerical designations are different from ISO, the book does an excellent job of explaining many types of seams and what their best uses are. You can purchase or download a copy here https://abcseams.com/products/book-101-sewing-seams/
And lastly, as you prepare your costing sheets and plan for how much thread you need for your production run, these thread consumption calculating spreasheets ("anacalc") will save you time and frustration! Just plug in the information from your pattern specification sheet and it does all the hard work for you! http://www.amefird.com/technical-tools/thread-consumption/anecalc/
All the best!