This article may be useful for those API customers and software developers who come from printing technology background and are not familiar with embroidery.
The fundamental nature of embroidery fonts creates some limitations that are inherent to the embroidery technology.
Scaling Embroidery Fonts
The Wilcom API calls use Embroidery Fonts that are manually digitized for the best stitching quality.
Each font was tested and Wilcom recommends a MINIMUM and MAXIMUM size within which the letters provide excellent stitch quality.
Let’s see what happens if we scale down the letters below the recommended minimum size (for example down to 3mm):
You can see that the result is unacceptable.
Please note that if this was a printed font, it would be still ok the outline vectors of the letters are fine.
Let’s see what happens if we scale this up too far (in this case to over 60 mm)
We can see that the stitches cannot cover the width of the columns, the Wilcom software automatically applies a function, called AutoSplit, so at least the area can be stitched but it is not considered good quality. This is because the maximum embroidery stitch on most machines is about 12.5 mm. But Satin Stitch that is typically the proper stitch type for Lettering is not considered good quality above 7 mm. (This is why AutoSplit get activated, once the column width is over 7mm.)
You may also notice the Automatic Shortening feature working here because if every stitch would reach the inner side of the sharp corner in the letter “e”, the too many and too close needle penetrations would cut the fabric or break the needle.
Closest Point Connection – Trimming The Thread
In the previous pictures we did not show an important production issue: how the thread connects from one letter to the next?
What you see in this picture is the stitch connection between the letters “b” and “c”. First, this font was digitized with closest point connection, therefore the software works out the optimum stitch sequence to exit from “b” and enter “c” at the closest points between the two. This makes the connecting stitches the shortest. Still, if we enlarged the letters to extreme size, as you can see, there is a significant gap opening between the letters. So, the connecting stitch would be very visible. In such case the Automatic (Thread) Trim function gets activated (marked with the “∆” sign), which makes the embroidery machine to cut the thread between the letter if the distance is larger than a pre-set value, which you can see on the right, is set to 2 mm. Still, you need to consider that each time the machine trims you lose about 70 stitches worth of production run time on the machine. Expert digitizers always try to minimise the number of trims in embroidery designs, to save costs in embroidery production.
What Does This Mean for API Calls?
When you are making API calls where you allow your website visitor to scale designs or Lettering, and you capture the size parameters from your front end graphic design software, you need to implement limitations that are suitable for the embroidery technology.