These two features help printers of all kinds: commercial printers printing business cards, book printers setting up yearbook columns, or label printers setting up layouts in the most efficient way possible to make the most of their sheet.
In a modern, flexible, and dynamically automated prepress workflow, three areas are of significant importance:
- How does data get into the system and what relevant customer, processing, and billing information do I have to create?
- What needs to happen with(in) the file to get it print-ready; in case of errors, which corrections and modifications need to made?
- What do I need to do to set up the print layout in the most efficient way, in accordance with the printing system in use and dependence on the next steps (e.g., finishing)?
The term "nesting" comes into play especially for large format printing (but not only, as will be shown later). "Nesting" means the space-saving arrangement of smaller print elements on a larger sheet and is the exact opposite of tiling/paneling. In tiling/paneling, a print element is larger than the available print sheet format and is divided into several tiles and printed individually to be assembled afterward.
Let's concentrate on the topic of nesting.
Nesting - the theory
As mentioned earlier, nesting is a layout strategy that allows artwork to be placed on a sheet in such a way to utilize space optimally.
The combination and arrangement of different elements of artwork on a sheet has always been done by print shops, however, mostly manually. For instance, the front and back pages of a printed product were mounted on the same plate, regardless of whether it is a card or a brochure, to be run as “work and turn“ or “work and tumble.“ That way, since half of the number of printing plates are saved the production cost of the individual print product is lowered.
The good news is there is special software to get this done automatically: an algorithm evaluates all variables, analyzes the print jobs in the queue and determines the best combinations to maximize printed areas and eliminate as much sheet waste as possible.
Which variables must a software take into account during nesting?
The most important variables are a fixed size, as well as the substrate. Only print jobs on the same substrate can be ganged - and this applies equally to all print products.
This following also needs to be taken into account:
- the dimensions, i.e., the height and width of the print product,
- the print quantity/number of copies,
- the deadline for the order.
The simplest stage of nesting is arranging rectangles, or rectilinear shapes, as shown in the picture below:
In a next step, the ability to rotate the elements is being added, giving an additional way to save space:
Maximum optimization is achieved in the third stage, when placing smaller or differently shaped objects in the free areas:
The optimal solution then includes the components "free shapes" and "freely selectable rotation angle" and therefore consists of the largest possible number of print objects that can be placed on the print sheet. Here is an example of a fully automatically generated sheet from our Wide Format Automation Suite:
Different types of nesting
- Free-form nesting
The latter type of nesting is also known as free-form nesting. Here, the elements can be arranged completely freely in terms of shape and angle of rotation, but a corresponding processing device is needed.
Since nesting always is about positioning smaller print elements on a larger print sheet, the process of cutting these smaller print elements off the print sheet needs to be considered as well. In free-form nesting digital cutting systems are used. These cutting systems also obtain their cutting information from the nesting software. In the case of the Wide Format Automation Suite from OneVision, the integrated Cut-Line Manager generates a separate cut line file (either PDF or the file format the cutter requires) in accordance to the nested print file.
- Guillotine Nesting
Another form of nesting is guillotine nesting. The name says it all: it involves straight, continuous cuts as made by guillotine cutting machines. This type of nesting and cutting is used mainly in the production of posters or banners.
- Matrix Nesting
Matrix nesting combines different print jobs arranged on the substrate for gang-run printing. The print elements are optimally collected and output on the print sheet according to a given matrix or a given panel size.
Sub-nesting is mainly used when printing stickers. It is the repeated nesting of several previously nested print jobs. Stickers nested on individual smaller print sheets are nested again on larger print sheets
What needs to be considered during nesting concerning further processing?
As mentioned earlier, the finishing or cutting is an essential component of nesting, because it determines to which method the jobs need to be nested and what other time-saving technologies can be used.
Sometimes nesting is carried out according to the trim box (the final format of a PDF file). However, nesting is usually carried out based on the cut line, which is why cut line generation and detection is critical:
The nesting software needs to support the fully automated detection and – if not set up properly – correction of cut lines. For instance: cut lines might be dotted or incomplete, or multiple cut paths might need to be merged. A cut line manager doing all of this automatically, such as the one integrated in the Wide Format Automation Suite, comes in handy and saves much time.
Merging cut lines is also called "Common Line" technology. Based on the recognition of adjacent pixel values, it reduces cutting times drastically.
In a fully automated, modern, flexible and dynamic prepress workflow that uses nesting to create the most efficient way of getting multiple print jobs printed in the same print run, a nested print file and the associated cut line file with all identifying elements, such as barcodes and register marks, are generated simultaneously.
On the left side of the video you can see how individual artworks are nested fully automatically after copying them into a hotfolder, including pre-repairing the cutting lines (name or outline of the cutting line are fixed). The nesting creates a file for printing and a second file for the cutter. On the righthand side of the video this happens exactly the same, but manually. The disadvantages are mainly the downtime, but also the poor utilization of the substrate.
Advantages of fully automated nesting
Nesting as an element of setting up a print layout is therefore a very individual, powerful, and increasingly important tool. Especially in today's extremely competitive world of print services; one has to stand out, which again is only possible through advantages in quality, speed, and/or price.
By using a fully automated nesting tool, it has become a lot easier to score points, especially in the areas of speed and costs (and hence price,) to gain a decisive competitive advantage.