One of the essential parts of the folding carton packaging manufacturing process is proper die-cutting of the printed cartons. Depending on the substrate, printing technology, dimensions, and job run length, different die cutters can be used.
Die-cutters in review
The following is a review of available die cutters for folding cartons from some well-known manufacturers.
Bobst Flat Bed Die-Cutters
The BOBST flatbed die-cutter line ranges from press widths of 30” to 82”. They are also known as cutter-creasers or punching machines. Just to name a few:
The SP 162 CER - Autoplaten® die-cutter is recommended for long runs and continuous operation. It delivers fully stripped, separated, stacked, and batch counted cartons. It can cut 7,000 sheets per hour, with a pressure of 715 tons.
On the other end, the NOVACUT 106 - Autoplaten® die-cutter is the entry-level machine, cutting all types of products and materials, up to 29.125 x 41.75 in sheet size. It runs at 8,000 sheets per hour using a 286-ton force.
Bernal Rotary Cutter Creasers
Specialized in rotary die cutting, Bernal offers high-speed, continuous web converting systems that can fit web widths from 1 inch to 110 inches.
Their rotary die cutters work with flexographic, gravure and offset presses. They offer both mechanical and electronic cutter drives. Rotary dies can cut, sheet, form, emboss, vacuum transfer, heat seal and ultrasonic seal.
Highcon Digital Die Cutters
The laser die-cutting process saves on tooling development time and costs. It allows for shorter production runs, prototyping, and changes. The Highcon Beam is their top-of-the-line digital cutting and creasing machine, cutting up to 5,000 B1 / 40 in sheets per hour. The Highcon Pulse is a digital die-cutter that handles up to B2 / 29 in cartons, at a speed of 2,000 sheets per hour.
Heidelberg Die Cutters for Folding Cartons
Heidelberg has a full line of die cutters. Their beginner model is the Easymatrix 106 C/CS die-cutting machine. It can process 7,700 sheets per hour, up to the 106 format. It can cut and crease materials from 90 to 2,000 g/m². It is a reliable machine if blanking is not required. It can perform die-cutting and embossing, to service most commercial client needs. Many tasks are automated, which simplifies workflow and prevents errors.
Their highest performance model is the Powermatrix 106 CSB.
Its optical register system regulates the sheet position in the gripper system, assuring perfect alignment between cutting tools and the printed piece. It works faster and minimizes waste. You can also remove a sheet on the fly while the job is done.
Marbach Rotary and Flat Die Cutters
Marbach develops custom dies, machinery and suppliers for several applications including paperboard folding cartons. They offer rotary die cutters (which also crease and emboss), for high volume jobs, like cigarette boxes, pharmaceutical cartons or liquid packaging, claiming a running accuracy less than 2 μm.
They also have several flatbed die cutting technologies and materials. The Multiplex is their standard line, made from high-quality wood, very rigid, stable and durable. Their Greenplate line is made of 30% birchwood and 70% recycled secondary wood sources. The Solidplate consists of a Greenplate core between 2 steel plates, adding more dimensional stability, for a cost-effective price. The Duramar line is based on fiber-reinforced plastics and steel, with high durability and register accuracy.
Rotary Pressure Cutting Dies
Rotometrics manufactures a system that uses two flexible dies running on special magnetic cylinders to convert folding cartons, pizza boxes or liquid packaging solutions, from medium to long runs. Maximum plate size is: 35” x 35” managing up to 660-micron caliper board.
Molded Rotary Die Cutting
WPM produces molded cutting dies and related custom machinery, for inline and offline die cutting. The offer standard and magnetic die cylinders. Registration accuracy can be controlled in 0.0001" increments, with a motorized mechanism. As regards the cutting dies in themselves, their TruCut converting dies are a steel-to-steel cutting, creasing and perforating solution. They also provide flexible magnetic dies and rotary soft anvil dies - a more stable alternative to wood substrate cutting dies.
Insignia Flexible Die Cutters
The Insignia die cutter handles from 50 lb cover weight stock to a 30 pt card stock.
Insignia5 die cutters accept flexible dies which are mounted into a recessed scribe line that locks the die parallel with to the cylinder. Flexible dies are attached to cylinders just by simple magnetism.
Insignia6 die cutters use an external pin system, for more precise alignment of the dying tools.
Insignia die cutting machines can exert up to 3,000lbs of force onto the upper magnetic cutting cylinder to warrant that the flexible dies can properly cut the sheet.
About the die-cutting process in folding cartons
Die-cutting and creasing are usually done together in flat-bed die-cutting machines. Flatbed dies can be off-line or in-line with the printing press. Except for cigarette packaging, other folding cartons are cut and creased offline.
Whether it is Solid Bleached Board, Folding Box Board or White Lined Chipboard, every paper grade needs special settings for proper die-cutting and creasing. The main parameters to bear in mind are grain direction, thickness, moisture content and surface treatment. The sheet or web should keep its integrity while being transferred to the stripping station, and on the other hand, the blanks should be easy to strip from the waste part.
Traditional die cutters versus laser die-cutting
As regards tooling, there are performance and quality differences between traditional and laser die-cutting.
Traditional die-cutting involves cutting and creasing rules. The die impacts the paperboard, which is placed on the make-ready. Then the cut sheet is withdrawn, and the cycle starts over.
Laser cutting allows for very precise designs. First, the original is etched on a copper template. Then the laser beam scans the area and vaporizes the board through the etched (design) areas.
The advantages of the laser method are 50% less setup time, high accuracy (as accurate as the CAD program allows), less need for press tuning and decreasing tooling costs. The downside is that the total throughput is slower.
The traditional die-cutting process
The first part of the system is the feeder: sheets are extracted from a pile and moved into the machine in-feed, either by suction or pushing.
The in-feed mechanism picks one sheet and makes it match the cutting tools.
The platen area is where the cutting die impacts the sheet, with the cutting plate behind it. Depending on the depth and sharpness of the die design, cuts, creases or embossing are achieved.
When the sheet arrives in the stripping section, internal, side and rear scrap is removed using specific tools.
Finally, the individual cartons are pushed away and collected onto piles of flat blanks. Alternatively, if the cartons are not fully separated, they are delivered attached to each other by nicks (small uncut pieces of board on the sheet).
Impacts of cutting and creasing in design and estimating
In the design stage, simplicity in shapes helps prevent production setbacks. Working knowledge of how the cutting process takes place is an advantage for the packaging designer.
Once the design is approved, the final quotation should consider how it will fit the sheets and how the cutting work will be done. You should also imagine how the sheet will travel along the process and if there may be chances of parts of the design getting trapped, wrongly cut or misfed. This can affect workload, quality, and budget.