TRADITIONAL DIE CUTTING
Traditional wooden dies have proven to be an excellent solution for die cutting.
The mounting in the frame at the correct position and the positioning of the counter creasing lines is however quite time consuming. It is often required to under fill the die for correct cutting on the total surface depending on the machine and the mechanical condition. It requires operator skills for good results. The average make ready time is 45 minutes. The die cutting is often combined with a guillotine cut as a second operation in order to avoid nicks with the waste. This means in general that minimum another 30 minutes needs adding to the total process of getting a finished product. The standard cutting angle of a steel rule is 55°.
ADVANTAGE
- Cheap dies
DISADVANTAGES
- Complex mounting
- Skills required
- Lifetime limited
- Spacious storage
NEW TECHNOLOGY DIE CUTTING
The new technology dies have many similarities with the traditional ones, only the wooden base has been replaced by a thin metal layer allowing the mounting on a magnetic cylinder. The accuracy of the height of the cutting lines is within a few micron thus allowing a fixed gap between the magnetic cylinder and the anvil cylinder. Counter creasing lines can be mounted in the traditional way by using self-adhesive lines, which is as time consuming as the old system. Alternatively it is possible to use double magnetic cylinders with 2 flexible dies. Both dies are registered with pins and holes and are mounted simultaneously. The elimination of adjustments allow make ready times of a few minutes.
The dies are too complex to manufacture in-house and needs to be purchased at a die manufacturer. The process starts with a metal sheet with a photosensitive layer on top. The sheets is exposed with the image and developed afterwards. The exposed sheets is than passing en etching machine were the exposed material is removed until a basic thickness is achieved between 0,15 and 0,2 mm. The sheet with blunt lines is now going to a grinding machine for sharpening the lines. Depending on the application different cutting angles and types of finishing is possible. The cutting angle can vary between 40° and 110°.
Dies are available in different qualities:
- The standard quality is etched and sharpened only. These dies will last up to 300.000 revolutions, a perfect quality for regular use.
- The hardened die is suitable for standard products that are made in high volume, or repeated products, they last 2 to 3 times longer than the standard quality.
ADVANTAGES
- Simple mounting
- No special skills required
- Small storage space
- Long life
- Also available with counter crease lines
DISADVANTAGES
- Old dies become useless
DOUBLE DIES TECHNOLOGY
The double dies technology allows superfast make ready. The male and female dies are manufactured with highest accuracy and guarantee a perfect register between the two. The parameters of the creasing lines are virtually without limits. The thickness and depth of the male line can be chosen the same way as with traditional dies. The width of the counter lines depends on the material thickness of the board or paper that needs creasing. Double creasing lines at very short distance are no problem at all. Old fashioned quality with a setup time of 5 minutes
DIE CUTTING MACHINES
OFFLINE FLATBED DIE CUTTER
ADVANTAGES
- Cutting of thick materials
- Low investment
DISADVANTAGES
- Long set up time
- High waste
- Nicks required between product and waste
- Qualified operator required
- Simple cutting shapes
- Dangerous to operate
- Very slow
OFFLINE SEMI ROTARY DIE CUTTER
ADVANTAGES
- Low investment
- Also complex cutting shapes
DISADVANTAGES
- Long set up time
- High Waste
- Nicks required between product and waste
- Qualified operator required
- No thick materials
- Dangerous to operate
- Slow
INLINE ROTARY DIE CUTTING
ADVANTAGES
- Inline process
- Complex cutting shapes
- Safe to operate
DISADVANTAGES
- High hourly rate
- Long set up time
- High waste
- Nicks required between product and waste
- Dust in the printing process
- Qualified operator required
- Thickness of material limited
- Limited die life
OFFLINE ROTARY DIE CUTTER
ADVANTAGES
- Fast set up time
- Low waste
- No skilled operator required
- Complex cutting shapes
- Low hourly rate
- Very fast
- No tool operation
- Safe to operate
- Automatic stripping and blanking is possible
DISADVANTAGE
- Thickness of material limited to 600 microns
COSTS OF FLEXIBLE DIES
Flexible dies are known to be very expensive. This is however not true, comparing 2 totally different cutting shapes is in general causing the difference. With the traditional cutting method a second pass in the guillotine is used, eliminating a number of cutting lines, see example1. In the rotary die it is common to cut all the lines eliminating the guillotine cut, see example 2.
The difference is 1115 mm extra cutting line resulting in a higher price of the die!
Calculating the rotary die with the same file as the flatbed die will result in similar pricing with a difference of maximum 10% which is justified by the faster make ready and at this point we eliminated a complete finishing step in the entire process, the guillotine!
The counter creasing lines can be realised with self-adhesive lines that need manual cutting and positioning on the counter plate. This is very time consuming and takes in average 45 minutes. Using a counter die on a second magnetic cylinder can shorten this whole process. This increases the die cost a little but reduces your make ready time from average 45 minutes to 5 minutes! The 90 % time improvement and the elimination of a finishing step as mentioned before will mean a huge improvement on your productivity in the entire finishing department