General Technical Data
The number of impressions that you can expect to achieve with different types of dies is difficult to quantify. There are many factors which will determine how long a die will last:
• Type of stock (smooth or textured)
• Thickness of stock
• Amount of tonnage used on your press
• The press operator’s care when handling dies
• The press operator’s make-ready technique
• How many “up” the job is running
Like everything else with hot foil stamping and embossing, there is an element of trial and error on what will work best for a specific job.
Unlike offset printing where proofing can be difficult, time consuming and costly, proofing a hot foil printing die is usually very easy, quick and inexpensive. Test embossing may take longer than just printing but for a skilled operates, not much longer. Once the die has been made, you can easily mount it on your machine and produce a few test prints /proofs, embossing. If you don’t already hold them in stock, you can ask your foil and or substrate supplier for samples. You can test, evaluate, make changes and get final approval of the print and or embossing before commercial production. When quoting always allow for any unforeseen problems, proofing, proof checking, approval, delivery, specification changes, etc.
Ownership of Printing Die
Before the printing or embossing die is produced, it’s a good idea to look into who retains the property rights to the die. Occasionally the ownership of the die remains with the printer / converter, but usually the die is the property of the end customer. Though end customers may own the dies, it is the printer / converter who store them for the customers. This prevents customers losing or damaging the dies. Ensure the end customer has the rights to use any logo, illustrations, photos, and other images on the print / embossing job.
Hot foil printing and its associated processes are an environmentally safe and friendly print technology. It is a totally dry printing system, with no inks, solvents or vapours’ associated with it. The waste foil will biodegrade in a landfill within 3 to 12 months, and foil printed paper stock, can be easily recycled to create new recycled paper and board. The manufacturing facilities where the foil and substrates are made are mostly complaint with international environmental regulations and many exceed them.
Wear and Tear
When you suspect a die has become worn, compare a current output with samples from the beginning of the run or from a previous run, which used the same die. Reduced depth or clarity of the embossed or stamped image is a good indicator that the die is worn. Check the die itself for dull, rounded edges. Perform these checks after each production run if you plan to keep the die for a future run, and replace at the first signs of wear. Always keep samples from the beginning, middle and end of each production batch and mark them so they are easily identifiable. In that way you will be able to see the deteriorations of the die.
Surface Area Pressure
The pressure required to achieve optimum results depends on the size of the surface area being embossed or debossed. In most cases, subject to the design and substrate, the larger the square area the greater the pressure required to emboss or de-boss.
Length of Press Run
As a general rule of thumb, the longer the embossing run the greater the wear on the embossing die and counterforce. However, this is also very dependent on other external factors, and even the length of what is considered a long or short run is subject to each companies own interpretation. The abrasive characteristics of the substrate, the quality of the die and the counterforce, the correct alignment of the two, heat (where applicable), pressure etc. are some of the factors can reduce the metal embossing die. It is possible to achieved runs in the upper tens of thousands Magnesium. If you are using heat, and have a long print and or embossing run, Brass or Copper are recommended as the preferred choice of die manufacturing material.
Handling and Maintenance
The tolerances on your press should be checked regularly as poor tolerances will increase wear and decrease the life of your embossing dies. Poor tolerances will also increase your make ready and setup time. Prepare your make ready with great care as scratching and dents can easily occur. With careful handling, you can avoid damaging the embossing die and counterforce. Store your metal dies with care, a good way to store your dies is to first spray coat the metal dies with JetStream release spray or alternatively an aerosol based oil such as WD40, extra virgin olive oil, canola oil etc. Wipe any dripping oil off the die then place a thin plastic sheet in front of the image area such as a sheet of polyester then place in a thick clear self-seal (Ziploc) plastic bag. Label each pack correctly for easy identification, job name, number, customer details etc. Do not place dies one on top of the other. Place the dies in a strong plastic or metal box, upright as you would store documents in a filing cabinet. Most engraved or etched dies will corrode and it is important to test the different oils and surface treatments available to see which ones work best for you. When handled and stored properly you will be able to use the dies quickly with minimum surface cleaning.
Glue stick is available in most good stationary shops and the standard version available is a temporary adhesive but a permanent bond version is also available. It is this permanent bond version that can be used to bond layers of embossing board together and the boards to the counterforce mount. This dry glue stick adhesive is applied like a crayon, and when the layers of embossing board are compressed under pressure the adhesive creates a good bond between the layers. The layers of embossing boards can still be separated from the mounting plate / chase when hot. Most of the strength of a counterforce made with the glue stick is horizontal to the press’s force. The counterforce will not shift sideways. No “drying” time is required and a counterforce can be cut immediately after being glued. You may have to experiment with the different brands/makes of the glue stick before you find the right one for you.