Frequently Asked Questions About Rotary Hot Stamp Cylinders
Hot stamp registration has been and will continue to haunt even the best press operator. There are two elements involved in the manufacturing process that determines how well your hot stamp cylinders line up. The first one is correct heat reduction. You must be exact in telling your supplier how hot you intend to run your cylinder. An ambient (room temp) temperature difference of 10 degrees will alter the outside diameter by a few tenths of a thousandths of an inch.
The other reason for registration problems is the method by which your supplier captures the art image. If they are using a scanner to capture the image, you risk skewed compositions. The thickness of the film, and the inherent problems of getting the film perfectly lined up on the flatbed, will always alter the image slightly. At Precision Hot Stamp, we only use digital files. We accept PC or Mac files, we have both, and the difference is incredible. We have actually created a copy of each and produced an overlay comparison, and were shocked to see the difference. You may wish to try this on your own.
Depending on the type of hot stamp unit you are using, you must apply varying amounts of pressure. This is why cylinders tend to loose their crispness. The top edges of the image actually start to round off, leaving you with a seemingly adequate engraving, but a less than focused image. You can bring that image back to life by purchasing a Gesswein super-fine ruby polishing bench stone. These are worth their weight in gold. You simply polish the images, in the direction of the web, until the surface of the brass is polished down, and you will get your sharp edges back. Another way is to take your cylinder to a competent machine shop and instruct them to skim cut a half a thousandths off the diameter. This however, is a last resort, and is not recommended. At Precision Hot Stamp, we extend the shelf life of our cylinders by making them with a higher grade of brass. Most suppliers use 360 "free-turning" brass, which is softer. We use 377 European brass. Because of the hazardous material constraints in Europe, it is the only available brass allowed by law. It has less lead in it, so it is more brittle than 360. And it allows us to engrave infinitely finer details. Out dies last longer because we use the best brass available.
This is typical of a cylinder that is out of concentricity. Here's what you can do to correct it. First, it is recommended that you have bearer bars put on the cylinder. Bearer bars allow you to put pressure on the cylinder without it bouncing. Bouncing occurs when you have gaps between the images around. The further in you place the bearer bars toward the image the better off you are. Everyone has a preference. Gears are another reason for lost concentricity. At Precision Hot Stamp, we instruct our customers to tighten the gear to the cylinder after it is put onto the heater shaft. By doing this, you are picking up the concentricity of the heater shaft. Although we use precision made templates to drill our bolt holes for the gear, it is nearly impossible to make them perfect, so tightening them after the fact will align the gear to the cylinder.
The old saying "you get what you pay for" certainly applies to hot stamp cylinders as they are made by skilled craftsmen, using very expensive equipment, and the latest technology. At least, that's what you expect. CNC engraved cylinders cost more than photo etched cylinders because they are simply better. Better definition, tighter registration, and the capacity to make smaller point type all single out engraved dies as the better method of the two. At Precision Hot Stamp, we have gained the reputation of producing high quality cylinders for less than the competition. The reasons are simple. First, because it's the only thing we do. Second, our production approach is streamlined so we can receive an art file and put it on the CNC machine in a matter of minutes. Most suppliers charge upwards to $100 an hour to "clean up" the artwork once they scan it. This involves putting the corners back in place (few films actually produce sharp corners) and smoothing out the radiuses. We have invested in 2 items that remove this step entirely. We have a Windows NT server with 1GB of memory, and it does nothing but run a unique custom made conversion program that will take an image file, received via Email, and convert it to the CNC language. It can convert a moderately sized, fully stepped project in about 30 minutes. To scan that same project, and rework the art to perfection can take 4 to 8 hours. Thirty words on a label can take up to 5 hours of "clean-up" time. So you see, we save time in production, which in turn saves our customers money. We have recently initiated a "Core Credit" program where we take in your old unusable cylinders, inventory them, and then turn them down to the nearest tooth size, and provide a credit of $100 to $200. We also maintain a huge inventory of "blanks"; pre-made cylinders for the most popular press and tooth sizes, ready to put on the engraving machine. Once the CNC is running, with automatic tool changing, we put a job on at night, and it engraves on its own, unattended. So you see, we run jobs 24/7 with very little hands on time. We can save most customers up to 20% off their hot stamp budget! The reason segmented dies have become popular of late, is to reduce the cost of brass and therefore the price of a hot stamp order. The reality is that an 80 tooth Arsoma cylinder has less than $100.00 of raw material, and only a few hours of machining labor. Our goal from day one remains: To provide the best quality, less expensive hot stamp cylinders in a timely fashion so our customers can sell more of this sought after, high end process without paying a high end price.
A good supplier has no limitations, but it is always wise to ask. At
Precision Hot Stamp, our motto is, "If you can put it on a film, we can
engrave it in brass". The biggest factor in determining the amount of
detail in a job is based on the type of foil you use, and the creativity of the
designers If you find a foil that lays down well for you, don't be
content, find one that's better.
And don't be fooled into buying into any fancy engraving processes like
"heat conducive black paint coatings" on cylinders to get crisper
detail because it just isn't so. No more so than a black barbeque grill having
the capacity to cook a better steak. It's in the hands of the
operator. Take a look at our "Precision"
web pages, and we'll show you some examples of detailed engravings.
And if you really want to get inspired, go to this page to see some REAL
engravings. We don't believe there are limitations. The only limitations
are in the minds of the designers. We for one would like to encourage
designers to step up to the next level. Do you wish to simply catch the
consumers eye, or capture his imagination? With our quality and
affordability, we have been, and will continue to do both!