One of the things we know, as ink systems experts, is that size matters. Blade size, that is. In fact, when a customer asks us to evaluate their inking systems, one of the first things we check is the type and size of the doctor and containment blades they are using.
Across the U.S., in every size and type of shop, we have found inaccurately or inconsistently cut blades to be a leading cause of chamber leaks and excess consumption of blade material. It is easy to overlook a blade that is cut a fraction of an inch too short, but the ink wasted due to that blade can add up quickly, especially over a long press run, increasing the effective cost for each job. This seemingly minor issue is one that must be addressed to help keep costs under control and get the best possible performance from your presses.
Small differences count
At just one mid- to-wide-web packaging printer, for example, we found chamber leaks on three different presses, all due to blades that were cut just a little too short, resulting in leaks that dripped money every time the press was running. In this instance, we recommended that the customer begin purchasing blades pre-cut to specific lengths. For this customer, the regional Provident technical sales rep measured the proper length for all three presses and with shop management agreed on increasing blades to the following lengths: 49.6755”, 45.725”, and 65.475”. As a safeguard we shipped two samples of each size to re-confirm proper length before ordering pre-cut blades. It is important to note that blades are measured to the thousandth and even ten-thousandth of an inch: further proof that size can really matter. Remember, your ink chambers are pressurized, so even a small leak on a 6-, 8-, or 10-color CI press can have a big impact on the amount of ink used, especially on a run of say, 150,000 six-color, large-size dog food bags.
It’s also important to remember that all blades on a press are equally important, so your containment and metering blades must also be precisely measured and correctly installed.
So how do you get there? Begin with exact measurements, such as those supplied by the press manufacturer. However, there are four or more anilox rolls on a CI press and we know first-hand that blade lengths are not necessarily interchangeable across those rolls. So be precise when you place your order.
Accuracy is especially important if you are taking your own measurements. Remember, these can get down to the ten thousandth of an inch, so a tape measure from the local big box store may not provide the accuracy you need. You need to either buy a tool for precise measurement—and use it correctly—or have your press or doctor blade supplier make the measurements for you.
We at Provident regularly take blade measurements for customers and get pre-cut samples to be sure the blades will work as intended before ordering more.
In past blogs, we have often talked about the advantages of the materials used in doctor blades, but the materials not the only aspect of these consumables that can make a bottom-line difference in your business and affect productivity. Make sure your blades are sized correctly, and if you have any doubts at all, please contact us for an ink systems evaluation to help ensure your presses are running as efficiently as possible.
By Andy Gillis