Tag Archive: cycles

  1. Ink Adhesion Part 2: Bi Component, Pre-Treatment and Post Cure

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    Have you ever looked on the back of an object and seen the recycle symbol? It tells you what material the object is made of. When it comes to plastics, Polypropylene and Polyethylene are considered the two of the most difficult materials to get ink to adhere to due to their relatively low surface energy. Polypropylene is used to make a wide variety of items and low and high density Polyethylene is commonly used in food packaging. When it comes to these difficult substrates it becomes necessary to pre-treat to affect a change in surface energy to make the surface amenable to bonding with – or cross-linking – with the ink.  This causes the substrate surface to become more receptive.

    The most commonly used methods of pre-treatment are:

    • Plasma and Corona: Electricity applied to the surface.
    • Flamer: Liquid propane (LP) or natural gas. With Flamer there may be variation due to cleanliness of the burn and how the flame will pre-treat any given substrate.
    • Chemical Pre-Treatment: Usually manually applied with a liquid soaked rag.

    Unfortunately on any given substrate you cannot assume that you will affect an equivalent change in the surface energy from one pre-treatment to another. Finding the correct ink pre-treatment may consist of 3 different segments: cleaning, activation and surface bonding.

    Plasma surface treatment is a process that raises the surface energy of various materials in order to improve the bonding characteristics when ink is applied. Plasma is used widely in the medical industry. This is because you don’t have the bi-product of the other 2 pre-treatments such as carbon from the flaming process or residual VOC’s left behind from the from the flashing process of a chemical pre-treatment. Corona treatment is commonly used on materials such as polymers, papers, films, glass and metals.

    Plasma is a good option for components that require a longer treatment hold. Some of the key advantages include: surface chemistry and 3 dimensional treatments. Corona is another form of plasma that can be used with in-line processes. When working with corona the systems are easy to maintain and user friendly.

    Flame pre-treatment can also be integrated into inline processes, and require careful and sometimes precise setup in order to be safe and effective. Proper air to gas ratios, flame intensity and dwell time all play into successful pre-treating. Flame plasma systems combine compressed air and a flammable gas which is combusted to create a flame. One advantage is that the material surface only has to be exposed to the flame for a brief period of time to become polarized through oxidation. One setback is the heat level required for this treatment may cause damage to the parts.

    Chemical priming is yet another way to pre-treat difficult to adhere to substrates and is generally considered a last resort due to the generally manual nature of application. Essentially primers are used to chemically modify the surface by removing contaminants, adding reactive sites for bonding and increasing surface energy. One disadvantage is that these primers often contain chlorinated solvents that are considered volatile organic contents.

    Many substrates will require pre-treatment to satisfy customer’s individual requirements for print longevity. But with the correct treatment and testing, our technical service technicians will test the inks and provide samples for the individual customer’s review.

    For information about Engineered Printing Solutions’  custom solutions, standard pad printers, industrial digital ink jet, consumables and other auxiliary equipment, visit Ink Adhesion Part 3: Ink Mixing, Contamination, Blooming and Mold Release Agents, email sales@epsvt.com or call
    1-800-272-7764.

  2. Ink Adhesion Part 1: General Education

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    Have you ever looked down at a water bottle and wondered how the logo got there? Personally I know I have. Before the colors and image can get put together on the object the first question that needs to be answered is how to choose the right ink for the job. Simply put, ink adhesion is ink that sticks to any given product to a known specification. One of the most common tasks our Technical Service team are charged with is to “find me an ink that sticks to the surface of my product.” It wouldn’t be realistic if I told you that our Technical Service team has magic powers and can automatically determine the perfect ink for the material being printed on. Even though inks are produced to stick to a particular substrate; the question is which ink is best suited to adhere to your particular substrate based on your requirements?

    There are many different substrates and even more sub-sets within each . Not all polypropylene’s (PP), for example, are created equal. An ink that may exhibit flawless adhesion to one PP product may not adhere at all to another. We therefore need to match the ink series with the particular substrate being presented. However if you supply our Technical Service team with the parts you wish to print on, they will be able to begin working their “magic”. They will be able to first make an educated guess as to which ink will meet the customers’ expectations based on experience, then begin testing the inks and provide samples for the individual customer’s review.

    For information about Pad Print Machinery of Vermont’s custom solutions, standard pad printers, industrial digital ink jet, consumables and other auxiliary equipment, visit Engineered Printing Solutions, email sales@www.epsvt.com or call 1-800-272-7764.

  3. Pad Printing in Multiples

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    Compared to the world of manual pad printing, the world of automation is virtually unlimited, within reason. Here at Engineered Printing Solutions we have taken a standard KP05 bench mounted printer and stripped it of the software and hardware. We then completely customized it to be able to produce 8,000 pieces per hour, all the while requiring minimal operator involvement.  How do you decide if automation is right for you? Well you need to ask yourself 3 questions: How many pieces per hour do you need to print? How many colors on the image? Finally what is the size of the image? With this machine, it all starts with the Bowl Feeder which aligns the parts all the same direction and feeds them down a track to the printer, printing the parts and finishing with the items going out under an infrared heater, ensuring that the images are dry enough to continue down the production line to other operations or to packaging. However with every innovation there are obstacles which we must work through.

    Some of the technical problems that can arise are:

    • Being able to efficiently feed the parts to keep up with the printer.
    • Printing multiple images in one pad stroke can create some undesirable results. This may require custom pads.
    • Being able to efficiently process parts through the system without damaging even the most delicate part.
    • Ensuring that the printed image is dry enough to withstand downstream operations as soon as it leaves the system.

    In this case we are printing 8 pieces at a time so our engineers need to make sure that the images are being placed correctly on each of the 8 parts every time.

    For information about Engineered Printing Solutions custom solutions, standard pad printers, industrial digital ink jet, consumables and other auxiliary equipment, visit Ink Adhesion Part 3: Ink Mixing, Contamination, Blooming and Mold Release Agents, email sales@www.epsvt.com or call 1-800-272-7764

  4. Safe and Efficient: Best Print Environment Ever!

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    To get the most out of your printing operation, you need to account for many factors, including lighting, adequate compressed air supply, controlled temperature and humidity, quality consumables, etc. Everything of value in your operation must be put in place, maintained, serviced and supplied. One factor often overlooked is the operator, and more pertinent to this discussion, operator ergonomics.

    An operator who exerts as little energy as possible per print cycle and who has everything needed to complete the assignment within the production cell will deliver consistent and predictable productivity throughout the shift. Additionally, job satisfaction and, most importantly, safety will impact your company’s throughput and profit. Never dispute the value of a happy employee.

    Ergonomics
    When designing your operator’s production cell, keep in mind the following to improve working conditions:

    • The distance / height of reach for an item
    • Comfortable seating
    • Proper floor mats, also known as anti-fatigue mats.
    • Temperature and humidity control in the work environment including heat exhaust from nearby heaters or dryers.
    • Rotations within shifts. This prevents repetitive stress disorders and boredom.  It also ensures crew flexibility and increases the employee’s perception of value to the operation, putting the emphasis on the importance of production.
    • The right tool for the right job. Avoid cheap multi-tools with every hex-key ever made. Our pad printing equipment should not require the use of more than 4 hex-keys.

    Safety
    As mentioned above, safety will most definitely impact your bottom line. OSHA provides an interactive program on their website called $afety Pays  to help determine the financial impact of injuries. This number can be used when calculating ROI of safety equipment.

    • Always hang cables and hoses from the ceiling; never lay them on the ground.
    • Wear gloves, goggles, and aprons.
    • Do not disable safety features on machines. They are installed for a reason.
    • Keep pallets out of the way. If possible, keep pallets out of the production area completely. Moving an empty pallet around creates extra work and aching backs.
    • Fixtures should be designed carefully to ensure fingers stay out of way of the pad.
    • Take the time to properly train every production member on how to lift with their knees. On-the-job training means it is a requirement of the job.

    Preparation
    Try always to be proactive instead of reactive. For example, instead of requesting or preparing ink during the changeover time, someone should have the ink ready for the operator before the job begins. Any way you can keep the printer printing will improve your up-time.

    • Keep all thinners and other supplies available at the production cell.
    • Keep a supply of cleaning materials at the production cell.
    • Use outside help for non-printing tasks, like handling boxes, proofing jobs, work orders, removing pallets, etc.
    • Printing can be a bottleneck. Exploit it by keeping the printer printing.

    Job Satisfaction
    A happy employee is a productive employee. Think about it. If your employees are frustrated about working conditions, they are distracted from their job.

    • The less your operator deals with job frustrations and physical fatigue, the more printing cycles will take place.
    • Removing frustrations and dangers from your operator allows more commitment to quality, service, and exceeding production goals, resulting in …
    • The best print environment ever!

    Need Help?
    PPMOVT’s Sales Engineers are really smart! Why not use them? They’ll help you figure out the holes in your operation and recommend ways to plug up productivity drains.  Call us at 1-800-272-7764, or use Live Chat on our Home page https://www.padprintmachinery.com

    Then we can add your business to the list of best print environments ever!

  5. The Skinny on Plate Types

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    Engineered Printing Solutions reps often hear the question “what plate type should I use?” The answer is standard for pad printing:

    • What is the intended application
    • How detailed is the artwork (fine lines? large solid areas?)
    • What are the environment’s conditions (dusty? flying debris?)
    • What is the thickness or opacity of ink required?
    • What is the size of the run?

    Your rep is here to help you analyze your job and narrow your choices, including plate type. There are two major image plate types:  Steel and Photopolymer. Let’s take a closer look at each.

    Steel Plates

    • Thick Steel Plates. These are old-fashioned and originally used in pad printing because it was usually the only choice. There were few to no other more affordable materials. These thick steel plates were tempered and machined flat prior to acid etching. Very expensive and requiring an outside plate-maker service, their redeeming quality was longevity, often providing several-hundred-thousand print cycles.
    • Thin Steel Plates. These plates have gained in popularity due to the improved materials used. They provide excellent flatness for proper functionality and higher tempering (into the Rockwell 70’s) for long life. Their cost is much lower than thick steel plates and can be used on the same standard plate stages as polymer plates. These plates also need an outside plate-maker service – acid bath required.

    Photopolymer Plates
    Photopolymer plates come in a variety of types and are made of photosensitive material that changes chemical composition when exposed to ultraviolet light. Using a film positive, the image is etched into the plate, preventing the image area from being exposed to the UV-light. To control etch depth in larger color areas, a second exposure with a screen is necessary.

    • Double Exposure. These plates are available in several polymer materials depending on the etch depth and the number of impressions needed. An exposure unit is required to expose the plate and would require using a line screen. This material is available in either alcohol- or water-based development. A full list of plate materials can be found on our website – Printing Plates here.
    • Single Exposure. This special material provides a very thin photopolymer coating, clad to a very thin steel backing. The plate can only be etched to a .001” depth and requires a single exposure. This material has a shorter impression life than conventional Double Exposure plates. Since it lacks the customary screen in the artwork area, it is used only on fine line or text artwork. It is not used to print bold artwork or solid backgrounds.
    • Laser Etched. These plates are used in conjunction with a laser etching device such as our RapidFire Laser Etcher to produce plates similar to the conventional Double Exposure plates, including screened artwork areas of all types. Bringing this ability in-house eliminates the need for artwork films and provides multiple benefits in speed, turnaround, corrections and profitability.

    Where do I get help?
    Recommendations, troubleshooting and assistance in all areas of your production cycle are at the end of your phone or mouse! Call the trained and experienced Pad Print people at 1-800-272-7764, or use Live Chat on our Home page  https://www.epsvt.com
    We’ll stop by for a cup of coffee!

  6. Stuck with Pre-treating for Adhesion?

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    Pad printing’s a great way to transfer images to 3-dimensional parts. Its versatility handling shapes and substrates composition surpass almost every other automated marking method. However, getting that ink to ADHERE to all these parts can present a challenge, especially parts molded from Polyethylene (PE) or Polypropylene (PP).

    These two substrates exhibit a low surface energy (usually measured and described as the “Dyne level”). There are other substrates like those possibly containing Teflon that are also problematic. But PE and PP are so widely used in different industries, we’ll stick (no pun intended) with them for the purposes of this discussion.

    Most ink manufacturers provide inks that are “suitable” for PE and/or PP. In many cases you’d just treat it like any other pad printing job with no issues. However, depending on the customer’s expectations of image durability, this may not prove a viable option. It is, however, the first place to look.

    Pre-treating for adhesion choices

    There are four choices when faced with adhesion issues:

    • Special ink
    • Chemical wipe
    • Flame treatment
    • Corona discharge

    Pre-wiping parts by hand with a chemical that allows the ink to bond is a “second-tier” option, best suited to prototypes and short runs. Many firms hesitate to introduce another chemical into their work flow, and you’ll be exposing operators while increasing run time as well.

    For longer runs and constant production speeds, you really have to look at the final two options – flame or corona – usually in a print cell, or actually integrated either into the machine configuration or in-line.

    Flame treatment is more cost-effective, easily integrated and in some cases, actually provides a better surface pre-treatment. However, some firms choose not to have an “open flame” in their workplace, regardless of the fact that most flamers are heavily guarded and the actual flame is no more than 1” to 2” in length.

    Electrical discharge units (some call it corona while others refer to a plasma-jet) are just that: an electrical charge across or through the substrate that raises the energy level to a point where ink will cross-link and adhere. These are more costly to purchase, but better suited to some substrates.

    Please note that there’s no “magic bullet” when it comes to pre-treatment technologies. Some work better with substrate “A” versus substrate “B.” To complicate matters even further, there are a large number of different blends of plastics, especially PE and PP, while other plastics may include recycled (“re-grind”) material; flame-retardant additives; colors, etc., all of which can affect adhesion characteristics.

    To conclude: your choice is based on throughput speeds and budget, plus environmental issues.

    Your ink or machine supplier will be able to assist you with testing and choices, as you need to find out what works best, will meet your production rates, and is most cost-effective.

    One final note: If you are importing molded parts, be aware that the “blend” of materials may change without notice; what works this month may not work in the future. New batches may require new research. If you can, check with your parts manufacturer and bring that information back to your ink supplier.

    Join the conversation! We have technical ink experts available to answer your questions and work through any problems you may encounter. Confused? Connect with the right person to help. We make the complicated seem easy!

  7. Print Pad Durometer or Hardness – Same Thing

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    Albert F. Shore developed the measurement device called a durometer in the 1920s to measure material hardness. As a result of the Shore ratings, the terms hardness and durometer became interchangeable. Many pad print pad manufacturers color code the standard durometers by adding pigment to the silicone itself or by coloring the pad base. The following chart shows the durometer range for each silcone material (color) we typically recommend:

    Color                             Hardness
    Blue                                  10 – 60
    White                               20 – 65
    Red                                   30 – 75

    The harder the pad, the higher the Shore durometer rating. Three basic pad durometers are standard in the industry and cover most applications. Custom pad durometers are also available through most pad suppliers. We suggest you invest in a durometer gauge, valuable for all pad printers for determining pad hardness and quality control of pads in rotation. This simple tool is available through silicone-rubber suppliers and many general-service dealers in the screen printing and pad printing industries.

    Choosing the proper pad hardness for a job is often a combination of experimentation and experience. As a general rule, the harder the pad, the better the performance, the longer the pad life. But hard pads may be impractical in some applications. Here are some guidelines for durometer selection and maintenance:

    • Use softer pads when printing on heavily contoured surfaces or on fragile items.
    • Use a softer pad if the power of your machine can’t compress the pad sufficiently to achieve a satisfactory rolling action.
    • Use hard pads for textured surfaces, or printing an image in a recessed area where the pad must roll over a “step”.
    • Use hard pads in a pad “nest” where a number of pads are spaced with small gaps (for example, printing computer keyboards).
    • Consider a special pad for printing on abrasive substrates and textured finishes. Example applications include automobile control arms like turn-signals and windshield-wipers, when the pad must resist the abrasive nature of the substrate.
    • Avoid using pads of different durometers on the same application. The thickness of the ink deposit will vary on the substrate.

    Custom Pads – Custom Service
    Confused about durometer? Need help selecting pad durometer for a custom job? We have a full pad department to help and we don’t charge for phone calls! Click Cylindrical Printing Padsor call 800-272-7764 for our undivided attention. We are here to help you!

  8. A Long and Happy Print Pad Life

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    Our pad department asked me to investigate why a long-time customer had stopped buying our pads. The idea crossed my mind that our pad department was questioning the quality of our pads compared to an unknown competitor’s. So, since I had been planning a trip that included this particular customer, I confirmed a meeting with them.

    After our initial welcome, we sat down to talk. I asked them bluntly why they had started using another supplier for their pads without discussing their issues with us first. The customer became defensive, insisting they had not stopped ordering from us. They then brought me on a tour of the production area, where I saw the rows of machines we had supplied some years earlier, all working beautifully – with our pads.

    The real shocker was their final disclosure: they were getting about 250,000 cycles plus per pad because they had adopted our recommended method of pad rotation. Based upon the number of machines in operation, we calculated they had saved about $12,000 per year over the past 2 years because of the way in which they cared for their pads.

    I thought that I was going into this meeting to battle for this customer’s pad business. I had prepared a strategy of careful analysis and special pricing. I walked away feeling a bit silly when I realized they could have paid a lot more for our pads than we were charging and still remained a loyal customer. But I was happy that we were saving our customer money by selling a superior product and giving away solid, money-saving advice for free. We were heroes.

    This true fairy tale ends with “and they all lived happily ever after,” because this particular customer was smart enough to listen to and implement our suggestions. Please understand that these same pads can also wear out after 50,000 imprints, and pad life is very dependent on ink type, substrate and maintenance. 

    For additional information, see our previous blog Pad 101. If you’re not getting individualized attention from your supplier, call us. We even customize our service!