Comments Off on Tech Tip Tuesday: When Should You Replace Your Ceramic Rings?
More often than not, the ceramic rings do not make it to expiration of the useful production life. The more likely scenario for replacing them tend to be mishandling. The rings will often be set down incorrectly or dropped causing a chip in the ring that renders it unusable.
If the ring is to make it to the end of its useful production life, one of the symptoms is heavy shadowing of ink on the cliché. The lapped flat, when new, is approximately 0.005″ wide. When the flat wears to a point where the mean width approaches the 0.010″ to 0.015″ width, you can safely say the ring has served you well.
In my experience you can see upwards of 5 – 6 years of useful life out of a ceramic ring (dependent on usage).
Check out our Pad Printing Machines at www.epsvt.comthere you can also find more information about Engineered Printing Solutions custom solutions, standard pad printers, industrial inkjet, consumables and other auxiliary equipment. Email firstname.lastname@example.org or call 1-800-272-7764 if you would like more information.
Comments Off on Tech Tip Tuesdays: Frequently Asked Pad Printing Pad Questions?
How long should my pad printing pad last? Depending on how “rugged” a surface you’re printing on, a pad should last between 50,000 and 100,000 impressions. Improper use, careless machine operation or stray grit however, can decrease the pad’s life.
What should i watch for when I’m pad printing? Make sure your substrate is free of sharp particles and debris. Avoid printing on sharp edges, which can puncture the pad. Use as little pad pressure (downstroke) as you can to pick up and deposit your image. (Tip: Too light an image could be an improperly etched cliche’)
What causes the most damage to pads? Overly aggressive solvents, mechanical damage, poor storage practices, dirt/dust/debris and careless use are the most common causes of damage to pads. Additionally, some inks have aggressive solvents as part of their mix that will be absorbed by the pad and cause the image to “spread” on the pad. This isn’t permanent, as the solvent will evaporate if warmed or left to stand.
How should I clean my pad? The best way to remove ink and debris from your pad surface is with regular packing tape. You may also use a mild solvent, such as alcohol. Always clean your pad before starting a printing job and never use a sharp object on your pad.
What is the best way to store my pad? If a pad arrives in a protective shell or with a protective cover, remove it and do not reuse. It could trap grit and debris that can damage the pad. Never store a pad on top of or compressed against another pad. Handle and store your pads carefully.
What’s the nest way to extend my pad’s life? We sell 8 oz. bottles of Pad Rejuvenator (Ask for Part Number PAD OIL when you call our customer service department.) The other way we recommend extending a pad’s life is to have two pads that you alternate one shift on, one shift off, to “rest” the pad and let it restore to its uncompressed state.
How do I prevent pad wear? Correct design and tooling of fixtures will help eliminate pad wear … a major cause of image distortion.
Have you ever run into the problem of producing a printed image with weak coverage on solid areas despite using the right amount of ink? If you have then we have the solution for you.
Engineered Printing Solutions’unique Ink-Saver Ring agitates the ink as the cup slides across the cliché, allowing the ink to evenly flow and mix over the print area. The patented Fan Blade design scoops and mixes the pigment as it passes through each chamber allowing the ink to spread evenly throughout the ink cup, providing even coverage over the entire image.
Figure 1 shows what normally happens to a printed image when the ink does not disperse evenly and tends to leave the sides unprinted. Solid areas can also be affected with weak print opacity.
On the other hand, Figure 2 shows the difference when using the Ink-Saver Ring. The image prints evenly while using the same volume of ink – 25 grams in the cup.
Another issue for most decorators is the waste associated with bi-component inks. When using the Ink-Saver Ring, less ink can be mixed and more ink can be used, resulting in less ink waste at the end of the day. Over time, this adds up to significant cost savings for any print shop.
The Ink-Saver Ring is available for all Engineered Printing Solutions’cup sizes, as well as for other vendor’s closed cup systems.
For information about Engineered Printing Solutions’ standard pad printers, industrial ink jet, custom solutions, consumables and other auxiliary equipment, visitwww.epsvt.com, email email@example.com call 1-800-272-7764.
Comments Off on Ink Viscosity and Seasonal Adjustments
Pad printing is a thin film process. It starts with an etch depth in the cliché of approx. 25-75 microns and only a fraction of that ink film is picked up by the pad. Of the wet ink, 50% is a solvent that evaporates leaving only a 5 micron dry ink deposit. You can easily see why such a thin ink film is so susceptible to changing temperatures, humidity levels, static charges and even variations in airflow. Listed below are the ways you can control the ink viscosity and seasonal adjustments.
Control the rate that solvents evaporate from the ink • Solvents evaporate too slowly – The surface of the ink may not be tacky enough to pick up or release images from the pad • Solvents evaporate too quickly – Ink might not pick up from the cliché because it has dried in the etched portion of the plate, or dried on the pad in transit to it’s destination.
Same for the pad • Solvents evaporate too slowly – Only some of the ink will release from the pad to the substrate • Solvents evaporate too quickly – Ink dries and stays on pad.
Tips • Warm environments: Add solvents every 20 – 30 minutes. Always add a measured amount, use a viscospatula and don’t guess! • Control temperatures: Keep printer out of the sun, away from drafty entrances, exits, dryers. • Keep the temperature of the substrate to room temperature. • Don’t let printed part drop below 59°F until fully cured – 4 days or longer. • Good housekeeping: Dust and vacuum floors instead of sweeping. Avoid cardboard boxes in production area. Wipe down all surfaces using a damp cloth. • Static electricity feathers the print. Slow the down stroke and pickup. • Too hot: Solvents in the ink will evaporate very quickly. Solvents are attracted to water vapor molecules in the air. – Speed up the forward travel of the pad stroke. – Thinner / retarder mix (75% Thinner to 25% Retarder) • Too cold: Solvents won’t evaporate quickly enough. Ink won’t be tacky enough between pickup and and lay down to transfer completely to the substrate. – Slow down the forward travel of the pad stroke – Select a faster drying thinner – Use a hair dryer pointed at the pad as it travels forward after ink pickup to speed up the evaporation of the solvent – Raise ambient temperature.
Comments Off on Pad Printing Pads: Is Pad Size Important?
Size minimizes distortion An important variable to consider in quality pad printing is the pad size, especially as it relates to the image size. In pad printing, the larger the pad size used, the less the image is likely to distort in the printing process.
Pad size is measured in length, width and height without the base.
As a general rule, your pad should measure 10% to 20% larger than the image’s length and width.
Remember the “throat” – or the distance between the cliché and the body of the machine – often determines the maximum pad size you can use.
Special pad printing pads for large images In some situations, a large image area must be printed and the machine does not have the power to compress such a heavy pad in a smooth motion.
Two solutions to this problem are available:
The first is to use a pad with a hollow interior that provides the same surface hardness. The hollow interior also reduces the cost of silicone rubber used in a large pad.
The second option is a dual-hardness pad, where the core of the pad is made of a softer material and the outer layer is the harder rubber. Either method helps, but using dual-hardness allows for a more stable pad.
Of course a third option would be to use a different imaging process like screen printing.
There’s another unusual pad configuration that is like an inflated pig bladder. Specialized machines use hollow pads inflated with air just prior to ink pick-up. The pad stays inflated until it comes into contact with the substrate. Then the air is released. The deflated pad can conform to a wider area of the substrate, printing up to 180 degrees compared to 100 degrees with a standard pad on a cylinder or sphere.
Join the Conversation!Have you had problems with print distortion or image size? Click Cylindrical Printing Pads or call us at 800-272-7764 for our suggestions on pad size usage. We love your challenges!
Comments Off on Print Pad Durometer or Hardness – Same Thing
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!
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!
Choosing the right print pad for a pad printing job is not an easy decision. Five key pad characteristics (shape, durometer, size, surface finish and material) affect the quality of the printed image. But shape is the most important variable in selecting a pad, so let’s discuss why in today’s blog.
The Different Pad Shapes Pad suppliers offer many pad shapes in their standard inventory, but most are based on three basic shapes:
Although hundreds of pad shapes are available, most are based on these three shapes.
Each of these shapes could have either curved or flat printing surfaces, depending on the part to be printed. But regardless of what shape the pad has, it must “roll” onto both the cliché and substrate for good printing results. If at all possible, avoid flat-bottomed pads that have a tendency to trap air as it contacts the cliché.
Air trapped between the pad and the cliché, or between the pad and the substrate, can cause print distortion and pin-holes, a result of uneven ink pickup or imprint. To produce a quality print image, the pad surface must roll onto the cliché picking up the ink, and use the same rolling action depositing the ink onto the image area. The better the roll, the more ink that is transferred. The shape of the pad largely determines how well the pad will roll. This is what makes shape the most important variable in selecting a pad.
Ordering Custom Pads For very unusual parts and imaging needs, sometimes custom pads are a good choice, combining two different profiles on one pad. They are expensive and must be carefully designed and tested to avoid print distortion. For more information, Cylindrical Printing Padshere or call 800-272-7764 to discuss if this is a viable choice for you.
Comments Off on Pad Printing Tips: Production Speed
You’re not ready to invest in faster equipment yet. Still, you wish you could increase your number of imprints by end of day. A simple way for pad printers to increase their production speed, which in turn increases print volume, is to change your operating speed.
Here’s one way how:
Maximizing Speed Means Minimizing Strokes
1. Minimize your stroke by increasing the base height of the pad so the pickup stroke on the cliché starts from about 10mm or less above the cliché.
2. Then bring the part fixture as close to the pad surface as possible to minimize the print stroke as well.
3. Make sure that the end-of-cylinder stroke dampeners are open enough to do some cushion work, but not so much that they slow down the stroke of the cylinder.
This concept applies to all pad printers. The closer the pad begins from the surface of the substrate, the faster they will connect and move on.
Keep Your Part-Loading Area Clear
Try to design your tooling so that the part being printed is slid into a cavity, thus preventing the pad on the print side from causing a loading obstruction. PPMOVT has machines where this is not an issue. The clichés move back and forth and the pad, in its stopped position, is back away from the print surface.
Follow these tips and you’ll find your business with extra product by day’s end.
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