Comments Off on Tech Tip Tuesday: Maximize The Production Life of Print Heads
It is very important that whether it is an operator or maintenance that care is always taken when working with drop-on-demand print heads. They are generally expensive and delicate. If you want to maximize the production life of print heads only trained personal should be handling them. A filtration of some sort should be used between the supply of ink and print head to filter out impurities before reaching the head. For UV curable inks with heads stray UV should be shielded, and take precaution to keep from over exposure and curing of the face plate.
To maximize the production life of print heads care must be taken by keeping the head and especially the face plate clean. Use the appropriate flush for the ink set being used. Not all flush is compatible so if not certain call your ink supplier. Wipe the heads prior to printing with the flush and a clean lint free head wipe. Maintenance jetting or head cleaning should be done daily/weekly to exercise all jets in the head depending on usage. While printing all nozzles may not be printing so this exercise ensures all nozzles fire. It is then best to perform a jet test. By doing so you will actually print on to a substrate to witness a pattern/image of the individual nozzles firing. Doing this routine on a daily basis ensures you see a possible problem before it become unrecoverable. Many heads are recoverable if taken care of and signs of blockage are caught early enough and no physical damage to the head. Talk to your ink/head supplier for possible head recovery procedures or service.
Check out our industrial inkjet printers 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 email@example.com or call 1-800-272-7764 if you would like more information.
Comments Off on Tech Tip Tuesday: What Is The Difference Between A Polymer Plate And A Thin Steel Plate?
There are two major differences between a polymer plate and a thin steel plate:
Printing Plates are etched by means of a UV exposure unit whereby a series of steps are taken to burn the image to the surface of the plate while exposing the surrounding area. Depending on the type of polymer (alcohol or water wash) the unhardened material will be washed away to leave a positive impression of the image.
The Printing Plates process is similar however to get to the end result the steel must see an acid bath for the etching process.
There are many different types of polymer plate materials and associated estimated production lives. This speaks to the importance of selection of a material that is cost-effective for the anticipated production run. There are plate materials that are rated anywhere from 10k – 15k impressions with higher end materials can provide an estimated 60k – 70k impressions.
The thin steel plate material has been estimated in the 500k+ impression range for durability.
The above factors have bearing on the cost of the material. As you might imagine, the photosensitive polymers tend to be much cheaper, in particular on the lower end of the durability scale, while the thin steel plate’s durability tends to be a bit higher.
Thick steel plates are another option. Thick steel plates are usually about 10mm thick and rated for a production life of close to one million cycles.
Want to learn more about printing plates? Drop us a line!
Comments Off on Tech Tip Tuesday: Tools Required To Operate Pad Printing Machines
[vc_row][vc_column][vc_column_text]In the traditional sense there are very few tools required to operate pad printing machines. In most cases you will find that a single M4 Allen key will be all that you put to the machine in order to get it setup and functioning.
However there are a few tools outside of formed metal that come in much more handy. Common sense, diligence and a little elbow grease. If the former two attributes are employed, from day one, the latter decreases exponentially as do the issues that impose themselves when allowing the process and machine to get a bit messy.
For instance, one of the leading causes of premature wear of Printing Plates is dried ink between the mount surface of the cliché and the cliché support. Simply wiping both surfaces prior to setup contributes greatly to maximizing the production life of the cliché. When ink infiltrates the surface between the two mating parts, the inkcup tends to work at what becomes a raised portion of the cliché. You will find that a divot will develop as the inkcup shaves away, ever so slightly, the material. The next time the cliché is used, the divot that has developed will catch ink. If near on in the image area the cliché will be rendered useless.
Tip number one imparted during all training sessions is to keep the process and equipment as clean as is feasible. Excess ink will seep into places that may seem innocuous at the time but down the road, after the ink has had a chance to dry and cure, it will act as an adhesive and beget many a cuss word as screws are stripped and adjustments made impossible due to parts sticking together.
Cleanliness makes for a happy process!
Want to learn more about pad printing? Contact our Sales Team:
Comments Off on Tech Tip Tuesday: How Do You Correct Distortion With Pad Printing?
Distortion means different things to different people. Beauty is in the eye of the beholder.
We will first speak to pad printing.
If we are to stay with a fairly standard definition of distortion … the printed image is the same size and clarity as the film from which the cliché was made were it overlaid … the most common causes are odd shape, e.g.: cylinder, obstructions in and around the print area, e.g.: raised elements of the product, knockouts, etc., and the product not being perpendicular to the print stroke.
For odd form printing the first line of defense is utilization of a pad that is a bit oversized for the job. There begin to be issues that are tangential such as compression capability and cliché clearance but we will assume that the machine is capable. In this case the larger the pad … the less distorted the image starts to become.
Obstructions can be overcome with design of a custom pad to circumvent obstructions coming in contact with the pad.
Part not perpendicular can sometimes be tricky but the easy answer is to adjust tooling for presenting the part so that the image area is as perpendicular as is possible.
In all cases, when it comes to a point where the pad size, tooling corrections, custom pads no longer help artwork distortion (distortion correction) can be used to account for predictable distortions introduced from the above defined issues.
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.
Comments Off on Tech Tip Tuesday: What Happens If Your Plate Is Not Etched Properly?
Although a fairly straightforward process, there are a number of things that can affect the pad print process if your plate is not etched properly.
Common complaints range from edge definition to ink transfer issues. Improperly etched clichés can allow for inconsistent image opacity or even missing portions of the images in certain circumstances.
Some keys to properly etching a cliché (but not limited to), 1. Size of the components of the image, eg. are there bold areas and small copy in a given image, 2. Orientation of image on the cliché, 3. Type of material you are etching, 4. Substrate to be printed.
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 firstname.lastname@example.org call 1-800-272-7764.
Comments Off on Ink Adhesion Part 3: Ink Mixing, Contamination, Blooming and Mold Release Agents
Before printing on any parts there are several factors which are of vital importance: ink mixing, product cleanliness and substrate additives. Regardless of proper ink preparation and chemistry, surface contamination, blooming and mold release agents may all interfere with your ability to achieve satisfactory adhesion.
The two most important factors that must be addressed when dealing with ink mixing are: How are you mixing the ink? What components are you using? Inks are formulated to be mixed at specific ratios, and any deviation may result in adhesion failure. You must choose the correct ink and mix it to the exact manufacturer specifications. It is a common misconception that adding hardener over manufacturing specifications will allow for better adhesion.
Surface contamination is a huge factor in whether or not the ink will adhere to any given object. The first reason contamination may occur is because people are not handling the object correctly. Oils on the handler’s hands can be transferred onto the objects. Contamination can also occur as a result of secondary processes being performed on the parts. For instance, if you choose to wash the objects with a detergent, this may leave a residue behind on the object and the ink may not adhere properly. Here at EPS we use alcohol. This is a standard solution which readily flashes off and is used to wipe the parts of any dust, oils or any contaminants before printing. With proper handling, cleaning the parts may be unnecessary, but wiping with alcohol does assure that there will be a clean surface to print on.
Blooming is a term used in the plastic industry and it denotes a plasticizer or other additive coming to the surface of a part over time. The difficulty with this contamination is that you can wipe the surface of the part free of contaminates but over time the part will re-bloom and the contaminants will interfere with the bond between the ink and the parts.
Mold release agents (also known as de-molding agent, form oil, parting agent or release) are substances used in molding and casting that aid in the separation of a mold from the material being molded and reduce imperfections in the surface. While these additives make the plastic manufacturing process simpler, they can wreak havoc on attempts to achieve adhesion.
Comments Off on Ink Adhesion Part 2: Bi Component, Pre-Treatment and Post Cure
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.
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