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 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 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.
Comments Off on Ink Adhesion Part 1: General Education
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 aboutPad Print Machinery of Vermont’s custom solutions, standard pad printers, industrial digital ink jet, consumables and other auxiliary equipment, visit Engineered Printing Solutions, email@example.com call 1-800-272-7764.
The days of looking up the parameters on a job set up sheet and entering them by hand are no more!
In the world of engineering anything is feasible when you really think about it. Engineered Printing Solutions has taken the standard hand held barcode scanner and integrated it into our machines, creating new generation of custom pad printers.
When the barcode scanner option is installed in the printing system, the risk of improper parameters being loaded when changing from one print job to the next is virtually eliminated. All the operator and setup individual has to do in order to load the correct printing parameters is to plug in the hand held barcode scanner and scan the barcode for the product. The system then automatically loads the print parameters for that product.
While this option has been popular with our customers in the medical industry due to stringent process validation requirements; we feel many other industries would benefit from this feature as it requires much less operator and setup involvement in the configuration of the system for the new print job. There by reducing the time required and virtually eliminating parameter errors, thus reducing misprinted parts. If however the operator chooses to manually enter the code they are still able to hook up a keyboard and enter the program information.
Our engineers at Pad Print Machinery of Vermont can install this option into almost any of our machines that are custom built in our Facility. The bar code scanner option can be configured to be compatible with almost all barcodes. At the moment Pad Print of Machinery is using 1st and 2nd barcodes. But our engineers are able to adhere to whatever barcode needs to be read by the product at hand.
Comments Off on Printing on Cylindrical Items the Myths and Truths: Image Distortion and Pad Choices
In the world of Pad Printing there are continual possibilities. However with all of the potential, there happen to be certain particulars that we must learn and develop from. The opening rule of thumb when printing on cylindrical items is: it is best suited for an image that covers only ¼ the circumference of the cylinder. Often times the cylinder is hollow, i.e. water bottles, if these cylinders are collapsible under the pressure of the pad it is possible that internal support, e.g.: pressurizing the cylinder or internal mechanical support, may be necessary to minimize collapsing the cylinder and therefore contributing to distorting the image.
The second rule of thumb is going to be: the bigger the machine the better. The pad needs to be compressed to a point where the outer portions of the image are on the downside of the curve of the cylinder. This, coupled with a pad that has sufficient meat and print area to transfer the image, are more suited to a machine capable of higher compression force.
Beware of Distortion.
The image, when transferred, will tend to stretch as you compress the pad to reach the outer portions. This is to say, you can have a 5.25″ image etched in the plate but you will end up with a 6″ image when measured on the circumference of the cylinder.
Images tend to either smile or frown. This is more evident when there is “straight” copy at the top or bottom of an image being transferred.
Now when printing on cylindrical items there is a myth that a flatter pad will provide an easier vehicle, due to decreased need for compression, to transfer an image. However a flatter pad, as with most pad printing applications, will nearly always introduce other issues, i.e.: pin holing, to the process and cause distortion. If the image is screened, you are going to find decreased opacity of the image at the outer portions due to stretching. This stretching caused the screen pattern to be more apparent and opens up the “holes” in the screen… decreasing opacity.
For the past three years Engineered Printing Solutions has been utilizing robotics to increase production, lower operator costs and improve the overall decorating process of various parts. The use of robotics has evolved from (a) pick and place systems to (b) SCARA robots loading tooling to (c) 6 axis robots with vision orienting and loading tooling. SCARA robots were then utilized as the actual printing arm with the capability of changing pad styles during the print process. A robot being used as a printing arm has been proven to be the most effective way to print on various three dimensional products that require multiple prints in different locations. In prior designs an elaborate fixture would be designed to rotate the part to different print positions so the 4 axis SCARA robot could print down on the specific location. The development of the smaller 6 axis articulating robots with increased power has led to advancement in our current robotic pad printer designs replacing the SCARA robot with a 6 axis Robot. The part fixture now remains stationary because the 6 axis robot allows you to print at any angle. This eliminates the need for an elaborate multi axis servo driven fixture. The pad printing cycle is also shortened because the robot is no longer waiting for part rotations.
Features of the six axis robot printer:
End of arm tool to hold print pad
Automatic tape cleaner
2 sets of independent clichés to allow set up of next part to run without stopping the current print process
Clichés can hold multiple artworks
Touch screen HMI controller display on strong arm
Camera vision system to detect orientation of part
Up to six color printing
Automatic pad changer with use of up to six different pads
In feed & out feed conveyers
Currently the Engineered Printing Solutions team includes many highly motivated individuals with full engineering, software development and tech support. Our #1 goal is Customer Satisfaction. Our company is constantly pushing the envelope, discovering more and more ways to seamlessly incorporate pad and ink jet printing into customers’ manufacturing environments.
Compared to the world of manual pad printing, the world of automation is virtually unlimited, within reason. Here at Engineered Printing Solutionswe 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.
Comments Off on Inkjets: How Do I Choose the Right Inkjet Printer?
That’s the million dollar question! (Don’t worry. It won’t cost that much.) We’ve already outlined how you might benefit from the addition of an inkjet printer, and how to justify the cost of another piece of equipment, in a previous post. Now you have to match your workload and job requirements to the right machine configuration.
What’s the best inkjet machine solution?
That depends. Here are a few criteria used to get that answer:
Image quality – higher resolution means higher priced heads (or more passes).
Throughput – there are “multi-pass” versus “single-pass” options (more on that later).
Part size – limitations on height / width = machine size.
Image size = part size = machine size.
Substrate used – Regardless of the print technology, some substrates (PP & PE come to mind) still require pre-treatment for best image adhesion.
Number of colors required – dark substrates will need White base-coat layer, plus CMYK
What’s the best inkjet technology for me?
Do you need high volume / throughput with minimal part handling? Consider an automated conveyor, single-pass inkjet printer. You’ll typically get:
A print width that will be a minimum of 2.75″ and can be wider on a custom configuration.
Print resolutions up to 720 dpi in a single pass.
This is a great configuration for in-line applications, especially when pre-treatment is required. In many applications, you might require tooling of some sort to make sure parts are spaced and aligned consistently. Some units will incorporate a series of sensors to detect the part, and software that tells the heads when the part is in position for printing. We’ll help you with those.
Do you need higher resolution (up to 1200 dpi) but less speed? Perhaps a flatbed printer is your best option. These units offer:
An advantage for smaller / identical parts that can be placed in machined trays or nests.
A vacuum platen so you can print flat “stock.”
A series of print heads (arrays) on a rack that moves across the bed, printing and curing as it goes, giving you the capability of printing in a single direction, or printing in both directions, depending on your needs. It’s not as fast, but print resolution may be a higher priority.
With either of the above technologies, you will have the capability of adjusting print speeds, ink density / droplet size, head heights, and color hues. Speaking of colors, if you are printing process color on a dark substrate, you will need to print a white base layer first, but both technologies can accommodate that. In addition, it’s possible to print a clear-coat to protect the image or provide a more glossy appearance, but you’ll probably have to sacrifice one of the white arrays.
Do you only print in one color? Obviously, it’s possible to print monochrome or spot colors with inkjet, but keep in mind that it’s not practical to change or flush colors in the same array. With most high end industrial inkjets, ink is fed from bulk tanks, not cartridges (helps to keep the consumable costs down).
Therefore, if you are thinking of printing with one color only, monochrome machines are available, but you need to be very sure that you will only require that one color. Custom machines have been built with white and black arrays, so the customer can print either (and even mix both to get a gray hue).
Does your customer ask to make changes on press or repeat exact specs? Inkjet will usually provide the capability to manipulate the images at the machine, with the assistance of on-board graphic art software such as Adobe Illustrator or CorelDRAW. Some machines are capable of storing jobs (or job “queues”) so operators can simply select from a drop-down box. Custom machines are network-capable, so jobs can be entered remotely, and many in-line / automated units can be accessed remotely for both job entry and diagnostic capabilities.
Now you know a lot more about inkjets than the average pad printer. Don’t forget: at PPMoVT we build your inkjet the same way we build your pad printer — from the ground up to your specifications. That makes it clean, efficient and engineered for accuracy and cost effectiveness.
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