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.
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, firstname.lastname@example.org 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 Pros & Cons: Pad Printing in a Clean Room Environment
Pad printing is a fantastic, fast, quick-drying process allowing for adjustment to ink coverage, density and evaporation each step along the way. It is also vulnerable to the changing conditions in the environment surrounding your pad printing area. You may find it beneficial to consider setting up a clean room to protect your jobs from exposure to any sudden variables and contaminants that could impact the quality of the finished product. Today we’d like to help you evaluate the pros and cons of investing in a clean room.
Controlling temperature and relative humidity (RH) allows for consistent ambient climate conditions. Very helpful in a pad printing environment to guarantee the same quality over multiple runs.
Eliminating items with a propensity to throw off dust particles from the closed clean room keeps your operation free of dust and other airborne contaminants. Get rid of those plywood pad bases – typically standard issue for pad printing – and replace them with something cleaner, like aluminum.
Replacing flame pretreatment eliminates another source of soot contamination, as well as the risks of working with an open flame.
Producing a consistent, clean product improves your reputation in the marketplace, increases your daily production and attracts new customers.
Providing a stable climatic environment opens the opportunity to implement an ink maintenance program to systematize the process, a further guarantee for consistency across runs and between operators.
Commissioning a pad printing machine for use in a clean room allows for special procedures to be undertaken at an opportune time. Special sterilization and validation is carried out on the equipment prior to initial use, often by expert third party providers. Any component of the machine’s design which may be subject to dust or contaminant generation is outfitted with additional guarding to minimize this exposure.
Pretreatment options are somewhat limited. Flame pretreatment is usually prohibited because of the possibility of generating soot from an open flame.
The use of air blowing at the pad to assist on ink transfer may not be workable.
Some installs are presented with no way to adjust climatic conditions.
Many clean rooms exhibit lots of air turbulence due to pressurization and air exchange frequency. This can create drafts and negatively affect ink pickup, especially in cupslide machines, requiring heavy use of a retarder or more frequent thinner additions.
There can be a high learning curve required in making often severe adjustments to former ink working mixes once the environment is stabilized.
All in all, usually the Pros outweigh the Cons. Once a proper print process has been established, it can be used reliably every day.
Think you’re ready to come clean? PPMoVT’s engineers can help put you in a clean world of your own! Whether they help you design a new pad printer for your clean room, or design retrofits for the old one, call us at 1-800-272-7764, or use Live Chat on our Home page. Pros & Cons: Pad Printing in a Clean Room Environment
A word of warning: You may find yourself wanting a clean room at home.
Comments Off on Safe and Efficient: Best Print Environment Ever!
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
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 Paysto help determine the financial impact of injuries. This number can be used when calculating ROI of safety equipment.
Alwayshang 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!
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