Nearly every person buying a press asks the price, but almost no one asks about the manual press construction and features that determine profitability.

Wouldn’t you think people would be interested in the quality of printing, because that is the reputation of the screen printing shop? A good reputation attracts repeat business. Press construction and features also determine how long a job takes to set up and print. That is more money in a screen printer’s pocket than the difference in purchase price…..a lot more! No one asks these questions. So Printwear Magazine will provide the most important questions and answers.

Rigid Construction A manual machine that moves during printing can produce colors out of registration and worse. All screen printers say they prefer tight screens over loose screens, because they also know ink releases better from tight screens and is less likely to be driven into the fabric of the garment. A platen that deflects will have the same effect.

The first question is whether the platen deflects when pushed down. If there is any movement at all, even with a very tight screen, holding registration and preventing ink from being driven into a shirt will be difficult. Printing at 55 dots per inch means 100% dots are .018" in diameter. A 50% dot is .009" and a 10% dot is .0018". Not very much movement has to occur for dots to shift. If an image appears to be in registration at the beginning of the print stroke, but out of registration at the end of the stroke where there is less support for the platen, this is the shift that has occurred from platen deflection.

An objective is to shear ink and deposit that ink on the surface of the garment covering up the color of the garment. A consistent thickness to the ink deposit is difficult to achieve when the foundation to the print is moving. A concrete foundation does not move, and the platen needs to be as rigid.

Question also the rigidity of the color arm that holds the screen. When the arm is up and out of the registration gate, you should not be able to twist the arm. Try it. When the color arm is down in the registration gate, you should not be able to move the color arm laterally, or you have a registration problem.

People occasionally ask about the merits of nylon bolts in the registration gate as compared to two wheels into which a keel under the color arm seats. Both work, and your choice is a matter of preference. Both wear, but very slightly. Neither will wear out. My preference is nylon to avoid metal on metal shock waves running through the machine and the banging sound. With nylon, the bolts should never be tightened when the color arm is between the bolts, because nylon compresses, and will expand when the color arm is lifted out of the gate. Then the bolts will be worn by forcing the color arm between the bolts.

Quick Set-Up The time spent setting up is time lost from printing and making money. Construction and features that reduce set-up time need to be questioned.

Certainly tight screens and platens that do not flex make registering screens easier and faster. Micro registration can save lots of time, too, especially when there are more colors like four or six. If the screens are loose and the platen deflects, don’t waste your money on micro registration.

Micro registration is a fine, micrometer-like, adjustment to bring the screen into alignment with the positive or the print from another screen. The 55 dots per inch might only need to be moved the distance of a 30% dot. There are two basic kinds of micro. The better micro moves the screen in a predictable straight line. The micro you don’t want has the X and Y axes linked so that moving the screen in one direction also results in the screen moving in another direction. When a screen moves over a curved line, predicting the destination is frustrating.

A manual machine with side clamps versus an end clamp to hold a screen is not the issue it once was. Years ago wood and other low tension screens were more prevalent than today. Side clamps were considered a way of stabilizing the image during printing. Today frames are made of larger diameter material. Aluminum tubes are more frequently used. So the frames are stiffer and do not need the support of the side clamps. End clamps can be faster to register screens, and certainly lighter to pick up, put down into printing position, and rotate.

Screen printers agree that they get their best registrations when the image in the screen touches the positive, and their best prints when the screen is off-contact from the garment. Ask how these opposite objectives are achieved.

A simple, no cost, solution is to lay a piece of Plexiglas or other material 1/8" thick on the platen and adjust the height and pitch of the screen so that the color arm rests on the off-contact bolt while the screen rests flush to the Plexiglas at the four corners of the Plexiglas. A screen should first be checked against plate glass to make sure any pitch between the screen and platen is machine adjustment and not a warped screen. This Plexiglas shim allows putting the positive on top for on-contact registration, and removing the Plexiglas for off-contact printing. This is simple, fast and no tools are required.

The old fashion method was to register to a positive on the platen without any shim. Then to print off-contact, the off-contact bolt would be turned, but that creates a pitch between the screen and platen. Fine adjustments from a micro registration feature can be lost. Also, on a multiple platen machine each off-contact bolt might be turned a slightly different amount creating different pitches.

Today some equipment companies offer a pitch adjustment in the color arm to compensate for the pitch created by the off-contact bolt. In my opinion, such pitch adjustments should not be used. First, getting the screen absolutely parallel to the platen by this method is only a dream. Second, each screen will be pitched differently according to the off-contact adjustment, and then the pitch changes again as the screen is rotated to another registration gate. Third, such pitch adjustment further detracts from the value of a micro registration feature. Fourth, the pitch is made on a threaded connection which becomes a weak, or deflecting point, between where the screen is being raised and the fulcrum of the color arm. Fifth, once the off-contact bolt has been rotated and the color arm pitch changed, both need to be re-adjusted to the starting point after the screens are removed, and that is a very time consuming requirement, if the job is done right.

On older, used machines, sometimes there are thumbscrews or a similar bolt to change the pitch of a screen at a point like the corner. This was to compensate for warped screens. Today the equipment manufacturers advocate screens that are not warped and do not include this adjustment. Warped screens will not register accurately on technical work regardless of whether such adjustments are on the press or not.

Printing Speed Screens go around in a circle. The larger the diameter of the machine, the greater distance the screens have to be pushed. That circle is measured by Diameter times Pi (3.14). A one foot addition in diameter means an extra 3.14 feet the screens need to be pushed on every shirt. Each 100 shirts means 314 extra feet to push screens per foot difference in diameter of one machine compared to another.

A question to ask is the diameter of the machine. Larger diameters mean slower printing. However, if the diameter is too small, adjoining screens, depending on their width, might bang into each other. So the next question is the width of the screen the machine can accommodate. A machine that allows changing how high the color arm will go can accommodate wide screens when the screens do not come up as high an angle to the platen.

A table top four color might only have a diameter of three feet, and therefore seem to be faster printing than a floor model with a diameter of eight or ten feet. Not necessarily so. When flash curing is required, the larger machine will be faster. That is because one shirt or jacket is printed and rotated under the flash dryer while a second shirt or jacket is being loaded and printed. Two jobs are being performed at the same time. With a table top press, printing has to stop while the image is being flashed, and then the ink might have to cool before printing again.

To make printing and flashing fast, question how light or heavy the platens and screens feel when rotating them. Even better, push the screens and platens around, and then stop them for each press being considered. This is a repetitive motion business. Aluminum is lighter than steel. Wood platens are lighter than rubber coated aluminum or steel platens. Cylindrical bearings provide better support than ball bearings.

Platens with smooth edges allow sliding shirts on faster than platens with rough edges. Platens with necks help center the shirt and provide a place to draw lines showing how far down the platen the shirt should be pulled by size of shirt. Shirt platens with necks are more costly to produce.

Some manufacturers offer some form of quick release platen for quick change over of platen size, or attachment, during a job. You can ask if a company offers this feature and how the manufacturer knows the platen is square to the platen arm and in the right position. Certainly you want to observe any knobs under a platen to see if they will interfere with removing a wet shirt possibly causing a smeared shirt.

Safety You don’t want equipment that would injure anyone. You might wonder what risks there are. There is one. Some companies have their springs heat tempered so the springs will lift greater weights. That’s the good news. The problem with heat tempering is that metal becomes brittle and is likely to snap. If you have a spring that snaps, pieces of metal will explode through the air like gunshot. Numerous screen printers have reported this experience with fright in their voices. If you are struck in the eye, you will likely be blind, and maybe dead. One such manufacturer has taken the steps to protect customers by shrink wrapping the springs, but several others know of the defect and are not telling or protecting their customers. Not all manufacturers have this problem.

Features These are the extras that might spell the difference when choosing between suppliers. "All heads down" means any screen can be printed on any platen in registration, and is simply a statement of quality. No one would station six people around a 6 color machine, because they would only print at the rate of the slowest person. A company may claim this feature, but they would need to make key parts on an expensive CNC machine to achieve this level of precision. You can ask how their parts are made.

Another feature affecting your business is the range of screen sizes available. Screens have a weight, and that weight is displaced based on the size of the screen. A screen that is too small for the machine will launch the squeegee into the next county. A screen that is too heavy or large will drop when being rotated. What are the machine’s limits? Does that limit the work you can accept, and therefore your revenue?

Most companies offer a variety of attachments, such as a jacket hold down, sleeve attachment, or maybe a cap attachment. Attachments are potential revenue as a printing business is expanded into new areas to attract new customers. What potential for development in revenue is the manufacturer offering?

In addition, you will want to ask what other features are offered. Also ask about guarantees and warranty. Can a machine be returned or traded, and for what period of time? A manufacturer is happy to sell to you, but is he proud to take his own equipment back?

There are a lot of questions to ask. What appear to be even only small differences between products can pay huge dividends by investing wisely rather than cheaply. Buyer, beware!

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