2. Is pad printing easy, like making a photocopy ?

3. How do I determine if pad printing is the best way to mark my product ?

4. How do I select the right Printex machine for my application ?

5. Can I run my pad printer as fast as I want ?

6. Can pad printing machines print with other fluids besides ink ?

7. Is pad printing good for applying serial numbers or date/lot codes ?

8. Can I pad print very large images or objects, such as a 10" x 20" panel, or a 55-gallon drum ?

9. Can pad printing reproduce photographic images ?

10. Can I pad print parts while they are moving on a conveyor ?

11. When pad printing multi-color images, does the ink have to dry between colors ?

12. Can I mount my Printex sealed inking pad printer sideways or upside down ?

13.Can I incorporate pad printing on a machine that performs other work as well?

1. Question : how does pad printing work ?

Answer : please see our excellent Introduction to Pad Printing, available on the web (or call customer service to request a copy).

2. Question : is pad printing easy, like making a photocopy ?

Answer : According to our customers, pad printing is more difficult than photocopying, and slightly easier than screenprinting, if that comparison makes any sense to the reader. Despite all the advancements in pad printing technology that have taken place in the last several years, pad printing is still wet-ink transfer printing, incorporating old-world principles; in other words, it is a craft. The successful pad printing machine operator will be a bit of a craftsman at heart.

3. Question : how do I determine if pad printing is the best way to mark my product ?

Answer : by process of elimination. If pad printing has been recommended to you, chances are better than 50% that pad printing is the best way (and possibly the only way) way to mark your product effectively. As with any other technology, you must weigh its benefits and limitations against your requirements to determine if you have the right match. We at Printex are always available to discuss your application with you, in a plain English no-nonsense fashion.

4. Question : how do I select the right Printex machine for my application ?

Answer : assuming that pad printing is the best solution, the primary criteria for selecting equipment are: image size, overall part size and geometry, the number of print positions per part, the number of colors per image, and the number of parts per minute required. With any application, there is likely to be more than one equipment set which will accomplish the task. For most first-time pad printers, choosing the right machine is a daunting task. We at Printex routinely evaluate applications for our customers, and provide a written quotation for the recommended equipment.

5. Question : can I run my pad printer as fast as I want ?

Answer : Cycle times vary widely, with a handful of interdependent factors. Most machine manufacturers (Printex included) quote top machine speed in their literature and specifications. Actual printing rates will rarely, if ever, match this speed. The main reasons for this are as follows :

Inks.
Pad printing inks dry quickly, but not instantly. Even inks which are designed to print "wet", such as UV-curing inks, need a short gel time before being transferred in order to obtain acceptable results. This time window will vary with climatic conditions, ink type, plate depth, coverage, and your own standards of acceptability. The time could be as little as one second to as much as 10 seconds or more; typically it is 3 - 4 seconds without forced acceleration, such as air flow or heat.

Flooding/Doctoring Systems.
Whether they are open ink well systems or sealed ink cups, flooding/doctoring systems will create a wave action with the ink supply, and at high speeds this phenomenon may begin to work against you. Symptoms can range from over-flooding or backsplash (open inking systems) to incomplete flooding and dry spots on the plate (open or sealed systems).

Pads.
Being a very soft, three dimensional shape, pads (especially larger ones) may tend to vibrate at higher machine speeds. Vibration during ink pickup or transfer will yield unacceptable results, so the machine must be slowed to allow the pads to steady themselves. Additionally, pads which compress over a large print area can offer some resistance to machine movements, slowing the cycle further.

Operator and/or Auxiliary Operations.
Just how quickly can an operator load and unload your parts without fumbling? Must the operator stop periodically to move trays of parts, open boxes, or perform some other necessary function? What about upstream or downstream operations, with which you must synchronize your pad printing process ?

6. Question : can pad printing machines print with other fluids besides ink ?

Answer : yes. In addition to cosmetic ink markings, pad printers have been used to apply conductive materials, lubricants, solder paste, wax, adhesives, coatings, biomedical chemicals, and more. The pad printer does not care what media it is transferring, as long as it meets a few basic criteria: the viscosity is similar to pad printing inks; the material is cohesive (does not bead up or lose it's shape when lifted out of the plate); the material is reasonably homogenous (does not separate or precipitate); material sticks better to the pad than to the printing plate; the material sticks better to the target object than to the printing pad; the material does not corrode the printing plate, pad or machine parts. We do not intend to make this sound easy. Printing of specialty fluids requires much testing and validation, but it can be done.

7. Question : is pad printing good for applying serial numbers or date/lot codes ?

Answer : possibly - it depends upon the frequency at which the variable information changes. Serial numbers typically change with each individual part. Since pad printing is a plate-based process, this would require a new printing plate to be made for each part, which is impractical. Date codes and lot numbers may change after several hundred or several thousand parts, and therefore may be feasible with pad printing using relatively inexpensive photopolymer plates. One must weigh the cost of a printing plate and the down-time required to change the plate in the machine when considering this method.

8. Question : can I pad print very large images or objects, such as a 10" x 20" panel, or a 55-gallon drum ?

Answer : possibly, but you are advised to explore other methods of marking or labeling for those items. Printex has produced pad printing machines large enough to print the control panels on barbecue grills and an 8.5" x 11"sheet of paper with 100% coverage. Due to the nature of pad printing, these machines and the printing pads they utilize are necessarily very large and expensive, and they apply hundreds of pounds of pressure to the part during printing. On the other hand, screen printing can be used to easily print poster-sized flat items with relative ease, and it is (by comparison to pad printing) a simple matter to apply a label to the side of a 55-gallon drum. As you may have gathered, pad printing is most efficient for smaller items.

9. Question : can pad printing reproduce photographic images ?

Answer : yes, in both black-and-white and color. The pre-press preparation is a little different than what is required for standard offset printing. Photo-quality pad printing is among the most challenging of pad printing applications, particularly when attempting a high-resolution reproduction, but the results can be quite impressive.

10. Question : can I pad print parts while they are moving on a conveyor ?

Answer : no. Standard downward-stamp pad printing requires that the part be stationary and secured during the ink transfer.

11. Question : when pad printing multi-color images, does the ink have to dry between colors ?

Answer : no. Pad printing inks are designed to be fast drying, and their drying speed is enhanced by the thinness of the ink film layer; therefore, "wet-on-wet" multi-color pad printing is possible. In practical use, best results are usually achieved with moderate cycle times (less than 1000 cycles per hour). Occasionally the use of air flow across the pads or printed parts to accelerate the out-gassing of solvents from the printed ink is necessary.

12. Question : can I mount my Printex sealed inking pad printer sideways or upside down ?

Answer : No. Printex Sealed Inking Pad Printers are designed to operate upright. The Sealed Ink Cup works on the principle of Gravity. Gravity pulls the ink down into the etching on the plate. However, Printex offers the RP-60R and potential modifications of the same as a solution for horizontal and upside-down printing.

13. Question : can I incorporate pad printing on a machine that performs other work as well ?

Answer : yes, as long as a the basic requirements of pad printing are met. Printex provides solutions to mate with existing automation, and can design and manufacture custom systems which incorporate pad printing with pre- and post-print secondary operations. If you have a need for this service, please fill and out send our electronic quote request form, and we will contact you to discuss the detail