Could I pad print parts while they are moving on a conveyor?

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Q: Could I pad print parts while they are moving on a conveyor?

 

A: No. Standard pad printing requires that the part be stationary and secured during the ink transfer.

Could I pad print very large images or objects?

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Q: Could I pad print very large images or objects, such as a 10" x 20" panel, or a 55-gallon drum?

 

A: Possibly, but you are advised to explore other methods of marking or labeling for those items. 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 and images.

Can pad printing machines print with other fluids besides ink?

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Q: Can pad printing machines print with other fluids besides ink?

 

A: Yes. In addition to cosmetic ink markings, pad printers have been used to apply conductive materials, lubricants, solder paste, wax, adhesive 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).

The material transfers onto the pad, rather than stick to the printing plate.

The material sticks better to the target object (substrate) than to the printing pad.

The material does not corrode the printing plate, attack the pad or machine parts.

We do not intend to make this sound easy. Printing of specialty fluids requires much testing and validation, but most times can be done.

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

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

 

A: 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, or a re-adjustment of pad and part position 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.

Could I run my pad printer as fast as I want?

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Q: Could I run my pad printer as fast as I want?

 

A: Cycle times vary widely, with a handful of interdependent factors. Most machine manufacturers quote top machine speed in their literature and specifications. Actual printing rates will depend as follows:

 

Inks.

Pad printing inks dry quickly, but not instantly. Even inks that are designed to print "wet", such as UV-curing inks, need a short gel time before being transferred in order to obtain acceptable results. The time will vary with climatic conditions, ink type, plate depth, coverage, etc. It 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.

 

Pads.

Being a soft, three-dimensional shape, large pads may tend to vibrate at higher machine speeds. Vibration during ink pickup or transfer will yield unacceptable print results, so the machine must be slowed to allow the pads to remain steady. Additionally, pads that compress over a large print area will 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?

 

These are some of the elements that will actually determine in real time the speed at which you could run the machine.