Fast PCB Produce – Find out Just How to Produce a Successful Bet..

The electronics Printed Circuit Board industry is evolving as new production technologies become offered at low cost. Direct digital printing is making inroads into the traditional photolithography and screen printing processes which have been used to manufacture Ultrafast PCB Prototype for the last two decades.

Here we shall focus on the usage of direct digital printing to individualize PCBs just just before their assembly. The objective is always to print a unique mark on each board that can be used to identify the board. The mark must be permanent and can probably contain 1D or 2D machine readable codes together with alpha numeric characters. The marks should have a 600 DPI (dots per inch) resolution or better as a result of size constraints on the PCB. We shall also give attention to applications that need more that one thousand,000 boards per year. At these volumes automated material handling starts to become extremely important for the overall success in the system.

High volume PCB fabricators use screen printing with thermally cured ink to print the legends which cover either side from the board. At this time digital printing can not print the complete side of any board at a price that competes with screen printing. Even though many printers, such as the PPS7000, could print all of the nomenclature on the board, here we are going to focus on using digital printing just to print the individualizing marks.

Several individualizing options exist such as the following:

Preprinted Label Application

Many low volume products get started with labels printed on office equipment and hand placed on each Special Offer For 2layers PCB before or after assembly. As the product volumes ramp the reliability and expense of hand applying labels becomes a problem. Automated systems that print and apply labels can be purchased. (see this site ) As a result of PCB space constraints these systems must place labels very accurately, a large problem for most label application systems. The labels are not permanent. At high volumes the labels can be more expensive than other marking methods.

Advantages

* Low Initial Cost

* High Contrast Mark

Disadvantages

* Not Permanent

* Higher Incremental Cost

* Challenging to Change Label Size On The Fly

* Mechanical Complexity For Automated Application

Solvent Based Continuous Ink Jet Digital Printing. Continuous ink-jet technology has been adapted to mark on many industrial products including PCBs. By using these systems a continuous stream of ink droplets is steered towards the desired location using electromagnetic fields. Solvent based inks produce permanent marks on porous surfaces. The marks are less permanent on non-porous surfaces where smearing may be considered a problem for that short period of time its takes to dry.

Advantages

* Competitive Incremental Cost

* High Contrast Mark

* Many Colors Available

Disadvantages

* Complex Ink Viscosity Process Can Be A Challenge To Control

* High Resolution (Greater Than 300 DPI) Difficult To Achieve?

* Solvents May Be Released Into Atmosphere, Most Companies Attempting To Reduce Solvent Issues

* Mark Not Immune To Some Cleaning Solvents

Laser Ablated Ink Patches – Many industries use lasers to engrave marks onto a variety of parts. Lasers have already been utilized to engrave marks onto PC boards with limited success as a result of lack of contrast of the resulting mark. A newer approach is to achieve the circuit boards printed with ink patches, the ink patch is then selectively removed (ablated) through the laser creating the mark to get printed. (see here ) PPSI provides the capabilities to build up a laser based marking system.

Advantages

* Competitive Incremental Cost

* High Contrast Mark If Ink Patch Can Be Used

* Very Fine, Highly Reliable Marks Available With Laser Galvo Head

Disadvantages

* High Initial Cost

* Requires Preprinted Ink Patch

* Even At Low Power Laser heat May Damage (by Fracture) Traces, Causing Intermittent Reliability Problems

* Particle Generation May Require A Cleaning Step

Piezoelectric Drop At Will Digital Printing, Solvent Based Ink. For any concise description of drop on demand digital printing see here [http://www.aellora.com/documents/whatisdodij.pdf]. For me this choice represents a slight improvement over option 2.

Advantages

* Competitive Incremental Cost

* High Contrast Mark

* Many Colors Available

* Easier Process To Regulate Than Continuous Ink Jet

Disadvantages

* Standoff Distance lower than 2mm, Suitable For Unpopulated Boards Only

* Solvents May Be Released Into Atmosphere, Many Companies Trying To Reduce Solvent Emissions

* Mark Not Resistant To Some Cleaning Solvents

Piezoelectric Drop At Will Digital Printing, Thermally Cured Ink. A startup company in Israel “Printar” has introduced a printer geared towards low volume, fast turn PCB fabricators who need to minimize the cost and lead time related to small lot screen printing. Interesting could be the thermally cured ink that reportedly has better adhesion capability than other ink systems.

Advantages

* Good Ink Adhesion ?

Disadvantages

* Requires Large Oven For 350-400 deg F Heat Cure

* Will Not Include High Volume Material Handling

Piezoelectric Drop When Needed Digital Printing, UV Cured Ink. Markem Corporation has developed an ink/print head system ( the Model 4000, see here ) that several OEMs and integrators are using to print on PCBs. The device uses an ink that is certainly less viscous at high temperature and almost solid at room temperature. The print head operates at 68 deg C, the ink drops cool once they contact the PCB becoming almost solid. This enables the system to print fine detail on PCBs without ink running or smearing. When subjected to UV light the ink undergoes a chemical reaction transforming into a solid plastic like substance. The cured ink is impervious to common solvents.

Advantages

* Competitive Incremental Cost

* High Contrast With Fine Detail (600 DPI)

* Before Cure, the Ink Can Be Wiped Off And the Board Reprinted

* After cure, The Ink Can Not Be Removed Except By Scraping

* High volume Material Handling Available

* Works Well With Inline Inspection (Inspect Before Cure, Cure Only Good Boards)

Disadvantages

* Ink Adhesion Can Be Considered A Problem On Certain Substances

* Necessitates the PCB Be Clean (No Finger Oils)

* Standoff Distance Under 2mm, Appropriate For Unpopulated Boards Only

The PPS7000 continues to be designed to print individualizing marks on Ultrafast PCB Produce using option 6. The program utilizes a SMEMA compatible edge belt conveyor to maneuver PCBs to the print area where they may be printed and optically inspected. After inspection they are conveyed to the inline curing station and after that the back from the machine. When being automatically loaded by a board destacker, panels exit qhzwxo system about once every 10 seconds. Each panel usually contains multiple boards that every receives a unique serial number. The overall throughput of the machine is extremely dependent on the number of boards in each panel. The greater boards in each panel the higher the throughput in boards a minute. A drag and drop WYSIWYG (Everything You See Is Exactly What You Receive) programming system continues to be developed that enables a brand new panel to be programmed in approximately 5 minutes. An offline programming method is made available.

We have been the only real PCB board marking system that creates a lasting (solvent resistant) high contrast mark, incorporates SMEMA compatible high volume material handling and incorporates inline inspection.

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