Echo Graphic PCB Film Processors
The function of a PCB Film Processor
Echo Graphics PCB Film Processors serves as a key function between the laserplotter and the exposure machine for development of silver films. We offer a range of processors compatible with all laserplotters on the market independent of the film width.
In the menu to the left, you will see a “compability chart” stating which processor is recommended for a list of various plotters along with technical specifications for each model in our product portfolio. Below, we have made a video that shows how an exposed Kodak PCB film is developed using the EG901PCB processor. Furthermore, the functionality of the user interface is presented in the video.
Video of all functions
In the following video, we present all the functions of our automatic film processor. The video is showing the EG430NDT processor for the Non-Destructive Testing industry, meaning that the widt is only 43 cm. For the PCB industry, our processors is available from 75 to 166 cm. However, most of the functions is the same, and therefore the video gives a good understanding of the quality:
Our brands in the market
During the years, our machines have been sold under different names in different regions. If you are looking to replace or buy spareparts to one of the following brands, you have come to the right place:
- – Hope
- – Carnfeldt
- – Echo Graphic
What makes our machines unique?
Our processors are known for reliability and easy maintenance. Deep tanks and long rack lengths determine the process speed and contribute to an even density.
The automatic film processors are of modular construction. The modular system allows you to choose between rack lengths of 32 or 43cm. The racks are built after the principle “staggered rollers”, which ensures a safe and smooth transport through the processor.
All processors are designed to operate as a complete integrated system with the photoplotter. The electronic communication between the photoplotter and film processor ensures an optimum utilization of the capacity of the imagesetter.
Dryer units are designed to operate at low temperatures e.g.35 degrees guarantees dimensional stability.
Compatibility with all PCB films from Kodak, Fuji and Agfa
At Echo Graphic, we test our film developer machines with film from all leading suppliers – both Kodak, Agfa and Fuji. If you are looking to replace an old processor from G&J (Glunz & Jensen) or Colenta, our equipment is the perfect choice. We offer a broad range of film development equipment.
Compatibility with First-EIE and Ucamco plotters
We are fully compatible with plotters/photoplotters from First-EIE and Ucamco. Please refer to the compatibility chart for more information.
More information about development of PCB films
Before we delve deep in to the mechanics of PCB, here’s how a PCB film is developed: When the PCB film is exposed to the plotter, the energy of the laser light interacts with the silver halide crystals suspended in the coated gelatin layers. The exposed silver halide crystals undergo invisible changes to form a latent image.
The chemical processes involved in development, changes the exposed silver halide crystals in to metallic silver; as a result, the reaction is catalyzed by the latent image and the image becomes visible. After this step; comes fixation, where the fixer thwarts the development and eliminates the unexposed silver halide grains residue, which is on the non-image areas.
The film can be impacted, i.e. turn brown, if the residue from these grains is left as is. PCB film processors serve as a key mediator between the laser plotter and the exposure machine for development of silver films. Here’s a breakdown of each process involved in developing a PCB film:
In this stage, you aspire to expose your film correctly, so that you can glean topnotch photo tools with optimum processing, and it gives the correct line width when used onto photo resist for imaging. Make sure that the most pertinent processor is set up for the kind of film you are using, before making any adjustments to the plotter. To know the necessary processing conditions, you can consult the film technical data sheet.
Mix and dilute the chemicals as explicitly stated, and set the replenishment rates, temperature, and time to recommended values. This makes you more apt to execute an “exposure series”. Some plotters are very efficient and allow you to carry out the various exposure values on the same plot, thus saving time.
Sometimes, you can choose a narrow range of exposure values of the setting you have been employing, if you had already been running a film. However, if you are starting with a new film in another plotter or changing plotter resolutions, a broader range of values will be required for the first experiments.
Some plotter manufacturers provide you with a test file of varying patterns and widths. If possible, try an exposure using this film and try to process it. The value of the D-max should come out to be about 4.0 and 5.0 with a densitometer. If however, you do not have a densitometer, this procedure should suffice: First check the pattern of the film with naked eye, and then subsequently with a 100 x lenses.
With a naked eye, you can instantly recognize if the initial selection of exposure values is in the right range. If the film appears to be overexposed, there should be an obvious fill-in in gap patterns and equal lines; the lines have been deliberately grown to fill gaps. On the other hand, if the film in underexposed, the narrow gap patterns and smaller width lines wouldn’t appear at all.
Evaluation and Process Control
While making the D-max Measurements, remember that it is not enough to measure the maximum density alone to ascertain the right exposure value. In a rising series of exposure values, you would glean a suitable maximum density value prior to the correct line width.
After you have made sure that you are in the right range, discern the patterns using the lens and try to measure the line widths. Only select those exposure values where the line widths are nearest to their intended values.
You can repeat the test with a smaller array of exposure values, if necessary. On some plotters, changing the resolution entails you to determine a new exposure value. As a general rule, a lower resolution than the current one requires a higher exposure intensity, awhile a higher resolution requires lower exposure intensity.
While running the production films, monitoring your film exposure process is necessary. Many developers measure the plot charts and line width daily, and use the data in the statistical control process. You should remember to react only to trends in data, instead of minor excursions.
By now, you must be acquainted with the fact that film processing is nothing but a series of chemical reactions to reveal and stabilize the latent image, to safely archive the photo-tools. In renowned film development laboratories, film design works hand in hand with the processing chemicals to glean the finest image quality.
Let us drill you in to the mechanics of film processing: When the plotter exposure turns out the latent image, it needs to be transformed in to visible silver grains. The actual chemistry involved in film development is rather intricate; however, one thing that you need to comprehend is that the film developer incorporates certain chemicals to hamper development and avert fog formation, and a developing agent, such as hydroquinone.
Development often favors a higher PH. However, Chemical by-products produced during development alleviate the PH, so certain buffering chemicals are incorporated in the developer to maintain the higher value of PH. The PCB films of today also comprise other chemicals to boost the development process and allow you to garner top-notch high-contrast images.
Some manufacturers divide these chemicals amongst the developing solution and the film, while others directly incorporate them in the film. This is the reason why a film won’t develop efficiently in another manufacturer’s chemicals.
If you think of development in the context of the involved chemical reactions, it would be easier to comprehend. When certain conditions effecting the reactions, such as PH and the temperature are optimum, and the concentrations of various elements and components are favorable, the reactions proceed smoothly without a glitch.
Replenishment is an indispensable element, if you see development in context of a series of chemical process, as it serves to keep the PH stable, eliminate unwanted by-products, maintains developer concentration, and a host of other valuable functions.
Another important component of a series of chemical reactions is fixation. Fixation is imperative to cease the development process and garner a stable image. The Fixer is much more acidic, in contrast with the developer, and serves to hinder any further development. Fixer incorporates thiosulphate, which serves to extract and dissolve any unexposed silver halide on a PCB film.
Fixation also eliminates unnecessary dyes from the film. However, due to the acidic nature of the fixture, it is indispensable to thwart it from contaminating the developer. Fixer is wholly consumed in the process, just like a developer, and the fixer tank is left filled with the buildup of materials washed out of the film.
Thiosulphate reacts with the buildup of silver to form complexes that hampers the efficiency of the fixer. When the silver levels are high, these complexes become highly unstable and the silver crystallizes out of the solution to form a black sludge, which settles at the bottom of the tank.
This dilemma could be aggravated if you process films with a lower area of exposure. Another predicament could ensue if some thiosulphate/silver compounds are carried over to the wash and decompose, depositing a layer of silver at the bottom of the wash tank.
Some of these silver particles mat even attach themselves to the film and ruin its integrity. This quandary can be averted by using a silvery recovery process. This process purifies the fixer of silver, and consequently prevents the accumulation of unstable complexes. Such units would save the customer a lot of money and trouble, down the road!
Washing and Drying the PCB Film
After adequate fixation, the film needs to be washed thoroughly to cleanse any by-products and residual processing chemicals. Ambient temperature of water is most feasible for this stage. While heated water enhances the efficiency of the process, it also introduces and encourages microbial growth as well. The issue of microbial growth is a common problem associated with this phase.
However, judicious use of biocides, and careful processor maintenance would avert the problem altogether. Ideally, the rate of water replenishment should be at least 1 liter/minute.
Now that you are done with the washing stages, drying the film is another important stage and one that needs to be done right. The ideal condition is to dry the film while maintaining a good dimensional stability. Today, most PCB films have varying gelatin content, and it is indispensable to match the drying temperature to the particular PCB film.
As a general rule, double sided films need a higher dryer temperature than the single sided ones. The set temperature and the drier’s efficiency would be dependent on the ambient humidity as well. The size of the film and the configuration of the drier also have an influence on the efficacy of drying. Ideally, drying should be slow at a moderate temperature. One advantage of the 45 second development time is that it allows ample drying time at moderate temperatures, lessening the risk of changing the film’s size.
Most processors produce viable results, but some machine, such as crafted by Echo Graphics; have better features than the rest to result in more competent processing. Remember that the steps involved in film processing revolve around the chemical reactions between the fixing solutions, the developing solutions, and the PCB film itself.
In a narrow, deep tank, the surface area to volume of the tank is much heftier than in a shallow tank. This procures a relatively less oxidation of the developer at the surface and the developer tends to be more stable. Another feature which will have a small influence is the number of “roller strikes”; the more there are, the more likely you are to obtain even development across large sheets.
Additional features that are desirable in a good processor are filter units to keep the various solutions clean, recirculation pumps to aid mixing of replenishment with existing solutions, and level sensors. There are other considerations when choosing a processor. How easy is it to clean? Are the racks easy to remove and the rollers accessible for wiping off? What are the control features for turning the machine off at night or over the weekend?
Five Keys to Successful Processing
1. Correct chemical dilution.
You do not need to be extremely accurate about dilution – use the containers themselves and remember to keep count! If you are using a mixer, make sure the values are input correctly. Mix well to obtain a homogenous solution.
2. Set the replenishment rates correctly
You might think that you are saving money using lower rates, but the recommended values will ensure good and reproducible image quality over the lifetime of a developer batch. If you are processing less than 20 to 30 films a day (24” x 24”), you will need to add extra replenishment so that the total amount of developer exchanged in a week is one tank turnover (25 L). Adjusting the level of anti-ox does this.
3. Set the development conditions correctly
For most of our films development time should be 45 seconds at a temperature of 35°C (95°F). Slight deviations from these values will not affect the quality of processing, but lowering the temperature to, say 30°C (86°F), will seriously affect density and probably line width. Severely shortening the development time will also compromise image quality.
4. Set the fixing and drying conditions correctly.
The fixing temperature should be between 32 and 35°C (90 and 95°F). Losses due to evaporation are higher at high temperatures, and fixation may be hampered at too low temperature.
5. Maintain the processor properly:
Clean the racks at least once a week. Refrain from using any abrasive or harsh materials, since they might cause scratching on the rollers. Whenever the chemicals are changed, the filters should be changed with them, or sooner if it is thought they are blocked. Some users may wish to use systems cleaner once a month or when the chemicals are changed.