Keyword: PCB factory, PCB process
Film, is to use one of the important raw materials of PCB factory. With the photographic film is the same working principle, thus to save and use conditions has a very high requirements. Slightly inappropriate treatment will create many problems. This issue we will talk about some defect causes and elimination method of film
A. light draw for film
1. Question: the film fog, contrast is bad
(1) the old developer, development time is too long. Solution: the new developer, development time is short, the negative contrast good (i.e., black good).
(2) the development time is too long. The solution: to shorten development time.
2. Question: film line edge glow
Developer temperature too high cause too. The solution: developer temperature within the scope of process control.
3. Problems: lack of transparent film with fog
(1) fixing bath too old silver precipitation increase the film the fog. Solution: replace the new fixing bath.
(2) fixing time is insufficient, the base of color is not transparent. Solution: keep fixing time more than 60 seconds.
4. Problem: photographic plate change color
Inadequate fixation after cleaning. Solution: after fixing need plenty of liquid water washing, it's better to keep more than 20 minutes.
B. the raw copy my homework
1. Question: the turn of the diazo film graphics deformation is all wires thinner and not neat
(1) improper exposure parameter selection. Solution: according to the negative state, optimize the exposure time.
The optical density
(2) the original film did not reach the process data. Solution: determination of optical density, make the light to over Dmax4.0 data; Does not demand the transparent part of its light under Dmin0.2.
2. Question: the turn of the diazo film its local wire width to fine without edges
(1) exposure machine lighting technology parameters is not correct. Solution: the instrument is uv light source lamp energy attenuation, such as more than service life should be replaced.
(2) the need to turn the diazo area beyond the best range of exposure box. Solution: according to production situation to reduce the puzzle area or too close because of the light source, the light source to improve to pull open with the appropriate lighthouse distance, make sure that the large size film in good light sensitive area.
3. Question: the turn of the diazo bad all or partial of the resolution
(1) the original use of the film quality is poor. Solution: check the original film lines on the edge of the imaging condition, technology measures to improve.
(2) exposure machine surface vacuum system failure. Solution: check carefully whether the guide gas pipe hole or damaged.
(3) exposure film bubble exists in the process. Solution: check whether exposure machine surface is stained with dust grains; Check the child with exposure machine interface in mat black paper for pitting or crease.
4. The problem: the turn of the diazo film conductor is wider, lack of transparent area (i.e., Dmin data is too large)
Improper choice of exposure parameters. Solution: A. Select the appropriate exposure time. B. may close to ammonia diazo piece storage environment or the presence of ammonia, cause varying degrees of development may go.
5. Question: after making the diazo film shading area less than (on3dmax data too low)
(1) making diazo film, development is not correct. Solution: a. check whether developing machine malfunctions. B. check the ammonia water supply system, determine whether concentration in beryllium 'more than 26 (i.e., specific gravity of 1.22).
(2) the original diazo piece of material. Solution: the determination of the original film materials, optical density on3dmax is above 4.0.
6. Question: the making of diazo film dark space shading performance low on3dmax occasionally
(1) the double system of diazo film developing is not correct. Solution: check the ammonia developing machine fault state, and to adjust.
(2) the original film material storage environment is bad. Solution: according to the deposit film material specifications, particularly to avoid light shines or close to the ammonia repository.
(3) developing machine improper operation. Solution: in particular, check the temperature of developing machine conveyor belt, heat discoloration was adopted to put stickers, shall comply with technical requirements (not ammonia tank control probe).
7. Question: the making of diazo graphics area appeared pinhole or hole
(1) a dirt or dust particles in the zone of exposure. Solution: in particular, carefully check mesa of exposure, original and new diazo film surface clean, and try to wipe.
(2) the original film of poor quality. Solution: check in through figure mesa, and carefully repaired (to prove the original film quality is second to remake, verification of the same, for example, to prove that the).
(3) the use of diazo quality has a problem. Solution: take will not exposure of original diazo direct ammonia development, make the film a shade of dark brown, again carefully check whether there is a pinhole and the hole, if so, can prove it.
8. Question: the shape of making diazo slice deformation occurred
(1) The environment temperature and humidity control is lax. Solution: a. equipped with digital temperature controllers and humidity controllers, adjust indoor meet the process requirements. B. the working environment temperature and humidity control: temperature of 20-270 - c; Humidity 40-70%. High accuracy requirement of the film, the humidity control in 55-60% RH.
(2) the show after fixing, improper control of drying process. Solution: according to the technological requirements will be blowing, dry film in horizontal. Should not be hung to dry, so easy to deformation.
(3) before making diazo stable improper handling. Solution: should store 24 hours between film storage environment, stable processing.
C. black and white film making process
1. Question: all turned over and the black and white film conductor width is thinner and not neat
(1) improper exposure process parameter selection. Solution: first check whether is turn negative or negative are overexposed, should according to the actual modification.
(2) the original film poor quality. Solution: check the original film optical density, especially "shade density is too low.
(3) there is something wrong with the system development process control. Solution: check the developer concentration and the device.
2. Question: after making the film width of the outer conductor is thinner and not neat
(1) the exposure equipment check expiration. The solution: to check according to process requirements, check that the light energy is within the technical requirements.
(2) the light is too close to the larger size film. The solution: to adjust the light source distance or switch to large exposure machine.
(3) light reflector distance and Angle disorder. The solution: to adjust the reflector surface distance and Angle.
3. Question: is not ideal, turned over and the film of the resolution film conductor is not sharp edges
(1) the original film quality. Solution: check the original film conductor margin status.
(2) functional differential exposure machine vacuum system. Solution: A. In particular, check the contact part is sealed and the contact part of the film. B. such as extraction, to check whether the suction hose is damaged.
4. Question: by making bad local film of the resolution
(1) the original film quality. Solution: check the original film conductor on the edge of the bad situation.
(2) functional differential exposure machine vacuum system. The solution: A. Check the contact of the vacuum system and double contact part of the film. B. check pneumatic hose part to see if there is any breakage.
(3) there are air bubbles between exposure in the process of film. Solution: exposure machine surface has ashes, must strengthen the extraction system.
5. Question: after making short film optical density (mainly refers to the degree of dark area is insufficient)
(1) by turning the film developing process is not correct. Solution: check the development process condition and solution concentration.
(2) the original film poor storage conditions. Solution: need to be in accordance with the requirements of the process of indoor, in particular, avoid see the light.
(3) developing equipment function. Solution: check and repair, especially the temperature and time control system.
6. Question: the making of graphic film surface appear pinhole or hole
(1) with dust or particles of the exposure of the machine. The solution: should earnestly of the original film exposure, such as mesa clean job.
(2) the original film of poor quality. Solution: check the original film graphics surface state, when necessary, can try the second film, comparing to check.
(3) the original film base material quality is poor. Solution: the experimental inspection, make the whole piece of exposure imaging observation after dark area if there is a pinhole or empty brown.
7. Question: after making the film circuit graphics deformation
(1) working environment temperature and humidity is not correct. Solution: operation of environmental temperature and humidity control: temperature of 20-270 - c; Humidity 40-70% RH, high accuracy of film, the operational humidity should be controlled in 55-60% RH.
(2) the drying process is not correct. Solution: place the negative level, the drying time (100 microns), thick film drying 1-2 hours. The thickness of 175 microns, substrate dry six to eight hours.
(3) for making plate pretreatment is not appropriate. Solution: need to put in the film room environment for at least 24 hours, the stability of processing.
8. Question: transparent cloud area is insufficient or the base film
(1) in the original film base material for inclusion. Solution: choose high resolution quality of the original film.
(2) the original film base surface. Solution: make sure the environment temperature and humidity control.
(3) the original film poor quality. Solution: first to test for the original film performance and quality.
(4) exposure and development process has a problem. The solution: the equipment situation and the developer, fixing bath and technological conditions for inspection and adjustment.
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