Author Topic: dry film problem  (Read 15030 times)

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Offline 5282

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dry film problem
« on: December 01, 2013, 04:44:56 pm »
i have big problem with dry film

i buy from china negative dry film.
i use soduim carbonate to developing dry film . after developing i see the copper good

when i put pcb in ferric chloride to etching it. the some pcb area is not etching  because there are an Transparent layer protect copper from etching  " i use a correct layer of dry film i know there is 3layer sandwitch". i try all thing and no solve

are the problem in developer or what ?
 

Offline sleemanj

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Re: dry film problem
« Reply #1 on: December 02, 2013, 04:36:40 am »
are the problem in developer or what ?

You are not developing long enough.

I use 30g/L Sodium Carbonate at room temperature, developing will take a couple of minutes, I also use an old vibrating toothbrush and gently brush the board to make sure that all the remnants have been wiped away.

When you put the board in the etchant you should see the colour of the copper change to a sort of "pink" that indicates that the etchant has reached the copper, if you don't, then rinse and develop a bit longer.
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Online BravoV

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Re: dry film problem
« Reply #2 on: December 02, 2013, 04:56:16 am »
+1 to above comments.

Also if you're using the blue film instead of the green on like below :



I learned from the Korean's dry film resist instructions, download -> HERE(PDF), its stated during development, its advisable to spray the board with developing solution (sodium carbonate or potassium carbonate) especially there are fine resolution needed, I just used those water sprayer filled with the clean and freshly diluted solution and keeps squirting the board. It works better than without spraying.

Offline 5282

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Re: dry film problem
« Reply #3 on: December 02, 2013, 09:50:34 pm »
 i try all thing's and no solve  :-[ . it try from 2 month ago and problem is still.
i put my board in developer  along time and no solve .
 i try etching with  ferric chloride and try with hcl  + h2o2 and no solve
here is my pcb picture after putting it in  ferric chloride and  hcl  + h2o2 etching





 

Offline sleemanj

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Re: dry film problem
« Reply #4 on: December 03, 2013, 06:03:27 am »


Hmm, you are removing the top protective layer after exposure and before developing, aren't you?  If you don't, nothing's going to happen, it can't etch through the protective layer.

Also see my dry film tips.

In fact after re-reading your initial post, I think that indeed you are not removing the layer.

You have the process working up to exposure OK.  After exposure, you must simply peel off the transparent film on the top layer, then develop it, and etch.
« Last Edit: December 03, 2013, 06:07:21 am by sleemanj »
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Online BravoV

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Re: dry film problem
« Reply #5 on: December 03, 2013, 06:05:27 am »
Hmm, you are removing the top protective layer after exposure and before developing, aren't you?  If you don't, nothing's going to happen, it can't etch through the protective layer.

 :palm: if this really happened.

Offline 5282

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Re: dry film problem
« Reply #6 on: December 03, 2013, 04:00:27 pm »
i remove the protective layer  befor developing . after developing with "sodium carbonate" i can see copper very clear.
but when i put the pcb in etching solution it's not etching and i see copper very shiny.
 

Offline ElektroQuark

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Re: dry film problem
« Reply #7 on: December 03, 2013, 04:28:04 pm »
Is there any protective layer in the other side?

Offline 5282

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Re: dry film problem
« Reply #8 on: December 03, 2013, 05:18:35 pm »
Is there any protective layer in the other side?
noooooooooo
 

Offline Mr Smiley

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Re: dry film problem
« Reply #9 on: December 03, 2013, 05:33:51 pm »
"ferric chloride and  hcl  + h2o2 etching"

If you were using both, shouldn't  the solution be a murky dark brown  :-/O

Is it actually safe to mix them together  :-//

Is your enchant actually etching  :palm:

Have you tried, and timed, how long a bare test piece of copper board etches down to bare board  :-+

 :)
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Offline 5282

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Re: dry film problem
« Reply #10 on: December 03, 2013, 07:58:08 pm »
"ferric chloride and  hcl  + h2o2 etching"

If you were using both, shouldn't  the solution be a murky dark brown  :-/O

Is it actually safe to mix them together  :-//

Is your enchant actually etching  :palm:

Have you tried, and timed, how long a bare test piece of copper board etches down to bare board  :-+

 :)

the etching  solution work 100% . ferric chloride or hcl  + h2o2
 

Offline Mr Smiley

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Re: dry film problem
« Reply #11 on: December 03, 2013, 08:59:42 pm »
Is there any protective layer in the other side?
noooooooooo

This material has a protective layer on BOTH sides when you buy it, you remove one layer before you attach it to your copper board, and you remove the second layer before you  expose, develop then etch  :o

How many layers of protective film do you remove from start to finish  :-//

 :)
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Offline sleemanj

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Re: dry film problem
« Reply #12 on: December 03, 2013, 09:28:03 pm »
Here briefly are the steps to use Dry Film, so, read carefully and see if you are doing them all.  NB: It could potentially be you are exposing too long, but typically a long development would fix that.  Also, I guess it could potentially be that you have a PCB which has been coated in something, if using dry film you need only blank copper PCB not coated in anything,

Step 1: cut piece of film
Step 2: remove protective film from inside-curl
Step 3: adhere to your cleaned blank pcb
Step 4: expose to your artwork
Step 5: remove protective film from top of pcb/film
Step 6: develop in 30 grams Sodium Carbonate per Litre of water for a couple minutes, gently rub with fingers to help
Step 7: inspect board, see that all gunk has been removed, if not GOTO 6
Step 8: put board in etchant,
Step 9: inspect board to see that copper is "pinking", if not GOTO 6
Step 10: continue to etch

« Last Edit: December 03, 2013, 09:31:55 pm by sleemanj »
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Offline 5282

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Re: dry film problem
« Reply #13 on: December 04, 2013, 01:05:10 am »
Here briefly are the steps to use Dry Film, so, read carefully and see if you are doing them all.  NB: It could potentially be you are exposing too long, but typically a long development would fix that.  Also, I guess it could potentially be that you have a PCB which has been coated in something, if using dry film you need only blank copper PCB not coated in anything,

Step 1: cut piece of film

Step 2: remove protective film from inside-curl
Step 3: adhere to your cleaned blank pcb
Step 4: expose to your artwork
Step 5: remove protective film from top of pcb/film
Step 6: develop in 30 grams Sodium Carbonate per Litre of water for a couple minutes, gently rub with fingers to help
Step 7: inspect board, see that all gunk has been removed, if not GOTO 6
Step 8: put board in etchant,
Step 9: inspect board to see that copper is "pinking", if not GOTO 6
Step 10: continue to etch

i do all things above and i do step6 alot of times and after developing i see copper clear and shiny  :o but not etching   :palm:   . i try hundreds times and no sove i try since 2month  :'(  .
are potassium carbonate better than sodium carbonate. in my country potassium carbonate sell in big quantity so it expensive. if i try potassium carbonate can solve problem becuase if i buy potassium carbonate i will  spent a lot of money .
« Last Edit: December 04, 2013, 01:12:07 am by 5282 »
 

Offline eliocor

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Re: dry film problem
« Reply #14 on: December 04, 2013, 01:12:48 am »
please take a blank PCB  (absolutely do no laminate it!) and put a drop of etchant on its copper side.
Is copper corroded by etchant? Yes or not?
 

Offline sleemanj

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Re: dry film problem
« Reply #15 on: December 04, 2013, 01:16:48 am »
i do all things above and i do step6 alot of times and after developing i see copper clear and shiny  :o but not etching   :palm:   . i try hundreds times and no sove i try since 2month  :'(  .
are potassium carbonate better than sodium carbonate. in my country potassium carbonate sell in big quantity so it expensive. if i try potassium carbonate can solve problem.

If you are doing all those things, especially step 2 and 5, then I don't know what the problem can be.  It looks like you are developing it OK from your picture (again, assuming step 2 and 5 are both done), so I don't think it's the developer that is the problem.

My only guess is that the board you are using has a coating of some type (like perhaps it's an old pre-sensitised board).  Sand the board lightly with some fine sand paper before you clean it and apply the dry film.

Try a shorter exposure might help also.
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Offline 5282

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Re: dry film problem
« Reply #16 on: December 04, 2013, 11:30:34 am »
please take a blank PCB  (absolutely do no laminate it!) and put a drop of etchant on its copper side.
Is copper corroded by etchant? Yes or not?

yes it's work perfectly :scared: without dry film
 

Offline 5282

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Re: dry film problem
« Reply #17 on: December 04, 2013, 11:34:54 am »
i do all things above and i do step6 alot of times and after developing i see copper clear and shiny  :o but not etching   :palm:   . i try hundreds times and no sove i try since 2month  :'(  .
are potassium carbonate better than sodium carbonate. in my country potassium carbonate sell in big quantity so it expensive. if i try potassium carbonate can solve problem.

If you are doing all those things, especially step 2 and 5, then I don't know what the problem can be.  It looks like you are developing it OK from your picture (again, assuming step 2 and 5 are both done), so I don't think it's the developer that is the problem.

My only guess is that the board you are using has a coating of some type (like perhaps it's an old pre-sensitised board).  Sand the board lightly with some fine sand paper before you clean it and apply the dry film.

Try a shorter exposure might help also.
i use ordinary pcb without any thing it's etching excellent
i buy dry film from this seller
http://www.aliexpress.com/item/30cm-Photosensitive-dry-film-instead-of-thermal-transfer-production-PCB-board-photosensitive-film-longth-1-meter/670619523.html
 

Offline sleemanj

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Re: dry film problem
« Reply #18 on: December 04, 2013, 01:52:38 pm »
How long are you developing it for?   

How long are you leaving it in etchant?

Take a photograph of the board after etching and show it.

You might find this useful


And also this
« Last Edit: December 04, 2013, 01:55:51 pm by sleemanj »
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Offline 5282

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Re: dry film problem
« Reply #19 on: January 03, 2014, 01:57:27 pm »
after 5 months  :phew: and spend alot off money  :palm:  finally i solve the problem  :-DD  :scared:
« Last Edit: January 03, 2014, 01:59:46 pm by 5282 »
 

Offline sleemanj

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Re: dry film problem
« Reply #20 on: January 03, 2014, 01:59:32 pm »
after 5 month's  :phew: and spend alot off money  :palm:  finnally i solve the problem  :-DD  :scared:

Don't leave us in suspense, what did you discover?
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Offline Mr Smiley

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Re: dry film problem
« Reply #21 on: January 03, 2014, 03:53:15 pm »
You labelled the water bottle 'Developer'   :-DD

 :)
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Offline 5282

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Re: dry film problem
« Reply #22 on: January 03, 2014, 04:54:32 pm »
in the web the all tutorial say the iron can be used but this is cause of problem.
i buy used laminator and i set it at low temperature 80-110C but this work in some time and some time not so i damaged alot of double layer pcb and alot of money becuase i etching it.
and finally and i know the reason when i set laminator bet  80-110C ther roll heating swing or jumb between 80-110 and this cuase big problem.
so i modified the laminator to be in fixed  regulated temperature.
i use water and silkscreen squeegee to put dry film on pcb and this make no any air bubbles
and light exposing time depended on heating temperature degree .
my dry film need   fixed  regulated temperature it's very heating Sensitive
my  modified  laminator


« Last Edit: January 03, 2014, 04:58:19 pm by 5282 »
 


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