dry film problem

[5282]

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 ?

[sleemanj]

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.

[BravoV]

+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.

[5282]

 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

[sleemanj]

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.

[BravoV]

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.

  if this really happened.

[5282]

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.

[ElektroQuark]

Is there any protective layer in the other side?

[5282]

Is there any protective layer in the other side?

noooooooooo

[Mr Smiley]

"ferric chloride and  hcl  + h2o2 etching"

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

Is it actually safe to mix them together 

Is your enchant actually etching 

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

 

[5282]

"ferric chloride and  hcl  + h2o2 etching"

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

Is it actually safe to mix them together 

Is your enchant actually etching 

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

[Mr Smiley]

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 

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

 

[sleemanj]

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

[5282]

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  but not etching      . 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 .

[eliocor]

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?

[sleemanj]

i do all things above and i do step6 alot of times and after developing i see copper clear and shiny  but not etching      . 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.

[5282]

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 without dry film

[5282]

i do all things above and i do step6 alot of times and after developing i see copper clear and shiny  but not etching      . 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

[sleemanj]

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

[5282]

after 5 months  and spend alot off money    finally i solve the problem   

[sleemanj]

after 5 month's  and spend alot off money    finnally i solve the problem   

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

[Mr Smiley]

You labelled the water bottle 'Developer'   

 

[5282]

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