dry film problem - Page 1
Forum section: electronics / general

author: 5282
author_rank: Regular Contributor
timestamp: December 01, 2013, 04:44:56 pm
content: i have big problem with dry filmi buy from china negative dry film.i use soduim carbonate to developing dry film . after developing i see the copper goodwhen 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 solveare the problem in developer or what ?

author: sleemanj
author_rank: Super Contributor
timestamp: December 02, 2013, 04:36:40 am
content: Quote from: 5282 on December 01, 2013, 04:44:56 pmYou 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.

author: BravoV
author_rank: Super Contributor
timestamp: December 02, 2013, 04:56:16 am
content: +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.

author: 5282
author_rank: Regular Contributor
timestamp: December 02, 2013, 09:50:34 pm
content: 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 solvehere is my pcb picture after putting it in ferric chloride and hcl + h2o2 etching

author: sleemanj
author_rank: Super Contributor
timestamp: December 03, 2013, 06:03:27 am
content: Quote from: 5282 on December 02, 2013, 09:50:34 pmHmm, 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.Alsosee 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.

author: BravoV
author_rank: Super Contributor
timestamp: December 03, 2013, 06:05:27 am
content: Quote from: sleemanj on December 03, 2013, 06:03:27 amif this really happened.

author: 5282
author_rank: Regular Contributor
timestamp: December 03, 2013, 04:00:27 pm
content: 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.

author: ElektroQuark
author_rank: Unknown
timestamp: December 03, 2013, 04:28:04 pm
content: Is there any protective layer in the other side?

author: 5282
author_rank: Regular Contributor
timestamp: December 03, 2013, 05:18:35 pm
content: Quote from: EdoNork on December 03, 2013, 04:28:04 pmnoooooooooo

author: Mr Smiley
author_rank: Frequent Contributor
timestamp: December 03, 2013, 05:33:51 pm
content: "ferric chloride and hcl + h2o2 etching"If you were using both, shouldn't the solution be a murky dark brownIs it actually safe to mix them togetherIs your enchant actually etchingHave you tried, and timed, how long a bare test piece of copper board etches down to bare board

author: 5282
author_rank: Regular Contributor
timestamp: December 03, 2013, 07:58:08 pm
content: Quote from: Mr Smiley on December 03, 2013, 05:33:51 pmthe etching solution work 100% . ferric chloride or hcl + h2o2

author: Mr Smiley
author_rank: Frequent Contributor
timestamp: December 03, 2013, 08:59:42 pm
content: Quote from: 5282 on December 03, 2013, 05:18:35 pmThis 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 etchHow many layers of protective film do you remove from start to finish

author: sleemanj
author_rank: Super Contributor
timestamp: December 03, 2013, 09:28:03 pm
content: 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 filmStep 2: remove protective film from inside-curlStep 3: adhere to your cleaned blank pcbStep 4: expose to your artworkStep 5: remove protective film from top of pcb/filmStep 6: develop in 30 grams Sodium Carbonate per Litre of water for a couple minutes, gently rub with fingers to helpStep 7: inspect board, see that all gunk has been removed, if not GOTO 6Step 8: put board in etchant,Step 9: inspect board to see that copper is "pinking", if not GOTO 6Step 10: continue to etch

author: 5282
author_rank: Regular Contributor
timestamp: December 04, 2013, 01:05:10 am
content: Quote from: sleemanj on December 03, 2013, 09:28:03 pmi do all things above and i do step6 alot of times and after developing i see copper clear and shinybut 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 .

author: eliocor
author_rank: Unknown
timestamp: December 04, 2013, 01:12:48 am
content: please take ablankPCB (absolutely do no laminate it!) and put a drop of etchant on its copper side.Is copper corroded by etchant? Yes or not?

author: sleemanj
author_rank: Super Contributor
timestamp: December 04, 2013, 01:16:48 am
content: Quote from: 5282 on December 04, 2013, 01:05:10 amIf 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.

author: 5282
author_rank: Regular Contributor
timestamp: December 04, 2013, 11:30:34 am
content: Quote from: eliocor on December 04, 2013, 01:12:48 amyes it's work perfectlywithout dry film

author: 5282
author_rank: Regular Contributor
timestamp: December 04, 2013, 11:34:54 am
content: Quote from: sleemanj on December 04, 2013, 01:16:48 ami use ordinary pcb without any thing it's etching excellenti buy dry film from this sellerhttp://www.aliexpress.com/item/30cm-Photosensitive-dry-film-instead-of-thermal-transfer-production-PCB-board-photosensitive-film-longth-1-meter/670619523.html

author: sleemanj
author_rank: Super Contributor
timestamp: December 04, 2013, 01:52:38 pm
content: 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 usefulAnd also this

author: 5282
author_rank: Regular Contributor
timestamp: January 03, 2014, 01:57:27 pm
content: after 5 monthsand spend alot off moneyfinally i solve the problem

author: sleemanj
author_rank: Super Contributor
timestamp: January 03, 2014, 01:59:32 pm
content: Quote from: 5282 on January 03, 2014, 01:57:27 pmDon't leave us in suspense, what did you discover?

author: Mr Smiley
author_rank: Frequent Contributor
timestamp: January 03, 2014, 03:53:15 pm
content: You labelled the water bottle 'Developer'

author: 5282
author_rank: Regular Contributor
timestamp: January 03, 2014, 04:54:32 pm
content: 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 bubblesand light exposing time depended on heating temperature degree .my dry film need fixed regulated temperature it's very heating Sensitivemy modified laminator