PCB Photoresist Searching in India

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badrinath_ks

Joined: 17 Aug 2009
Posts: 2
Location: India

09 Oct 2009 9:10 Re: PCB Photoresist

Hi,

Is the photoresist from ideafactory available in Bangalore? Who is dealer ?

regards,
badrinath

shiveni

Joined: 06 Feb 2005
Posts: 31

09 Oct 2009 10:25 Re: PCB Photoresist

shiveni wrote:

rajudp wrote:

dear Shivashanmugam,

it is on the way to you

ear rajudp,

Man you'r great.

Thanks a lot Very Happy

Dear rajudp,

I have received the materials. Thnaks for your time & help.

Trying it today. will post the results.

rajudp

Joined: 27 May 2006
Posts: 239
Helped: 10
Location: India

09 Oct 2009 12:30 PCB Photoresist

the power is sodium carbonate, developer for negative photoresist

shiveni

Joined: 06 Feb 2005
Posts: 31

09 Oct 2009 19:48 Re: PCB Photoresist

rajudp wrote:

the power is sodium carbonate, developer for negative photoresist

Dear Rajudp,

The result is amazing. i am using wet lamination method.

I have a self made exposure box with Philips actinic BL 20 x2 tubes with a hight of 6 inch.

The first trial with 12 min exposure tracks are very good but the SMD pads are all joints.

The second trial with 5 min exposure 95% of tracks are perfect. 5% tarcks are joints in SMD.

Now tring the third trial with 2 min exposure.

Added after 1 hours 10 minutes:

shiveni wrote:

rajudp wrote:

the power is sodium carbonate, developer for negative photoresist

Third trial near to perfection but still some close tracks are got joints.

Here is the results.

The exposure tube height is 4.5 inch philips actinic BL20 x2 tubes.

exposed to 2.5 minutes. developing is not a problem.

Tracks are firm and withstanding for more presures when brushing up.

only issue is close tracks are getconnected.

Dear Rajudp,

Any advice on this.

I will post the result photos tomorrow.

Thnks......

rajudp

Joined: 27 May 2006
Posts: 239
Helped: 10
Location: India

10 Oct 2009 4:01 PCB Photoresist

for closed tracks i normally reduce the exposure time. please check the negative and put some weight on glass to make good contact between copper clad and negative. what type of negative you are using transparent sheet or true film , for very sharp and near tracks i will make negative from the positive , i normally use lith film but that require dark room i usually make negative in night with all door closed ( i don't have a dark room ). now i am using UV lith film( not required dark room ) but it is working with transparent positive but not with paper positive. ( i made my exposure box with 4 * 18 watt uv tube) . somebody told me paper positive will work with metal halide lamps. i bought the lamp but not tested yet.

wet lamination will work fine . i pass it through laminating machine after wet laminating the copper clad. if you have lamination machine try that else cover the copper clad with a soft cloth and use cloth iron to apply heat then it will give good result.

heat is needed for good bonding the copper clad and photo resist. make sure all water is wiped away

i am not using any brush i only use hand to rub while washing with water a soft brush will do the job

normally i use 90 to 180 secends for exposure

shiveni

Joined: 06 Feb 2005
Posts: 31

10 Oct 2009 10:44 Re: PCB Photoresist

Hai,

Here is the photos

trail - 1

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shiveni

Joined: 06 Feb 2005
Posts: 31

10 Oct 2009 10:45 Re: PCB Photoresist

Hai,

Here is the photos

trail - 2

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shiveni

Joined: 06 Feb 2005
Posts: 31

10 Oct 2009 10:47 Re: PCB Photoresist

Hai,

Here is the photos

This one is much better but still SMD pads are having joints.

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shiveni

Joined: 06 Feb 2005
Posts: 31

10 Oct 2009 10:50 Re: PCB Photoresist

Hai,

Here is the photos

This is one is much better.

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rajudp

Joined: 27 May 2006
Posts: 239
Helped: 10
Location: India

10 Oct 2009 12:27 PCB Photoresist

are you heat the copper clad?

shiveni

Joined: 06 Feb 2005
Posts: 31

10 Oct 2009 13:47 Re: PCB Photoresist

rajudp wrote:

are you heat the copper clad?

I have used hot water(around 80 C) for laminating the flim. after lamination i am using hair dryer to heat the PCB with lamination to 1 to 2 mins. Ensured that the PCB is not wet and limination is intact.

Should i try increasing the exposure distance to 7inchs and exposure time to 1min?.

What do you think adbout the trail PCBs above?...

I am now going out to get some Na2Co3 for developer.

Will post addtional results.

badrinath_ks

Joined: 17 Aug 2009
Posts: 2
Location: India

10 Oct 2009 14:18 Re: PCB Photoresist

Hi Rajdup,

Can u help me in getting the photo resist in small quantity. I checked with Idea factory, they sell only in bulk.

regards,
badri

shiveni

Joined: 06 Feb 2005
Posts: 31

11 Oct 2009 16:29 Re: PCB Photoresist

Hi Rajdup,

The distance is now 7 inches & exposure time is 90 seconds.

The result is excellent. Tried 5 sample PCBs and the result is consistent and perfect.

Here we go......

Sample 1 - SMD track SSOP.

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shiveni

Joined: 06 Feb 2005
Posts: 31

11 Oct 2009 16:31 Re: PCB Photoresist

Sample 2 - test mark track is <= 0.1 mm

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shiveni

Joined: 06 Feb 2005
Posts: 31

11 Oct 2009 16:33 Re: PCB Photoresist

Sample 3 - mask test

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shiveni

Joined: 06 Feb 2005
Posts: 31

11 Oct 2009 16:34 Re: PCB Photoresist

Sample 4 - text different font size.

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shiveni

Joined: 06 Feb 2005
Posts: 31

11 Oct 2009 16:42 Re: PCB Photoresist

Dear Raju,

Thanks once again. You are that man behind our success.

As of now we are getting pcb track negative film through photographic shop. We are giving the positive print out to them and they are providing negative film for the same.

Can you please provide us some light in making our own negative film from the printed circuit.

We are confident DRY film process. where can we order bulk Qty.

Shiveni....

Microkid.....

rajudp

Joined: 27 May 2006
Posts: 239
Helped: 10
Location: India

11 Oct 2009 18:02 PCB Photoresist

you can make negative using lith film . just make printout to normal paper(positive) . cut the film a little bigger than the required size and keep the positive above the lith film . i normally keep a black paper below the film. keep a glass sheet above the positive ( better use a thick glass i am using 5mm ) keep a 60w Incandescent bulb about 1 meter above the positive. just on and off the bulb very fast for 2 to 5 times ( exposure ). keep the film in lith A B developer. watch carefully for the development of image. the tracks will come in white color and the remaining will turn black. when it is clear white remove and put in hypo solution then the white parts will become transparent. all the above should done in dark room ( i don't have a dark room i was doing it in night). you can keep a red zero watt bulb in the room( i have seen some people are using 20w tube with some filter film covered). after that you can wash the film in running water and allow to dry.

now i am using UV lith film, just print the positive to a transparent sheet ( a good quality tracing sheet will do) and expose with UV light for about 5 to 10 sec. all the remaining procedure are same. in this process a small light won't make any problem. but it is not working for paper positive for me. i bought metal halide lamp hoping it will work with paper i was not assembled it.

Added after 6 minutes:

i bought the film from Bangalore

Added after 38 minutes:

you better make all process in a tutorial and post it

barrybear

Joined: 22 Nov 2001
Posts: 268
Helped: 6

11 Oct 2009 20:55 Re: PCB Photoresist

I use photographic paper and then a very hot iorn to transfer the black toner from the paper to the plain copper board . For me this is a simplar method as it realy only takes one action befor the copper sulphate emersion.

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piscrevathi

Joined: 04 Aug 2008
Posts: 1
Location: India

12 Oct 2009 6:50 PCB Photoresist

Dear Barrybear ,
Oh no.........Photographic paper,very hot iron,toner transfer etc...................... I think u r far behind the lattest development in PCB fabrication. People clarify their doubts on dryfilm photoresist PCB fabrication( Mr rajudp doing a very smart work. I expect a lot from him. Thank You raju ). But you are in old stone age. Come on , Come and join with us and share your knowledge with us

rajudp

Joined: 27 May 2006
Posts: 239
Helped: 10
Location: India

12 Oct 2009 15:57 Re: PCB Photoresist

in ebay they are selling photo resist go for www.ebay.com and search for photoresist the price is little high but ok for small volume buyers. around 9.5US$ for A5 size 10 sheets. postage is free

shiveni

Joined: 06 Feb 2005
Posts: 31

12 Oct 2009 17:40 Re: PCB Photoresist

rajudp wrote:

in ebay they are selling photo resist go for www.ebay.com and search for photoresist the price is little high but ok for small volume buyers. around 9.5US$ for A5 size 10 sheets. postage is free

Thanks man,

I have the account in ebay.
I have placed the order in ebay. delivery is expected in 10days.

I have a queary in lith film method.

Whether i can use normal tube light for expose or 60w filament lamp.

hypo is in crytal form.at what ratio should we mix it with water.

Shiveni....

rajudp

Joined: 27 May 2006
Posts: 239
Helped: 10
Location: India

13 Oct 2009 4:07 PCB Photoresist

you can use normal 60w lamp keep it about 1 meter above the unit. i will add only a small qty oh hypo to water but i think you can keep the solution for more than 1 day( i am not keeping it )

shiveni:

you asked for bulk qty. look your edaboard inbox . i have a pm for you.

shiveni

Joined: 06 Feb 2005
Posts: 31

13 Oct 2009 20:05 Re: PCB Photoresist

rajudp wrote:

Dear Raju,

i have tried lith film method as directed.

The initial result is - in negative the transparent area is ok. But the full dark area is not full dark but 70% dark.

I have compared the commercially produced film and mine. The dark area in my film is 30 to 40% less compared to the commercial one.

I used 60w bulb in 60cm and exposed to light rapidly 5 times as directed.

Then i put it in A&B developer for about 30seconds till i get the tracks coming in white color.

Then i put it to hypo solution for about 20 secs then rinsed in water.

Do you have any suggestion?.. how can we improve the black level to 100%.

Note :
1. If i level the film in A&B developer for more time to get full black the tracks are started to shrink.

Added after 3 minutes:

[quote="shiveni"]

rajudp wrote:

rajudp

Joined: 27 May 2006
Posts: 239
Helped: 10
Location: India

14 Oct 2009 7:47 PCB Photoresist

while developing take the film and check to the light source( red zero watt bulb ) if you can see the bulb through dark region put in developer again. if it is not working try changing the exposure time. i am not using any timing for developer. if i think it is very fast i will add a little water to it to slow the process.

the UV film is called as DAYLIGHT negative film. the film normaly come in 22" x 30' roll. for small qty you can ask any local polymer stamp makers/ suppliers. they will sell in A4 size. i bought in the roll form madras ( they give the best rate) but i think if you dont have that much use better go for small qty. if you have a dark room then the lith film is good i think. even lith film is cheaper than daylight film.

danibilabibah

Joined: 30 Jan 2008
Posts: 1

16 Oct 2009 5:09 Re: PCB Photoresist

piscrevathi wrote:

i think that is quite simple for developing custom pcb, but not for a large quantity PCB fabrication. i have a tutorial for developing small quantity pcb at my blog(indonesian language). it can transfer 0,1mm thick of the trace, just need 3-10 min to transfer from photo papper to pcb, and 10-15 min for etching.

shiveni

Joined: 06 Feb 2005
Posts: 31

16 Oct 2009 13:29 Re: PCB Photoresist

rajudp wrote:

Hi Raju,

Got DAYLIGHT film in local store and the result is excellent. It works very well even in day time. Planning to do a full size fine track PCB for complete process testing this week. After that i will submit the tutorial in PDF.

rajudp

Joined: 27 May 2006
Posts: 239
Helped: 10
Location: India

16 Oct 2009 16:11 PCB Photoresist

please check any way to make daylight film negative from normal paper printout. what you used for positive.
for me the lith film given good results with paper printouts

shiveni

Joined: 06 Feb 2005
Posts: 31

17 Oct 2009 3:45 Re: PCB Photoresist

rajudp wrote:

please check any way to make daylight film negative from normal paper printout. what you used for positive.
for me the lith film given good results with paper printouts

The lith film is very sensitive and is able to manage with normal white sheet prints. Daylight film is UV sensitive hence suffecient light source is required.

There are two option we found.

1. Tracing sheet printout (almost all tracing sheets are usable. The sheet specific to offset printing gives excellent sharp prints through laser printer.)

2.The dirty and cheap way is using oil over normal paper printouts to make it transperent.

shiveni

Joined: 06 Feb 2005
Posts: 31

21 Oct 2009 14:24 Re: PCB Photoresist

shiveni wrote:

rajudp wrote:

please check any way to make daylight film negative from normal paper printout. what you used for positive.
for me the lith film given good results with paper printouts