• Mingtao Plastic corporation is your one-stop shop for all your Clear PVC film & PE Stretch Film needs.


killer pcbs

by:Mingtao      2020-12-19
This instruction demonstrates the process of making a printed circuit board as small as 0.
005 is suitable for iqfp or QFN ICs using negative dry film anti-photoresist.
This will enable you to handle almost any integrated circuit available--
Ball Grid Array!
The picture shows the board with TSSOP14, QFN-
Use 40 packs of.
Flexible socket with 65mm pitch and zero insertion force. 5mm pitch.
After trying it for a while, I finally found a process that produced quite consistent results and actually looked very good.
I spent a lot of time trying to use a toner transfer method that was successful to varying degrees (
OK, different levels of failure may be more accurate).
I also tried the Philmore/Datak negative photo anti-spray and it turned out to be bad all the time (
These things eventually melt the nozzle that comes with it and leak it all over the place).
Not recommended in green.
Now I could have purchased the Premin board and saved a lot of trouble, but I found this material too expensive for the board I made.
I finally tried the dry film photo boycott and I\'m not going back!
I will not discuss the complexity of schematic capture or etching as these topics are well covered by other instructions.
No volatile compounds are used-
A simple alkali that can make the environment safe only by filtering the solid and by neutralization with HCl (
See manufacturer\'s instructions for the correct disposal procedure).
When combined with the peroxide/copper chloride etching process, this process forms a green PCB Development process responsible for the environment.
If you haven\'t tried the toner transfer method yet, do so.
Dry Film resistance will have a better effect unless you have magic Toner and/or paper, but the process will be more complicated.
If you\'re happy with toner-
In any case, the result of the transfer must be adhered to this method.
Standard warning Natural application: corrosive materials involved in PCB etching and dry film handling--
Be sure to use protective equipment with eyes-
Wash table is easy to use (
Or at least a bucket of water).
Please also note that the development and stripping of dry film involves a strong foundation-
Keep them away from your etched chemicals or they may react violently.
So far I have used three types of dry film anti-film and they all perform well :--
The dry film Price of MG chemical products is about $20.
At Frys, Altex and online, 5 feet at 12.
MG declined a large offer and would not disclose the manufacturer of its film. --
Think & Tinker Excellent offers DuPont Riston M115, which is more economical than MG if you want more quantity (
The 12 \"x 50ft is priced at $96.
$116 75, 12 \"x 100ft. 26).
Great costumes, very helpful, friendly people and a lot of great information. Terrific site! --
Kolon dry film Resist South Korean manufacturers sell for a slightly lower price than Think & Tinker\'s Riston, but the lowest price is 500ft.
What do you need-Laser Printer-
Home/office Press
Laser printerSpray Adhesive-
Anti-negative dry film photo
Boycott developers (
Sodium carbonate)-
Boycott the stripper (
Sodium hydroxide)-Glass Sheets-Clear Tape-
Yellow Bug light-Light-
Security area optional-
Vacuum bag or vacuum frame-
Calibrated UV source-
Rotating paper trimmer-
Step 21 Stouffer calibration sensitivity guide I assume you have captured your schematic and laid out your PCB on something like an eagle-
If you don\'t know what I\'m talking about, you \'d better start by learning schematic capture and PCB layout.
After you have laid out the PCB, you need to create a negative photo mask.
The negative photo mask is a transparency where you can see the copper and Black clearly where you want to remove the copper.
A tip: If you are used to filling the PCB layer with a ground or power plane, you will save a lot of toner.
Also, note that if there is no associated schematic file, you can tile the PCB layout in Eagle using the group copy command (
Otherwise, it will complain that you have to do this in the schematic \").
I found the process of reversing colors in your output very difficult, but in the end I solved this rather simple method using the open source vector drawing software Inkscape: 1.
Make sure you select only the layers you need for etching (e. g.
Top/bottom, pad, Vias). 2.
Output to PDF files using Eagle\'s print function.
Even if we print on transparent film, you still want to mirror the top layer so that the printed side is closest to the board to prevent bleeding. 3.
If you have not already installed Inkscape, download and install it now. 4.
Open PDF in Inkscape (
Accept default loading parameters). 5.
Open the layers pane (
Menu layer: layer). 6.
Click the button to add a layer.
What do you like (
My name is B). 7.
Click the down arrow to move the new layer to the bottom. 8.
Select the rectangle tool from the tool pane. 9. Right-
Click on the blue sample at the bottom of the screen and select set stroke \". 10. Right-
Click the gray color sample and select set fill \". 11.
Click and drag to draw a rectangle around the board. 12.
Select the arrow tool, then select each side of the rectangle and drag it to the right to the edge of the board.
The display should be like this: 13.
Right-click the black sample at the bottom of the screen and select set fill \".
Right-click the black sample again and select set stroke \". 14.
Close layer B by clicking on the eye icon in the layer panel. 15.
Click and drag to select the board (
Or click the select all visible icon on the toolbar). 16.
Negative Image (
Menu effect: Color: Negative)17.
Click again on the eye icon for layer B.
You should have something like this now: 18. Click Save-
As, then change the file type to PDF via Cairo and attach _ out to the file name (e. g. test_out. pdf)
This will not cover the original. 19. Click Save-
Save again as the default SVG format.
This part is also a challenge.
The problem is that most laser printers don\'t have real dark prints, so some light leaks from the black area.
I tried a lot of ways to selectively darken Toner: Dry-
Erase Mark, stamp-
Pad ink, crayons, charcoal, graphite, applications for softening/heating additional Toner, etc. .
No success.
Here is what works for me all the time: 1.
Starting with small art. -
I cut the transparent paper in half using a rotary paper cutter (4. 25 x 5. 5)2-
Three at a time.
Small artwork is better because of the heat
Related distortions in the transparency material will be reduced. 2.
Use Adobe Reader to open the PDF of the last step and then print to the laser printer loaded with transparent paper.
My printer (Brother HL-5250DN)
I use the following settings: user-defined paper size (4. 25 x 5. 5)
, No duplex, manual feed, 1200 dpi, the darkest density.
Here\'s a big tip: you can install multiple copies of the same printer in Windows, so add a new printer called pcb _ laser as a copy of the existing laser printer and right-click
Click and modify the default values as per the need for PCB transparency printing. 3.
Print artwork at the top and bottom.
Lift the artwork to the light: Do you see light penetration in the black area?
If your results are similar to mine, you will have enough penetration to cause a problem with your anti-resist.
Please note that you really need some larger black areas in order to accurately judge the toner density.
If you have super dense Toner then jump to Step 8, otherwise, keep printing your second copy of each slide. 4.
Next, you need a temporary lighting table to align the artwork.
It can be as simple as a piece of paper attached to a sunlit window, or a shallow tray with hockey --puck-
A piece of paper and a piece of glass covered with light of the size.
The backlight of the scanner makes a great light table.
Just run the scan in transparent/negative mode--
Most likely it will open the backlight for a few minutes after scanning, then remove the lid and flip it over.
Use of the head-
The installed magnifying glass will greatly help to adjust your work. 5.
Next, we put the transparency of the bonds on (
2 top, 2 bottom)
Double the density of carbon powder
To do this, please make one copy of each transparency and apply the spray glue on the toner side.
You can judge which side of the toner by observing the reflection of light on the transparent surface;
The toner on the toner side is dim. 6. Place the non-adhesive-
Transparent Toner-
Under the light table-
You might want to tie the corners of this piece of paper loosely to the light table (
Fold the tape at the end so you can easily tear it off later). 7.
Align carefully (register)the adhesive-
Coating transparency with uncoated transparency.
Once aligned, press hard to stick the two sheets of paper together. 8.
In the coldest environment, the aligned transparent film is passed through the layer press, and the layers are permanently combined. 9.
Align the top and bottom artwork (toner-side in)
And the tape firmly leaves enough space to slide the PCB between the two.
Or, if you have a minimum 1-inch border on the board, you can cover the rest of the mask by covering the corners of a sheet of paper, apply the spray to a 1/2 strap along two edges ---
Just make sure that there is no less than 1/4 \"between the tape and the edge of the cardboard \".
Clean copper carefully-
Materials covered with scrub pads and bleach-
Washing compound containing (e. g.
Soft Scrub with bleach.
Polish the surface with 320 or 400 of coarse sand wet/dry sandpaper to ensure proper adhesion resistance.
Be careful not to touch the board without gloves (
Prevent the transfer of skin oil to the board).
There are several possible ways to laminate PCB.
MG Chemicals suggests folders and lamination methods.
Hot or water is recommended by others (or both)
Adhere the material resistant to the PCB before lamination.
I\'m lucky with this method: 1.
Make your work area easy
Security: turn on the bug light and turn off any fluorescent or> 40 W incandescent lamps.
Cutting laminated material 1/2 larger than the plate (
If you do double the lengthsided board)3.
Carefully peel the first half inch of the endometrium that just came back (
Always inside the curl)4.
Align the laminate carefully to ensure that the laminate fully covers both sides of the board (if double-sided). 5.
Press the first half inch exposed laminate onto the board. 6.
Carefully drop the remaining inner layer to half
Once inch while pressing the exposed laminate onto the board.
Be careful not to have any wrinkles.
If necessary, proceed to the back in a similar manner. 8.
Through the Commission through the press (
Once the press reaches full temperature).
Flip and go through the laminating machine again.
Place the laminated PCB in the pre-
The registered transparent film and tape are in place safely.
Recording number 21
If you plan to calibrate the exposure process, do a step sensitivity guide on the opening section of the PCB.
You want to press the artwork tightly on the PCB to prevent the light from leaking under your marks.
You can do this with two pieces of glass, or it\'s better to use a vacuum bag or a vacuum frame.
You can then place this component in bright sunlight for about 5-
8 minutes per side or use another UV source of your choice.
Please note that although the PCB fits closely with the artwork, aim (
Parallel light)
It\'s important to implement fine tracking-
For instructions on constructing a calibrated UV light source, please refer to here.
Prepare the developer solution as instructed by the manufacturer (
Usually sodium carbonate or potassium carbonate)
And develop your board of directors (
Development removal resistance not exposed to UV light).
Use your favorite Etudes-
Just make sure you have some ideas for future disposal and consider green processes such as oxide/copper chloride etching process (
It\'s also Green).
If you want to delve into this
For details of the chemical reaction, this page is for you.
You need sodium hydroxide (NaOH)for this--
Brad Pitt burned Edward Norton\'s hand with this in Fight Club, which dissolves fat and your skin is mainly made up of fat, so be careful.
Check the local chemical supply company-
I was lucky: my neighbor made soap, so I suddenly came over and asked if I could borrow a soda!
Solder mask by scrubbing and re-applying
Double the thickness by using a new layer of resistance. Laminated etching stereotype, then removing the protective outer film and applying the second layer of resistance.
Now expose with stop and screen printing layers and develop as before (
Due to the increased thickness of the anti-exposure, the exposure time may be slightly longer).
About 10 minutes 220 degrees Fahrenheit (
Be sure to support the board so that the anti-resist does not stick to the toast machine).
Remove the board from the toast machine and fill in the screen printed text with White crayons while the board is still warm.
Wipe off the excess crayon wax with a towel and remove the excess wax from the grooves and marks with a toothpick.
If you have already walked so far, you must have been through a few nights and consumed a lot of carbonated water (Caffeine-containing)beverages.
If so, grab one of the soda cans and cut the top and bottom with scissors or light scissors.
Try to cut it neatly without a rough edge.
Next, cut vertically and produce an aluminum strip of about 8 \"4.
The strap will be very curly, but you can\'t \"bend\" it without wrinkles.
For the following steps, you can handle the curl, or annealing the metal by heating the metal to about 450 degrees F in the toaster oven, and then let it cool down slowly.
Next, you have to polish the inside and outside of the jar with 220 to 320 coarse sand wet/dry sandpaper to remove the paint (
Please note that there is clear paint inside the jar-
Otherwise, soda will eat it).
You can use some heavy
But the sandpaper looks a little greener.
Once you get all the paint off, soft scrub with bleach to remove every trace of oil.
As you do on the PCB, there is the next laminated anti-photoresist on both sides.
Use the tcream layer to make your work as before, but don\'t make negatives this time-
The output of the eagle is already negative!
Ensure that two transparent films are produced before and after (
And be sure to mirror the front so that the toner will hit the anti-resist).
Developed as before, etching in diluted HCl.
I diluted the HCl to about 50% (
Pour the acid into the water instead of the opposite).
Corrosion will start slowly until the oxide layer is removed and then significantly accelerated.
Do not etching too fast, otherwise the board will heat up and the anti-resist will fall off.
If you put the anti-stencil in place, you will have one ~ 5 mil template, or you can remove the anti-resist and get ~ Template of 2 mil ---
But be careful, sodium hydroxide will attack aluminum with a slightly lower toughness than HCl (
Depending on concentration).
The motherboard that failed to use next time (
You should have a few now)
Assemble solder paste fixture.
Apply the solder paste with a wiper or similar, place the part, and continue to return. . .
The stuff here is simple: heat until the solder paste melts and then cool.
Be sure to spread the heat evenly across the board using a rather strong copper or aluminum sheet.
Once all solder melts, remove the metal plate from the hot plate and place it on the radiator to quickly reduce the temperature-
Great cement garage floor-
Just make sure you use the oven mits (
But don\'t bake cookies with them after that. . . ).
You may need to clean up some bridging connections after recharging.
For this purpose, just use the welding Wick and a large amount of flux (
I like orange eyebrows).
Power On and ignite it!
BTW, I accidentally overtemperature on the first board and ended up getting a cool gradient color effect on the welding mask (
See the introduction chart).
I think the parts are still within the spec, but I didn\'t have a good radiator at the time, so I\'m not sure if the probe reads the same temperature as the motherboard sees.
But so far the board seems OK. . . Well that\'s it--easy eh?
Be sure to pay attention to my upcoming site IncoherentLabs. com.
Have fun now, save the world!
Custom message
Chat Online
Chat Online
Chat Online inputting...